Ecology midterm 2
In the case with snowshoe rabbit and lynx, why did their population show oscillation from year to year?
"bust and boom" A lot of rabbits means that there's a lot of lynx because the rabbits are the food so if there is a lot of rabbits as food then the lynx eats the rabbits and the rabbit population goes down so the lynx don't have any food so the lynx population will go down, then once the lynx population goes down (predators) then the rabbit population goes back up This is an example of density independent factor because the population of the lynx depends on the population of the rabbits and vice versa
What is allopatric speciation?
"other" geographic isolation which results in speciation
limiting reproductive success for females
# of eggs and/or pregnancies
limiting reproductive success for males
# of females mated
Density
# of individuals/ unit area -density goes down with body size - few larger things because less energy in these organisms and require more resources than smaller organisms
commensalism/facilitation
(+,0) an interaction where one organism benefits and the other is unaffected
Male lions
(1) Higher ranking male lions sire more young. (2) The larger the coalition, the more likely the male lions are related.
What are the benefits of territoriality?
- access to food - foraging time - reproductive success
What are examples of life history traits?
- age of maturity - life span - number of offspring - gestation
Describe how the age of a population influences its distribution
- all distributions vary with age ex: *young and small shrubs establish in high densities and produce a clumped distribution *mortality as the shrubs grow reduces clumping and produce a random distribution among medium shrubs *competition enforces a regular distribution among large shrubs
Why is sexual reproduction advantageous?
- allows population survival in various environmental conditions - provides allelic diversity
What are the costs of living in groups?
- competition for food - increased predation (visibility) - disease transmission
Discrete and continuous time growth comparison.
- continuous time is steeper (estimating in between)
What are the costs of territoriality?
- energetic costs of defense - predation risk
What can dispersion patterns tell us about a population?
- environmental/social conditions - population dynamics
Why do scientists think that we are in the 6th mass extinction?
- extinction rate currently 10-100x times faster than the "big 5" extinction events - currently loosing 18,000-50,000 species each year - in the next 5 centuries, 75% of the species inhabiting earth will go extinct
What are the benefits of living in groups?
- finding food - decreased predation (vigilance) - finding mates
Why is dispersal important for the long term persistence of most organisms?
- helps regulate population size and density (more dispersal, greater change to increase population) -drives spatial and temporal redistribution of genotypes
What kinds of factors can contribute to population collapses?
- hunting - habitat destruction - habitat fragmentation - critical flock size
Random Distributions
- individuals distribute themselves randomly -an individual has the same probability of dispersing anywhere *ignore other individuals
Why is cooperation advantageous?
- more durable, repeated interactions - better recognition and recall - be nice (never defect first) - don't try to "beat" each other - be forgiving, generous
What is an open access system?
- no user group - no excludability - no rules to prevent free-riding - resources users can't change rules
What is the likely purpose of plant secondary compounds?
- pesticides and anti-grazing agents -pigments, hormones and chemical agents
What factors help avoid the Tragedy of the Commons?
- private ownership - top down control - cooperation
What are the implications of a meta population structure for conservation?
- probability of local extinction decreases - MUST CONSERVE CORRIDORS BETWEEN HABITATS
When are animals likely to maintain territories?
- resource is defensible - benefits outweigh the costs of defense
What factors could contribute to a spaced dispersion pattern?
- resources widely available - limited social interactions
What are the conditions of eusociality?
- several adults living together in groups, most sterile - cooperation in nest building and brood care - reproductive dominance by one or a few individuals
What factors promote coexistence of competitors? (3)
- spatio-temporal variation/heterogeneity in resources -competition for multiple resources for which competitive abilities vary - predation or disease pressure that keeps competing species well below K
What are common pool resources?
- subtractive resource - defined user pool - users cannot/are not efficiently excludable
Describe the story of the black footed ferrets.
- thought to be extinct in the wild for 50 years - farmers poisoned prairie dogs, which were a food source for ferrets - ferrets bred in captivity, and the ones most well suited were reintroduced to the wild
What factors could contribute to a clumped dispersion pattern?
- uneven distribution of resources - social patterns - organisms that don't move much (plants) stay close to parents
What are the advantages of semelparity?
- waits for the right opportunity - massive effort increases success - energy is stored for the big moment - common in deserts - needs good adult survival while waiting
Geographic Range
- within a species range the habitat quality will be patchy- not uniformed - range of tolerance determines your range of living ex: 3 different types of Kangaroos live in eastern, southern, and western australia
What are the variables that affect the change in population size (growth or decline)?
-Birth -Death -Immigration -Emigration
in the Lotka-Volterra equation for competition, what are some factors that may determine whether species 1 or species 2 wins a competitive interaction?
-Defense mechanisms -Fecundity -Speed -Abundance -Predatory advantage -What your carrying capacity and how you can get there while also preventing your competitor from reaching their carrying capacity
Hansson looked at how the populations of fish, zooplankton, and algal and flagellate producers were related. What did he find?
-Fish control the density of their zooplankton prey, indicating top-down control -When zooplankton are reduced, algal ad flagellate producers increase in density in response to increased nutrient input, indicating bottom-up control
What are the L-V assumptions? (6)
-Growth of vitim population is limited only by predation -predator is a specialist - individual predators can consume an infinite number of victims -alpha and beta do not change -predator and victim encounter one another randomly in a homogeneous environment -no density dependence and no time delays
Know the six invasive species examples in the U.S. and their ecological and economic impact (if the monetary value is provided)
-Kudzu Plant ($500 million each year) they overtake other plants and kill off shrubs and trees by growing over it and smothering them and cutting of their oxygen -Zebra Mussels ($5 billion each year) they can grow a huge density and are very successful filter feeder which decreases food available for other aquatic organisms; also clog pipes -Water Hyacinth ($500,000 to 3 million per state per year) they choke river channels and irrigation pipes; they form dense mats that reduce light of other aquatic plants and algae, reduce water oxygen content, and kill aquatic animals because of decreased light, oxygen and food availability -Sea Lamprey (caused the plummet of other fish in the Great Lakes, amount of money it cost cannot be determined) because of the sheer volume it affected the Great Lake fishery greatly. -Chestnut blight (3.5 billion) microscopic fungus that can grow under the tree trunks and grow into the tree and blocks the nutrient and water transportation within the tree Blight damaged American chestnut trees in the 1950's -Emerald Ash Borer is a beetle that the eggs of the beetle lives in the tree trunks and once the larva hatch they create tunnels in the tree trunks and blocks the nutrient and water transportation within the tree and kills the tree in a couple years
What are the different species interactions?
-Mutualism -Commensalism -Competition -Predation -Parasitism
What are the three types of spatial structure of population?
-Random -clumped -spaced
how did Simberloff set up his experiment determining number of species present over time on islands of different distances away from the colonizer population? what did they find?
-Scientists went to the island with insecticide and killed all the arthropods on each of the four islands and then observed the increase in speciation from 0 species onward. -new speciation curves were very similar to the original speciation data prior to defaunation, and this showed that the equilibrium of colonization and extinction holds. *Small scale experiment*
What are the parameters (characteristics) to describe a population?
-Size -Density -Age Structure -Life History -Population Growth Rate
How are metapopulations interdependent?
-The probability that each population in the set exists is linked to the states of the other populations in the set. - populations are linked through extinction and recolonization
what is ecological niche modeling and how is it used?
-Tool to predict where you see different species -Where conditions exist, species could exist -Current distribution could reflect something that happened thousands of years ago, or could reflect current conditions (like competition) -->determine if biological or environmental driver?
What is a deterministic model?
-a model that is designed to predict a result without accounting for random variation in population growth rate -is a model that gives you the same exact results for a particular set of inputs, no matter how many times you re-calculate it.
What is the two-fold cost of sex?
-an asexually reproducing population will grow at twice the rate as a sexually reproducing population. -The reason for this is simple: members of a sexually reproducing population must produce both sexes, but effectively only half of them can "give birth" to offspring to their own. -In contrast, all offspring of an individual from an asexually reproducing population can potentially "give birth"
What are the 3 simplifications of the fundamental equation of population ecology?
-assume no density dependence -assume no heterogeneity -assume a closed population
What is functional response type I?
-assumes there is a linear increase in the intake rate with food density -assumes that the time needed by the consumer to process a food item is negligible, or that consuming food does not interfere with searching for food
What are the limitations of dispersal?
-barriers (such as distance or something physical) can limit geographic ranges even if a suitable habitat is available elsewhere
How is it possible for many species to coexist in an unstructured environment while all competing for the same resource?
-becuase competition exclusion principle is equilibrium based -non-equilibrium conditions is a potential mechanism
What are some additional costs of sexual reproduction? (3)
-break up of co-adapted gene combinations (would remain linked in asexual offspring) - sexes fecundity depends on the ability to bring gametes into contact with those from the opposite sex (hard at lower densities) -energy and risk (tramitted diseases, predation)
What are examples of mixotrophs?
-carnivorous plants -mycoparasites -hemiparasites -photosynthetic protists that are also predatory -
How could the L-V competition model incorporate facilitation or mutualism?
-change the sign of alpha or beta to postive and the other to neutral for facilitation -change the sign of both alpha and beta to positive for mutualism
What is the evidence for coevolution in the form of character displacement? (4)
-character displacement does not occur where either species occurred by itself - co-evolution response occurred when species are together -directional vs stabilizing selection -the evolutionary divergence of competing populations
What are the characteristics of the spaced spatial structure of populations?
-competition
What does the L-V model of interspecific competition demonstrate?
-complete competitors should not exist -coexistence of 2 competing species is mostly likely when inter<intraspecific competition or when competition coefficients alpha and beta < 1
explain the consumer-resource relationship seen in renewable resources?
-consumers reduce the immediate availability of resources but not their supply -by reducing populations of their resources, consumers potentially reduce the rate of renewal of their food supply
give an example of interference competition
-consumption -preemption (something gets there first) -overgrowth (blocks sunlight) -chemical interactions (allelopathy) -territorial (exclusion) -encounter
When is it important to consider population growth in discrete vs continuous time?
-continuous: properties of population include overlapping generation times
Experiment testing for host evolutionary response to parasitoid results?
-control cage: populations oscillated dramatically (host population cannot evolve) -host population evolved and remained high/constant while wasp (parasitoid) population remained low
Describe the correlation between body size and density
-density goes down with body size -there are more individuals in a given area if they are smaller
what are the two views on the subject of high biodiversity in the tropics?
-diversity increases without limit over time -diversity reaches an equilibrium in which factors adding species balance factors removing species
Why isn't the environmental heterogeneity theory explaining why there are so many trees in the tropics appealing?
-does not work for trees, edaphic (tree response to soil composition) and geologic heterogeneity does not appear to be unusually high in the tropics
What does Lotka-Volterra model for predator prey dynamics assume?
-doesn't have any density dependent factors -assumes predators are the only thing limiting prey
How does horizontal gene transfer occur in eukaryotes?
-endocytosis of bacterial cell -a gene escapes degradation and inserts into the chromosome
What are the different types of parasites? (4)
-endoparasites -ectoparasites -kleptoparasites -brood parasites
what is the relationship between speciation rate / extinction rate and number of species on continent
-equilibrium occurs when all niches on continent are filled -speciation flattens out as less niche available -extinction grows exponentially bc continents are larger with more resources and less competitions
What is a cohort life table?
-follow group of organisms born at same time (cohort) until death
What 3 factors affect the maintenance of genetic variation?
-genetic recombination -mutation -horizontal gene transfer
what influences local diversity? what can local diversity lead to?
-habitat selection from regional diversity -predators, pathogens, extinction; competitive exclusion; stochastic extinction
What are the workarounds to higher reproductive costs to females in resources to produce eggs, seeds, gestation? (6)
-hermaphrodites -fewer males -males help -females eat males -asexual reproduction most of the time (sexual only in times of environmental stress) -change sex with size or resource availabilty
What is the term (1-N/K)?
-how far below you are from the max carrying capacity
describe the reduced competitive exclusion theory explaining why there are so many kinds of trees in the tropics?
-if being rare is an advantage, competitive exclusion may not be as important -high speciation, low extinction -tree species may have been accumulating for millions of years
what influences regional diversity? what can regional diversity lead to?
-immigration and species production -mass extinction
why do the two species of clams live inhabit different regions of the rock? what ecological phenomenon does this display?
-in the upper intertidal zone, extreme dryness limits 1 species from living there, allowing species 2 to thrive -in the lower intertidal zone, species 1 limits species 2 by outcompeting it for space -asymmetric competition
Regular Distributions
-individuals are uniformly spaced through the environment *antagonistic interaction- tend to repel others
Clumped Distributions
-individuals live in areas of high local abundance, separated by areas of low abundance * attract other individuals
What are some key aspects to migration?
-involves directional movement of individuals of one species between distinct locations -not only follows specific routes and timing schedules, but also requires remarkable navigation abilities -across species, time scales span from diurnal to multi generational
what did Simberloff's test on number of species present over time show?
-islands closer to sources of colonists recovered more species faster than more distant islands -at the end of a year, species richness leveled off, suggesting that equilibrium had been reached -the new equilibrium numbers of species were similar to the numbers of species before defaunation
Keough investigated the colonization of artificially created bare patches by various sessile subtidal invertebrates that grow on hard surfaces. He created large or small proximate or isolated patches which were then occupied by colonists. Given competitor and ruderal species, which would dominate where and why?
-large/small proximate patches dominated by competitors (gap size didn't matter because they were easily filled by growth) -large, isolated patches dominated by competitors (easy target for colonization) -small, isolated patches dominated by ruderal species (competitors don't disperse well, allowing ruderal species to gain a foothold here and prevent colonization by competitors)
What factors lead to coexistence between predator and prey? (8)
-limitation from density-dependent controls on predator poppulation sizes unrelated to prey availability -predator self-limitation (territoriality or competition for prey) -migration or dispersal of prey -environmental heterogeneity refugia for prey (structural complexity) -prey swamping of predator or predator satiation -prey switching by predator -limits to predator numerical response -prey defense
What are the characteristics of the clumped spatial structure of populations?
-limited dispersal -clustered resources -group living
How can the logistic model incorporate environmental stochasticity?
-logistic model - r and K are normally constant -logistic model with environmental stochasticity- r and k are not constant and drawn from a distribution
Why would the Atlantic include 7 species of mangroves, while the West Pacific includes ~40?
-mangrove species are not genetically linked, but live in similar environments due to convergence. -isolation drives speciation in the West Pacific (more islands) so there are more species
How can individuals within a population interact?
-mating -social interactions -cooperative behaviors -competition for resources
The incredibly long distance migrations between fixed foraging and nesting sites result in large geographic ranges, how so?
-migrating across entire ocean basins -laying their eggs on tropical nesting beaches, but then migrating to foraging areas to feed on jellyfish -high use areas pose as potential danger zones in the pacific ocean
How does sympatric speciation happen mechanistically?
-must be an advantage to go in one direction -need to isolate themselves reproductively
Name two groups of endoparasites.
-mycoplasmas ( small bacteria that invade cells, pneumonia) -trypanosoma and malaria (protozoans)
Examples pf mutualistic symbioses critical to history of life? (4)
-mycorrhizae: essential for plans to colonize land -coral: reproductive area -gut flora: vitamin, breakdown, immune -N fixation: govern nitrogen availability
Ultimately how do positive and negative feedback differ?
-negative is immediate -positive is a build up over time with a eventual return to baseline
What are some examples of epigenetic effects?
-nutrition -exposure to toxins during development - developmental effects -maternal and paternal effects
explain the home-home, home-foreign experiment using plants and fungi
-plants/fungi from the same area show the strongest parasitism and mutualism effects -in some cases, even the direction of the effect depended on whether the two species came from the same or different areas
Are spiders good bio-controls?
-population growth should track victim growth in order to be a good bio-control -spiders reproduce once a year so not really (can't produce more spiders in response to an increase in prey)
What do you need to know to project future population size for age- or size-structured populations?
-population structure -age-specific fecundity and mortality
What are the conditions for predator-prey dynamics to generated Lotka-Volterra type stable limit cycles? (3)
-predators moderately efficient -feedbacks to predator and prey population sizes are rapid -refuges exist for prey
What are some mechanisms for non-equilibrium conditions? (3)
-predators or other natural enemies -presence of mutualists -environmental flucuations or spatio-temporal heterogeneity
What are the advantages of sexual reproduction? (4)
-prevent build up of harmful mutation - breaking up linked genes that contain positive and negative elements -maintain genetic diversity to keep up with pathogens -few clades asexual over deep evolutionary time
What are the characteristics of random spatial structure of populations?
-rarest in nature -null hypothesis
What is coexistence of predator and prey enabled by?
-refugia -immigration -mutual negative feedbacks
Knight looked at trophic cascades across system by studying the impact of fish on dragonflies. In a separate study, he looked at the impact of fish on pollinators such as flies, butterflies, and bees. What were the findings / significance of this study?
-removing fish led to more medium sized larval and adult dragonflies as well as a decrease in large dragonflies. -the absence of fish led to less pollinator species (fish eat dragonflies, which eat pollinators)
What does Tilman's resource ratio theory also depend on?
