Ecology CH 1-10

How might understanding one level of ecological organization help us understand processes occurring at a higher level of ecological organization?

In the case of a drought, understanding a change in species' interactions and how they might affect the flow of energy and matter will aid in evaluating how the ecosystem, overall, will respond to a drought.

At the population level, who would happen to a population of animals that was not in a dynamic steady state over long time periods?

A population that was not in a dynamic steady state over a long period of time would either experience overpopulation or extinction, given the type of imbalance it is experiencing.

Why are phenotypes the product of both their genes and their environments?

Phenotypes are the product of both their genes and environments because of natural selection through evolution.

How does the law of conservation of matter relate to understanding ecology?

Ecologists can apply the law of conservation of mass to the analysis of elemental cycles by conducting a mass balance.

If natural selection favors adaptive phenotypes, in what ways might prey populations evolve if they experience predators over many generations?

Prey populations may evolve (if they experience predators over many generations) to adopt characteristics of previous members of their species who survived, thus providing them the ability to survive and reproduce.

In the experiment on herbivore insects consuming the leaves of oak trees, describe how the researchers could have also conducted a natural experiment in addition to their manipulative experiment.

In addition to the manipulative experiment, the researchers could also conduct a natural experiment where they observe, given the tree, how many insects there are, in general without disturbing the insects or tree.

How might parasites have similar effects as herbivores that only consume a few leaves on a plant.

When experimental manipulations are conducted to test a hypothesis, what is the purpose of including a control?

It is meant to include all aspects of an experiment except the factor of interest in order to test the factor of interest.

Given the difficulty in conducting a manipulative experiment to identify the effects of elevated concentrations of across the globe, how might we be able to validate the mathematical models that have been created?

We may be able to validate the mathematical models that have been created by observing and measuring the amount of fossil fuels that burn carbon, while also including the effects of CO2 sinks.

Using the data for the caged trees from the "Working with Ecological Data" exercise (Section 1.4), calculate the sample variance if the variance of the mean stayed the same but the sample size were to increase from 10 to 100 to 1,000. How does sample size affect the estimate of the sample variance relative to the variance of the mean?

As sample size increases, the sample variance increases

Some sources of air pollution produce tiny black particles that can be transported around the world and settle on regions covered in snow and ice. Based on the albedo effect, how might this air pollution contribute to warming global temperatures, melting polar ice caps, and rising sea levels?

This pollution causes temperature differences between areas of ice. Because of this heat absorption , Ice melts and this water enters sea and rises it and global temperature raises due to high emission.

If Earth was not tilted on its axis, how would it affect the seasonality of rainfall at the equator?

The rainfall will be reduced to nil almost because in equator the climate will become hotter than usual.

What parallels can you draw between the processes that drive Hadley cells versus rain shadows?

The flow of air up to the atmosphere and creates a dry strip of land when blowing further or towards leeward side. Both of these processes results in deserts.

If there were no Coriolis effect, what would happen to atmospheric currents and ocean currents?

If there is no coriolis force, convectional current will become unstable and ocean current will not deflect . This reason is because of the Earth's rotation on its axis.

What are the processes that are responsible for the locations of the world's major deserts?

a. Ocean currents which are cold near them that stops formation of clouds and thus precipitation.

b. Global Wind system or anticyclonic conditions which is more between 20 and 30 degree latitudes

c. these regions mainly found in the offshore areas or the rain shadow region

Compare and contrast the factors used to categorize terrestrial biomes with those used to categorize aquatic biomes.

terrestrial: precipitation and temperature

aquatic: salinity, flow rate, and water depth

How do atmospheric currents help to determine the locations of tropical seasonal forests?

Atmospheric convection currents are driven by the intense sunlight that strikes Earth near the tropics. This solar energy warms the surface of Earth, which causes moist air to rise, cool, and release water as precipitation. As the air continues to rise, it reaches the top of the troposphere. The air, which is now cold and dry, moves toward the poles until it descends at approximately 30 degrees N or 30 degrees S latitude. As it descends back to Earth's surface, the warms and then moves back toward the equator.

