Ecology Md 1

3 general types of selection occur in pops. using a freq distribution to represent the variation of a trait w/in a pop, illustrate the 3 types of selection and explain how they occur.

1. Directional selection- traits favored by selection are at one end of the distribution causing a shift in allele freq to a new optimum. 2. stabilizing selection- traits favored by selection are those near the average, causing allele freq to remain stable 3. disruptive selection- traits favored by selection are alternative traits at either end of the distribution (extremes) and cause the allele freq distribution to bcm bimodal

under a prescribed set of conditions the freq of any given allele in a pop will remain constant or in equilibrium over time. this is called Hardy Weinberg equilibrium. 5 conditions must be met to achieve the equilibrium in allele freq. name the 5 conditions required for a pop to remain in equilibrium (not evolve)

1. NO gene flow/migration 2. large pop size 3. no mutation 4. random mating 5. no natural selection

what are the 3 themes that are fundamental to ecology

1. evolution- adaptation 2. ecological systems don't necc achieve equilibrium- homeostasis. 3. human impact on the environment and ecological processes

Darwin made a simple and cogent argument for natural selection as a mechanism of evolution. describe the 3 empirical observations that Darwin made upon which he based his argument and the logical deduction that follows from these observations.

1. individuals of a species vary in their traits and that this variation was heritable. 2. Organisms produce more offspring than survived 3. role of competition in nature and the degree to which competition for limited resources acted to limit individual survival and reproduction consequence; the most competitive individuals would persist and reproduce, whereas those that are not would die. over time individuals with these traits will bcm more common in the pop.

a scientist measures beak length in a pop of hummingbirds and discovers that the most common beak length is 3 cm. after 10 generations of stabilizing selection, the most common beak lengths in this hummingbird pop is/are most likely to be?

3 cm bc it said stabilizing selection

how did a major drought affect beak depth in the pop of medium ground finches on Daphne Island?

A severe drought occurred (caused by La Nina event). The drought caused greater mortality of plants producing small than large seeds. Birds with smaller beaks suffered greater mortality than large beaked birds, thereby increasing the proportion of large beaked birds in the pop

the illustration of a mountain range 10,000 ft elevation showing an ocean to its west and the prevailing wind direction. a. for each lettered location in the diagram (A-D) describe the temp and ppt conditions you would expect to occur at each location and why what is this phenomenon called?

A. high temp and low or median ppt B. median temp and high ppt C. low temp and median ppt D. highest temp and lowest ppt Rain shadow effect

as an air mass rises it bcms cooler. what is this phenomenon called? explain why this happens.

Adiabatic cooling. Adiabatic cooling happens when an air mass expands with increasing altitude (and thus bcms less dense). As the rising air bcms less dense, its internal energy decreases (traps less heat from its surroundings). This causes the air to cool. Adiabatic cooling causes air to cool at an average of 6 C per 1,000 meters of elevation but it can vary.

what is the greenhouse effect and how does it occur? Explain why the greenhouse effect is important to life on Earth.

CO2 and other gases in the atmosphere absorb heat (IR) energy that is radiated off Earth surfaces. its important bc the heat trapping capacity of CO2 and other atmospheric gases keeps the temp of the Earth's atmosphere in a range that is conducive to life

what type of selection was evidenced in this pop of ground finches? what evidence can you site to support your answer?

Directional selection. this is evidenced by the observed shift in the freq distribution of beak size toward one end of the distribution for that trait

why is summer solstice in the northern hemisphere in June and the summer solstice in the S hem in December? how does the Earth's tilt cause this seasonality?

Earth's tilt causes seasonality bc the solar radiation density (thus heating) on the Earth's surface varies annually. In the N hem the max tilt of the Earth is toward the sun in June (summer in N hem winter in S hem) whereas the S hem the max tilt of the Earth is toward the sun in December (summer in S hem winter in N hem)

under certain conditions long term geographic separation btwn two pop of the same species can result in speciation. How could such a pattern of evolutionary divergence occur?