-resource level (supply rate and consumption rate of the resource) -population growth rate
What are the assumptions of L-V model of interspecific competition?
-resources are in limited supply -competitive coefficients (alpha and beta) and carrying capicities are constant -density dependence is linear
Describe three factors that influence a species' rarity and vulnerability to extinction
-restricted geo range -narrow habitat range -small population sizes ex: passenger pigeons have a narrow nesting area, once area destroyed by humans, decreased population size
Describe L-V and predator-prey cycles:
-rise in prey population -followed by rise in predation -increase predators cauases decline in prey population -as prey falls it will support fewer predators -fewer predators causes prey population to rise again
What is functional response type III?
-similar to type II but search activity increases with prey density -not as good at hunting prey in the beginning but the rate of capture increases
What is population viability analysis?
-simulates temporal population changes -estimates extinction risk over a time period
how does number of species change based on island size? distance of islands?
-small islands support fewer species than large islands -islands near the mainland have more species than those farther away
Why is it important to understand the spatial structure of individuals within a population?
-spatial structure can reflects variation in habitat quality of patches
Hutchinson Niche
-specialization of a niche can increase biodiversity -considers all abiotic factors such as pH, sunlight, moisture, salinity, and temp -fundamental/realized niche
what determines whether a given member of the species pool can be a member of a given community?
-species must be able to tolerate conditions of the environment and find suitable resources (must fall within fundamental niche) -must also be able to persist in face of competitors, predators, and parasites (realized niche) -species sorting
in what level of the community structure are guilds found? what are they?
-species richness -group of organism that share a trait, even though they are taxonomically removed ex) nectar sippers
How do you estimate the intrinsic rate of increase from data?
-take the log of both sides of N(t) = N(0)e^rt which then looks like y = mx+b so plot it -r is the slope
What are some examples of density independent effects?
-temperature -floods -pollution
What are the different mechanisms of the pre-zygotic barriers?
-temporal isolation -habitat isolation -behavioral isolation -mechanical isolation -gametic isolation
what did Tansley conclude from his experiment with competition between species?
-the presence or absence of a species could be determined by a competition with other species -the conditions of the environment affected the outcome of competition -the present ecological segregation of species might have resulted from competition in the past
Linked 16-cell population cages to study competition. What were the results of this experiment? (3)
-there is a clear genetic basis for competitive ability that responds to natural selection -interspecific competitve ability can evolve rapidly at low density -sudden reversal in competitive superiority can occur
what is another theory for why there are more species in the tropics, looking at environmental stress?
-there is less abiotic stress in the tropics, meaning it is a more conducive habitat. -greater importance of species interactions than abiotic factors
Theoretical Model of Ideal Free Distribution
-there is no limit to the # of competitors who can exploit the resource. -every individual is free to choose where to go - 1st arrivals will go to rich habitat- too many then, then move to poor- rewards turn equally attractive - stickleback example
Genotype-genotype interaction experiment results?
-transplants within a tree were more fit than transplants between trees -evolution seems to be occuring between scale insect populations on adjacent trees -coevolution with the host in control (tree)
Why is it often important to incorporate age or size structure into population models?
-you are better able to predict population growth
In ecosystem development, growth and Pn/Pg approach ________ as maintenance uses all available energy
0
Neither exponential growth/decline, r is ?
0
What is polyandry?
1 female, many males
What is polygyny?
1 male, many females
Monogamy in animals
1 mate for a lifetime
Describe two factors that determine the total size of a population
1) Geographic Range 2) Density
What are David Lack's 3 proposed generalizations about life history traits?
1) Life history traits contribute to reproductive success, so they influence evolutionary fitness 2) Life histories vary in a consistent way with respect to factors in the environment 3) Hypotheses about life histories are subject to experimental tests
What are the three ways ecologist explain the patchy distribution of individuals?
1) Metapopulation models 2)Source-sink models 3)Landscape models
Why organisms don't go to free distribution
1) incomplete information- check out line example 2) lack of free choice- physically excluded ex: someone living in your front yard
Lyme disease positive feedback
1) mice eat moths 2) moths eat trees 3) trees make acorns 4) mice eat acorns 5) mice feed ticks 6) ticks spread Lyme disease more mice --> less gypsy moths --> more trees --> more acorns --> more mice --> more ticks and Lyme disease
What are the assumptions of the ideal free distribution?
1) patch quality is determined by resource amount 2) individuals move freely between patches (free move to highest quality patch) 3) All individuals have perfect knowledge of patch quality 4) increase number of individuals decreases patch quality
What are four conditions that support source-sink dynamics?
1) population is split into many small patches 2) risk of extinction 3) variation in survival between patches 4) recolonization
Actual Distributions
1) random 2) regular 3) clumped
What are the two different approaches to a sensitivity analysis?
1) stimulate small changes and see which has the biggest affect on lambda 2) stimulate BIG changes and see if they bring lambda above one
How do you detect density dependence (2) ?
1)Plot change in population size (lamda) against population size. If there is a linear decrease that is indicative. 2) Compare vital rates (birth/death/movement) to abundance. Would show a linear decline.
What are the top causes of population decline and ultimately extinction?
1. Habitat degradation 2. Invasive species 3. Pollution 4. Overexploitation 4. Disease
What are potential methods of preventing extinction?
1. Species approach (focus on one species in the wild) 2. Zoo-botanic garden approach (focus on one species in captivity for eventual reintroduction) 3. Ecosystem approach (preserve large tracts of land, manage them, allow natural ecological processes) 4. Habitat restoration 5. Protect keystone species
The population responds by growing when...?
1. carrying capacity or resource availability increases 2. size of the population falls below carrying capacity due to predation, disease, or a density independent event
What are some important features for a population?
1. genetic units that define the gene pool 2. requires a defined spatial boundary 3. structures defined by characteristics of the collective 4. Dynamic in time due to the continuous birth, death, and movement of individuals
How do corvids do this?
1. seed selection by avoiding seeds spoiled with fungi or insect larvae. Choosing viable seeds. 2. Seed transport by transporting seeds 20+ miles across a landscape 3. seed deposition by trying seeds underground. suitable habitats favor seedling establishment
Why do smaller populations have a higher risk of extinction?
1. vulnerable to random events 2. loss of genetic diversity 3. allee affect
Green Woodhoopoes live in territories defended by flocks of how many
2-16
How many species definitions are there? Despite the difference, what do all these definitions agree on?
26 All concepts agree that a species is a distinct, evolving lineage of organisms
If fitness is a representation of your genes in the next generation, what is an asexual "female"'s fitness?
2x greater
How many female lions does a pride include?
3-6 adults, but many contain as many as 18
the earth is approximately how old?
4.5 billion years
What is the percent of genes in full siblings
50 % genes
With geometric decline, lamda is <,=,> 1 ?
< 1
Neither geometric growth/decline, lamda is <,=,> 1 ?
= 1
With geometric growth, lamda is <,=,> 1 ?
> 1
Where is most of the human genetic diversity?
>75% is within populations (individual variation) -modern humans quite closely related due to recent expansion over the 70,000 years
How do you use an age structure graph to predict the future change of a population (increase, decrease, or stable)?
????
Population Pyramid
A bar graph representing the distribution of population by age and sex.
A pathogen dependent on the continuing survival of its host will evolve towards what relationship with its host?
A benign relationship (not harmful in effect)
What does density "dependent" and "independent" mean?
A density-dependent factor is one where the effect of the factor on the size of the population depends upon the original density or size of the population. A density-independent factor is one where the effect of the factor on the size of the population is independent of and does NOT depend upon the original density or size of the population.
Intrasexual selection
A direct competition among individuals of one sex (usually the males in vertebrates) for mates of the opposite sex.
negative feedback loop
A feedback loop in which a system responds to a change by returning to its original state, or by decreasing the rate at which the change is occurring.
interference competition
A form of competition involving direct antagonistic interactions between individuals
ratio-dependent functional response
A functional response in which the rate of feeding by a predator is a function of the ratio of prey population size to predator population size, i.e., the number of prey per predator.
What is a generalist? What is their adaption advantage and disadvantage?
A generalist uses a variety of environmental resources Advantage: unlimited supply Disadvantage: more competition
cohort
A group of individuals of the same age.
Population
A group of individuals that belong to the same species and live in the same area
What is a population?
A group of interacting individuals from the same species.
What is a phylogenetic species? What is the limitation?
A group of organisms that all share common ancestor and who all share common traits Limitation: Over-categorization of species; although, it provides leverage for conservation biology The features can include color, shape, behavior or genetic (nucleus or mitochondria DNA)
What is a morphological species? What is the limitation?
A group of organisms that share common measurable physical traits Limitation: the species can look the same but be different OR look completely different but be same species
What is a biological species? What is the limitation?
A group of populations whose members that can produce fertile offspring Limitation: it is hard to know these species without a lab or zoo Only experiments show biological species
metapopulation
A group of spatially separated populations of one species that interact through immigration and emigration.
What is hypovirulence?
A kind of biological control in which the virulence of a pathogen (its ability to infect, grow or produce spores) is reduced by being infected with a virus.
What is a stochastic model?
A model that incorporates inherent randomness.
What is symbiosis?
A mutual relationship in which the two species have a close association
Type II survivorship curve
A pattern of survivorship characterized by constant rates of survival throughout life.
Type III survivorship curve
A pattern of survivorship in which a period of extremely high rates of mortality among the young is followed by a relatively high rate of survival.
Type I survivorship curve
A pattern of survivorship in which there are high rates of survival among young and middle-aged individuals followed by high rates of mortality among the aged.
What is meant by population regulation?
A population is regulated if its long run population size is drawn from a stationary probability distribution (staying within fairly narrow bounds). -the mean doesn't change over time
What is phylogeny?
A proposal of how organisms are related by their evolutionary history It is based on the evidence that all living things are related by common descent.
vesicle
A small cavity or sac that contains materials in a eukaryotic cell
What is a specialist? What is there adaption advantage and disadvantage?
A specialist uses a narrow range of resources Advantage: less competitors Disadvantage: if their special resource gets used up, they can't survive
Disease
Abnormal condition
What did Huffaker's experiment with orange-eating mites and predatory mites show?
Adding barriers to dispersal allowed predators and prey to coexist. -predator prey coexistence without immigration
What are the advantages and possible drawbacks of using natural enemies for invasive control?
Advantage: It can effectively get rid of the invader Disadvantage: The new predator could get out of control
When does a diversity of evoluntionary solutions (forms) result?
Against biological forces (competition, mutualism, and predator-prey)
When does a convergence of evoluntionary solutions (forms) result? (not coevolution)
Against physical forces (physical and chemical environment)
What is an example of a population experiencing a large fluctuation?
Algae
Positive density dependence is also called BLANK.
Allee effects
Lotka-Volterra model for predator prey dynamics: What is alpha? dV/dt = rV - alphaVP
Alpha is capture efficiency which is the rate that the victim population is reduced by the addition of a single predator
Eusociality
An extreme form of sociality in which there is cooperative brood care, division of labor, and multi-generation groups. Exp: Ants, bees, naked mole rat, etc.
Commensalism
An interaction between two species in which one species benefits without harming the other; a type of symbiosis.
commensalism
An interaction between two species in which one species benefits without harming the other; a type of symbiosis.
Photoheterotrophs
An organism that uses light to generate ATP but that must obtain carbon in organic form.
What is a guild?
Any group of species that exploit the same resources, often in related ways, and are not necessarily related evoluntionarily
BLANK is the advertising by an animal to potential predators that it is not worth attacking or eating.
Aposematism
Changes in Creosote Bush Distribution
As plants grow, some individuals in clumps die, reducing clumping; distribution becomes more random. Competition among remaining plants produces higher mortality. >Eventually creates regular distributions. >Competition for water and nutrients reduces overlap in root distribution between adjacent plants.
BLANK are "self feeding" and capture their own energy and maker their own complex compounds.
Autotrophs
Change in population number = ?
B+I-D-E
What is lamda in a closed population?
B-D+1
If each individual gives birth to B offspring then B(N) = ?
BN(t) -birth rate times the number of individuals
Why are many of the global biodiversity hotspots around the world located on islands?
Because they are on islands, populations of island species are isolated
Patterns on Large Scales
Bird Populations Across North America. >Root found at continental scale, bird populations showed clumped distributions in Christmas Bird Counts. >Clumped patterns occur in species with widespread or restricted distributions. >Brown et al. found clumped distributions of bird species found in Breeding Bird Surveys (summer season). >at large scales, birds are clumped
what is the reasoning behind the holistic concept of community?
Body analogy unique emergent properties of a community
Abiotic and Biotic Influences on Distribution
Both abiotic and biotic factors are important in determining the distribution and abundance of a species. >Balanus appears to be more vulnerable to desiccation, excluding it from the upper intertidal zone. >Chthamalus adults appear to be excluded from lower areas by competition with Balanus.
Does population size or population density vary across space due to variation in species interactions and habitat suitability?
Both population size and density vary
Sociobiology/Ethology
Branch of biology concerned with study of social relations. Exp: Dominance, reproductive interactions, cooperation, etc.
How are populations thought to be regulated?
By a combination of density-dependent and density-independent processes.
Patterns on Small Scales
Can map the distribution of a species, showing the presence/absence of the species. Knowing how individuals are distributed across their range is also important.
Kangaroo Distributions and Climate
Caughley et al. found a close relationship between climate and distribution of the three largest kangaroos in Australia. >Eastern grey (Macropus giganteus) in the eastern >Western grey (M. fuliginosus) in southern and western regions. >Red (M. rufus) in arid / semiarid interior. Northern Australia is too hot, too wet, and/or too dry in winter for these 3 species.
character displacement
Changes in the physical characteristics of a species' population as a consequence of natural selection for reduced interspecific competition
What is the nutritional mode of nearly all aminals?
Chemoheterotrophs
What are the examples of mutualism and symbiosis relationship? In each example, what kind of benefit do the two players receive, respectively?
Clownfish and Sea anemones. The anemone provides protection for the clownfish, and the fish provides circulation, bringing in fresh water for cleaning services
Example of clumped spatial structure of a population?
Clumped oak trees or clumped coral reef
In metapopulation models BLANK and BLANK change the overall population.
Colonization Extinctions
What is the aposematic color? What is the evolutionary significance of this color?
Colors and / or patterns that act as a warning to predators that a potential prey species is unpalatable, toxic or dangerous. Gain protection
BLANK is the use or defense of a resource by one organism that reduces the availability of that resource to other individuals.
Competition
what's the difference between constancy and resilience?
Constancy: a measure of the ability of a system to resist change in the face of outside influences (resistance) Resilience: the ability of a system to return to some reference state after a disturbance
What scales can be limited?
Continental and local
Exponential populations (instantaneous population growth) occur in BLANK time.
Continuous time
What is beta?
Conversion efficiency
Where and what did Packer and Pusey study ?
Cooperation among African lions in the Serengeti
Lion Pride
Cooperation among related female lions to obtain food, raise young, and protect the group.
Evolution is accompanied by..
Cooperative feeding, defense of the social group, and restricted reproductive opportunities.
What is mechanical isolation? Give an example.
Copulation is attempted, but transfer of sperm does not take place (ex: Damselfly - shape of the male genitalia among different damselfly species)
What is an example of passive dispersal?
Corvids; they act as seed dispersers for oak and pine populations
BLANK the ability of an organism to conceal itself especially from a predator by having a color, pattern, and shape that allows it to blend into the surrounding environment.
Crypsis
If each inidividual has a chance of dying of D then the number of deaths is D(N) = ?
DN(t) -Death rate times the number of individuals
Animal Size and Population Density
Damuth found the population density of herbivorous mammals decreased with increased body size. Peters and Wassenberg looked at broader group of animals and found same pattern. >Aquatic invertebrates tend to have higher densities than terrestrial invertebrates of similar size. >Mammals tend to have higher population densities than birds of similar size.
The realized quality of a good patch __________ as its population increases.
Decreases
The creation of sub-populations Increase or decrease genetic diversity? Increase or decrease the risk of extinction?
Decreases genetic diversity increased risk of extinction
What is population cycling caused by?
Delays in feedback between population density and population growth rates.
What is the fundamental equation in a closed population?
Delta N = N(t+1) - N(t) = B(N) -D(N) -N(t+1) population at time step 1
Organism Size and Population Density
Densities of organisms in natural environments vary greatly. Densities of many are highly correlated with body size. >Small plants and animals generally live at higher population densities than larger ones. >Quantifying this relationship provides information about divergent environmental requirements. >Also provides a standard against which we can compare measured densities.
BLANK effects are a negative feedback on population growth.
Density dependent effects
What are the density dependent and density independent factors that can regulate population growth?
Density dependent factors: impact depends on current population, diseases, competition, predation *The higher the population, the higher the competition Density independent factors: environmental resources, stressors, and catastrophe (pollution etc) *the impact size is NOT dependent on current population size -doesn't depend on the population, depends on the environmental factors
Sexual selection
Differences in reproductive rates among individuals as a result of differences in mating success.