Given your knowledge of terrestrial biomes, why can temperate seasonal forests retain more of their soil fertility than tropical rainforests can aer they are logged?

their soils are naturally richer, have a greater capacity for water retention, and experience less intense rainfall, which reduces nutrient leaching

If northern latitudes continue to become warmer over the centuries, what effect might this have on lake circulation during the spring and fall?

there will be lake stratification throughout the year. Lake turnover (water mixing) will not take place.

As the upper layer(epilimnion) will continue to become warm.

Lower layer (hypolimnion) will be cold.

And there will be a thermocline separating the two layers,this is called stratification.

Usually at spring,when temperature of surface layer cools down,there is mixing of water and lake circulation due to wind occur,but due to continous warm condition,there will be lake stratification.

Compare and contrast swamps, marshes, and bogs.

• swamps contain emergent trees

• bogs have acidic water

• marshes have non-woody vegetation

As water cools below 4°C, it expands and becomes less dense. Why is this beneficial to organisms living in a lake during a cold winter?

Above and below 4°C, the water molecules are less tightly packed and the water becomes less dense. Below 0°C, pure water is converted into ice, which is less dense than liquid water. As a result of its lower density, ice floats on the surface of liquid water. This means that lakes experiencing cold winters will generally have a layer of 4°C water at their bottom. Above this layer will be water that is less than 4°C and on top of that will be a layer of ice.

Given that heat readily transfers between an organism's body and water, what would you predict about the temperature of the boundary layer around an animal's body compared to the temperature of the surrounding water in cold weather?

The temperature of the boundary layer around an animal's body will be more compared to the temperature of the surrounding water in cold weather because the metabolism rate of the animal increases inside the water which makes the body warm in water. The temperature near the body will be more while that of water will always be less

Based on the properties of water, why do nonpolar compounds such as fats and oils not dissolve well in water?

Non-polar compounds such as fats and oils not dissolve well in water because their ends are not charged. This means that fats are nonpolar while on the other hand water is polar, As a result the non polar molecures and water molecules do not bond and they do not share any electrons in any way. As a result , they end up floating in the water rather than blending into it.

Some lakes around the world have thick deposits of limestone, which is made up of calcium carbonate, and are resistant to the effects of acid rain. What parallels can you draw between these lakes and the smokestack scrubbers used in coal-powered factories?

Lake with thick deposition of limestone are resistant to the effect of acid rain whereas the smokestack scrubber installed at the emission point of coal-powered factory control the emission of harmful gases at their source of emission by utilizing the principle of flue gas desulfurization, where lime/ limestone is used to convert SOx ( x = 2, 3) to gypsum. Therefore we can conclude that both resisting mechanism of the lake against Acid Rain as well as the mechanism used by smokestack scrubber for preventing the formation of Acid Rain are same.

Both saltwater and freshwater fish have adaptations to control the movement of water and salts across their external surfaces. Describe what would happen without these adaptations.

They possess such adaptation to keep the optimum balance of blood salinity. If the adaptation is not there, saltwater fish will start to swell and increase in size. Thus, there might die from cell burst. Freshwater fish have scales on their external surface that lessen the diffusion of water via skin.

How would the process of natural selection favor the evolution of increased salt tolerance in response to increased use of road salt in cold latitudes that ultimately finds its way into streams and lakes?

The process of natural selection would favor the evolution of increased salt tolerance in areas that use rock salt by promoting the reproductive success of aquatic organisms that have a higher degree of salt tolerance due to genetic mutations.

Using your knowledge of how dissolves and reacts in water, explain why global increases in atmospheric should cause a decrease in the pH of ocean water.

It is true that with a global increase in atmospheric carbon dioxide, the pH of ocean water will decrease. When carbon dioxide gets dissolved in the ocean water, it results in the formation of carbonic acid. Carbonic acid then further breaks down, which leads to the formation of bicarbonate along with hydrogen ions.

