BISC302: Exam 2
Population size and growth
- a function of *survival* and mortality - (births + immigration) - (deaths + emigration) = population size - the balance of these determine population size and change • growing, stable or declining
How an organism is suited to live in a particular place is called: a) competition b) adaptation c) addition d) participation
b) adaptation
Epizootic Paper: An epizootic is ... a) an external parasite of an animal species b) an epidemic disease in a population of an animal species c) a disease that can be transmitted from animals to humans d) any small disease-causing animal, like a mosquito e) none of the above
b) an epidemic disease in a population of an animal species
Epizootic Paper: The disease in the paper ... a) is only known to affect house finches and domestic poultry b) is caused by a bacterium c) originated on both coasts of the US simultaneously and has move toward the middle d) appears to have different effects in different populations of finches e) all of the above
b) is caused by a bacterium
Which of these is a correct food chain? a) fish< fries< ketchup b) man <cow <grass c) cow >slaughterhouse >supermarket d) cow <Milk< Man
b) man <cow <grass
Rabbits are important grazers, maintaining some important grassland habitats. If another catastrophe were to reduce rabbit populations what would happen? a) important grassland butterflies would be lost b) there would be more grass for the surviving rabbits c) the grassland would be invaded by trees and shrubs d) all of the above
b) there would be more grass for the surviving rabbits
Size and Scaling are important constraints
- *allometry*: when one thing grows faster/more than another • proportional size of a babies head to its body º our body cannot sustain isometric growth - *isometric*: same rate of growth - surface area/volume ratio is important • surface area (of a cube) → area of side X # of sides • volume (of a cube) → length X width X height • SA/V = _____ units • a greater ratio interacts more with the environment º increase ratio with folding - solutions? (adaptations) → for exchange • want to maintain homeostasis
What is an individual?
- *genet*: a colony of plants, fungi or bacteria that come from a single genetic source; a group of genetically identical individuals (plants, fungi, bacteria etc.) that have grown in a given location, all originating from asexual reproduction of a single ancestor; a group of ramets; refers to a group of ramets that originate from a single seed - *ramet*: a physiologically distinct organism that is part of a group of genetically identical individuals derived from one progenitor, as a tree in a group of trees that have all sprouted from a single parent plant; refers to a single physiological individual produced by clonal propagation
Secondary Sexual Characteristics
- *monomorphic*: look similar (males and females) - permanently *dimorphic*: look different (mature sexes distinguishable) - seasonally dimorphic → mature sexes distinguishable ONLY at spawning time - *polymorphic* • multiple morphs of each gender • different looks of the gender (variety)
Mating System
- *promiscuous* • MOST COMMON • both sexes with multiple partners • little courtship rituals • no durable associations - polygamous • *polygyny*: males with multiple female mates º very common → sperm is cheap and can service many females º many reasons/variations ↳ leks → courtship behaviors, guys displaying ↳ resource defense → male controls resources ↳ harem defense → females ARE the resource ↳ male dominance → females don't have a choice, taken advantage of ↳ female choice → courtships, choosing whom the female wants to mate with (quality of sperm/traits) º 97% of all mammal species ↳ takes a while to reproduce ↳ females have to take care of the kids, males continue to mate º more female mates = better quality/characteristics of the male • *polyandry*: females with multiple mates º rare, but more common in birds º double-clutching º probably because of the high cost to females of producing young → do not have the energy to raise the kids, and would rather spread them out (more kids spread out, increases the likelihood that at least some will survive) º males do the choosing, raising the kids, making the nest, etc. • *monogamous*: mating pair remains together over time º *lifetime* → breed with the same mate until you die º *seasonal* → pair up in the future depending on if it was successful breeding with good offspring, NOT = move on º *serial* → within a season, stay with until you raise offspring then switch to another mate if needed º every monogamous system studied shows at least some cheating (both ways)
What limits growth?