What do the set of parameter values and initial conditions lead to in a stochastic model?
Different outputs
___________ this is the movement of an individual or individuals away from the population in which they were born to another location, or population, where they will settle and reproduce
Dispersal
Populations can be characterized by
Distribution - the size, shape, and location of the area it occupies. Pattern of spacing of individuals, the number of individuals (abundance), and their density. Age distributions, growth rates, etc.
What follows a logistic population growth model (2 example)?
E.coli 3 phases: -slow acceleration -maximum acceleration -reduced acceleration Paramecium aurelia -20 paramecium -added constant number of bacteria (food) every day
What is ecological speciation?
Ecologically-based divergent selection process by which ecologically based divergent selection between different environments leads to the creation of reproductive barriers between populations.
Populations
Ecologists usually define a population as a group of individuals of a single species inhabiting a specific area.
What are maternal and paternal effects?
Effects of the genotype and environment of a parent on offspring phenotype
Distributions of Plants Along a Moisture-Temperature Gradient
Encelia leaf pubescence corresponds to distribution on a moisture-temperature gradient. >E. frutescens has little pubescence while E. farinosa has pubescence and therefore E. Farinosa absorbs less radiant energy. >Both live in hot deserts and have similar leaf temperatures. >E. frutescens avoids overheating via evaporative cooling.
What's the difference between opportunistic and equilibrial life histories?
Equilibrial (tolerator) life history: tolerate harsh environment by adapting; quantity < quality Opportunistic life history: take immediate advantage of favorable conditions; quantity > quality
BLANK is the state of a system in which population size is not changing.
Equilibrium
Explain how species 1 wins in the Lotka-Volterra equation for competition using a graph?
Even when species 2 achieves K, density of species 1 increases; species 2 goes to extinction
Why do we stay host-parasite interaction is "ubiquitous"?
Every plant and animal has parasites; even parasites have parasites
Give examples of predator and prey species engaging in a "evolutionary arms race" or Red Queen Hypothesis
Evoluntionary escalation of the bat and moth and their ability to detect each other.
What animals/plants have the equilibrial life history? What are the characteristics of these examples ?
Example Elephants/Seals/Polar Bears etc Birth Rate - low Sexual Maturity - late Overall Lifespan - long Parental Care - lots Youth Survivorship - high Ability To tolerate - high
T/F All predators are animals
F They can be plants too (venus fly trap, amoeba)
T/F: "non-native" always means "foreign"
F "non-native" does not necessarily mean "foreign"
T/F defining an individual cannot be challenging
FALSE
T/F modules can look like individuals but are not actually genetically identical to the parent
FALSE
T/F: the incorporation of time lags between resource consumption and reproduction can cause populations to not go through cycles of population growth and decline
FALSE
T/F; density dependent factors are abiotic factors
FALSE
T/F; density independent factors affect and do regulate populations
FALSE
T/F; environments cannot influence population growth by affecting birth and death rates
FALSE
T/F; life tables cannot follow a cohort (a group of individuals in a population born in the same period of time)
FALSE
T/F; population increase is a function of the number of males in the population
FALSE
T/F; populations in nature regularly follow a smooth approach to their carrying capacity
FALSE
What are density independent effects?
Factors limiting the size of a population regardless of the density of the population.
Prides are always made up of close relatives.
False
True or False: Symbiotic means mutalistic.
False, this is how its properly used but does not necessarily imply this. Symbiosis can be mutualistic, commensal, or parasitic.
Logistic growth with regular population cycles: Know how to draw graph. Is feedback immediate?
Feedback is immediate. See lecture 3 power point
Physiological and population processes are regulated by what?
Feedbacks
Trends in R0
For disease to spread, R0 must be >1 ------------- epidemic: Lower R0 --> balance of people who have been sick and who hasn't Higher R0 --> more recovered individuals and less susceptible individuals -------------- endemic: Lower R0 --> lots of susceptible individuals, and balance of recovered and infected people Higher R0 --> decrease susceptible individuals and increase recovered and infected
BLANK is alpha x V.
Functional response
BLANK is the entire set of conditions under which a species can persist.
Fundamental niche
runaway selection
Genes for female choice and preferred male attribute can be inherited together. Females that show a preference for a particular trait will have sons with that trait, and daughters that have a preference for that trait (like their mothers). Eventually forces of natural selection will stop the positive feedback cycle.
What are 2 examples of evolutionary change via random processes?
Genetic drift Mutation
disturbance
Grime (1977): any process that limits plants by destroying plant biomass Sousa (1984): any discrete, punctuated killing, displacement, or damaging of one or more individuals that directly or indirectly creates opportunity for new individuals to become established White and Pickett (1985): any relatively discrete event that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment
What is population?
Groups of individuals belonging to the same species that live in the same region at the same time -individuals of one species -occupy the same general area -rely on same resources -affected by the same environmental factors -potential to breeds
Adult scorpion flies
Guard a dead arthropod to attract females. Salivate profusely when offering arthropod as gift to potential mate. Size of male fly and size of arthropod influence mating success.
competition
Harm,harm
Explain how competition can go either way in the Lotka-Volterra equation for competition using a graph?
Here, K2/β < K1 K2/β is the density of species 1 equal to carrying capacity of species 2 Final outcome depends on initial conditions
BLANK are "other feeding" and capture energy/complex organic compounds from other organisms.
Heterotrophs
Distributions of Tropical Bee Colonies
Hubbell and Johnson predicted regular distribution of aggressive bee colonies, and random or clumped distribution of non-aggressive species. >Potential nest sites were randomly spaced. Found four highly aggressive species had regular distributions. >Pheromones attract bees to nest sites. Found one non-aggressive species with random distribution.
Hutchinson's Niche
Hutchinson defined niche as an n-dimensional hyper-volume. >n is the number of environmental factors important to survival and reproduction.
What are the three types of functional responses?
I II III
What is a "mixed motive game"?
If A gets benefits, B's choice affects outcome; common interests; pure cooperation doesn't work (think Barney)
What is a "zero-sum game"?
If A gets gains, B gets losses; opposed interests; 100% competitive (think godzilla)
When is a population said to exhibit density dependence?
If present per capita population growth rates depend on past and/or present population size.
When can a long term population trend be negative even with positive r?
If the variance in growth rate is high.
What is the competitive exclusive principle? How do similar species co-exist?
If two ecological niches (roles) are too similar, they cannot coexist in the same place. Similar species use resource partition, which means they share resources
Learning experience
Improve future reproduction chances
How does the logistic model of population growth make the exponential population growth model more realistic?
In the exponential model the population will continue to grow exponentially (not realistic). In the logistic model the population grows exponentially first then levels off at a carrying capacity.
Lotka-Volterra Model
Incorporates oscillations in the abundances of predator and prey populations and shows predator numbers lagging behind those of their prey
What do we mean by no heterogeneity?
Individuals in a population have equal birth and death rates.
What is habitat isolation? Give an example.
Individuals mate in their preferred habitat, and therefore do not meet individuals of other species with different ecological preferences (ex: Blue Ghost Firefly - male firefly flash patterns in the Great Smoky Mountains National Park)
What is temporal isolation? Give an example.
Individuals of different species do not mate because they are active at different times of day or in different seasons (ex: Northern Red-Legged Frog, Foothill Yellow-Legged Frog; Fall Field-Cricket, Sand Field-Cricket)
What are the three major characteristics of eusociality?
Individuals of more than one generation living together. Cooperative care of young. Division of Individuals into nonreproductive and reproductive castes
Intersexual selection
Individuals of one sex consistently choose mates among members of opposite sex based on a particular trait.
Intersexual Selection
Individuals of one sex consistently choose mates among members of opposite sex based on a particular trait. birds, feathers or song quality
What do helpers gain?
Inherited territory, inclusive fitness, and learning experience.
Leibold measured phytoplanton biomass and how it affected zooplankton biomass. Then, fish, a predator of zooplankton, was added. What were the findings and what did they suggest?
Initially, the relative sizes of the two trophic levels are positively correlated, indicating bottom-up control. When fish were added, zooplankton decreased and phytoplankton increased, indicating top-down control -primary consumer density is controlled by both top-down and bottom-up control
BLANK competition is a among individuals of the different species.
Interspecific competition
BLANK competition is a among individuals of the same species.
Intraspecific competition
What is invasive species?
Invasive species - NON-NATIVE species that has established in a novel environment and causes environmental or economic damage by colonizing and dominating suitable habitats
What is ecological niche modeling?
Is a conservation tool used to predict the population sizes and distributions of a species by assessing the physical conditions of suitable niches.
What is the landscape model and what does it account for?
It builds on metapopulation and source-sink models by accounting for the impacts of the nearby habitat matrix on patch quality. -Actual movement and routes of individuals depends on the surrounding landscape and habitats found along the way
If the Grandmother effect is true, what role could it have played. in human evolution?
It could have allowed for the evolution of longer lifespans in human females, so that they may care for their offsprings offspring, allowing for the grandparents offspring to reproduce more
How is demographic stochasticity problematic for small population sizes?
It increases the risk of population extinction because it skews age structure and sex ratios.
What is hybrid speciation?
It is a form of speciation where hybridization between two different species leads to a new species, reproductively isolated from the parent species
What is delayed density dependence causes by?
It is caused by time lags (tau in the equation) in the negative feedback on population growth from population density
What is functional response type II?
It is characterized by a decelerating intake rate, which follows from the assumption that the consumer is limited by its capacity to process food (satiation)
What is a population?
Its a group of individuals of the same species that inhabit a given area
Explain how coexistence is reached in the Lotka-Volterra equation for competition using a graph?
K1 < K2/ β Therefore, species 1 cannot achieve density to eliminate species 2 (i.e., N1 cannot equal K2/β) neither species excludes the other intraspecific competition inhibits growth of each population; species limit themselves before one species limits the other
N1*=
K1-(alpha)N2
When N1*=0, N2=
K1/alpha
N2*=
K2-(beta)N1
When N2*=0, N1=
K2/beta
An individuals inclusive, or overall fitness is determined by its survival and reproduction rate, plus the survival and reproduction rates of family members
Kin Selection
High quality suitable patches are expected to have LARGER/SMALLER population density than low quality suitable patches of similar size.
Larger
SEE SLIDE on Lotka-Volterra competition model equilibrium solutions.
Lecture 7
If a pathogen spreads environmentally, hypovirulence is LESS/MORE LIKELY to evolve.
Less
Climate and Distributions
Limited distributions may not be directly determined by climate, but indirectly. >food >water >parasites >habitat Relationship between climate and species distribution can be stable for hundreds to thousands of years.
Sousa's controlled access to patch through the use of limpets and then measured structure of algal community with and without grazing. Due to limpets' grazing nature, are large or small patches more heavily impacted and why?
Limpets keep to the edge of patches to avoid predators. Therefore, small patches more heavily impacted; Tri-trophic situation.
linkage disequilibrium
Linkage disequilibrium (nonrandom association) between female choice genes and male expression genes
This model incorporates K into the exponential growth model..
Logistic model of population growth
hyphae
Long filament of cells that makes up the body of fungus.
What model can be used when two species need the same resource?
Lotka-Volterra competition model
HIGH/LOW quality patches are referred to sinks.
Low
What is an example of a population cycle?
Low prey abundance (hawks on iguanas) in one year would result in decreased birth rates the following year and population declines; abundant food in one year would result in increased birth rates the following year and population growth
Carrying capacity (K)
Maximum population of a particular species that a given habitat can support over a given period.
What allows sink populations persist in source-sink models?
Migration from source populations allows sink populations to persist.
What is the Lotka-Volterra competition model?
Modification of the logistic model for each species to include the competitive effect of one species on the population growth of another -alpha: effect an individual of species 2 has on the population growth of species 1 -beta: effect an individual of species 1 has on the population growth of species 2
immigration (+)
Movement of individuals into a population
What is polyploidization? Does this mechanism happen more often in plants or animals?
Multiplication of the whole chromosome complement and has occurred frequently in vascular plants Polyploidization happens more often in plants because
What is the origin of most genetic variation?
Mutation
What are the sources of genetic variation in prokaryotes?
Mutation Horizontal gene transfer
What is mutualism?
Mutualism is a species interaction in which both species benefit from each other
arbuscular mycorrhizae
Mycorrhizae in which the fungal partner grows into the soil, extending some distance away from the plant root, and also grows between some root cells while penetrating others.
Stable Predator Population (predator isocline)
N = m/ac
Formula for N(t) with r incorporated = ?
N(t) = N(0)e^rt
What is the formula for N(t) it is generalized for more than one time step?
N(t) = lamda^tN(0) Number of individuals at time t = population growth rate raised to time t times the number of individuals at time 0
Population growth equation
N=(B+I)-(D+E)
At what point does a population growing, logistic growth model, reach its maximum intrinsic rate of increase (r)?
N=K/2
What are the equilibria for logistic model of population growth?
N=k N=0
Fundamental equation in population Ecology
N_(t+1)=BN_(t)-DN_(t)+N_(t)=lambda*N_(t) B_(N): births in a population size N D_(N): death in population size N Assumptions: no density dependence, no heterogeneity, closed population
Field Test
Natural environment confirms that predators decrease abundance of colorful guppies.
neutralism
Neither species benefits or is harmed
Niches
Niche - summarizes environmental factors that influence growth, survival, and reproduction of a species. A niche consists of all the factors necessary for the existence of a species. Niche concept developed independently by Grinnell and Elton. >Grinnell focused on the effects of the physical environment. >Elton included biotic and abiotic factors.
Are all populations that are composed of subpopulations metapopulations?
No
Is there a feedback mechanism for development of a benign relationship?
No
Is human carrying capacity constant? Why or why not?
No Changes in agriculture productivity and treatment of infectious diseases.
Are population models that incorporate time lags necessarily stochastic? If not why?
No IF r and tau are a certain value you can get oscillations but they are predictable because you set the parameters and they don't change.
Do we expect the assumptions of the ideal free distribution to be commonly met in nature?
No, cost of spending the time to figure out which patch has the highest quality is too high. -also animals cant always move freely between patches
Do single males have a chance of claiming and defending a pride?
No, most form coalitions with other males. Probability of siring young depends on rank within coalition
How do you use "+" and "-" to show the different interactions?
One species (+) kills and consumes the other (-) AKA One side gains benefit (+) the other side loses their life, ability to reproduce etc (-)
What animals/plants have the opportunistic life history? What are the characteristics of these examples?
Opportunistic life history: take immediate advantage of favorable conditions; quantity > quality Ex: Mice/Rats Birth Rate - high (12+ offspring) Sexual Maturity - early Overall Lifespan - short (12 months) Parental Care - little to no care Youth Survivorship - therefore very low Ability To Tolerate - low
Distributions of Barnacles Along an Intertidal Exposure Gradient
Organisms living in an intertidal zone have evolved to different degrees of resistance to drying. Barnacles show distinctive patterns of zonation within intertidal zone. >Connell found Chthamalus stellatus restricted to upper levels while Balanus balanoides is limited to middle and lower levels.
Photoautotrophs
Organisms that use light as a source of energy to synthesize organic substances.
BLANK occurs in logistic growth when there are density dependent delays.
Oscillations
Inclussive fitness
Overall fitness of an individual is determined both by its own survival and reproduction as well as that of its family. Kin selection drives this behavior.
What is the equilibrium solution for predator prey population dyanmics?
P(hat)
How do most species make a living?
Parasite
What are endoparasites?
Parasites that live within the body of their host.
What does "reciprocal selective pressure" mean in parasitism? How does it lead lead to co-evolution in parasites and their hosts?
Parasites want to use the host, but there is pressure because if the parasite kills the host, then the parasite dies as well. The evolution is the host figuring out how to deal with the parasite, and the parasite effectively using the host
Rarity II: Extensive Range, Large Populations, Narrow Habitat Tolerance
Passenger pigeon. Harelip sucker.
Rarity I: Extensive Range, Broad Habitat Tolerance, Small Local Populations
Peregrine falcon, Falco peregrinus. Tiger, Panthera tigris.
What is direct competition?
Physical contact, direct fighting
Plant Size and Population Density
Plant population density decreases with increasing plant size. Underlying biology is different from animals, as one tree species can have range of sizes. >Tree seedlings often live at high densities. >As trees grow, density declines progressively through self-thinning. >Mature trees live at low densities.
What is polyploid speciation?
Polyploidy is when the number of chromosomes in an organism's cell doubles. This means that the organism has more chromosomes than other individuals of the same species, meaning it cannot mate with other individuals.
geometric population growth
Population growth in which generations do not overlap and in which successive generations differ in size by a constant ratio.
What are allee effects?
Population growth increases with population size in some cases
What is the the numerical response of the predator population?
Population growth of predators as a function of victim abundance -ability to turn victims into more predators
exponential population growth
Population growth that produces a J-shaped pattern of population increase. In ___________ growth, the change in numbers with time is the product of the per capita rate of increase, r, and population size, N. Assumptions: no density dependence, no heterogeneity, closed population
What do we mean by no density dependence?