How would countercurrent selection in fish gills be beneficial for an animal trying to get rid of ?

counter current selection in fish gills is an oxygen exchange which helps in blood pick up.here blood takes more oxygen so,they can be maximed then the amount of the blood contain water has the higher energy.with the hep of lungs they take oxygen from air and co2 gone out through the air.in fish gills helps in carrying oxygen out of water and water helps in carrying away the co2.

How does thermal pollution relate to the concepts of thermal optimum and critical maximum temperature?

Thermal Pollution is the harmful release of heated liquid into a body of water or heat released into the air as a waste product of a business. It causes a sudden unnatural change in the temperature of a water body, which harms the environment

If the algae that live in corals need as a carbon source for photosynthesis, why do scientists argue that global increases in are playing a role in the decline in coral reefs around the world?

Algae is a plant which produce their own by by themselves by using the CO2 and sunlight by the process called photosynthesis. That's why algae are called autotrophs. Whereas corals are not autotrophs they are heterotrophs. That's why they don't require CO2.

Second thing is that higher amount of CO2 in the ocean causes ocean acidification. This increases the acidity of water. The shell of coral is made up of calcareous material. We know calcite reacts to acids. That's why when ocean acidification occurs that time the shells of corals gets dissolution or bleaching. Due to this scientists are telling that ocean acidification is a threat for corals.

How do salty soils affect the matric potential and, in turn, affect root pressure and overall water uptake?

salty soils have less pores to maintain the matric potential. Less pores mean roots exert large pressure on soil and root pressure will increase --> less water uptake

Based on your knowledge of the relationship between volume and surface area, why do clay soils hold more water than sandy soils?

clay soils have a higher surface area per volume than sandy soils and are able to retain more water --> richer. Clay's soils also expand due to crack leading to an increase in volume. Smaller pores than sand leading to the more retaining capacity of water

If you were breeding cotton plants to have increased water uptake in dry soils, you could breed plants that contain more amino acids and carbohydrates in the root cells. Why would this be effective, and why might crop yield be negatively affected?

breeding plants contain more aa and carbohydrates enhances the pores in the soil by releasing the salt, neutralizing ions. in dry soils, increase in pores increase water flow and the water uptake will be higher

How do CAM plants solve the problem of obtaining for photosynthesis while minimizing water loss?

during the night so that its energy won't be lost in the day. utilizes the stored co2 in the daytime in photosynthesis rxn. During the day they won't go for evapotranspiration that the water won't be lost from them --> maintain the water retention capacity

How might the fitness cost of photorespiration in plants favor the evolution of plants?

favors the evolution of c4 plants because c4 plants minimize photorespiration by separating initial co2 fixation and the calvin cycle in space, performing these steps in diff cell types

How do leaf hairs that surround guard cells reduce water loss through the process of forming a boundary layer?

- presence of hair around guard cells creates local humidity by trapping moist air close to the lead

-leaf hairs and sunken stomata decrease exposure to air currents and the presence of hair further reduces airflow around the stomata

When animals hibernate, they lower their temperature. How would this reduce the rate of heat lost through conduction?

lowering the temp, the animal comes at a temp that is lower than its surrounding. heat will flow from the surroundings to the body of the animal preventing heat loss from animal's body

In addition to having highly efficient kidneys, what behaviors could you imagine desert animals using to reduce water loss?

desert animals have thick and tough skin that do not allow water to pass out, have fewer sweat glands and they store fat in unusual places

If you designed an experiment to determine how temperature and the species composition of seeds affect the growth and reproduction of seed-eating birds, what would be the independent and dependent variables?

Experiment to determine temperature and species composition of seeds , afecr growth and reproduction of seed eating bird. The independent variable - whos change doest affect by other variable. So temperature change is independent as it is not affected by other variables.

Dependent vatible which is determined or affects by independent varible like growth rate of seed eating bird. Here temperature affe t there growth either positive or negatively.

Compare and contrast the adaptations that have evolved in aquatic and terrestrial environments.

What is the difference between weather and climate in terms of temporal variation?

Weather is a DAILY Phenomena while Climate is a long term observation of any place

Climate is cofirmed after a reading/observation of rainfall, temp etc of a place for ATLEAST 30 yrs (more tha 50 yrs reading will give better accuracy). This gives a Generalized weather scene of any place (like how USUALY the place is with regards to temp, ppt, etc...)