Ensatina salameanders in CA descended from a common ancestral pop in Oregon. starting about 5 million yrs ago the ancestral species spread southward at mid elevations in the coast ranges and sierra nevade forming a ring. as the salamanders migrated S, sub pop bcm adapted to local conditions that varied. Adjacent sub pop are able to interbreed but those occurring on either side of the southernmost part of the ring either can't interbreed or do so. this reproductive barrier is likely occurred bc the pop had been separated for a long time and thus diverged genetically to the point where they were reproductively isolated

what drives global air movement?

Hadley cells

if experimental data are consistent with a hypothesis does this prove the hypothesis is true? Why?

NO. just bc a set of data are consistent doesn't prove that hypothesis. bc other hypotheses could be developed that are also consistent with the experimental results. Its important NEVER to say that a hypothesis was proved

is a pop w/ the following genotype freq in Hardy-Weinberg equilibrium? explain your answer.

No. the equilibrium is satisfied only when the genotype freq of the 3 genotypes defined by the equation p2+2pq+q2= 1

Name and describe the diff hierarchical levels of organization in ecological systems.

Organismal population community ecosystem biosphere

Do individuals or pop evolve through the process of natural selection? Explain

Pops evolve NOT individuals. natural selection is the process in which individuals who are better adapted to their environment survive and reproduce more offspring than those whose are less will adapted. bc natural selection occurs at the level of the pop, the pop is considered the unit of evolution

what is the relationship btwn proximate and ultimate factors in ecology and evolution?

Proximate + ultimate factors explain observed phen and cause and effect at diff levels.

what is the diff btwn a gene and an allele?

a gene is a heritable sequence of DNA that codes for a particular characteristic of an organism (ie flower color). an allele is on of two or more ALTERNATE forms of a gene (ie white, purple)

define: community

a group of op of diff species living and interacting w/ one another in a given area; exhibit interspecific interactions, such as competition, predator-prey relations, mutualism -a group of coexisting species.

define population

a grp of individuals of the same species that occupy a given area; pop are dynamic and fluctuate in size over time; the pop is the unit of evolution -interactions btwn a grp of indiv of a given species and the environment

using an organism give an example of a trait that varies among individuals ie hair color speed and likely increases fitness in its environment

a plant example production of an anti-herbivore defense chemical; the level of chemical defense can vary from one plant to the next; this helps defend it against insect herbivores; individuals that are better protected than others will likely exhibit increased fitness. ie; speed, beak size all vary btwn individuals

define adaptation

a trait that increases an individuals fitness in a specific environment

what is absolute fitness? relative fitness? how are they measured?

absolute fitness- total number of surviving offspring an individual produces in its lifetime. its quantified accordingly. relative fitness is derived from the ratio of the absolute fitness of a particular genotype divided by the absolute fitness of the fittest genotype

what is a stress according to Grime?

any external physical factor that would limit the ability of the plant to grow ie; climate (temp and ppt) and the presence of high concentrations of toxic heavy metals in the soil

define habitat

any place where an organism lives that meets the requirements for its survival and reproduction

how does the Coriolis effect influence global wind patterns? in turn how do these wind patterns determine ocean circulation in the Pacific Ocean?

as air moves from high to low pressure the Earth moves underneath it making the air curve to the right. in the N hem as air moves toward the equator it curves to the right and runs along the equator in an E-->W direction. As the winds move across the ocean they drive ocean currents in the same direction. In the N hem ocean currents circulate in a clockwise direction whereas in the S hem they circulate in a counterclockwise direction

how and why does the relative humidity of an air mass change as it moves up a mountainside? Explain what you expect to happen to water vapor in such a rising air mass

as an air mass rises it cools due to adiabatic cooling. as it cools the relative humidity increases. if the air mass continues to rise its relative humidity will increase. when the relative humidity reaches 100%, the water vapor will condense into fine droplets to form clouds. when those droplets of water bcm heavy enough they will fall as ppt.

why is natural history important in ecology?

bc info gathered through careful natural history observations are essential to developing informed hypotheses about causal mechanisms in ecology that can be tested through experimentation

why does a 1km2 area that is located btwn -+ 10 latitude receive more solar energy greater solar heating than a 1 km2 area located btwn 40-50 latitude?