Population size cannot feedback on population growth
Introduction
Populations vary in distributions and dynamics. >Some are small with restricted distributions. >Some are abundant with broad distributions.
POSITIVE/NEGATIVE density-dependent effects occur if a vital rate increases as density increases.
Positive
What is behavioral isolation? Give an example.
Potential mates meet, but choose members of their own species (ex: Vogelkop Bowerbird, Satin Bowerbird, Flame Bowerbird)
What's the difference between a pre-zygotic barrier and a post-zygotic barrier?
Pre-zygotic refers to any stage of the reproductive process before the formation of the zygote, while post-zygotic refers to any point of life after the ovum has been fertilized. Both terms are used when describing the fertilization and conception processes. AKA Pre-zygotic isolation is before the union of gametes(before fertilization) post-zygotic is after the union of gametes
What are the general time scales from most oldest to most recent?
Precambrian Paleozoic (early life forms) Mesozoic (middle life forms) Cenozoic (recent life forms)
What are phase graphs?
Predator density as a function of prey density
Type II Functional Response
Predator's rate of prey consumption begins to slow down as prey density increases and then plateaus when nation occurs takes longer to consume prey when density increases
Type I Functional Response
Predator's rate of prey consumption increases in a linear fashion with an increase in prey density until satiation occurs time to consume doesn't change when density changes
How else can population cycles be generated?
Predator-prey dynamics
What does the Lotka-Volterra predator-prey model demonstrate?
Predator-prey dynamics have the potential to generate population cycles- predator-prey coexistence is enabled by mutual negative feedbacks
What are the different kinds of strategies adapted by predators and preys to increase their fitness?
Predators: sharp teeth, claws, venom, speed, acute sensory organs, cryptic colors/shapes Preys: shells/quills, cryptic colors/shapes, apparent death, distraction (surprise predators), toxicity, mimicry
What is a real word application of ecological niche modeling?
Predicting the potential distribution of an invasive species to develop appropriate responses.
What is a pre-zygotic barrier?
Prevents mating or fertilization between different species (prevent formation of zygotes) SO the isolation happened between groups of the same species before an egg even thought about getting fertilized
What is the 2 person social dilemma we discussed in class?
Prisoner's Dilemma
Thermoregulation
Process of maintaining an internal temperature within a tolerable range.
What does (1-N(t)-tau /K) represent in logistic population growth with delayed density dependence?
Proportion of carrying capacity remaining from tua time steps ago.
What is r defined as with regards to linear density dependence?
R is still birth rate - death rate
net reproductive rate formula is?
R(0)= sum of l(x)b(x)
Applications: Rarity and Vulnerability to Extinction 1
Rabinowitz devised classification of rarity and commonness based on (3) factors: >Geographic range (extensive/restricted). >Habitat tolerance (broad/narrow). >Local population size (large/small). Populations least threatened by extinction have extensive ranges, broad habitat tolerances, and some large local populations. >All seven other combinations include some attribute of rarity.
What are the three modes of dispersion?
Random, Uniform and Clumped
At small scales, distribution patterns may be
Random, regular, or clumped. >Individuals in a population may attract, repel, or ignore each other. >Social interactions can be reinforced or damped by environmental structure.
BLANK is the set of conditions that are actually used by a species (may vary between individuals).
Realized niche
Species living in groups often cooperate how?
Rearing offspring
What is coevolution?
Reciprocal evolution in two or more interacting species of adaptations selected by their interaction
Density Dependent Death Rate
Refer to Image
Density Dependent Birth Rate
Refer to image
Density Dependent Death and Birth Rate
Refer to image
What is dispersal?
Refers to the movement if individuals from their birth site to a breeding site (natal dispersal) or from one breeding site to another (breeding dispersal)
What is migration?
Refers to the movement of large numbers of individuals from one suitable niche to another for a portion of their annual cycle or life history.
Density dependence is not a sufficient condition for a population to be regulated. Why?
Regulation may often be the result of the interaction between density-dependent and density-independent effects.
Sociality
Relationships among individuals change when they live in groups.
iteroparity
Reproduction that involves production of an organism's offspring in two or more events, generally spaced out over the lifetime of the organism.
What is a post-zygotic barrier?
Reproductive barrier that operates should interspecies mating occur and form hybrid zygotes (fertilized egg cannot survive or divide due to mechanisms that are chromosomal, biochemical etc) SO the parents can form a zygote together but after that it's all over for their lineage because the new baby is infertile Ex: Mule
BLANK is any substance or factor that is both consumed by an organism and supports increased population growth rates as its availability increases.
Resource
SEE POWER POINT FOR LINEAR DENSITY DEPENDENT EQUATION
Second power point towards the end
Logistic growth with large oscillations: Know how to draw graph.
See lecture 3 power point
What is character displacement caused by?
Selective effects of interspecific competition
What is the meaning of the "life-dinner principle"?
Selective pressure to evolve better adaptations to avoid being eaten or to better eat other individuals
What are metapopulations?
Sets of populations that are interdependent over time
Why are Daphnia parthogenetic (alter between sexual and asexual)?
Sexual reproduction is triggered by environmental stress so at the end of season they do sexual reproduction (bet hedging).
How does it reproduce?
Sexually via bee pollination, but also through asexual modular spread
How does positive density dependent factors affect populations?
Small populations usually suffer from these; its when the rate of population growth increases as population density increases
Hosts
Some animals are better hosts than others Ex) ticks and Lyme disease - opossums are better at removing ticks than mice are
What is a specialist?
Some predators, parasites, herbivores, mutualists, are restricted to one or very few species as prey, host, or partner
What are the 4 possible outcomes of the Lotka-Volterra equation for competition?
Species 1 wins Species 2 wins Eventually species 1 or 2 wins, depending Coexistence
Cooperative Breeders
Species living in groups often cooperate in process of producing/rearing offspring.
Extreme Rarity: Restricted Range, Narrow Habitat Tolerance, Small Populations
Species with these attributes are the rarest of the rare. California condor, mountain gorilla, giant panda. Many island species have these attributes. Many birds that have gone extinct since 1500 were from islands. Ash Meadows, a small area of desert wetlands, has many rare species.
What is gametic isolation? Give an example.
Sperm transfer takes place, but egg is not fertilized (ex: Sea Urchin Spawning - three different urchin species live in proximity but with different gamete traits)
Logistic growth with large oscillations represents what type of limit cycle?
Stable limit cycle
Geographic Range and Population Size
Strong positive correlation between size of geographic range and size of population for most organisms.
What are the examples of successful and unsuccessful invasion control using natural enemies?
Successful: Cardinal ladybug to attack cottony cushion scale Unsuccessful: Indian mongoose to control rats
What's the difference between survivor rates and survivorship?
Survival rate: probability of surviving to the next stage Survivorship: proportion of starting population that makes it to stage x (probability of surviving from 1 to x)
T/F: In allopatric speciation, natural selection or genetic drift could be the mechanisms that eventually cause speciation
T
T/F The reproductive isolation is the key to speciation
T Collection of mechanisms, behaviors, and physiological processes that prevent the members of two different species that cross or mate from producing offspring, or which ensure that any offspring that may be produced is not fertile Ex: liger
describe a climax
THEORETICAL endpoint of a sere, the final seral stage
What is inclusive fitness?
TOTAL fitness of a GENOTYPE responsible for a particular phenotype Inclusive = direct + indirect
T/F if we have a lateral structure, then it can produce vertical stems and a root system
TRUE
T/F individuals move within a population
TRUE
T/F within the geographic range of a population, individuals inhabit only locations where all factors fall within their range of tolerance
TRUE
T/F; density independent factors are not affected by population density
TRUE
T/F; individuals have a limited amount of resources that can be allocated to specific aspects of their life history
TRUE
T/F; population age or size structure have direct implications for population growth
TRUE
T/F; positive and negative dependence function to regulate populations
TRUE
T/F; some populations can exhibit large fluctuations
TRUE
What is conversion efficiency?
The ability of predators to convert each new victim into additional per capita growth for predator populations
life history
The adaptations of an organism that influence aspects of its biology such as the number of offspring it produces, its survival, and its size and age at reproductive maturity.
Equation for predator population growth: dP/dt = beta x V x P -qP What is qP?
The background mortality rate of the predator.
combined response
The combined effect of functional and numerical responses by consumers on prey populations; determined by multiplying the number of prey eaten per predator times the number of predators per unit area, giving the number of prey eaten per unit area. Combined response is generally expressed as a percentage of the total number of prey.
Distribution Limits
The environment limits the geographic distribution of a species. >Organisms can only compensate so much for environmental variation. >Compensation (regulating body temperature, water content, etc.) requires energy. No single species can tolerate the full range of earth's environments.
What is discrete time in population dynamics?
The evolution of some quantity does not occur continuously over time but at certain periods or time steps (every year, every month, every mili-second).
What is continuous time in population dynamics?
The evolution of some quantity does occur continuously over time.
What is allelopathy?
The excretion of chemicals by plant of some species that are toxic to plants of other species.
What does speciation mean?
The formation of new species
What's the difference between a generalist and a specialist?
The generalist can use a variety of resources and specialists are picky when choosing resources
What is the "hygiene hypothesis"?
The hygiene hypothesis says that more auto immune diseases are happening because we're "too clean" and aren't exposed to enough pathogens
What is r ?
The intrinsic rate of increase.
What is the net reproductive rate R(0)?
The mean number of offspring produced by a female over her lifetime.
What are B(N) and D(N)?
The number of births and deaths in a population of size N.
Fitness
The number of offspring (genes) contributed by an individual to future generations is influenced by social relations.
What is the mutualism relationship between the Euglossa bee and orchid flowers? Does the Euglossa bee benefit by obtaining nectar? If not, what is the benefit they obtain?
The orchid gets pollinated, but because they release the nectar, female bees are attracted as well, therefore the bees can mate
In a deterministic model what is the output of the model determined by?
The output of the model is fully determined by the parameter values and initial conditions.
How can births per women (per capita fecundity) be low and birth rates be high in a particular country?
The population is younger. Less old people = higher natural rate of increase.
Greehouse Test
The presence of a true predator decreases fitness of colorful guppies.
What is the demographic transition?
The process of change in a society's population from a condition of high crude birth and death rates and low rate of natural increase to a condition of low crude birth and death rates, low rate of natural increase, and a higher total population.
What is functional response?
The rate of victim capture by a predator as a function of victim abundance.
Geometric growth/decline ?
The rate with which population increases or decreases is exponential.
How does the example of the Plethodontid salamanders provide evidence to this mechanism?
The salamanders evolved based on their environment In some places they were dark with spots in order to blend in and hide from their predators In other places they became bright orange in order to resemble the deadly newt to try to scare off predators The hybrids between the two were unsuccessful because since they had spots and were bright orange they were not able to blend in with the environment and hide or scare away their predators
Behavioral ecology
The study of the evolution of and ecological basis for animal behavior.
phenology
The study of the relationship between climate and the timing of ecological events such as the date of arrival of migratory birds.
Grinnell's definition of niche
The sum of the habitat requirements and behaviors that allow a species to persist and produce offspring.
What is character displacement?
The tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species.
What is a biological control?
The use of a predator or parasite to control a pest species.
Lobster hierarchy (Jordan Peterson)
The winning lobster "flexes" because of influx of the neurotransmitter serotonin. If the loosing lobster is injected with serotonin, he too will "flex" and challenge the opponent again. Connection to humans: Hierarchy (winning and loosing) is part of the human nature. Victory or defeat can reshape the brain.
What to metapopulation models account for?
They account for the unoccupied patches and unsuitable habitat (habitat matrix). -subpopulations occupy patches of suitable habitats SEE POWERPOINT FOR PICTURE
How are sub-populations formed?
They are formed when there is barrier that reduces but does not eliminate interactions between individuals of a larger population.
What are source-sink models and what do they account for?
They build off metapopulation models by accounting for differences in patch quality and reproductive success in high and low quality patches.
What is an overshoot?
This is when the population grows beyond its carrying capacity (K)
A Tiger Beetle of Cold Climates
Tiger beetle (Cicindela longilabris) lives at higher latitudes and elevations than most other tiger beetles in North America. Schultz et al. found metabolic rates of C. longilabris are higher and preferred temperatures lower than most other species. >Supports hypothesis that species is adapted to boreal and montane forests. >Similarity across populations supports generalization that physical environment limits species distributions.
discrete time
Time thought of as advancing in distinct finite increments.
continuous time
Time thought of as advancing in extremely small increments.
Distributions of Desert Shrubs
Traditional theory suggests desert shrubs are regularly spaced due to competition. Phillips and MacMahon found distribution of desert shrubs changes from clumped to regular patterns as they grow. Young shrubs clumped for (3) reasons: >Seeds germinate only at safe sites. >Seeds not dispersed from parent areas. >Asexual reproduction.
What is the n-person dilemma we discussed in class?
Tragedy of the Commons
True or False: Genetic variation in a host may parallel genetic variation in pathogen/parasite/herbivore.
True
True or False: Heritable variation exists between populations according to Darwin's natural selection.
True
True or False: Heterogeneity among individuals have the potential to influence demographic processes.
True
True or False: Predators can influence the outcome of competition between prey species.
True
True or False: Species differ in their ability to adapt (through genetic change) and acclimate (through phenotypic plasticity) to human-induced environmental change.
True
True or False: Specific habitats can create sub-populations even on small scales.
True
True or False: The relationship between population size and per capita birth rate/ per capita death rate could be linear or nonlinear.
True
True or False: A heterotroph is any single or mulitcellular organism that preys on, parasitizes, or eats the decaying remains of other organisms.
True -includes animals, fungi, some plants (Dodder), many microbes, and non-photosynthetic protists
What is apparent competition?
Two or more species appear to be competing when in fact they share a common predator that suppresses both species. The abundance of one species increases the likelihood of consumption of other species.
This survivorship curve shows the survival rate as high throughout the lifespan, with most mortality at the end; convex look
Type I
What type of functional response is assumed by the Lotka-Volterra model?
Type I
This survivorship curve shows the survival rates not varying much with age
Type II
This survivorship curves shows the mortality is very high early in life
Type III
What type of survivorship curve would we select for marine turtles? why?
Type III curve; based on small amounts of data of survivorship of life stages for marine turtles, the curve looks like a type II. However, based on biological survivorship the curve is likely a type III.
Lotka-Volterra model for predator prey dynamics: What is VP? dV/dt = rV - alphaVP
VP is the probability of a random encounter between victim and predator
What is demographic stochasticity?
Variability in population growth arising from sampling random births and deaths.
What free floating aquatic plant is native to the tropical regions in South America?
Water hyacinth
How can we represent the population cycles mathematically?
We can represent these by using the logistic growth model. dN/dt=rN(1-N/k)
What is genetic bottleneck?
When a sudden environmental change drastically reduces the size of the population.
How does age structure affect population growth rates?
When birth and death rates vary with age, contributions of younger and older individuals should be calculated separately
What is allopatric speciation?
When one species diverges into two different species because of geographic isolation The two populations of the species may end up evolving differently because of the conditions are different in each geographic region Ex: Think of squirrels in CO vs squirrels in FL it might be colder so the animals in that geographic region may grow thicker hair and thicker layers of fat whereas in a warmer geographic region the animals may lose some fur and add a lot of sweat glands Given enough time, and given a complete lack of gene flow between the two populations, thick coated animals will only be able to breed with thick coated animals and thin coated animals will only be able to breed with thin coated animals
What is sympatric speciation?
When one species diverges into two different species without being geographically isolated because they are reproductively isolated in some other way Ex: Think of different types of dogs mating with each other and making a different type of dog so like poodles and lab and then they mate and make a labradoodle SO after enough time, labradoodles can't mate with labs or poodles, they have to mate with other labradoodles The gene flow between two populations would stop and they would become reproductively isolated and over time they would become different enough that they could no longer successfully breed together at all and thus become different species
assuming top down control, how do consumers affect the lower trophic levels?
When predators are removed from a community herbivore populations often increase so rapidly that they decimate the plant resources they feed on
What is predation?
Where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked) Example: snakes prey on and eat mice
What is competition?
Where both the species are harmed Example: cheetahs and lions; since both species feed on similar prey, they are negatively impacted by the presence of the other because they will have less food
What is commensalism?
Where one organism benefits from the other without affecting it The commensal (the species that benefits from the association) may obtain nutrients, shelter, support, or locomotion from the host species, which is substantially unaffected Example: the birds that stand on other animals such as rhinos
What is parasitism?
Where one species, the parasite, benefits at the expense of the other, the host Example: tapeworms, fleas etc
What is mutualism?
Where two organisms of different species exist in a relationship in which each individual benefits from the activity of the other Example: bees and flowers
Plant Distributions Along Moisture Gradients
Whittaker examined distributions of woody plants along moisture gradients in several North American mountain ranges. Documented gradients from moist canyon or valley bottoms up drier southwest-facing slopes. >Trees had highly clumped distribution on these gradients. >Distributions reflected moisture requirements of each species.
n the video we watched, Dan Janzen discussed which one of the following as being a major obstacle to forest restoration efforts in Costa Rica where he works?