Weather changes from place to place and time to time... and hour to hour too...

How could spatial heterogeneity be perceived by an organism as temporal heterogeneity?

Moving through environments that vary in space, an individual experiences environmental variation as a sequence in time. In other words, a moving individual perceives spatial variation as temporal variation. The faster an individual moves and the smaller the scale of spatial variation, the more quickly the individual encounters new environmental conditions and the shorter the temporal scale of the variation.

Why do we have to consider the mean fitness across all environments when evaluating whether evolving a phenotypically plastic genotype will be favored over a nonplastic genotype?

The environment determines what traits make an organism more fit. For example, a trait allowing organisms to store water would increase fitness in a desert environment.

The biological fitness of an organism is dependent on its ability to survive and reproduce in a given environment. If different traits or alleles increase the fitness of an organism, those alleles will consequently increase in the gene pool, and that trait will increase in the population.

For individuals born in good environmental conditions, mean fitness increases as the adult environment improves. For individuals born in poor environmental conditions, mean fitness may increase weakly or decrease with improvement of the adult environment.

In this way we can say that we have to consider the mean fitness of the individuals across all the environment not at a particular environment, in order to avoid any biasness.

How would the presence of unreliable environmental cues affect the evolution of phenotypically plastic responses to environmental variation?

Would the frequency of experiencing predator versus no- predator environments affect the evolution of phenotypically plastic traits?

If predators reduce prey abundance to very low levels, how might variable predator environments affect the evolution of flexible mating strategies?

If the environment becomes full of the predator bearing organisms, then the thing that would affect the flexible mating strategies of the organisms are the extent of predatory. There would be greater chance of mating if the strategies made by the animal bearing more kills are profitable than the ones with less kills.

If a plant can improve its ability to obtain water by growing more roots, why shouldn't the plant always grow more roots?

In evolutionary psychology, there is a phenomenon which can explain the certain extents upto which a certain morphology can grown. A morphological character can be grown upto a limit where it attains its full growth and hence it is controlled by certain genes called the regulatory and hox genes. These are some of the genes which control the regulation and function of a certain morphological character. Just like that of the human ear, it cannot grow infinitely, but it will stop groing after attaining a certain limit. The same psychology is applied in the case of the plants where it is not allowed to gro roots infinitely.

How could you experimentally determine whether migrating birds use length of the day or temperature as an environmental cue for migration?

A simple experiment or rather a fact which can answer to the question whether a bird migrates due to temperature or day length is, the bird always chooses a specific season for its migration. Also there are various diurnal migrations which takes place throughout the year. Therefore it can be said that the it certainly depends upon the temperature as an environmental cue because had they have choosen length of the day, they would have hibernated for a longer periods of time in the nights, which would not be possible if they had to make migrations twice a year.

What is the relationship between correlation and causation?

Correlation is said to be the relationship between two variables which can define the measure of dependence of the one variable to that of the other. Whereas, Causation is said to be the a measure of the causality of any event. It certainly doesn't say weather a event is completely effected or caused by that specific cause, but in turn it says about a probability of that being a cause.

The relationship betweeen correlation and causality is that both of these measures the highest probability of a variable and its extent of interdependence towards the other.

When determining whether to feed on small, medium, or large prey, why should predators evaluate the energy obtained from each prey item, the abundance of each prey item, and the handling time of each prey item?

1) predators should rank their prey in order of their energy value per unit of handling time

(2) they should attack only items that increase their rates of energy acquisition

(1) First, as a predator catches more prey, the time spent handling each item (i.e. pursuing, subduing and consuming it) cuts into searching time

(2) Second, predators must eventually become satiated and cannot feed any faster than they can digest, assimilate and move food through the gut

Given that mutations are rare in populations, how does a mutation spread through a population and become common?

-If the mutation confers a selective advantage, it will spread through the population because it increases individual fitness.-Because mutations produce dominant alleles, they spread rapidly through the population by masking recessive alleles.-Mutations increase the frequency of crossing over during meiosis, producing more chromosomes that are carrying the mutation.-As the population grows larger, the chance that the same allele will mutate in the sex cells of multiple individuals increases.