bc solar radiation hits the Earth's surface more directly. at 40-50 latitude solar radiation is spread out across a larger area compared to -+10 latitude and thus has a lower solar radiation density than the -+10 latitude region

explain the scientific method and its key steps

body of methods used to investigate phenomena, advance understanding and revise understanding of previous knowledge. its key steps include: observation, hypothesis testing, measurement and experimentation, analysis of results, and conclusion

Grime's 3 axis model defined 3 reproductive life history strategies in plants. For each of Grime's life history strategies describe the ecological conditions that select for that life history strategy

competitive- selected for when there is low stress and low disturbance. under these conditions plant growth, survival and reproduction are limited more by competition with other species than they are by external stressors or periodic disturbance stress tolerant- selected for when stress is high and disturbance is low. under these conditions plant growth, survival and reproduction are limited most by physically stressful conditions. Ruderal- selected for when there is low stress and high disturbance. plant growth, survival and reproduction are limited most by freq periodic disturbance

what moves wind currents?

coriolis effect

what is mid-latitude deserification? how and why does it occur?

desert climate tends to occur at 30 N and 30 S due to descending warm dry air at these latitudes bc the warm dry air masses are descending at these latitudes due to hadley cell circulation.

define proximate factors

direct, immediate causes and their ecological effects on organisms. ex: decreasing day length in the fall signals deciduous tress to re-translocate nutrients and drop their leaves.

the range of color patterns in Mimulus flowers. these patterns serve as nectar guides for pollinators. Name the kind of selection occurring in this plant species and explain why it occurs in this species.

disruptive selection bc two contrasting traits are selected for simultaneously while the intermediate traits are selected against. disruptive selection occurs bc two types of pollinators visit the flowers and each exerts diff selection pressures on the morphology of the nectar guides. insects prefer large guides pointing toward the center of the flower and hummingbirds small heart shaped guides.

Abiotic factors in environment continually change from one location to another. Mean annual temp decreases with increasing altitude; intensity of photosynthetic radiation declines with increasing water depth; soil moisture content tends to diminish with increasing distance from a water body; you will see a ecological response curve. using an abiotic factor/condition draw the ecological response curve you might expect for a species across the range of that condition.

elevation vs. performance for a plant species. it assumes that performance will drop off rapidly at the lightest elevations. reproduction would likely occur at the narrowest and most optimal range than growth and survival.

what is the goal of hypothesis testing?

elimination of incorrect ideas ex to weeding out process, which will ultimately lead to better understanding of how a system works. hypotheses allow us to make testable predictions. either our predications will hold true or they will be falsified through experimentation

what does the ecosystem exhibit?

energy fluxes and cycling of nutrients

what is the diff btwn an environmental factor and a resource?

environmental factor- ability of organism to survive grow and reproduce but is not actually USED by the organism. across the range of conditions that any species experiences, there will be an optimal range of conditions/factors over which it can thrive (achieve adequate growth/reproduction). resource- component of the environment that an organism USES and that is necc for its survival growth/reproduction. ie plants take up N in the soil and carnivores consume their prey. both N and prey are considered resources bc organism uses each. Soil pH in the case of plants and temp of carnivores would be environmental factors bc they influence the survival, growth and reproduction but aren't used by the organism

what is a disturbance according to Grime?

event or factor (either physical or biological) that reduces plant biomass

name some characteristics of a species that can be used to define its ecological niche

foraging location food size nesting location seasonality vegetation type

the realized niche of a species can diff substantially from that of its fundamental niche. what is the diff bwtn these niche spaces and how is each determined?

fundamental niche- full range of resources it can use to survive and reproduce without interference from other species. realized niche- actual observed niche a species occupies in the face of interactions with other species that limit its use of resources it might otherwise be able to use. the fundamental niche can only be measured by removing other species that are presumed to interfere with the focal species' use of resources and then quantify the ranges of resources it uses w/out those interactions. the realized niche can be measured by quantifying the ranges of resources the species uses in the presence of interactions with other species.

In terms of 5 conditions explain how deviation from this condition would lead to a shift in allele freq in the pop over time.

gene flow- movement of individuals and thus alleles into or out of a pop will alter allele freq in a pop genetic drift- chance deviation from expected allele freq are more likely to occur in small versus large pop mutation- mutation introduces new alleles into a pop random mating- changes in freq of homo vs hetero allele combinations. natural selection- selects some alleles over others; eliminates alleles that are maladaptive.