Wild fires burning park property
Roads serve as movement barriers for some animals and create sub-populations. How is this overcome?
Wildlife crossing structures
Is density dependence a necesary condition for a population to be regulated?
Yes
N(t) = lamda^tN(0) What is the assumption with this formula?
You have the same population growth.
sociobiology
a branch of biology concerned with the study of social relations, founded in Darwin's theory of evolution
arbuscule
a bush-shaped organ on an endomycorrhizal fungus that acts as a site of material exchange between the fungus and its host plant
competition coefficients
a coefficient expressing the magnitude of the negative effect of individuals of one species on individuals of a second species
growth form
a combination of plants structure and its growth dynamics
define asymmetric competition
a competitive relationship between two species in which each has an advantage with respect to different limiting factors in the environment
predator satiation
a defensive tactic in which prey reduce their individual probability of being eaten by occurring at very high densities; predators can only capture and eat so many prey and so become satiated when prey are at very high densities
regular distribution
a distribution of individuals in a population in which individuals are uniformly spaced
positive feedback loop
a feedback loop in which change in a system is amplified
aril
a fleshy covering of some seeds that attracts birds and other vertebrates which act as dispensers of such seeds
prey-dependent functional response
a functional response in which rate of feeding by a predator is a function of prey population size only
survivorship curve
a graph that represents the distinct patterns of species survival as a function of age
Caste
a group of individuals that are physically distinctive and engage in specialized behavior within a social unit, such as a colony
What is Batesian mimicry?
a harmless species mimics a harmful one
predator
a heterotrophic organism that kills and eats other organisms for food; usually an animal that hunts and kills other animals for food
static life table
a life table constructed by recording the age at death of a large number of individuals; the table is called static because the method involves a snapshot of survival within a population during a short interval of time
define a life table..
a life table is an age or stage specific account of survivorship and mortality
cohort life table
a life table that follows a group of individuals born at the same time from birth to the death of the last individual
polymorphic locus
a locus, or gene, that occurs as more than one allele, each of which synthesizes a different allozyme
What do we get if rT is small?
a logistic growth when rT<0.37
Comparative Method
a method for reconstructing evolutionary processes and mechanisms that involves comparisons of different species or populations in a way that attempts to isolate a particular variable or characteristic of interest, while randomizing the influence of confounding, or confusing, variables on the variable of interest across the species or populations in the study
facultative mutualism
a mutualistic relationship between two species that is not required for the survival of the two species
obligate mutualism
a mutualistic relationship in which species are so dependent upon the relationship that they cannot live in its absence
clumped distribution
a pattern of distribution in a population in which individuals have a much higher probability of being found in some areas than in others; in other words, individuals are aggregated rather than dispersed.
logistic population growth
a pattern of growth that produces a sigmoidal, or S-shaped, population growth curve; population size levels off at carrying capacity (K) Assumptions: no fluctuations in environmental conditions, linear density dependence, no delays in the feedback between density and population growth rate, closed population, no heterogeneity
What does having a stable limit cycle (rT>1.57) mean?
a pattern of population growth in which the population continues to exhibit large oscillations over time
What does having damped oscillations (0.37<rT<1.57) mean?
a pattern of population growth in which the population initially oscillates but the magnitude of the oscillations declines over time
What are hemiparasites?
a plant that may obtain part of its food from parasitism
stable age distribution
a population in which the proportion of individuals in each age class is constant
What is the key point about the logistic growth?
a populations per capita growth rate gets smaller and smaller as a population size approaches a maximum imposed by limited resources in the environment
subpopulation
a portion of a larger population, with which it sustains a connection through immigration and emigration
Amensalism
a relationship in which one organism is harmed and the other is unaffected
What is a tradeoff?
a resource used for one function cannot be used for another function
-3/2 self-thinning rule
a rule resulting from the observation that plotting the average weight of individual plants in a stand against density often produces a line with an average slope of approximately -3/2
describe primary succession
a sere beginning with chemical and mineral precursors, but NO biological precursors. autotrophic needs only
describe a sere
a series of stages of community change in a successional sequence leading to a climax condition
priority effect
a situation in which a species establishing itself in greater numbers in a place before the establishment of potential competitors wins in competition with species arriving later
elaisome
a structure on the surface of some seeds generally containing oils attractive to ants, which act as dispersers of such seeds.
food web
a summary of the feeding relationships within an ecological community
life table
a table of age-specific survival and death, or morality, rates in a population
fecundity schedule
a table of birthrates for females of different ages in a population
scatterhoarded
a term applied to seeds gathered by mammals and stored in scattered caches or hoards
adhesion-adapted
a term applied to seeds with hooks, spines, or barbs that disperse by attaching to passing animals
K selection
a term referring to the carrying capacity of the logistic growth equation; a form of natural selection that favors more efficient utilization of resources such as food and nutrients. K selection is predicted to be strongest in those situations where a population lives as densities near carrying capacity much of the time. (Low birth rates, long life span)
r selection
a term referring to the per capita rate of increase; a form of natural selection favoring higher population growth rate. r selection is predicted to be strongest in disturbed habitats. (High Birth rates, short lifespan)
Philopatry
a term, which means literally "love of place," used to describe the tendency of some organisms to remain in the same area throughout their lives
disturbance
abiotic event that kills or damages some individuals and thereby creates opportunities for other individuals to grow and reproduce
density-independent factor
abiotic factors in the environment, such as floods and extreme temperature
Are density independent effects most biotic or abiotic?
abiotic or nonliving, "Exogenous"
ecological niche
abiotic+ biotic conditions that the species needs to grow, survive, and reproduce
This describes the number of individuals in the population but provides no information on their characteristics
abundance
competitive plant
according to Grime (1977) _______ occupy environments where disturbance intensity is low and the intensity of stress is also low, must compete with others for resources
What are the three types of dispersal?
active dispersal, passive dispersal, migration
ramet
actually or potentially independent members of a genet
If life history strategy is __________, we expect higher _________ than other strategies
adaptive; fitness
indirect fitness
additional reproduction by relatives that is made possible by an individual's helpful actions
Who do we see having a type II survivorship curve?
adult birds, rodents, reptiles, many perennial plants
Why is it important to determine if a situation is a zero sum or mixed motive game?
affects whether or not cooperation or competition will be more effective
What is an example of semelparity in plants?
agave -> payoff for reproduction highly dependent on variable environment, greater energy investment leads to better success
___________ is the number or proportion of individuals in different age classes of a population
age structure
reproductive effort
allocation of energy, time, and other resources to the production and care of offspring
What are the two types of speciation?
allopatric and sympatric
what's the ecological significance of the panama canal?
allowed movement of organisms between pacific and atlantic oceans, allowing marine genetic movement and slowed evolution -broke up terrestrial mobility (mix of different animals that colonized, now groups evolve again since no movement)
whats the difference between alpha and gamma diversity?
alpha: local diversity gamma: regional diversity
allozyme
alternative form of a particular enzyme which differs structurally but not functionally from other allozymes coded for by different alleles at the same locus
what is potential evapotranspiration?
amount of water that could be evaporated from soil and transpired by plants
sigmoidal population growth curve
an S-shaped pattern of population growth, with population size leveling off at the carrying capacity of the environment.
what are dominant species?
an abundant species in the community ex) "oak community"
granivore
an animal that feeds chiefly on seeds
population dynamics
an area of population ecology concerned with the factors influencing the expansion, decline, or maintenance of populations, including rates of births, deaths, immigration, and emigration
Ectomycorrhizae
an association between a fungus and plant roots in which the fungus forms a mantle around roots and a netlike structure around root cells
niche partitioning
an evolutionary process whereby organisms decrease direct competition by differentiating in their use of resources by altering which, how, or when resources are used
Gonadosomatic Index (GSI)
an index of reproductive effort calculated as ovary weight divided by body weight and adjusted for the number of batches of offspring produced per year
Hermaphrodite
an individual capable of producing both sperm or pollen and eggs or ova
What is frequency-dependent selection?
an individuals fitness can depend on what others are doing often occurs through interactions with other organisms (predators, pollinators)
parasitoid
an insect whose larvae live as parasites that eventually kill their hosts
exploitation
an interaction between species in which one species benefits while the other is harmed
indirect commensalism
an interaction in which one species benefits another species indirectly, through an intermediary species, without itself being helped or harmed
Hutchinson definition of niche
an n-dimensional hypervolume, where the dimensions are environmental conditions and resources that define the requirements of an individual or a species... for its population to persist
parasite
an organism that lives in or on another organism; one who lives off another person
what is iteroparity?
an organism undergoes multiple reproductive cycles in their lifetime
what are keystone species?
an organism which has a disproportionate effect of ecosystem structure or function
the cenozoic era is dominated by
angiosperms, mammals
Territoriality
animals defend food, nesting resources and mates
pathogen
any organism that can cause disease
what is a resource?
any substance or factor that is both consumed by an organism and supports increased population growth rates as its availability increases
Smith treated different species of coral with antibiotics and compared their viability to untreated samples. what ecological phenomenon does this display? what did he find?
apparent competition -although coral without antibiotics showed varying growth patterns, most (but not all) of the coral species survived better when treated with the antibiotic
Density independent effects affect population size and ARE/ARE NOT themselves affected by population size.
are not
Small-scale phenomena
areas over which there is little significant environmental change.
large-scale phenomena
areas over which there is substantial environmental change.
what are the general trends given by species-area curves?
as area increases, number of species also increases
what is the relationship between size of the regional species pool, abundance, and local species richness?
as the size of the regional species pool increases, average species abundances and numbers of habitats occupied by species in local communities decrease while local species richness increases
Emery observed zones dominated by different species of species. what ecological phenomenon does this display? what did he find?
asymmetric competition -lower boundaries (towards increasing physical stress, such as soil salinity and anoxia) were set by physical stress -upper borders set by competition
When do allee effects generally occur?
at small populations
In ecosystem development, at what point of the sere is biodiversity the highest?
at the intermediate stages, then drops slightly at the end
In ecosystem development, at what point of the sere is community complexity the highest?
at the intermediate stages, then drops slightly at the end
What is K with regards to linear density dependence?
b(0) - d(0) / a + c -a + c = density dependent decrease in births and increase in deaths
What represents what they will contribute to the next generation while living?
b(x) which is the fecundity rate; the average # of female offspring produced per female per time period; R(0) is the net reproductive rate
What are the equations for linear density dependence that add density dependence for birth rate and death rate?
bN = b(0) -aN a is some density dependent deduction in births dN = d(0) + cN c is some density dependent increase in deaths
Why do these reductions in population growth come about?
because of increases competition and stress, decreased reproduction and increased dispersal
Name 2 groups of ectoparasites.
bed bugs ticks
how do we begin using the model for population cycles?
begin by defining the amount of time delay (T) between resources consumption and reproduction for your particular consumer
describe secondary succession
biological precursors at the beginning of the sere, including organic materials in the soil, detritus, seeds, etc ex) tree falls, fire, flood, and anthropogenic causes
density-dependent factor
biotic factors in the environment, such as disease and competition
What are vital rates?
birth death movement
What determines net reproductive rate?
birthrate and survivorship
What increase population density?
births and immigration
What causes changes in population size?
births, deaths, immigration, emigration
mutulaism
both organisms benefit
What are the two types of genetic drift?
bottleneck effect and founder effect
in ______________ control, increased production results in greater productivity at all higher trophic levels
bottom-up
Sociobiology
branch of biology concerned with stuyd of social relations
when given a choice female guppies will mate with..
brightly colored guppies
How is a realized niche determined?
by abiotic and biotic factors
How is the population structure defined for unitary organisms?
by age or developmental stages
How are fundamental niches determined?
by habitat suitability and tolerance
How do birds of paradise avoid competing with each other?
by living in different parts of the jungle
How can the estimation of birthrate be improved?
by separating males and females in a population in which only females give birth; determining the birthrate for females by age class (age specific birthrate)
How is the population structure defined for modular organisms?
by size or genetic unit
So how is population growth controlled?
by; 1. rate at which new individuals are added to the population 2. rate at which individuals leave the population
What are altruistic behaviors?
can increase fitness of relatives while decreasing your own fitness ex: protecting babies, territory defense
What is K?
carrying capacity (population size that resources can support)
What does K represent in logarithmic growth?
carrying capacity of the population
Infectious disease
caused by pathogenic agent
balanced growth
cell growth in which all cell constituents, such as nitrogen, carbon, and DNA, increase at approximately the same rate
numerical response
change in the density of a predator population in response to increased prey density
"Continental drift" has resulted in
changes in ocean currents rising of sea levels an overall warming of the planet
describe community development
changes in the structure and function of a community
What are secondary sex characteristics?
characteristics of sexes that appear during puberty
pheromone
chemical substance secreted by some animals for communication with other members of their species
in lowland rivers what preys on adult guppies
cichlid
what is limited in the continental scale?
climate including temperatures and precipitations
what community occurs at the end of succession
climax comunity
In ecosystem development, nutrient cycles become progressively _____________
closed
What describes populations in which movement into and out of the population does not occur?
closed populations (rates of movement in and out are equal; births=deaths)
contrast the closed and open community approaches
closed: Clements recognized 14 climax communities in NA open: a multitude of climax community possibilities depending on the location of the disturbance along the environmental continuum of interest
intrasexual competition leads to the evolution of . . .
combat, sperm competition, infanticide, alternative male reproductive strategy(sneaker males)
What are mixotrophs?
combine photosynthesis and heterotrophic nutrition (get carbon by consuming)
describe the individualistic concept of community
community structure and function simply express the interactions of individual species, and do not reflect any organization above the species level
interspecific competition
competition between members of different species
intraspecific competition
competition between members of the same species
Tansley's experment where he grew two species alone and then together displayed what ecological phenomenon? what were the results of this experiment
competition between species -the species grew best on the type of soil that it was found in nature, but was able to grow on the other type of soil when alone. -when grown together, the species found in nature on that type of soil outcompeted the other species
define apparent competition
competition between two or more species that is mediated by their consumers
what is the competition coefficient β?
competition coefficient that quantifies the per capita effect of species 1 on species 2
what is the competition coefficient α?
competition coefficient that quantifies the per capita effect of species 2 on species 1
What is pre-emptive competition?
competition for reusable resources
Gause grew two species of bacteria separately and together, which showed what ecological phenomenon? what were the results of this experiment
competitive exclusion principle -both species thrived when grown separately -one species died out in the presence of the other
What is eusociality?
complex social system where non-breeding adults raise offspring of one/few reproductive individuals
Why did naked mole rats evolve eusociality?
conditions to reproduce are slim because burrows are deep and extensive, so only queen becomes reproductively mature and causes stress that produces hormones that prevent puberty
What methods constitute horizontal gene transfer?
conjugation (F factor) transformation (environment) tranduction (viral)
stress
consists of and strong negative environmental conditions that induce physiological responses in an organism or alter the structure or functioning of an ecosystem
what are the two essential concepts of stability?
constancy and resilience
in a life table, what tells us when they will die?
d(x) and q(x) where d(x) is our age specific mortality and its the difference between the number of individuals alive for the age (n[x]) and the next older age class (n[x+1]); q(x) is our age specific mortality rate that is determined by the number of individuals dying during a given time interval (d[x]) divided by the number alive at the beginning of that interval (n[x])
What is the logistic equation for regulated population growth?
dN / dt = rN(1-N/K)
What is an alternate form of the fundamental equation of population ecology when there is instantaneous population growth?
dN/dt = bN-dN change in # of individuals over the change in time = (birth rate -death rate) # individuals
Prey Population Equation
dN/dt = rN-cNP
What will the time delay formula look like?
dN/dt=rN(1-N[T]/K)
logistic equation
dN/dt=rN(K-N/K)
Predator Population Equation
dP/dt = acNP-mP
Equation for predator population growth:
dP/dt = beta x V x P -qP
What is the formula for the Lotka-Volterra model for predator prey dynamics?
dV/dt = rV - alphaVP -V is victim (prey) -P is predator -rV rate of growth x victim population
What do we get if rT is intermediate?
damped oscillations when 0.37<rT<1.57
mortality (-)
death rate
what decreases population density?
deaths and emigration
What mechanisms lead to density dependent decreases in birth and increases in deaths?
decreases in birth: - less energy is put into reproduction -longer to get to reproductive maturity -smaller litter sizes increases in death: -disease
delayed density dependence
delays in the effect that density has on population size caused by time lags in the negative feedback loop on population growth
What are the two types of limiting factors?
density dependent & density independent
Define density dependent limitations
density dependent limitations effect the influence a population in proportion to its size
Define density independent limitations
density independent factors can limit population sizes regardless of the populations density
What is an example of the structures defined by characteristics of the collective?
density, age distribution, spacing
allopatric
describes the condition in which populations or species have nonoverlapping geographic ranges
sympatric
describes the condition in which populations or species have overlapping geographic ranges
Positive feedbacks are inherently STABILIZING/DESTABILIZING and AMPLIFYING/DAMPENING.
destabilizing,amplifying
What do realized niches determine?
determines geographic range of species or various populations
What is the objective of a sensitivity analysis?