Compare and contrast genetic variation caused by random assortment versus recombination.

random assortment shuffles chromosomes, while recombination exchanges genetic material between chromosomes, leading to new combinations of alleles

The insecticide DDT has been widely used to control the mosquitoes that carry malaria. How would you explain the fact that many mosquito populations are now resistant to DDT?

They have evolved to be resistant to it over the course of generations of natural selection for the traits that are resistant to DDT.

How does the introduction of new individuals to a population help offset problems associated with genetic drift?

Introducing new individuals, or gene flow, counteracts genetic drift by introducing new genetic variation and alleles, thus preventing the loss of alleles due to random chance and maintaining a larger, more diverse gene poo

Compare and contrast evolution by artificial selection with evolution by natural selection.

Artificial selection typically focuses on specific traits chosen by humans, whereas natural selection acts on random variations in traits shaped by environmental pressures

Compare and contrast stabilizing, directional, and disruptive selection with regard to how each affects the mean phenotype of the population as well as the variance in the phenotype.

Directional: variation reduced. Mean changes

Stabilizing: variation reduced. Mean stays the same.

Disruptive: variation maintained or increased. Mean stays similar

How does the breeding of domesticated animals provide evidence for the power of evolution on diverse phenotypes?

Over its lifetime, each domesticated animal develops new phenotypes to help it adapt to the diet provided by human breeders.

How is it that polyploidy can allow us to observe the evolution of a new species within one generation?

when a polyploid is formed, it instantly becomes a species that is genetically distinct from its parents.

Distinguish between microevolution and macroevolution.

Microevolution refers to changes in allele frequencies within a population over a short period, while macroevolution encompasses larger-scale evolutionary changes, including the emergence of new species and higher taxonomic groups over long periods

What is the difference between the processes involved in allopatric speciation and sympatric speciation?

allopatric speciation requires geographic isolation.

Allopatric speciation is more common than sympatric speciation because the geographic isolation that's present in allopatric speciation prevents the flow of genes between separate populations of a species, allowing genetic drift to have a greater effect on the separate groups.

How should selection for greater longevity affect time to maturity and size at maturity?

The benefits of maturing later and at a larger body size includes: (1) longer growth which leads to larger size at maturity and thus increased fecundity (since fecundity often increases with size), (2) lower adult mortality (and thus potentially higher lifetime fecundity) due to a larger size (mortality due to predators is often lower for larger individuals), and (3) higher quality offspring (e.g., increased investment per offspring, better parental care) which improves survival of the offspring produced. Therefore, time taken to reach sexual maturity with larger body size at sexual maturity favors greater longevity.

Compare and contrast the concept of a regression versus a coefficient of determination.

Regression analysis can tell us how two variables are related mathematically (like linear regression). Coefficient of Determination tells us how variable are related and how closely they are related.

What factors might favor the evolution of semelparity versus iteroparity in different species of salmon?

In salmon, the evolution of semelparity (single, fatal reproduction) versus iteroparity (multiple reproductive events) is likely influenced by factors like high adult mortality risk, the energetic cost of reproduction, and the availability of resources in specific environments

Compare and contrast the two leading arguments regarding why temperate bird species lay one or two more eggs than closely related tropical bird species.

1. temperate birds lay less eggs than tropical birds because they have less access to resources available to feed their offspring2. different overall strategy.

Given your knowledge of how predators and resources can affect life history traits, hypothesize how the four combinations of high resources, low resources, predator presence, and predator absence would affect the size at maturity of a prey species.

If the number of resorces increase, the predator and prey will grow uncontrolled it will cause imbalance in echosystem. The same thing will happen if the resorces decreases.