- *stochastic* (random) processes especially important in small populations and early on - occur at the beginning of the J shaped curve • genetic drift • inbreeding • allee effect
Influences on population dynamics
- *stochastic* processes → random processes (storm/abiotic factors) - deteriorating habitat → droughts - introduced species → invasive, competitors, predator, etc. - human activities → oil spills, pollution, logging - *allee effect* • ex: hyenas/ wild dogs • important for sexually producing organisms • when population gets to low (declined) it is really hard to find a mate to reproduce (hard to recover from) • once it is too small it is hard to recover from
Quadrat Estimation
- N(estimate) = [N(count)]/ (proportion of habitat sampled) • proportion of habitat sampled = size of area
Limiting Factors
- a resource that is *scarce* relative to its demand • ex: time, supply & demand, water, nutrients - living organisms must adapt to the limitation, become better at "mining" the resource, or not be present in that location • must adapt to the limit • migrate away from those conditions or adapt - the *law of limiting factors* (law of the minimum) → changes based on the environment • how fertilization works (nutrient cycling) • the *most limited* factor determines if the organism will be there º determines species range - organisms with *NARROW* ranges of tolerance are often referred to as *indicator species* • some aspect of the environment causes a change • canary bird: sensitive to gas (coal miners) º indicate bad in the environment because of the low range of tolerance - range of tolerance can change over time → adapt over long periods and can get used to the fluctuations (acclimate) - there may be *synergistic* effects of these factors • greater impact • eg. heat and humidity º put the two together = miserable - can alter tolerances through *acclimation* • isozymes, heat shock protein • adaptation → change in the genome - there are limits to abilities to acclimate • typically genetic - the *threshold* effect → cannot make the next adjustment so the species die-off - may have the ability to escape harsh variables (migrate away) - evolve (only a long term solution) • evolution takes a long time to happen - *adaptation* — compared to/with acclimation • a long-term solution → genetic • only occurs in populations → NOT individuals
Abiotic Factors
- abiotic = non-living things - biotic = living things (breathing)
Trade-offs shape life histories
- among 3 aspects of reproduction • maturity → physiologically capable • parity → how many times you can reproduce • fecundity → how many offspring you reproduce
Indicator species
- an animal or plant species that can be used to infer conditions in a particular habitat
Trade-off
- between somatic (growth) and reproductive growth - increasing the number of eggs increases fitness but decreases the chances of surviving until the next year (less E into growth) - mayflies and salmon (reproduce once and die) - all energy into reproducing - between the number of offspring and their "maturity" at "birth" • more eggs → less energy stored in eggs → less developed - *altricial*: less developed at birth (opossum) • more offspring • needs a lot of energy after birth - *precocial*: very developed at birth (horse) • less input of energy after - parental care • increases the probability of offspring survival º due to reduced predation risk º due to increased access to food ↳ provisioning/teaching them • costs energy — energy *fecundity* º reduce the ability to produce a lot of kids • takes many forms º brood hiding (behavioral) → tuck kids away, less obvious º nest guarding (behavioral) → keeps predators away and deters away from the nest ↳ "broken wing" tactic º internal gestation (physiological) → giving all resources, guard and protect
Abundance
- can be estimated in a number of ways including .... • *quadrat estimation*: mean ± standard deviation º even = similar; clumped = vary (big or small) º accuracy varies º square area • *point count/ transect estimate/ ...* sample environment • *mark-recapture*: tags, wires, sticky tags, etc. º N = [2nd sample size (number marked)]/ number recaptures - techniques vary depending on characteristics of species of interest (must recognize mark) • mobility: immigration/ emigration • life-span: average lifespan - need to recognize (and address) assumptions of techniques
More with life tables