determining what is the effect of changing an element in the projection matrix A
In ecosystem development, grazing food chains shift towards __________ food chains
detritus
Simple metapopulation model
df/dt=pf(1-f)-pe(f) -Assumptions: homogenous patches, no spatial structure, no time lags, constant pe and pi, pi and/or pe are functions of f, large number of patches -colonization rate=higher the better -extinction rate=lower the better -habitat patches available=more the better
Sexual Selection
differences in reproductive rates among individuals as a result of differences in mating success
How can life history traits be plastic?
different environments have different abilities to support eggs because of resource limitation
Why do different plants have different mating systems?
different strategies can reduce costs or enhance success, depending on environmental conditions
define interference competition
direct antagonistic interactions between competitors over shared resources (usually by behavioral or chemical means)
Why females prefer certain male characters?
direct benefits, good genes model, sensory bias, runaway selection
Geometric growth occurs in BLANK time.
discrete
From early to late successional species, a shift occurs in strategies away from adaptations promoting ____________ toward adaptations enhancing __________________
dispersal, competitive ability
What defines the spatial extent of a population?
distribution
What reflects realized niche of a species?
distribution
_________ is the spatial boundary in which all individuals reside at a defined scale local or regional
distribution
random distribution
distribution in which the location of members in a population is totally random, location of each individual is determined by chance
In what ways is asexual reproduction advantageous?
doesn't need gonads, don't have to find mates, all genes passed to the next generation
Describe the example with the 3 grasses in relation to functional diversity?
each grass has a different tolerance for rainfall; in drought conditions, some individuals still survive to reproduce
describe Whittaker's Gradient Analysis
each species has its greatest abundance at a different point on the moisture gradient
distinguish ecoclines and seres
ecoclines are changes along a spatial gradient seres are along a temporal gradient
structural complexity of habitat is included in what type of diversity?
ecological diversity
The parasitism-mutualism continuum is context-dependent (checks and balances) in BLANK time.
ecological time
what are ecotones? give an example
edges of communities with rapid replacement of species along a gradient (closed community concept) -edaphic, climatic, fire, physical/chemical.
describe the herbivore and pathogen pressure theory explaining why there are so many kinds of trees in the tropics?
efficient predator specialists in the tropics reduce prey to rare levels, allowing many autotroph species to share limited resources -being a rare tree in tropics is a selective advantage (less attraction to herbivores, pathogens, and predators) -survival of seedlings is highest at distance from parent bc not competing, although density is highest close to tree
intersexual competition leads to the evolution of . . .
elaborate coloration, exaggerated secondary male characteristics, courtship behavior
what is the functional web's approach to depicting trophic relationships?
emphasizes the influence of populations on growth rates in other populations
SEE POWER POINT FOR STATIONARY VS. NON-STATIONARY SERIES
end of power point 2
geographic range
entire geographic region over which a species is found
what is an example of habitat suitability?
environmental conditions, resource availability
example; K=100, r=1.1, T=1. 10 plants in year 1, 20 plants in year 2. What will the expected change be in population size for year 3 and 4?
equation should look like this; for year 3, dN/dt=rN[yr2](1-N[yr1]/K)=20 as the expected change for year 4, dN/dt=rN[yr3](1-N[yr2]/K)=35 as the expected change
absolute population size
estimate of populations actual abundance
What is sexual selection?
evolution of traits that increase mating opportunities
Zahavi's handicap hypothesis
exaggerated male traits are essentially handicaps, but females prefer males with these handicaps because males have demonstrated an ability to survive in spite of these handicaps Ex: Peahens prefer peacocks with absurdly long tails because such males have demonstrated an ability to survive despite such tails
Cooperation generally involve..
exchanges of resources or other forms of assistance
hermaphrodites
exhibit both male and female function. most common in plants
Reproductive ratio (R0)
expected number of secondary infections per infected individual when introduced into a susceptible population the # of people that one sick person will infect on average R0 = ß/ (d+v+re) Slower re (recovery rate), higher v (virulence) or higher ß (more infectious) --> higher R0 Assumes an immune response
What type of growth are we to get with closed populations?
exponential growth
What type of growth cannot continue indefinitely?why?
exponential growth; because of limited resources
What is the difference between extinction and extirpation?
extinction: disappearance of a species from earth extirpation: loss of a species from a local area or part of its natural range
What are the 3 categorical processes of community development?
facilitation inhibition tolerance
true or false: keystone species are the most abundant species in an ecosystem
false! just have a disproportionate effect
true or false: diversification and speciation are synonymous
false: diversification is influenced by speciation but also relative importance of extinction
What ideal conditions are exponential growth observed under?
favorable environments; maximum reproductive rates, minimum death rates, highest per capita growth rate, low population density
How does competition determine relative fitness?
favors organisms that are large, self investing, and have similar offspring
How does predation determine relative fitness?
favors organisms that are small, higher numbered, and have small offspring
What is b(x)?
fecundity b(x)=F(x)
In the net reproductive rate R(0) formula what is m(x)?
fecundity at age x
strong interactions
feeding activities of a few species that have a dominant influence on community structure
intersexual competition
female choice
How do secondary sex characteristics play a role in sexual selection?
female choice: females pick more fit males male-male competition: more fit males earn the mate
Maternal effect example?
female desert locus alter the trajectory of their offspring in response to their own experience of crowding
why is there such a range of coloration in male guppies?
females love coloration in guppies, however colorful guppies are easily seen by predators
fisher's runaway model
females prefer males with extreme traits, giving rise to sons with extreme traits and daughters with a preference for extreme traits
How are most animals unitary?
fertilized zygote grows into a genetically unique organism, organism passes through a series of predictable life stages
How does lower survival rates affect reproductive strategy?
few individuals survive to old age, and there is little selection to delay senescence
In what ways is sexual reproduction costly?
first you have to attract a mate, then meiosis, gamete formation, fertilization, and zygote formation must occur
what is an example of clumped dispersion?
fish colonies
Explain the Prisoner's Dilemma?
for either of B/A's decisions, A/B is better off betraying, resulting in a worse outcome for both than if they both remained silent
as flock size increases what happens to foraging efficiency, food availability, and energy spent foraging?
foraging efficiency increases food availability decreases energy spent foraging increases
what is the reasoning behind the individualistic concept of community?
fortuitous assemblage Natural selection acts on individuals, so each to its own
What aspects of a mussels fundamental and realized niches contribute to their endangerment?
fundamental: lives in stream beds (susceptible to toxins) realized: depends on the presence of a specific host fish species
how is biodiversity measured within populations?
genetic diversity (genetic variation among individuals)
clones
genetically identical copies of oneself
distribution
geographic area where individuals of a species are present
____________ is the broad scale distribution in which the defined area encompasses all individuals of a species worldwide
geographic range
How do graphs of a population with a stable growth rate vary between geometric and logarithmic?
geometric: exponential curve logarithmic: straight line
graminoid
grasses and grass-like plants, such as sedges and rushes
What is the energy-diversity hypothesis?
greater energy --> shared by more species, and more individuals, so less chance of extinction
what does greater resource diversity mean for niche diversity potential?
greater niche diversity potential; greater community niche volume potential
sociality
group living generally involving some degree of cooperation between individuals
population
group of individuals of the same species that live within a particular area and interact with one another
lamda and r both represent = ?
growth constants
How are the amplitude of a population cycle predicted?
growth model
What is the growth rates of sinks?
growth rate < 1
What is the growth rate of sources?
growth rate > 1
the mesozoic era was dominated by
grymnosperms, angiosperms, mammals, birds
BLANK is a physical area where an organism can live.
habitat
habitat vs niche
habitat= abiotic (address) niche= biotic (job in the community)
What can low densities lead to?
harmful effects of inbreeding and a higher predation risk
Schistosomiasis
has a snail reservoir Things that increase snail prevalence (damming rivers, eutrophication by nutrients, etc.) increase disease prevalence in people -------------------- experiment: shrimp eat snails take out shrimp --> peak in snails then decrease --> decrease to less infected snails Decrease snails = decrease disease
dioecious plants
have male and female reproductive structures on different plants
Dawn Chorus
heightened volume of bird song at dawn, advertises fitness, less ambient noise, better sound travel, no other activities
forb
herbaceous plants other than graminoids
What are epigenetic effects ?
hertiable changes in gene activity not cause by changes in DNA
HIGH/LOW quality patches are referred to source.
high
what were the three groups john endlers used in his experiment
high predation, low predation, and no predation
What is the survivorship of an individual with a type I survivorship curve?
high survival later in life
Ebola
high virulence so doesn't infect too many people (they die too soon) R0: Hep C < Ebola < HIV < Measles
Will genotype carried by more offspring have a higher or lower inclusive fitness?
higher
Eusociality
highly specialized sociality generally including 1. individuals of more than one generation living together 2. cooperative care of young, and 3 division of individuals into sterile, or nonreporoductive and reproductive castes
Red Queen hypothesis
hosts evolve resistance, pathogens involve infectivty hosts have to evolve to keep up with their diseases why sexual reproduction may be favored over asexual reproduction - shuffles the genome
What is l(x)*b(x)
how many offspring each individual born is likely to contribute at each stage
What are deterministic models?
how r applies to all organisms, all the time (doesn't show variation); if r is positive, population can't fail
Who do we see having a type I survivorship curve?
humans, other mammals and some plants
What is a social dilemma?
if an individual acts in self interest, everyone is worse off
Herd immunity
if everyone else is vaccinated, you don't have to be (protected)
How do life history traits affect fitness?
if heritable, they are subject to natural selection ex: having 20 offspring increases your genetic representation only if others have fewer than 20
Why would a plant use selfing as a mating system?
if there is a sizable distance between individuals and fertilization between individuals is unlikely
In David Lack's experiment, how might clutch size contribute to fitness?
if you have more eggs and thus more individuals will survive and reproduce, you increase your fitness
What is the Red Queen Hypothesis?
if your enemies can adapt, you must be able to adapt too
What is a proximate explanation?
immediate mechanism; what triggers the response ex: snowshoe hares change color in response to day length -> color change provides camouflage and increases survival
Coinfection
immune response of one disease increases or decreases response to another disease Ex) Giardia infection reduces worm infection Ex) nematodes increase cape buffalo susceptibility to bovine tuberculosis
Inclusive fitness
improve survival and reprodcutve rates of family members
Where are organisms denser?
in areas with better conditions
what is the evidence for the "diversity reaches an equilibrium in which factors adding species balance factors removing species" view on tropical biodiversity?
in the tropics, factors adding species weigh more heavily, or factors removing species weigh less heavily.
what increases chances of genetic disease?
inbreeding
self-incompatibility
incapacity of a plant to fertilize itself; such plants must receive pollen from another plant in order to develop seeds
Simple epidemic models
include host, pathogen and maybe environment
Zoonoses (animal borne diseases) epidemic models
include human, pathogen and reservoir and maybe environment Ex) rabies, schistosomiasis Ex) people living close to farm animals
vector borne diseases epidemic model
include human, pathogen, reservoir, vector (need other species to transmit it) and maybe environment Ex) malaria (mosquitoes), dengue, Lyme disease (ticks)
What are the tradeoffs between growth, survival, and fecundity for plants?
increased survival -> increased competition -> decreased growth increased growth -> increasing disturbance -> decreased fecundity increased fecundity -> increased stress -> decreased survival
In ecosystem development, efficiency of nutrient cycles __________
increases
species richness (increases/decreases) going towards equator
increases
How does kin selection affect fitness?
increases inclusive fitness by assisting others who carry your own genes
In ecosystem development, as B/Pg increases, R/Pg ___________
increases toward one
Environmental Enrichment
increasing the complexity of the environment of captive animals to foster behaviors characteristic of the species in the wild; may be critical to the survival of captive bred animals reintroduced to the natural environment
define exploitation compeititon
indirect competition through use of shared resource
What is the Tragedy of the Commons?
individuals act of their own self interest, which negatively affects the population
clumped dispersion
individuals grouped together (most common)
Allee effect
individuals have a more difficult time surviving or reproducing if the population size is too small
Intrasexual Selection
individuals of one sex compete among themselves for mates.
How can you describe a random dispersion?
individuals position is independent of those of the others; typically solitary animals
regular dispersion
individuals relatively evenly spaced throughout habitat
What are ectoparasites?
infest the outside of the body
the most abundant type of organism is
insects
mutualism
interactions between individuals of different species that benefit both partners
define allelopathy
interference competition among plants by means of toxic secondary compounds
distinguish infraspecific and interspecific competition
intra: among individuals of the same species inter: among individuals of different species
resource competition
intraspecific or interspecific competition for limited resources, generally not involving direct antagonistic interactions between individuals
What is the relevant growth constant in a population with instantaneous population growth (exponential populations)?
intrinsic rate of increase
Example of enemy release: green crabs
invaded all around the world have a lot of parasites in Europe - parasitic castrators, parasitoids, egg predators, trophically-transmitted parasites in Australia, only have trophically-transmitted parasites
what is the general relationship between colonizing and competitive abilities?
inversely related
What is refugia?
is a location which supports an isolated or relict population of a once more widespread species.
What is the enemy release hypothesis?
is among the most widely proposed explanations for the dominance of exotic invasive species. In its native range, a species has co-evolved with pathogens, parasites and predators that limit its population. When it arrives in a new territory, it leaves these old enemies behind, while those in its introduced range are less effective at constraining them.
what is the driver of speciation?
isolation
How long does an overshoot last?
it depends on how many stored resources there are to support inflated numbers
What does seed selection do for the dispersing?
it increases the quality of dispersed seeds relative to available crop on trees
Carson and Root removed a beetle species from a community, resulting in a decrease in plant species richness. What does this imply about the beetle?
it is a keystone predator
What is unique about the water hyacinth?
it is able to clone itself and large patches are likely to all be part of the same genetic form
What does it mean for a species to be threatened?
it is likely to become endangered in the foreseeable future
What does it mean if R(0)=1?
it means that the females on average produce one daughter, replacing themselves; population is stable
What does seed deposition do for dispersing?
it reduces the seed predation risk
What results from the logistic model?
it results in a decreased rate of population growth as the population approaches the carrying capacity (K)
What does it mean for a species to be endangered?
it's in imminent danger of going extinct
What is a die-off?
its a substantial decline in density that typically goes well below the carrying capacity
What is life history?
its an organisms pattern of growth, development and reproduction
define population size...
its the absolute number of individuals present
Define a realized niche...
its the actual range of conditions under which a species persists
What is the gross reproductive rate?
its the average number of female offspring born to a female during her lifetime
What is diurnal?
its the daily movements of individuals
Define a fundamental niche..
its the entire set of conditions under which a population or species survive and reproduce
define active dispersal..
its the movement of the entire organism through its own ability
What is the MVP (minimum viable population)?
its the number of individuals necessary to ensure the long-term survival of a species (100+ years)
define population density...
its the number of individuals per unit area or volume (120 individuals/m^2)
What is carrying capacity (K)?
its the population size that particular environments can support
Define migration...
its the round trip movements of individuals among subpopulations
Because of population cycles, there is delayed density dependence, what is this?
its when the population density changes based on a population density at some time in the past
Peace & Grubb grew plants with and without the presence of fertilizers. what ecological phenomenon was displayed? what were the results of this experiment
joint influence of light levels and nutrients (synergy) -fertilized plants used light resources more efficiently than unfertilized plants -N and P were synergistic in promoting plant growth (together > each alone)
How does frequency dependent selection affect sex ratios?
keeps sex ratio 1:1 if males are less common, selection favors parents that produce more of them
In Sousa's marine succession, limpets (a grazing predator) acted as a _________
keystone species
what preys on juvenile guppies in headwaters
killifish
What forms of cooperation do lions exhibit
kin selection and inclusive fitness
in a life table, what represents how long with they be around?
l(x) which is the number (or %) of individuals alive at the age x interval; this is our survivorship. it is determined as a proportion of the original cohort (n[x]/n[0])
What are the values of lamda and N when a system is at equilibrium?
lamda=1 N=0
Logistic growth with large oscillations population cycles: size of r?
large
Levin's Classical metapopulation
large network: -of similar small patches -with local dynamic occurring at a much faster time scale than metapopulation dynamics -sometimes used to describe a system in which all local populations have a high risk of extinction
in Sousa's marine succession study, how were the patches colonized
large patches colonized by edible algal species, small patches by inedible algal species. Mussels ultimately dominated the large patches
What is the Endangered Species Act?
law intended to reverse the trend toward species extinction "whatever the cost"
To help us, what provides us a schedule of age or stage specific mortality and survival?
life tables
What is a ultimate explanation?
lifetime fitness consequence, evolutionary "explanation", what makes that response advantageous ex: snowshoe hares can reproduce once a month in warm weather -> ensures reproductive success if there's a late freeze or an early winter
resource limitation
limitation of population growth by resource availability
what limits male reproduction
limited by mate access
what limits female reproduction
limited by resource access
dispersal limitation
limited capacity for dispersal prevent species from reaching areas of suitable habitat
What is the relationship between life history traits and environmental conditions?