Genetic drift (non-Darwinian evolution) is a phen in which random changes in allele freq occur in pop over time. under what conditions is genetic drift most pronounced in a pop?

genetic drift is most common in small populations bc of chance alone

individuals in a pop vary in their genotypes and in their phenotypes. what is the relationship btwn genotype and phenotype? its ever possible for individuals with the same genotype (clones) to have diff phenotypes? explain

genotype- sum of genes in an individual phenotype- physical expression/appearance of the genotype phenotype is influences by both the genetic make up of the person and its environment. Yes its possible for individuals w/the same genotype to diff in phenotypes. due to the range of influences that the environment can have on the expression of the genotype; the possibility of a genotype to give rise to diff phenotypes under contrasting environmental conditions called phenotypic plasticity

the niche concept is a central concept of ecology. how does the concept of the niche differ from that of a habitat?

habitat is a physical place where a species lives, the niche is an abstract space (graphically) that is defined by the conditions it requires and the resources it uses

which of the following is required for evolution by natural selection?

heritability time genotypic variation selection

what is the consequence of high niche overlap for 2 species using a single resource? what effect can high niche overlap have on the evolution of traits in 2 such species?

high niche overlap results in a high intensity of competition btwn the species for those limiting nutrients where the niche of the species overlap. in evolution terms, when intense competition occurs bwtn 2 species where their niche overlap it can create strong directional selection that reduces niche overlap and therefore competition btwn the species.

define organismal level of organization

individual organism and its interactions /the environment; the individual is the fundamental unit of ecology

can loss or fixation occur in a large pop?

its possible but highly unlikely bc large pop have many individuals and thus copies of alleles. the high # of alleles in the gene pool of a large pop makes it unlikely that all alleles of a particular gene could be lost or fixed.

why did finches with large beaks have higher fitness than those with small beaks?

large beaked birds were able to crack open the large hard seeds, whereases smaller beaked birds in the pop couldn't. As a consequence, birds with larger beaks survived better and had greater reproduction (fitness) than smaller beaked birds.

what is a life history strategy? give an example

life history strategy- set of life history traits/pattern of growth, life span, timing and quantity of reproduction a species has that are adaptive for the species in its specific ecological setting.

small number of lizards from a large mainland pop establish a founder pop on an island. the genetic diversity of lizards in this founder pop is likely to be ___ the mainland pop

lower than the mainland pop bc the founder effect; isolated location and start a new pop (chance event), reduce genetic variability and have genetic drift

what is the rainshadow effect in general?

more ppt fall on the windward than the leeward side of a mountain range.

what are two sources of genetic variation in pop other than natural selection?

mutation genetic drift/migration

what evolutionary forces could cause the color diff observed among subspecies of the Ensatina salamanders?

mutation and natural selection are most likely to introduce new color variants in the pop

explain how mutation can introduce genetic variation into a pop. What is mutation pressure?

mutations introduce new alleles. they can be harmful, neutral, or beneficial. mutation pressure is the change in allele freq caused by the intro of new mutations

In ecology, what is meant by the term interaction?

network or web of relations that exits among organisms of the same and diff species in an ecological system, as well as the relationship organisms have w/their physical and chemical surroundings. ex temp, ppt, nutrients, pH, salinity, dissolved oxygen ect...

what does natural history involves?

observing and describing plants, animals and microbes as they occur in their natural environments.