- can use life table to calculate R0 (net reproductive rate) • if R0 > 1 = population growing • if R0 < 1 = population declining - also calculate T (generation time) = [∑x • Lx • Bx]/[∑Lx • Bx] • average age to give birth • rate of population growth INCREASES with a smaller T value (younger mothers) º the greater the T value the SLOWER population growth occurs (older moms)
Mark-recapture Estimation
- catch individuals, tag them, recapture then see how many marked and unmarked that was captured - issues • ear tags ripped off and torn, etc. can show inconsistency (mess up estimate) • likelihood of recapture º trap happy → benefits from the resources ↳ not giving chances ↳ denominator high ↳ "a low" estimate º trap-shy ↳ can be traumatic ↳ avoid these areas that correspond to the traps ↳ abundance number becomes low ↳ "a lot" of species = a high estimate - mobility • mark-recapture for mobile species • quadrat for non-moving species - lifespan • short lifespans use a quadrat
Can build life tables
- cohort (dynamic) or static (time-specific) - table in notes • x = age class (years, months) • Nx = numbers (at a specific age) • Lx = survivorship • Dx = deaths (any period) • Qx = mortality rate (Dx/Nx) - *cohort*: group of individuals in a given time period (ages) • something in common = age • dynamic → follow until the individual dies (good for short life expectancies º follow as it changes each year - *static*: look at a specific time (take a picture) • use this for species that have long life expectancies - survivorship • Nx/N0; the number of individuals of the ORIGINAL population still alive at the time we are interested in
Cost of Males
- males are not super important because 1 male can create a lot of offspring
Survivorship Curves
- conditions affect the life curve "switch" - plot [log] survivorship vs. age (gives shape) - gives the percentage of the cohort surviving at each age - three types of general patterns • *Type 1* = high survivorship when young (parental care) than die off as you get older º ex: humans • *Type 2* = equal chance of dying each year º ex: birds, squirrels • *Type 3* = huge infant mortality, but if you make it past those years you have a high change of living to old age º ex: fish, sea turtles, trees
Temperature
- controls physiological activity → denaturation - high temperatures • denature enzymes, may lead to dehydration, osmotic stresses (loss of water) - low temperatures • slow down reactions (kinetics slow down), affect properties of membranes (permeability), slowing functions - microclimate: what affects smaller organisms/species, etc. - macroclimate: big climate situations • what we pay attention to
Two general patterns of population growth
- dN = change in number; dt = change in time - J-shaped (*exponential*) • dN/dt = rN; r = reproductive rate/ reproduction, N = population size • but some factors become *limiting* — possible outcomes? • effects of density → more individuals means a fast rate of running out of resources - S-shaped (*logistic*) • dN/dt = rN [(K-N)/K] º K = carrying capacity → the max number of individuals a habitat can support indefinitely • exponential growth early on but checked/plateaus by natural factors - relationship between N and K • N < K: [(K-N)/ K] close to 1 → exponential • N = K: [(K-N)/ K] = 0 → growth is at zero so it is at a plateau • N > K: [(K-N)/ K] is neg → growth is declining (coming back down)
Abundance (size/number) and Density (per area/ volume)
- define the size of the population - estimates are very dependent on *dispersion* pattern • hard to count every single one so estimates are used
Sometimes populations cycle
- delayed density dependence → don't know how close they are to K - predator-prey dynamics - reproductive time lag → gestation period • shorter reproductive cycle better at predicting K º short life spans estimate S shaped curve better - genetic factors: genetic diversity (competition)
Principle of Allocation
- divide amongst the functions - all organisms must distribute their limited resources to one of life's functions (growth, reproduction, strength, etc.) - evolutionary *tradeoffs* → natural selection pushes into certain directions - therefore most organisms perform best under a *limited* range of conditions (including thermal) • recall optimum zones
Density *Independent* Factors
- does NOT rely on the amount in the population (density) - factors that do NOT tend to increase population size when they are small and decrease it when they are large, have the "same" effect on population regardless of its size - variation in weather → fire, drought, storm, etc. - abiotic factors • exception: humans → we hunt no matter what until we get to the point of extinction
Point count/ transect estimate/ ...