The food chain in echo system connected to each other. When one thing is increasing uncontrolled, it will affect others. for example Imagine a forest. It will contain lot of small animal and large animal. We can select Rabbit and Lion as two animals (Prey and Predator). If the number of Lion is increased uncontrolled, the no of rabbit decrease and after some days they cant get prey as food. Gradually that animals will disapprear from the forest. If the number of Lion is less, the the number of rabbit will increase and it will leads to lack of resorces for rabbit. Gradually it will die without food. That will affect the remaining Lion. So the nature always maintain a perticular ratio in the ecosystem.

Why might natural selection act more strongly on traits that improve reproductive success early in life rather than later in life?

growth over fecundity during the early years of its life.

Many organisms do not survive to reach the age where the traits increase survival

Give two reasons why a mammal such as a gray wolf could face a trade-off between offspring number and offspring size.

the number of offspring in any given pregnancy can only increase if the size of each individual offspring decreases. The trade-off between offspring number and offspring size for a given reproductive event can also be limited by energy and nutrients.

What is the mechanism by which parental care can increase current fitness but decrease future fitness?

Parents increase their current fitness by producing more offspring, but decrease later fitness by investing too much energy and time into all offspring.

Why might an organism use cues such as photoperiod to predict the future state of its environment?

Organisms can detect the length of photoperiods, so the longer a photoperiod, the hotter the environment will be in the future.

In terms of environmental cues, hypothesize why some, but not all, species of plants flower earlier in association with warmer spring temperatures.

Some plants are sensitive in warmer temperatures so using photoperiod detection can cause spring plants to flower sooner.

How does the Red Queen hypothesis help us understand the fitness benefits of sexual reproduction?

The Red Queen hypothesis shows that through sexual reproduction there is an easier time adapting to new pathogens or parasites

Freshwater snails exhibit both sexual and asexual reproduction. Why might natural selection favor such a mixed breeding strategy?

it provides a balance between the advantages of rapid asexual reproduction and the benefits of increased genetic diversity through sexual reproduction, allowing for adaptability to changing environments

Given that self-fertilization leads to inbreeding depression, under what conditions should a hermaphrodite use self- fertilization?

when population density is low and the individual cant find a mate then it should self fertilize bc it is better than not reproducing at all

What strategies do monoecious plants use to avoid possible negative effects of inbreeding?

1) pollen release before stigma is receptive2)another stigma so pollen cant be intact with stigma3) self incompatibility to prevent self pollen from fertilizing ovum by inhibiting pollen germination

In addition to affecting sex ratios, what other traits might be affected by the artificial selection caused by intense fishing?

growth, development, and reproductive characteristics.

Turtle embryos incubated at lower temperatures typically produce males, whereas those incubated at higher temperatures produce females. In the face of global warming, how might turtles evolve to change their egg- laying behavior to maintain an even sex ratio?

Compare and contrast monogamy, polygyny, polyandry, and promiscuity.

Monogamy involves one male and one female pairing, while polygyny has one male with multiple females, polyandry has one female with multiple males, and promiscuity involves multiple partners for both sexes with no lasting pair bonds.

Explain how extra-pair copulation has favored the evolution of mate guarding.

Male doesn't benefit if mate breeds with other males, use this to prevent extra pair copulations.

Why might exaggerated secondary sexual characteristics in males demonstrate a superior genotype to females

They often reduce fitness, which signifies a better genotype for survival. If a male can survive with sexual traits that require extra energy/increased risk, these traits might signal a superior genotype. For example, a male bird with elaborate plumage shows that because he has the energy to build elaborate feathers, he can resist parasites and pathogens

How might genetic resistance against parasites be exhibited by males in ways to allow female selection?

Males can exhibit genetic resistance to parasites through exaggerated sexual displays or traits that females perceive as indicators of good health and vigor, leading to female selection for males with those traits, thus indirectly selecting for resistance genes

If living in large groups has costs and benefits, under what conditions would natural selection favor group living?

Survival

Feeding

Mating

Why might individuals give up defending territories if the density of their population increases?

As long as a resource can be defended and the benefits of defending the resource outweigh the costs, animals are likely to maintain territories

Explain the costs and benefits that might influence the optimal flock size in birds.

the dilution effect, more time to feed, and better chances of mating

Compare and contrast the conditions under which natural selection favors cooperative versus altruistic behavior.