What are the 4 postulates of Darwin regarding natural selection?

organisms produce more offspring than survive some organisms variability is heritable organisms vary genetically from one another some survivors are better suited to the environment than others.

what is the H-W equation?

p2+2pq+q2=1

for the adaption you chose describe a quantitative measurement you could take to determine its fitness.

plants; defense chemical, # spines, photosynthesis rate; animals running speed, beak size, claw length fitness: # seeds or seedlings produced (plants); # cubs per litter, # eggs laid or fledglings (birds), # flowers per plant

what are 3 features makes for a good hypothesis?

predictions that are testable through measurement and experimentation. its also must be falsifiable. this means that a result through measurement and experimentation must be possible that will demo that the hypothesis is not supported (false) 1. predictions 2. falsifiable

what is the principle of allocation? how does it lead to trade offs among reproduction growth and survival?

principle of allocation- predicts that organisms should balance out their allocation of energy to reproduction, growth and survival. this leads to trade-offs bc energy allocated to survival is not available for growth or reproduction and energy allocated to reproduction isn't available to survival and growth. the degree to which a species allocates energy to one of these life history properties over another (its pattern of energy allocation) has evolved in response to its environment. see r-K as example

r-selected theory attempts to explain the variation in reproductive life history strategies based on the degree to which the species experiences a more stable and thus competitive environment or a more variable disturbed environment. what king of general reproductive strategy is emphasized in an r-selected species? a k-selected species?

r-selected species- QUANTITY of offspring over quality k-selected-QUALITY of offspring over quantity

explain why these life histories produce the types of growth curves they do. for r and k selected species.

r-strategist-shows pattern of periodic high and low abundance which reflects the temp nature of the availability of suitable resources/habitat. k-strategist- shows a more stable pop over time which reflects a resource base/habitat that is relatively more constant. NOTE: the pop crash and then recovery of the K strategist illustrates the concept of carrying capacity; after some kind of disturbance (ie fire or hurricane) the pop will tend to return to a stable size that can be supported/carried by an otherwise more or less stable environment

list 2 traits of an r-strategist and 2 traits of a k-strategist. how might those traits be selected for in the two contrasting ecological conditions?

r-strategist; high reproductive rate short lived rapid development, small body size, high # of offspring, min parental care. Strategy of quantity over quality. habitats that are variable in their resource availability; it allows the species to quickly exploit newly available habitats. habitats that experience high levels of disturbance have high but variable resources and where competition is low. K-strategist- few offspring, long lived, slower development and growth rates, delayed reproduction, large body size, more parental care. strategy of quality over quantity selected for in habitats that are stable but competitive. habitats that are more stable and in which species stiff competition for limited resources

which set of ecological conditions selects for each of these two r-selected or k-selected reproductive strategies?

r-strategists- habitats that experience high levels of disturbance have high but variable resources and where competition is low. k-strategists- habitats that are more stable and in which species stiff competition for limited resources

on a rocky intertidal shores, the distribution of the barnacle Chthamalus is restricted to the drier upper intertidal one by competition from below by Balanus. Bc of its interaction with Balanus, the niche of Chthalamus is called an

realized niche

define homeostasis

regulatory mechanisms that maintain an organism's physiological parameters within specific limits

air masses circulate globally. what causes these air masses to circulate?

solar heating is highest at the equator. this causes air masses to rise near the equator and circulate in very large atmospheric cells that range from the equator to around -+ 30 degrees latitude. these equatorial cells are called Hadley cells, and they drive global air movement

Grime developed a 3-axis model for plant reproductive life history strategies based on the types of ecological pressures they face. According to Grime which 2 main factors are plants limited by?

stress and periodic disturbance

evolutionary fitness

survival and reproduction determined by its characteristics

two plant species co-occur in an oak savanna. one is fairly long lived and produces few large seeds. the other is short-lived and produces many small seeds. what are the trade off of these 2 life histories?

the advantage of producing few large seeds is that each seed has a store of energy reserves that increases its chances of survival after germination (ie in face of low light, low nutrients, or competition with other species). the trade off is that large seeds aren't easily dispersed to new locations bc of their weight and so the plant sacrifices dispersal (colonization of new habitats) for increased seedling survival. on the other hand, small seeded species benefit from high seed dispersal bc of their small size but these seeds suffer high mortality once they germinate bc they don't have enough energy reserves to survive very long and compete in locations where nutrients or water are limiting.

define ecosystem

the biotic community and its abiotic environment fxing and studied as a system;exhibits energy fluxes and cycling of nutrients

define adiabatic cooling

the decrease in air temp that occurs at higher elevation or altitude

define selection pressure

the environmental factors biotic and abiotic that determine fitness

What did CKH conclude about the source of phenotypic variation in Yarrow?