- draw a line and walk along to determine individuals within the area → transect - a specific point → point count
Logistic Growth
- equation: dN/dt = rN [(K-N)/K] - describes changes in intrinsic (dN/dt) growth rate - exponential phase then a plateau phase (level off at K) then a decline phase (occurs when you go above the carrying capacity and need to get back down) - where is the highest rate of increase? • growing the fast at the inflection point • where N is half of K, then will slow down - environmental resistance is connected/fluctuates around K - why? • K = carrying capacity - do NOT know the actual value of K • it is not a constant (especially in temperate zones) • fluctuates with abiotic and biotic factors • humans can provide food aid/help to the communities (try to change K by increasing it), unethical but better for the "excess" to die off - can see where we are doing environmental damage
Uniform/ Evenness pattern
- evenly spaced individuals - what would lead to this type of pattern? • usually *direct interactions* among individuals • competition for resources • can have multiple patterns in one area (understory shrubs clustered) - example: Northern Gambit nesting colony • 2 nests and 2 beaks apart
Behavioral adaptations for reproduction
- female choice • sexy-son hypothesis → females choose hottest male with expectation of their offspring to be hot and have a lot of their genes passed on º based on looks • runaway sexual selection → drives evolution (showy) º female choice → female looks at physical characteristics to be passed on (i.e. elk antlers) º expensive for the males º good at getting resources = good quality, a lot of adaptations to survive/handle change • handicap principle º able to maintain quality = have good genes, but using outside features º may look good but sperm may not be - courtship — color, size, movements important • driven by female choice
Population characteristics
- geographic range — distribution • where do you find it - dispersion: patterns you find in individuals in a population - density: the number of individuals in an area - size - age structure: young, middle age, old - does not make sense in individuals
Density *Dependent* Factors
- have a *greater* effect when the population is large and a *lesser* effect when its small • ex: food, diseases, resources, predators º cut down density to cut down the spread (diseases) º crowding effects size º more females nesting = less surviving because of habitat availability, food - tend to be biotic factors - result in population regulation • fluctuate together around K • prey increases = predator increases → prey decreases = predator decreases
Animals need energy and nutrients
- herbivory (plant-eater) vs. carnivory (meat-eater) vs. omnivory (both) → reduces competition • changes gut morphologies in the species - gut specializations • hindgut/foregut *fermentation* º hindgut = back end → *coprophagy*: eating fecal matter that has the nutrients from the microbes º foregut = front end → microbes break down grasses (in cows), throw it back up to rechew and swallow the cud and then send them through the body to absorb nutrients - mineral needs (salt, etc.) • especially in the spring for herbivores → plant growth high in potassium influences kidneys to hold onto sodium and having high potassium and losing magnesium is bad • need sodium (natural salt licks) - large intestine absorbs water, the small intestine absorbs nutrients - *secum*: out pocket of the digestive tract • houses microbes to digest food (break down) º nutrients cannot move backward, so (rabbits) reingest it for the nutrients the microbes released
Regulating body temperature
- how is heat exchanged? • *evaporation*: recall latent heat transfer (always lose heat) • *conduction*: in contact with another thing • *convection*: recall sensible heat transfer º with the environment/atmosphere • *radiation* → gain or lose heat • *metabolism* → always gain heat - equation: • body heat = metabolism ± conduction ± convection ± radiation - evaporation → Hs = Hm ± Hcd ± Hcv ± Hr - He
To maintain homeothermy
- in cold: • shiver (generate body heat) • increase metabolism (glucose intake) • *vasoconstriction* → blood vessels don't have to move to places that lose a lot of heat • *pilomotor* response → puff up fur/feathers, thicken coat (goosebumps on humans) • huddle (other behaviors) → share radiation º can overheat in the middle º make yourself as small as you can (decrease the SA/V ratio) - in the heat: • evaporate (sweat) → get rid of water, panting (in dogs), not as much energy • *vasodilate* → increase blood vessel size º elephants → ears give off heat to cool off, convection with a fanning motion
Exponential Growth
- intrinsic rate of increase (r) or reproduction - but conditions in nature are rarely ideal for long → run out of resources, space, etc. causes a die off - causes growth to depart from exponential - mosquitoes during a dry spell will cause a die off - boom and bust cycles (0/low numbers to large numbers) - equation: N=N0 e^rt