limited time and resources impose constraints and generate trade-offs environmental conditions may make life history traits more or less successful
What are some common factors for negative density dependent?
limiting resources such as food, nesting sites, physical space
isoclines of zero population growth
lines, in the graphical representation of the Lotka-Volterra competition model, where population growth of the species in competition is zero
In ecosystem development, _________ becomes more supportive of life
litter
How do you relate lamda to r?
log lamda = r
What is an example used in class for age specific birthrates?
loggerhead sea turtles
what are the concepts of ecological release?
low gamma diversity -density per species should be higher -habitats used per species should be higher -constraints on species are lifted
What is the survivorship of an individual with a type III survivorship curve?
low survival when young and high survival until later in life
stamen
male organ of a flower
Evolution of the sneaky male sunfish from parasite to mutualist
male sunfish mimic female sunfish and fool other male sunfish
intrasexual competition
male to male competition for mates among species
What is sexual dimorphism?
male-female differences, often due to sexual selection
What is haplodiploidy?
males are haploid; females are diploid present in bees to form social structures with drones (males produced by direct development) and queen/workers (females produced by sexual fertilization)
What is a great example when studying life history of a species?
marine turtles
Inherited Territory
may increase helper's probability of future reproduction and recruiting helpers
Do diseases cause extinctions?
may not be likely because disease transmission is density dependent - reduce infection when hosts are rare may be likely if reservoirs maintain parasites (either in the environment or alternate hosts)
What is generation time G or T ?
mean age of parents of all offspring produced by a single cohort See power point for formula
what does it mean when R(0)<1?
means that females on average produce less than one daughter; population is declining
what does it mean when R(0)>1?
means that females on average produce more than one daughter; population is growing
What does having a logistic (rT<0.37) mean?
means that the rate of population growth slows as population reaches carrying capacity. Populations remain stable at their carrying capacity unless some disturbances occur
selection coefficient
measure of the relative intensity of selection against a genotype; equals 1 minus fitness
Logistic growth with damped oscillations in population cycles: size of r?
medium
grandmother hypothesis
menopause evolved to switch women from investing in offspring production to investing in kin
What are examples of frequency dependent selection?
mimicry, prey search images
SIR model
models the spread of infectious disease Susceptible (hosts that aren't affected but could be) Infected Resistant (used to be sick, can't get sick again) -------------------- dS/dt = rS - ßSI dI/dt = ßSI - dI - (re)I - vI dR/dt = (re)I - dI -------------------- r = birth rate - death rate S = susceptible hosts I = infected hosts R = recovered individuals ß = infection rate v = virulence (how much infection elevates your death rate) d = death rate (not considering infection, just regular death rate) re = recovery rate = 1/infection duration
What type of organisms are plants? Meaning they are developed by branching or repeated units of structure
modular
what is limited at the local scale?
moisture availability and pH at the base of host conifer trees
What is considered multigenerational? (also seasonal)
monarchs in eastern N america. They fly from Canada and US to winter sanctuaries in the mountains of central mexico every fall. Populations return in the spring and summer for breeding. It usually involved 3 or 4 generations
Eusociality
more complex level of sociality
What is functional diversity?
more different roles makes a system work better because different tasks are getting done, making the system more EFFICIENT
describe the biodiversity patterns of mammals from west --> east in the US?
more species of mammals occur in the topographically heterogenous western mountains than in the more homogeneous east; decrease in diversity down the peninsula indicates the effect of dispersal distance
higher structural complexity supports (more/less) species
more! creates more habitats habitats with simple vegetation structure tend to have fewer species than more complex habitats with similar productivity levels
In the bat diversity study, how did they determine niche diversity from the local species?
morphological diversity in the bat community reflect the evolutionary response of the bats to this opportunity
what is most prominent in other age classes?
mortality
What's Robert Axelrod's explanation of "Tit for Tat" in evolution of cooperation?
most robust: 1. Cooperate first 2. Do what opponents did in last round
Chemoautotrophs
mostly prokaryotes that derive energy from the oxidation of inorganic compounds
negative phototaxis
movement of an organism away from light
positive phototaxis
movement of an organism toward light
emigration (-)
movement of individuals out of a population
What is functional redundancy?
multiple individuals fill a single role; makes populations more RESILIENT because if you lose one organism the function is still fulfilled
polygamy in animals
multiple mates at one time
How do you calculate a coefficient of relatedness?
multiply probability from each sex recombination
What is the major source of variation in prokaryotes?
mutation
What is lambda?
n(t+1)/n(t) value tells you the population growth rate
What's the difference between sexual selection and natural selection?
natural selection passes down traits by selecting by trait sexual selection passes down traits by selecting by mate
extrafloral nectary
nectar-secreting glands found on structures other than flowers, such as leaves
POSITIVE/NEGATIVE density-dependent effects occur if a vital rate decreases as density increases.
negative
With exponential decline, r is ?
negative
what are the two types of density dependent factors?
negative and positive density dependent
apparent competition
negative effects as a result of two species sharing a predator or herbivore or as a consequence of one species facilitating populations of a predator or herbivore of a second species
How can you describe uniform dispersion?
negative interaction among individuals; typically competition, territory between individuals
direct interaction
negative or positive interaction between two species, including competition, predation, herbivory, and mutualism, that occurs without the involvement of an intermediary species.
indirect interactions
negative or positive interaction between two species, including trophic cascades, apparent competition, and indirect mutualism or commensalism, that is mediated through a third species.
Evolution and influenza-a
new strains emerge every year from an animal reservoir (usually pigs in China) new strain is closely related to previous year's Host (human) immune response prevents outbreaks of old strains
Is density dependence a sufficient condition for a population to be regulated?
no
Is the habitat for most species continuous across the landscape?
no
What is indirect competition?
no actual contact, just using the same resource
Would we expect species that are closely related to coexist locally?
no- most closely related species tend to occur in different habitats
What does it mean for a species to be of special concern?
not a legal definition, but populations are declining for reasons that may not be understood
population size
number of individuals in a population
relative population size
number of individuals in one time interval or place relative to the number in another
abundance
number of individuals of a species that are found in a given area
population density
number of individuals per unit area
fitness
number of offspring (genes) contributed by an individual to future generations
What is fecundity?
number of offspring in a reproductive episode
what does the outcome of plant competition usually depend on and why?
nutrient levels in soil bc nutrients control growth of plant shoots and their ability to shade competitors
Heffaker's Predator-Prey Lab Experiment
o Manipulated number and distribution of oranges in a tray with oranges and rubber balls and observed dynamics of predator prey relationships between mites in different environmental conditions o Findings: ♣ If a predator has too easy of a time obtaining prey, prey populations plummet, eventually causing predator populations to plummet ♣ Stable population cycles can be achieved when the environment is complex enough that predators cannot easily find scarce prey ♣ Delays causing populations to cycle: • Result of predators moving more slowly between food patches than their prey • Result of time needed for predator numbers to increase through reproductions
In David Lack's experiment, how can we test whether a certain clutch size is associated with higher fitness
observational: compare survival of birds with different clutch sizes manipulative: manipulate the number of eggs in a clutch and see how many chicks fledge successfully
line transect approach
observer travels along a transect line and each individual that the observer can see from the line is counted and its perpendicular distance from the line is recorded
What is negative frequency dependent selection?
occurs between enemies one does better by avoiding the other
What is positive frequency dependent selection?
occurs between friends one does better when found by the other (partner fidelity and co-dependence_
Sweaty T-Shirt Experiment
odors influence human mate choice Females not on oral contraceptives sniffing the T-shirts recently worn by males favored the scent of those whose immune response genes were different from their own. Odor preferences of women on oral contraceptives were reversed as they favored the scent of men whose immune response genes were similar to their own, women prefer the scent of unrelated men
predation/parasitism
one species benefits and the other is harmed or affected
What are temporary parasites?
only on host to feed
What are permanent parasites?
only on the host to disperse
What is unique about woodhoopoes and breeding
only one pair breeds
Which is more likely to fall victim to the Tragedy of the Commons, common pool resources or an open access system?
open access system because there's no monitoring of the resources
What describes populations in which emigration and immigration occur?
open populations
how did continental drift lead to speciation
opening and closing of passage ways bridge for land mammals
What can be applied to life history?
opportunity cost, allocation and trade-offs
describe succession
orderly change in a community through time
In ecosystem development, progressively larger proportion of nutrients are held in ___________ rather than _________________
organic tissue; inorganic reservoirs
What is semelparity?
organism breeds once and dies, most are short lived
what are endemic species?
organisms that are only found in specific localities
What are mycoparasites ?
organisms that have the ability to parasitize fungi
dominant species (foundation species)
organisms, such as abundant forest tree species or coral reef species, that substantially influence community structure as a consequence of their abundance
What if a environment is very complex and predator can't get to prey what happens to the predator-prey population cycles?
oscillations in the cycles are damped
the second most abundant type of organism is
other arthropods
what maximizes genetic diversity?
outbreeding
deterministic model
output fully determined by parameter values and initial conditions
Inclusive Fitness
overall fitness, which is determined by the survival and reproduction of an individual, plus the survival and reproduction of genetic relatives of the individual
Who do we see having a type III survivorship curve?
oysters, fish, many invertebrates and many plants
Stable Prey Population (prey isocline)
p = r/c
Enemy Release Hypothesis
parasites and species invasions species have co-evolved pathogens in their native range and leave them behind when they invade (may have higher fitness outside of their native range because they leave all the pathogens behind)
Example of red queen: snails and parasites
parasites from native lake infect snails better than parasites from other lake lakes with more parasites --> sexual reproduction favored
What are hyperparasitoids?
parasitoids have their own parasitoids
beta =
per capita effect of species 1 on the population growth of species 2
alpha =
per capita effect of species 2 on the population growth of species 1
What does (1/N)(dN/dt) mean?
per capita growth rate
What is the allee effect?
per capita growth rate becomes smaller as the population becomes smaller; chance of extinction rises faster
direct fitness
personal reproduction
large-scale phenomena
phenomena of a geographic scale rather than a local scale
small-scale phenomena
phenomena that take place on a local scale
What is the nutritional mode of nearly all plants?
photoautotrophs
define passive dispersal..
plants and animals that can't move themselves use dispersal units to exploit new habitats
stress-tolerant plant
plants that live under conditions of high stress but low disturbance
BLANK occurs when one gene influences multiple unrelated phenotypic traits.
pleiotropy
loci
plural of locus
even though marshes have high productivity, why do they have low diversity in general?
poor vegetation structure
What is N(t)?
population at time t
What is N(t+1)?
population at time t+1 (the next generation)
What is lamda?
population growth rate
The logistic model growth tracks the current population size, but for population cycles....?
population growth tracks density relative to K at T units back in time
What is an example of abundance?
population of red deer in scotland remaining relatively stable for 30 years. The population of 200-400 individuals
Why are climate envelope models usually overly optimistic?
population range and distribution changes are not always predictable
What will happen if the A matrix remains constant?
population swill settle into a stable age distribution and a constant population growth rate (lambda)
What is interference competition?
populations behave in a way that reduces the exploitation efficiency of another individual or population
What is exploitation competition?
populations depress one another through use of shared resource
How does higher survival rates affect reproductive strategy?
populations have an older age structure, and hence they have a greater chance of selection for changes in survival or fecundity
define trophic levels
position in the food web determined by the number of energy transfer steps from primary producers
With exponential growth, r is ?
positive
how is species diversity correlated with niche diversity?
positively
stochastic model
possess some inherent randomness (same set of parameter values and initial conditions will lead to an ensemble of different outputs
Dilution effect and Lyme Disease
possible hosts: mice, opossums, squirrels, etc. How many infected ticks are removed by each host? - mice are the best hosts because others get rids of ticks or aren't capable of hosting the bacteria
The Dilution Effect
predator effects (removing infected individuals) - if predators make prey stay in one place, less likely to infect others - predators can prey on susceptible hosts - etc. Community interactions can affect any stage of epidemic more diverse hosts decreases infection rate because have more noncompetent hosts
Type III Functional Response
predator exhibits low prey consumption under low prey densities, rapid consumption under moderate prey densities, and slowing prey consumption under high prey densities
Phase graphs: What is q/beta in words ?
predator mortality rate/ predator growth rate per victim population
What were the results of Gause's experiments?
predator prey coexistence only possible with immigration of predators
What is a parasitoid?
predator that acts like a parasite but kills its host
Moran's study involved the effect of the number of predatory newts per pond on the relative weight and survival of different species of tadpoles. What did he find?
predators can influence the outcome of competition between prey species -at high predator numbers, the 3 tadpole species grew equally well -in the absence of predators, one species dominated the ponds and another species was nearly eliminated
What is P(hat)?
predators will maintain the victim population at 0 growth at victim per capita growth rate r and predator functional response (capture rate) alpha P(hat) = r/alpha
What is climate envelope modeling?
predicting the future of the climate using correlations between existing species distributions and environmental variables to define a species tolerance
plants are where in the food web?
primary producers
competitive exclusion principle
principle that states no two species can occupy the same niche in the same habitat at the same time
What does a straight line in a logarithmic scaled survivorship curve represent?
probability of dying doesn't change with age
describe facilitation. give an example.
process by which one species increases the probability of a second species becoming colonized N2 fixing by alder
Females
produce larger, more energetically costly gametes.
Monoecious plants
produce male and female flowers on the same plant
males
produce small, less energetically costly gametes
the precambrian era was dominated by
prokaryotes, protists, fungi, and invertebrate animals
What is the coefficient of relatedness
r quantifies kinship; shows probability of sharing a genotype
For the alternate form of the fundamental equation of population ecology you assume a closed population. What is redefined?
r = b-d
What is the r in stage or size-structured populations?
r = lnR(0) / G can be inserted into N(t) = N(0)e^rt
What does (1/N)(dN/dt) equal?
r(1-N/K)
What does dN/dt equal?
rN(1-N/K) r = per capita growth rate N = number of individuals K = carrying capacity
What doe stochasticity mean?
randomly determined
What is a realized niche?
range of ecological limitations ex: predators, diseases, food resources, competitors, mutualists, pollinators
What is a fundamental niche?
range of physical conditions of a population ex: climate, soils, water pH
ruderal plants
rapid growth, produces seeds quickly, good dispensers, high intensity disturbance, low stress, can easily disperse to newly disturbed environments
What does dN/dt mean?
rate of population growth
Phase graphs: What is r/alpha in words ?
rate of population growth of victims / loss of victims to predators (capture rate)
Which imposes stricter limits on a species' distribution: fundamental or realized niche?
realized
What is smaller? fundamental niche or realized niche?
realized niche; b/c of dispersal, competition, disease, herbivory, predation
ritualized antagonism _______ costs
reduces
self-thinning
reduction in population density as a stand of plant increases in biomass, due to intraspecific competition
What is a metapopulation structure?
regional group of connected populations of a species
What are population cycles?
regular oscillation of a population over a long period of time (overshoots and die offs)
What is Liebig's Law of the Minimum?
regulation of populations limited by the single resource that is most scarce.
define Liebig's law of the minimum
regulation of populations limited by the single resource that is most scare
What determine how quickly or slowly a population grows?
relative proportions of each age group
"Biodiversity Hotspots" are defined as areas which have
relatively high levels of both endemism and diversity of species
What does r represent in stage or size-structured populations?
represents the distribution of survivor ship and reproduction across a population
What are the tradeoffs between survival and fecundity for animals?
reproducing more NOW reduces chance of surviving to breed AGAIN
What is restricted in certain age classes?
reproduction
semelparity
reproduction that involves production of all an organism's offspring in one event, generally over a short period of time
what affects the biodiversity patterns of reptiles in the US?
reptiles are strongly influenced by the temperature gradient from south to north
What is R* in the R* model?
resource level at which population growth balanced by population loss
What is Hamilton's rule
resources will be diverted to kin when benefit to helper exceeds cost to help
sexual selection
results from differences in reproductive rates among individuals as a result of differences in mating success due to intrasexual selection, intersexual selection, or a mixture of the two forms of sexual selection
what did "the world is green" initially say when trying to figure out what controls the number of herbivores?
said it was top down since the world is green, there is plenty of food for them
What is an example of semelparity in animals?
salmon -> cost of migrating to breeding site is huge
Describe the colonization of Krakatau after a volcanic eruption caused a primary succession event
sea-dispersed species appear first, then wind-dispersed, then animal-dispersed after ~100 years, the highest number of species are the reverse
early successional species produce a ____________ of opportunistic seed waiting for the right moment for germination
seed bank
the paleozoic era was dominated by
seedless plants, insects, fish, amphibians, reptiles
What is an example of uniform dispersion?
segulls
Kin Selection
selection in which individuals increase their inclusive fitness by helping increase the survival and reproduction of relatives (kin) that are not offspring
serial monogamy
several mating partners, but only one at a each mating period
A pathogen NOT dependent on its first host to spread to its second host will tend to maintain?
severe virulence
Haplodiploidy
sex inheritance in which males are haploid and females are diploid
What is Fisher's principle?
