Exam 43: Ecological and Evolutionary Consequences of Interactions Within and Among Species

Bear population growth rates are affected by both intraspecific competition and the supply of their prey (in this case,salmon).Assume that the per capita growth rate is equal to 0.0025 S - 0.02 B,where S is the number of salmon that flow into the river and B is the number of bears in the population.If there are 100 bears,what is the minimum number of salmon that must flow into the river to maintain the bear population?

Organisms that acquire their energy from eating primary consumers are

Use the following to answer questions : There are two species of microbes,A and B,which can be grown together or separately.If G_A is the per capita growth rate of species A,G_B is the per capita growth rate of species B,D_A is the density of species A,and D_B is the density of species B,the per capita growth rates for each are the following: G_A = 0.18 - 0.019 D_A + 0.008 D_B G_B = 0.22 - 0.012 D_B + 0.005 D_A -The interaction between species A and B most closely resembles

The effect that the removal of wolves from Yellowstone National Park had on aspen is best described as

Two species of plants that are competitors in nature are grown together in the greenhouse.When they are fed additional nitrogen,species A thrives at the expense of species B.When they are fed additional phosphorus,species B thrives at the expense of species A.Increasing the concentration of carbon dioxide has no effect on either species.Both species show improved growth when they are given additional sunlight,but additional moisture has little effect on either one.Based on this information,which resource is most likely to be limiting for both species?

A species of spider that typically feeds on herbivorous insects is a(n)

What further information is required to determine that the relationship between T.freemani and T.castaneum is one of competition?

Refer to the figure below showing a food web in the grasslands of Yellowstone National Park.Based on the relationships shown,which trophic cascade would most likely result from the removal of gray wolves? [Note: Red arrows refer to animals consumed by carnivores;blue arrows correspond to plants consumed by omnivores and herbivores.]

The relationship between a zebra and the lion that eats it is an example of what kind of interaction?

A population of plants has a per capita growth rate of -0.15 per year.The presence of a mutualistic earthworm increases the per capita growth rate of the plant by 0.0025 per worm per meter square.What is the minimal density of worms needed to bring the per capita growth rate of the plant to above zero?

Which invasive species is harmful to native species because it crowds them out?

In Joseph Connell's studies of rock barnacles and Poll's stellate barnacles,the limiting resource was shown to be

A species of mouse mainly eats grasses.Individuals of this species are smaller in locations where it co-occurs with a second,larger rodent species that also eats grass than in locations without that larger rodent.What is the most likely cause of this difference?

Two species of beetles have partially overlapping distributions,with the range of species A extending farther north and the range of species B extending farther south.The distribution of species B is limited mainly by cold temperatures,while that of species A is limited mainly by competition from species B.Given these parameters,the distribution of species _______ would most likely move farther _______ if the other species went extinct.

Use the following to answer questions : A biologist examines three species of plants (A,B,C)and finds the patterns shown in the chart below.The effect by a species is the extent to which any individual of that species lowers the per capita growth rate of a given species.The effect on a species is how much the per capita growth rate of a species is affected by a given species.Thus,every individual of species A would lower the growth rate of species C by 0.017;and every individual of species C would lower the growth rate of species A by 0.014. -Based on these observations,should species B and C be able to coexist? Why or why not?

At low densities and in the absence of any competitors,the population of a strain of the flour beetle Tribolium castaneum grows at a per capita rate of 0.3 per week.Under certain lab conditions,the presence of each 100 individuals of the same species reduces that rate by 0.02.The addition of a competitor,Tribolium freemani,reduces the population growth of T.castaneum by 0.04 for every 100 T.freemani individuals.If there are 800 T.castaneum and 400 T.freemani individuals,the per capita growth rate of the T.castaneum population is _______.

Although most herbivory involves an antagonistic interaction (i.e. ,one species benefits,the other is harmed),some herbivorous interactions do not.Which example is least likely to be an antagonistic interaction?

Two competing species usually can coexist when interspecific competition is (weaker/stronger)_______ than intraspecific competition.

Use the following to answer questions : Refer to the figure below showing a food web in the grasslands of Yellowstone National Park.[Note: Red arrows refer to animals consumed by carnivores;blue arrows correspond to plants consumed by omnivores and herbivores.] -Which plant items could be affected by a trophic cascade involving removal of short-tailed weasels?

Leaf-cutter ants originated in