Investment in Gametes
- investment = resources and energy - *isogamy* ("iso" = same) • sexes and gametes are roughly the same sizes º algae, fungi - *anisogamy* ("an" = not) • females produce FEW expensive gametes º costs more per unit → in nutrients, energy • males produce MANY cheap gametes - predict for anisogamous species? → courtship ritual is an example • females should be choosy • males should not — mate whenever possible - conflict with anisogamy is that females are VERY selective with their mates because they want the best partner to create offspring that are able to survive, and since female eggs take a lot of resources to produce they do not want an unfit partner to fertilize their eggs
Counter-Current exchange
- keep blood vessels near the interior of the appendage to exchange heat with other blood vessels and NOT the environment - cold blood isn't good for recirculation - good for conserving energy (keep phalanges cool) - cool blood to not denature proteins
Random pattern
- lack of predictable pattern • NOT symmetrical, lines, etc. - absence of attraction or aggression • environment is homogenous so it doesn't matter where you land - not very common in nature • NOT a lot of environments are the same • NO interactions, least common
Mortality and Survival
- mortality rate → proportion who die in a given year - survival • survival rate → used more frequently to show how many make it to the next year • life expectancy → how long to expect each individual to live - life tables • describe differential population growth (and to describe what is going on in the population) • include age, mortality rates, number surviving at each age, often fecundity, etc. º survivorship: proportion surviving º fecundity: births
Gender System
- most species are *gonochoristic* (single-sex, fixed at maturity) → cannot change their gender • may be genetic or environmentally determine º ex: (environmental) turtles are temperature-dependent gender determination species ↳ cold temperature = male and hot temperature = female ↳ can create a mixture depending on the depth of the egg in the burrow • implications for global warming º increasing the temperature = favoring one gender = decrease in the other gender - *parthenogenic* • females copulate, but don't use sperm • fertilize their own eggs • do meiosis for gametes • may not have males in the population • "virgin births" • asexual reproduction • pro → in a stable environment • con → in a variable environment - *hermaphroditic* • *simultaneous*: functions as male and female at the same time º pros → ex: earthworms cannot see since they do not have eyes so it's easy to mate if you have both parts • *sequential*: start life as one sex, change sex after maturity º *protandrous*: male first, female later º *protogynous*: female first, male later - resources for hermaphrodites • takes more energy to make eggs so species switch genders to save energy/be resourceful • ex: clownfish are protandrous since sperm is cheaper and uses fewer resources to make - protogynous is advantageous when ... • life-span (short lifespan will do this to be able to reproduce) • territorial species (small female to big male)
Clumped/Clustered pattern
- not even or random - organisms are found in groups • ex: a school of fish, trees, sea stars - what would lead to this pattern? • *patchiness* of resources → around certain areas migrate to those areas • aggression or attraction → reason to be together º *aggression*: defense against predators, better in groups º *attraction*: always have a mate, social interactions • MOST common in nature º Northern Gambit rocks are clustered, but the actual birds are even (based on viewpoint)
Parity
- number of episodes of reproduction in a lifetime - do not confuse with life span terms: • *annuals*: live only one year º reproduce only in one season (marigolds) • *biannuals*: live through AT LEAST one non-breeding season (wild carrots) • *perennials*: live multiple years - *semelparous*: reproduce only once (then you usually die) • NOT the same as annual • pour all of their energy and resources into the offspring (either many or well developed offspring) º ex: Northern Quoll (males put ALL their energy into mating, fighting, etc.), Blanchard's cricket frog, and century plant • cost of reproduction is too high to repeat • extreme or unstable environmental conditions º tundra, desert, droughts, monsoons, etc. - *perennials*: live many years • *iteroparous* º live and reproduce over many years, repeat reproducers º continuous breeders → humans, don't worry about the resources available º seasonal breeders → produce when most successful, enough resources
Fecundity
- number of offspring produced/ breeding episode • survive less in individuals with more offspring - what are the trade-offs? • maximize current and future reproduction • more now, less later (offspring) • more energy into them, less into me - siblicide? • killing your sibling • masked booby example → older sibling kills younger one • why? º more nutrients for the one that survives º have another kid as a backup plane (spare)