the height variation in yarrow across this elevation gradient is due to a combination of genetic and environmental influences. yarrows from the high elevations maintained their small stature, suggesting that genotype determined their growth. the other yarrows showed phenotypic plasticity in their growth when planted at locations other than where they originated suggesting that the environment was primarily responsible for their growth form

what is the fundamental unit of ecology?

the individual

in an El Nino year, normal climate conditions throughout the Pacific Ocean can be altered. What happens in an El Nino year?

the ocean thermocline in the eastern Pacific Ocean would move deeper -more freq fires on islands in the wester Pacific Ocean -increase flooding and unusually warm temp in Ca -a reduction in upwelling off the coasts of Ca + Peru -decrease in ocean productivity off the CA coast bc decrease upwelling

what are two possible consequences of genetic drift in a small pop?

the pop loses genetic variability and it's more susceptible to extinction

what is the unity of evolution?

the populations

define natural selection

the process in which individuals who are better adapted to their environment survive and reproduce more offspring than those whose are less will adapted

two plant species co-occur in an oak savanna. one is fairly long lived and produces few large seeds. the other is short-lived and produces many small seeds. which species is most likely an r-selected and which species is most likely a K-selected species? Explain in terms of principle of allocation AND the kind of environmental conditions to which these two life histories tend to correspond.

the short lived small seeded species is r-selected bc it allocates less energy to longevity/survival and more energy to reproductive output and dispersal. the long lived large seeded species is K-selected bc it allocates more energy to longevity and competitive ability but less energy to reproduction. r-selected species tend to occur in habitats that are short lived and relatively unoccupied, so there is a premium on dispersal to newly established locations ( like following a disturbance) where resources are generally not limiting and there are few other species (noncompetitive situations) k-selected species tend to occur in habitats that are more stable (that is more long lived and constant) so there is a premium on being competitive in locations where resources are limiting due to the presence of many other species.

define biosphere

the sum total of the entire biotic and abiotic world fxning as a single global system

What are the properties of H-W

there is no mutation p+q=1 q is the freq of the recessive alleles 2pq is the freq of the heterozygous condition

What is true about the Hadley cells?

they are caused by solar heating they are a tropical atmospheric circulation pattern they drive ocean currents they influence the tradewinds NOT cause the Coriolis effect

In the study with phenotypic variation in Achillea millefolium. taller in low elevations and shorter in high alpine zone of the Sierra Nevada. What experimental approach did CKH use to distinguish btwn a genetic and an environmental basis for phenotypic height variation in Yarrow?

they used a reciprocal transplant study

What is the science of ecology about?

understanding the relationship btwn organism and their environment. understanding the natural world using scientific method and includes biotic and abiotic components and their interaction w/one another

how and where does upwelling occur and why its important for oceanic life?

upwelling occurs along the western coasts of continents where there is a long N-S running coast. bc of the Coriolis effect, winds moving across the ocean surface cause surface waters to move at right angles to the direction the winds are blowing. in the N hem surface currents are driven to the right of the wind direction; in the S hem they are driven to the left. this causes deep cold and nutrient rich water to rise up to replace the surface waters. bc the bring nutrients to the surface, upwelling currents feed the base of the food chain and support abundant and diverse bio life where they occur

why is the scientific method important in ecology?

uses the scientific method as the key approach to investigating ecological phenomena advancing ecological understanding and modifying existing ecological knowledge.

deserts often occur at 30 degrees N and S latitude bc?

warm and dry air masses descend at these latitudes

what general weather conditions ( ie temp and ppt) would you expect along the coast of California in an El Nino year? Explain how an El Nino event could lead to these conditions. Is this an El Nino year?

warm temp and high ppt. this occurs bc in El Nino years the trade winds that normally blow warm moist air twrds the western pacific relax and cause this air to accumulate in the eastern pacific. California is affected by this climatic pattern and in an El Nino year can experience warmer than usual temps and higher than usual ppt

define ultimate factors

why a particular phen occurs and generally involve evolutionary causes. Ex: deciduous tress shed their leaves in fall bc it protects them from mortality due to freezing temp and favors trees with deciduous habit. - the deeper cause of a phen that explains why it occurs