sex ratios tend toward 1:1 See power point for explanation
Male
sex that produces smaller, lest costly gametes (sperm or pollen)
Female
sex that provides larger, more energetically costly gametes (eggs or ova)
What are the sources of variation for eukaryotes?
sexual reproduction mutation horizontal gene transfer transposable elements
Intrasexual Selection
sexual selection in which individuals of one sex compete among themselves for mates
Intersexual Selection
sexual selection occurring when members of one sex choose mates from among the members of the opposite sex on the basis of some anatomical or behavioral trait, generally leading to the elaboration of that trait
"Phylogenetic effects" refer to
shared characteristics, which are not driven by environmental factors, of a lineage of organisms
Vaccinations
shift infection to older individuals since they do not acquire immunity May only alter the amplitude and period of cycle (how severe and how often epidemics occur), not eliminate epidemics Begin vaccination --> decrease susceptible individuals until increase again --> infection (cycles)
how did continental drift influence climate
shifted from more arid to more humid
what is the energy flow web's approach to depicting trophic relationships?
shows connections quantified as energy
what is the connectedness web's approach to depicting trophic relationships?
shows feeding relationships among organisms
What are stochastic models?
shows natural variation in success, can predict extinction even when you have a positive r
What is a life cycle graph?
shows what happens in a population from one year to the next using fecundity and survivorship
random dispersion
similar to what would occur if individuals were positioned at randomly selected locations
genet
single genetic individual
Why does haplodiploidy favor the evolution of mating system in which female workers help rear their sisters?
sisters are more related than mothers and daughters; helps in passing on their genes
What can be more appropriate descriptors of a populations structure?
size structure/developmental stage classes
what are drivers for recolonization?
size, how close you are to what colonizes you
What is an example of a random dispersion?
slothes
Logistic growth with regular population cycles: size of r?
small
what was a huge issue for Darwin
sociality
What island did we focus on in the sea turtle lecture?
soloman islands
Garter snake female mimicry
some males release female pheromones that attract other males, which increases the mating success of the faker
Why do disturbances like flood and fire help in conserving species?
some species are dependent on these disturbances to survive fire: prevents underbrush from taking over; some species require heat/smoke for seeds to begin growing
dispersion
spacial arrangement of individuals in a population
What is a stolon?
specialized stems that grow above the ground surface
what is a rhizome?
specialized stems that grow below the ground surface
Tilman's Resource Ratio Hypothesis
species ability to maintain itself in a civility determined by level of limiting resource that results in zero net population growth
What is Tilman's resource ratio theory?
species ability to maintain itself in a community determined by level of limiting resource that results in zero net population growth (ZNPG)
what were the results of the resource diversity study using stream fish?
species diversity increases as a stream becomes larger and has more habitat and food diversity
What is PET thoery?
species richness increases with PET up to a certain threshold
What species survives when the resource ratio theory is applied to 2 competitors for a single resource?
species that can survive while driving resources below R* of competitor wins
What is a critical habitat?
specific area that has essential features for conservation of a species
Negative feedbacks are inherently STABILIZING/DESTABILIZING and AMPLIFYING/DAMPENING.
stabilizing, dampening
What do we get if rT is large?
stable limit cycles when rT>1.57
What does F stand for in a life cycle graph?
stage-specific fecundity; number of offspring per individual (probability of going from an adult to a seedling)
What does P stand for in a life cycle graph?
stage-specific survivorship (probability of going from one stage to the next)
heterogeneity
state of being dissimilar, composition from unlike elements
What is the survivorship of an individual with a type II survivorship curve?
steady decline in survival throughout life
What are kelptoparasites?
steals food from other organism
How do asexual modular organisms spread?
stolons and rhizomes
What is cyclic succession driven by?
stressful environmental conditions
SIR model and influenza
strong seasonal driver (temperate zones, etc.) --> consistent peaks (why we know when flu infections are likely to pick up) Weakly seasonal driver (close to equator) --> inconsistent peaks
describe seral stage
structure of a community at a given moment during the sere
What is demography?
study of changes and distributions of population sizes
Behavioral Ecology
study of social relations. interactions between organisms and the environment mediated by behavior
Behavioral Ecology
study of the relationships between organisms and environment that are mediated by behavior
The life table and fecundity tables from lecture (in the powerpoint) shows us which stage is least effective to focus on conservation and protection?
sub adults?(can't remember)
spate
sudden flooding in a stream
describe the disturbance and gap dynamics (aka intermediate disturbance hypothesis) theory explaining why there are so many kinds of trees in the tropics? why isn't this theory appealing?
suggests that moderate disturbance would increase environmental heterogeneity, increase opportunities for gap pioneer specialists, etc. -trees die at same rate in other systems -gap invaders were not primarily gap specialists
What is s(x)?
survival rate s(x)=P(x-1,x)
What can negative density dependence impact?
survival, fecundity and dispersal
What is l(x)?
survivorship l(x)=l(x-1)*s(x-1)
In the net reproductive rate R(0) formula what is l(x)?
survivorship at age x
What is endosymbiosis? Example?
symbiosis in which one of the symbiotic organisms lives inside the other. -mitochondria and chloroplast
mychorrhizae
symbiotic association of plant roots and fungi
parasitism
symbiotic relationship between a parasite and its host
source sink
system where at low density, there are subpopulations with negative (in the absence of dispersal) and positive growth rates
What is a open population?
takes into account immigration and emigration along with births and deaths
What do male lion contribute
territory defense
natal territory
territory where an individual was born
drift
the active or passive downstream movement of stream organisms
realized niche
the actual niche of a species whose distribution is restricted by biotic interactions such as competition, predation, disease, and parasitism
net reproductive rate (R0)
the average number of female individuals produced by a female in her life span
what is an example of diurnal?
the coast jellyfish individuals migrate about 600 meters per day tracking plankton prey
Hamilton's Rule
the conditions under which helping kin should be favored by natural selection: RgB-C>0 Rg: genetic relatedness of the helper and the recipient of the help B: reproductive benefit gained by the recipient C: reproductive cost to the helper of giving aid
Why os polygyny more common than polyandry?
the cost of making eggs higher than making sperm
What does the decreased growth rate in the logistic model result from?
the decrease in birthrates and increase in mortality
how is diversification measure?
the difference between extinction and speciation
age distribution
the distribution of individuals among age groups in a population; often called age structure
describe the continuum concept
the distribution of species along an environmental gradient
niche
the environmental factors that influence the growth, survival, and and reproduction of species
pistil
the female organs of a flower, comprising the stigma, style, and ovary.
sexual selection
the fitness advantage that some individuals have over the same sex solely with respect to reproduction
Distribution
the geographic range of an organism or the spatial arrangement of individuals in a local population
Clements supported which concept of community?
the holistic concept
Fundamental Niche
the hypervolume, the physical conditions under which an organism can live.
Gleason supported which concept of community?
the individualistic concept
amensalism
the interaction between two species whereby one species suffers and the other species is not affected
What is the amplitude of a population cycle dependent on?
the intrinsic rate of growth (r) and the time late between resource use and reproduction (T)
describe tolerance
the lack of influence by one species on another; poor competitors can tolerate each other
What is frequency dependent selection?
the less common phenotype has an advantage helpful in avoiding predation and diseases
what does active dispersal depend on?
the local population size, resource competition, and habitat quality and size
what is defaunation?
the loss of animals from ecological communities
intrinsic rate of increase
the maximum per capita rate of population increase; may be approached under ideal environmental conditions for a species
what is beta diversity?
the measured turnover in species competition from one habitat to the next within a region
What is ecological time?
the minute-to-minute time frame of interactions between organisms and the environment
MacArthur and MacArthur used foliage height of plants to look at bird species diversity. What did they find?
the more diversity in foliage height, the more bird species that can be supported
What is the relationship between phylogenetic relatedness and resource portioning?
the more related you are, the more you partition resources -->Evolve to use different resources
Senescence
the natural physical decline brought about by aging, accumulation of molecular defects and harmful mutations
what is species richness?
the number of different species represented in an ecological community
clutch size
the number of eggs laid by a bird, reptile, amphibian, or fish. The term is also sometimes applied to the number of seeds produced by a plant.
fecundity
the number of eggs or seeds produced by an organism
density
the number of individuals in a population per unit area
birthrate
the number of individuals produced in a population generally expressed as births per individual or per thousand individuals in the population
What is ideal free distribution?
the number of individuals that aggregate in an area is proportional to the resources available there
What is fitness?
the number of offspring that survive and reproduce; involved passing on +/- genes to future generations
describe local diversity?
the number of species in a small area of homogenous habitat
What is parity?
the number of times an organism reproduces during its lifetime
Equation for predator population growth: dP/dt = beta x V x P -qP What is Beta x V?
the numerical response of the predator population
allelopathy
the phenomenon of an organism producing a substance that is harmful or lethal to another organism
fundamental niche
the physical conditions under which a species might live, in the absence of interactions with other species
What is habitat complexity and why is it important?
the physical structure of an environment, influences community composition in a number of ways. Complex habitats can promote species coexistence by providing a wide range of niches, thereby reducing niche overlap and increasing diversity
What is an example of age structure?
the population of red deer in scotland contain many 2-8 year old females
What is sympatric speciation?
the process through which new species evolve from a single ancestral species while inhabiting the same geographic region
Reproduction (+)
the production of offspring
geometric rate of increase (lambda)
the ratio of the population size at two points in time lambda=N_(t+1)/N_(t) N_(t+1)=size of the population at some future time N_(t)+ size of pop at earlier time
What is the founder effect?
the reduced genetic diversity that results when a population is descended from a small number of colonizing ancestors.
What happens when a population size increases with negative density dependent factors?
the resources would be divided among more individuals and per capita resources will decline to a level at which individuals find it difficult to grow and reproduce
Realized Niche
the restricted conditions under which an organism does live due to interactions with other organisms.
Eltonian niche
the role of a species in its community
What are life history traits?
the schedule of an individual's life include behavioral and physiological adaptations; ultimately affect fitness
describe character displacement
the shifting of a realized niche depending on the other organisms inhabiting that area
colonization cycle
the situation in which stream populations are maintained through a dynamic interplay between downstream drift and upstream dispersal
define a species pool
the species that occur within a region
germination
the sprouting of seeds
Grinnellian niche
the sum of the habitat requirements that allow a species to persist and produce offspring
describe inhibition
the suppression of one species by another (can create the "priority effect")
Abundance
the total number of individuals, or biomass, of a species
lifetime reproductive success
the total number of offspring produced by an individual over the course of a lifetime
describe regional diversity?
the total number of species observed in all habitats within a barrier-free geographic area
describe ecological diversity
the variety of habitats, niches, trophic levels, and community interactions
describe species diversity
the variety of species present in an area; includes the number of different species that are present as well as their relative abundance
red to far red ratio
the wavelengths at which a plant's photoreceptor pigment react
human carrying capacity
theoretical estimates of the number of humans who could inhabit Earth at the same time, increases with improving technology
another paper rejected "the world is green." what did they say?
there are a lot of things herbivores can't eat, so it has to be bottom-up control
How does negative density dependent factors affect populations?
these factors decrease the rate of population growth as a population density increases
what affects the biodiversity patterns of trees and amphibians in the US?
these species are strongly influenced by the moisture gradient from east to west
What are the soloman islands important for in regards to sea turtles?
they are important nesting sites for endangered marine turtles; its the longest single species monitoring effort in the south pacific
what do adult male scorpionflies do to attract mates
they collect dead arthropods and guard them. and then show them off to females as skilled to show off their collection skills
philopatry
they do not move much
When do die-offs occur?
they occur when a population overshoots its carrying capacity
Why do we use log scales for survivorship curves?
they tell us about proportions, and show what proportion is still alive
How do ecologists use life tables?
they use them to examine systematic patterns of mortality and survivorship within populations
How can we think of populations to better understand them? why?
think of them as being analogous to a swinging pendulum; populations are only stable at their carrying capacity (K) when dN/dt=0. The momentum of the increasing and decreasing in a population relative to K causes it to oscillate in size
explain the MacArthur-Wilson Equilibrium Model for Island Biogeography?
this model compares immigration and extinction rates as a function of patch size and patch isolation; heterogeneity of the habitat is not considered
How many types of survivorship curves are there?
three types
meristematic tissue
tissue made up of the actively dividing cells responsible for plant growth
niche model
tool that predicts a species' geographic distribution based on the environment conditions at locations the species is known to occupy
in ________________ control, consumers depress the trophic level on which they feed, indirectly increasing the next lower trophic level
top-down
What factors are considered density independent factors?
tornadoes, floods, hurricanes, extreme temperatures, and droughts
what is the evidence for the "diversity increases without limit over time" view on tropical biodiversity?
tropical habitats, being older than temperate and arctic habitats, have had time to accumulate more species
true or false: temporal variation in the environment can influence competitive interactions
true competition can exist because of temporal changes in conditions
define the competitive exclusion principle
two species cannot coexist indefinitely on the same LIMITING resource
What is the competition exclusion principle?
two species cannot coexist indefinitely when the same resources limits both
what are complete competitors? do they exist?
two species that live in the same place and that possess exactly the same ecological requirements no
How can you describe a clumped dispersion?
uneven distribution of resources asexual reproduction and social groups; typically the most common mode of dispersion
spatial heterogeneity
uneven distribution of various concentrations of each species within an area
Most animals are what type of organisms which exist as unique individuals?
unitary
What is environmental stochasticity?
unpredictable spatiotemporal fluctuation in environmental conditions
environmental stochasticity
unpredictable spatiotemporal fluctuation in environmental conditions
alturism
unselfish regard for the welfare of others
What can we do to get the birthrate?
use a fecundity table
define competition
use or defense of a resource by one individual that reduces the availability of that resource to other individuals
fecundity tables...
use the survivorship column l(x) from the life history table in addition to b(x); multiply b(x) by l(x) that gives us mortality; the value l(x)b(x) is the mean number of females born in each age group adjusted for survivorship
How does population viability analysis estimate extinction risk over a time period?
using data on the age or size structure of population of threatened species
per capita rate of increase (r)
usually symbolized as r, equals per capita birthrate minus per capita death rate: r=b-d
reproductive value
v(x)=(number of offspring produced by individual of age x or older)/(number of individuals of age x)
demographic stochasticity
variability in population growth arising from sampling random births and deaths, in small populations it risks extinction
describe biodiversity
variety among organisms and ecological systems at all levels of organization
What is a generalist?
versatility with prey, host, or partner
total fitness
viability+fecundity+longevity+mating success
after endlers experiment what where the results?
water without predators resulted in colorful males.
describe the holistic concept of community
we can only understand each species in terms of its contributions to the dynamics of the entire system assumes discrete communities
the more crowded a population, the (stronger/weaker) the effects of competition
weaker
"The World is Green" was used to describe
what determines the number of herbivore individuals
When does an overshoot occur? why?
when K of a habitat decreases from one year to the next ( a delay between a change in environmental factors and the time the population reproduces) because resource availability varies
So when is a population stable?
when a population is at its carrying capacity; dN/dt=0
What is ideal free distribution?
when individuals distribute themselves among different habitats in a way that allows them to have the same per capita benefit -as more individuals increase, patch quality decreases -at one point poor patch with few individuals and good patch with alots of individuals can be equal
What is a dominance hierarchy?
when individuals order themselves by social rank or status (within a group)
describe a trophic cascade
when the indirect effects of consumer-resource interactions extend through additional trophic levels of a community
When does positive density dependence occur?
when the population is at low densities; making it order for individuals to find mates (the sex ratios are uneven)
When will altruistic behaviors evolve?
when they give greater inclusive fitness than purely selfish behavior
What is coevolution?
when trait evolution depends on interactions with other species species fitness depends on its phenotype AND phenotype of other organisms
What is Mullerian mimicry?
when two species are poisonous and they look similar to reinforce the effects of each other (cuckoo bee and yellow jacket)
what is senescence?
when you loose reproductive output over time and become weak and die
according to the MacArthur-Wilson Equilibrium Model for Island Biogeography, where does the number of species on an island occur?
where there's a balance between extinction and colonization
what dispersal units do passive dispersal use?
wind, water, animals capable of active dispersal
who often controls sexual selection
women
In a life table, what determines who's in our population?
x and n(x) where x is the age of the individual and n(x) is the number of individuals alive at the beginning of the age x interval
What is on the axis of a survivorship curve?
x: time y: number of individuals
Can factors be limiting at different scales?
yes
Can the parasitism-mutualism continuum shift over evoluntionary time?
yes
Is birthrate age specific?
yes
T/F; you're going to pass this exam
you know it's true.
what is the modification of the Lotka-Volterra model for each species that takes into account the competitive effect of one species on the population growth of another?
α= coeficcient of competition N2= number of species 2 αN2= effect of species 2 on species 1 (same with β and N1)
What is a closed population?
○ Can only grow through natural increase (difference between births and deaths at a given time) -no immigration or emigration
Top Predators:
♣ Consume both herbivores and mesopredators ♣ Ex: wolves, mountain lions, sharks
Mesopredators
♣ Relatively small carnivores that consume herbivores ♣ Ex: coyotes, weasels, feral cats