Determinate (birds, elephants, humans, mammals) vs. Indeterminate growth (trees, koi)
- often related to fecundity • number of offspring/ attempt - *determinate*: no increased fecundity with size • will stop growing once it reaches the adult size - *indeterminate*: increased fecundity with size • produce more when bigger • continue to grow over lifetime (based on provided environment)
Dispersion pattenrs
- pattern species that end up in - 3 patterns • uniform/ unevenness • random • clumped/ clustered - what you see may depend on the distance from which you're looking (pattern depends) • viewpoint determines the pattern - affected by resources, dispersal, behavior • resources → clustered, food, water, and habitat • dispersal is the act of moving
Life History Patterns
- patterns of growth, development, and reproduction - *fitness*: results in evolution (your genes that are passed on) - what strategy would you use to maximize your fitness? - there are *tradeoffs* between growth and reproduction - *allocation*: of energy/resources must be between survival and reproduction (metabolism/somatic growth vs. reproductive growth) - adaptations to biotic factors (other organisms) • in addition to abiotic ones (environmental conditions) - results in phenotypic *plasticity* • *polyphenism (spadefoot toad tadpoles) • *plasticity*: change in the look of the species, but has the same genes and DNA º environmental → metamorphize fast to survive (tadpole example) º chemical → from predators - mutation, recombination, and immigration of genes can lead to variation in a population - types of reproduction is a basic life-history trait • sexual → other organism is needed • asexual → can be done by yourself º many plants can do both - most protists, prokaryotes and many "higher" organisms reproduce *asexually*, at least at times - other organisms reproduce *sexually*
Population Abundance
- populations vary in space and time (some dramatically) • mayflies: only live a day • hummingbirds: migration - relative population size (more, less, about the same) • compare two time periods, or locations using an index of population size (# of bird calls) ... - annual surveys interested in is more or less then previously
Maturation
- put energy into themselves first (mature later) - the age at first reproduction • earlier reproduction can have more cycles, yet they are smaller so they have fewer offspring • older maturity = greater fecundity - influenced by longevity • short life-span = mature early - long-lived: expect to reproduce annually for many years → late maturation, grow instead • ex: tortoise • energy and resources put into themselves - short-lived: must reproduce quickly, higher proportion of energy goes to reproduction • ex: lemmings • go quickly to maintain the population size • smaller chance of longevity which is why they mature fast to reproduce - bad survival rate = won't wait to reproduce, so they do it early - good survival rate = put energy into growth and reproduce later
Impacts of Abiotic variables
- recall terrestrial biomes • depend on climate (temperature and precipitation) — vary with latitude (and altitude) • plants (and animals) have adaptations that enable them to live in certain conditions - each species has an *optimum* level (or zone) for each variable • impact organisms (physiology) • bell curve - entire range over which a species can survive is its *range of tolerance* • high and low extremes = limits - high and low extremes are the limits of *tolerance* and between the limits and the optimum are *zones of stress* (physiological) • specific levels of (healthy) stress amounts to do work and relax
Strategies for dealing with extreme changes
- relocation/ migration • leave for a better location - storage • *stockpile*: hid food to maintain metabolic rate • *store fat*: on your body - dormancy/*hibernation*/torpor/estivation • depends on biological rhythms º circadian/circannual • *dormancy*: a period in an organism's life cycle when growth, development, and (in animals) physical activity are temporarily stopped; this minimizes metabolic activity and therefore helps an organism to conserve energy; dormancy tends to be closely associated with environmental conditions • *hibernation*: a way animals conserve energy to survive adverse weather conditions or lack of food; it involves physiological changes such as a drop in body temperature and slowed metabolism º requires you to act like a poikilotherm • *torpor*: a state of lowered body temperature and metabolic activity assumed by many animals in response to adverse environmental conditions, especially cold and heat • *estivation*: long-term torpor during summer for survival of hot and dry periods º burrow down, make a cacoon, lower body rate until resource comes back
Age Structure