Natural selection favors cooperation when it benefits both parties involved, while altruism, a seemingly self-sacrificing behavior, is favored when it benefits relatives (kin selection) or through reciprocal altruism, where the favor is returned

How could helping raise the offspring of another couple improve the helper's fitness if the helper is not related?

Why are selfish behaviors less favored when the donor and recipient are related to each other?

They cause an indirect reduction in fitness for the donor

Compare the coefficient of relatedness between brothers and sisters in diploid organisms with that of haplodiploid organisms.

In diploid organisms both male and female have two sets of chromosomes. The male sperm contains one of its two sets and in the same way female egg contains one of its two sets. So when fertilisation occurs the fertilised egg bears two sets of chromosomes; in which half is from the male and half from the female. So, the average degree of relatedness between brothers and sisters who are diploid is 50%.

(In haplodiploid organisms brothers and sisters are less closely related than in diploid organisms)

What evidence is there that a haplodiploid sex- determination system is not required for the evolution of eusociality?

-Naked mole rat colonies are dominated by a queen and several kings who produce diploid male and female offspring.-Termite colonies are dominated by a queen and king who produce diploid male and female offspring.

Why might selection based on groups of domesticated goats result in greater meat production than selection on individual goats?

it allows for the evaluation of multiple traits simultaneously and can leverage genetic diversity within the herd, leading to more efficient and robust breeding programs. 

Provide a hypothesis for how a plant attacked by an herbivore could communicate to conspecifics which species of herbivore is attacking?

releasing a unique blend of herbivore-induced volatiles (HIVEs), which are species-specific and trigger a specific defense response in neighboring plants. 

Why is the realized niche considered to be a subset of the fundamental niche?

-The fundamental niche is the area of a species' livable range of abiotic conditions, but the realized niche is the area other organisms do not prevent the species from occupying.-The fundamental niche depends on biotic factors that influence a species' ability to thrive, whereas the realized niche depends on both biotic and abiotic factors.-The fundamental niche is the geographic area covered by a species' population, but the realized niche is only the area with a positive population growth rate.-The fundamental niche is the actual geographical area where a species persists, whereas the realized niche is the potential area where a species can persist.

How might we use an ecological niche model to predict the future spread of the emerald ash borer?

The American bullfrog is native to eastern North America, but it has been moved by humans and now thrives in western North America. What does this suggest about the cause of the bullfrog's historical geographic range?

One way researchers have overcome this challenge is by using historic data on the distributions of populations. Such data are often available from collections of preserved organisms stored in museums and herbariums. In addition, when species have been introduced from other continents,researchers can try to determine the suitable habitat conditions found on the originating continent.

With continued global warming, what dispersal barriers might arise for reptiles that try to move to higher latitudes?

areas of environments that they cannot cross

In a forest, why might you observe young maple trees exhibiting a clustered pattern of dispersion?

Young maple trees may exhibit a clustered pattern of dispersion as many species will form clusters surrounding areas with rich resources. Clusters of young maples could also be seen if the parental tree used vegetative reproduction to send up new shoots.

Suppose that 100 cattle were allowed to graze in either one of two pastures. If the grass was three times more productive in pasture A than in pasture B, how many cattle would be in each pasture if they followed an ideal free distribution? What might prevent this distribution of cattle from happening?

Ratio distribution, due to ideal free distribution, would be 31 cows. Equal productivity of grass in each pasture will prevent the distribution of cows.

You gather a sample of 20 horseshoe crabs and mark- release them. If you return the following week and collect 30 horseshoe crabs and 6 possess marks, how large would you estimate the crab population to be?

M/N = R/CN=MC/RN = 20 30 / 6 = 100

Why do birds have their highest densities near the center of their geographic range?

for more energy and high fitness

Why might you expect to find a negative correlation between adult body size and population density in fish?

In species that live at high population densities, individuals have limited space for existing and obtaining resources, which restricts growth of individuals to a small body size.

How might the presence of a predator alter the predictions from an ideal free distribution?

individuals will settle in habitats based on the relative fitness payoffs: they will avoid areas with higher predator rates