- shows beneficial reproductive age - humans are around steady/stable (like a column) - likely to grow when the base is big - differential population growth → decline, stable, increase - differential birth/ mortality rates - differential reproductive output - figure out the contribution of each age group → offspring - sex ratio may change over time → females typically live longer • mammals - males generally shorter (males move) • birds - males generally longer (females move) - *dispersal*: moving around • emigration → into a place (move out) • immigration → out of a place (move-in)
Reproductive traits that vary with life-history patterns — *Frequency*
- single spawning effort in life (*semelparous*) • partition effort for metabolic efficiency (offspring amount over growth) • maximize fecundity • match offspring to ideal growing conditions º want to give offspring an ideal environment to live • overwhelm predators º some will survive • risk waiting too long (dying too early) - repeated spawning efforts (*iteroparous*) • increase chance to spawn before dying (energy into yourself first) • spread offspring over multiple entry times º different environmental advantageous/disadvantages for offspring • reduce fecundity to ensure SOME reproduction
Life history strategies
- so once you've found a "mate" - there are tradeoffs between growth and reproduction → allocation and fitness maintain you OR offspring - back to *allocation* — of energy/resources must be between survival and reproduction (metabolism/somatic growth vs. reproductive growth)
Comparing outcomes of regulating body temperature
- spacial heterothermy: keep specific areas at different temperatures • sharks → keep certain muscles warmer because it works better - endotherms are usually homeotherms - ectotherms are usually poikilothermic - very few ectothermy homeotherms (where temperature stays stable → the tropics)
Why reproduce sexually in the first place?
- takes a lot of energy and resources - the cost of *meiosis* → splitting up genotype into two daughter cells - *outbreeding* depression → too different = offspring not suited for that environment - but ... • *Red Queen* Hypothesis → stay one step ahead of parasite, disease, etc. and the offspring will be fit enough to survive against it º variability can help resist diseases º mutations create a more resistant pattern in offspring • variability among offspring º not all are susceptible to predation, disease, etc. ↳ assume some will survive º survival of the fittest
Sexual Terminology
- terms ending in *"gamy"* (= spouse) • refer to the number of partners or characteristics of gametes - terms ending in *"gyny"* (= woman) • refers to females - terms ending in *"andry"* (= man) • refers to males
Homeotherms
- the *thermoneutral* zone: the range of ambient temperatures without regulatory changes in metabolic heat production or evaporative heat loss • not working to maintain metabolism • low, stable metabolic rate • low critical temperature (LCT) and an upper critical temperature (UCT) º UCT → need to increase metabolic rate to cool off, but generating heat warms you up - surface area/ volume ratio importance • lose more heat • LCT/UCT varies - increasing metabolism generates more heat - homeothermic = stable - *hypothermia*: run out of energy to crank up metabolism, body temperature drops and freeze (harder to stay cool when you warm-up) - *hyperthermia*: heat denatures enzymes (not sustainable) • tropical species do not do well in the cold, and arctic species do not do well in the heat
Geographic Range
- the distribution of a population in space • within the range the distribution is still *patchy* • also includes the entire life cycle (birth → death) • abundance varies throughout the range as well º density: widespread, clusters, even within a range - why is a population found where it is (based on range)? why not in other places? • *habitat* → not appropriate environment • *biotic interactions* → predators, dangerous competitors, parasites • *dispersal ability* → can't get to the location (distance, other factors), overcome by humans • *behavior* → individuals have a habitat preference based on familiarity, preferences (water, warm/cold, mountains) • *history* → the location isn't suitable, haven't gone there (need help), fires/floods/disturbances & successions - use niche models to predict current and future distributions • variables preferred and see if species can survive • aware of GIS (soil, temperature, wind, etc. and map them to see a pattern)
Population ecology
- what is a population? • definition: a group of individuals in a species in an ecosystem; in a specific location and the potential to interact on a daily basis - individual = must define what you are classifying as an individual - interactions are important
Mechanisms that determine body temperature
- where heat is coming from MECHANISMS - *endothermy*: uses heat generated by internal mechanisms • metabolism to maintain body temperature - *ectothermy*: use environmental sources to control body temperature • sun radiation, cooling in the shade OUTCOMES - *homeothermy*: maintain same body temperature no matter the environment • humans - *heterothermy*: change in body temperature (hibernate) • bats • temporal → overtime changes (day/night) º a lot of energy ex: the hummingbirds high SA/V ratio • drop/raise body temperature based on saving energy - *poikilothermy*: goes/follows with the environment • cold-blooded • reptiles
T/F: Freshwater habitats are independent of terrestrial habitats
False
T/F: An ecosystem consists of biotic and abiotic factors
True
T/F: An organism's niche includes its habitat
True
T/F: Clearing a forest would reduce the amount of energy available to the consumers
True
T/F: Cutting down trees in a forest alters the habitat of the organisms living in the forest
True
T/F: While an understanding of the interactions between organisms and their environment was very important to early hunter and gatherer humans, it is even more important today because humans are having significant effects on the environment
True
Pupfish Paper: Which of the following conditions caused a shift to a morphology more like the Devil's Hole species (smaller with a larger head, no pelvic fins ...)? a) food restriction b) cooler water temperatures c) increased salinity d) increased thyroid hormone levels e) all of the above factors caused this shift
a) food restriction
'Biodiversity' is described as: a) the range of different species in an environment b) the seasonal and daily changes in an environment c) the way species differ from one another d) the influence of physical factors on an environment
a) the range of different species in an environment
A habitat is: a) a place to buy furniture and furnishings b) the same as an ecosystem c) a particular area inhabited by plants and animals d) the number of different organisms living in a specific area
c) a particular area inhabited by plants and animals
The biggest impacts are made on the environment by: a) the migration of organisms b) predation c) human interference d) competition
c) human interference
Pupfish Paper: This study primarily examined ... a) ultimate causes of phenotypic plasticity b) descriptive answers to questions about different phenotypes of pupfish populations c) proximate causes of phenotypic plasticity d) the natural history of one population of pupfish e) none of the above
c) proximate causes of phenotypic plasticity
All the energy in a food chain originates from: a) plants b) farmers c) the Sun d) an electric outlet
c) the Sun
The arrows in a food chain show: a) who eats who b) the route of food to the shops c) the movement of energy between organisms d) heat energy being lost
c) the movement of energy between organisms
Epizootic Paper: Identify the mismatched pair ... a) threshold prevalence :: ≥ 20% b) house finches :: introduced to the eastern US c) highest finch populations :: first to be affected by disease d) conjunctivitis :: introduced to control growing finch populations e) none of these are mismatched
d) conjunctivitis :: introduced to control growing finch populations
Pupfish Paper: Phenotypic plasticity ... a) only affects external anatomical phenotype b) is unrelated to genetic variation within a species c) is directly responsible for speciation in pupfish and Darwin's finches d) is seen in the pupfish morphology, their behavior, and their physiology e) always results in an irreversible shift in phenotype
d) is seen in the pupfish morphology, their behavior, and their physiology
Epizootic Paper: Which of the following statements is TRUE according to the paper? a) the only explanation for the associated declines in finch abundance is density dependence b) all populations of affected finch declined in abundance following infection c) theory predicts that disease should always result in stable density-dependent regulation of host populations d) it appears that this disease has a comparatively low rate of transmission in the wild e) none of the above statements are true
d) it appears that this disease has a comparatively low rate of transmission in the wild
Pupfish Paper: The pools and springs of Death Valley ... a) are good habitats for small fish, being relatively stable, protected from predation and rich in nutrients b) are basically stable in size since they don't depend on regular rainstorms for replenishment c) dry up for a period annually and have to be constantly repopulated by fish d) are freshwater habitats resulting from rain and runoff e) are primarily artesian (groundwater-based)
e) are primarily artesian (groundwater-based)
Epizootic Paper: The study obtained its data ... a) by monthly surveys of the bird population size b) from the annual bird count held around Christmas time c) from reports of diseased birds at specific locations d) by trapping birds and recording what proportion were diseased e) both b and c
e) both b and c
Pupfish Paper: Identify the mismatched pair ... a) goitrogens :: interfere with thyroid function b) morphological changes in refuge populations :: phenotypic plasticity c) paedomorphic :: Devil's Hole pupfish d) territorial behavior :: AVT hormone e) pupfish :: 5-6" long as adults
e) pupfish :: 5-6" long as adults
