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Population Ecology | 35 mins | 0 completed | Learn |

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Suppose researchers marked 800 turtles and later were able to trap a total of 300 individuals in that population, of which 150 were marked. What is the estimate for total population size?
a. 200
b. 1,050
c. 1,600
d. 2,100

Which of the following is the most important assumption for the mark-recapture method to estimate the size of wildlife populations?a. More individuals emigrate from, as opposed to immigrate into, a population.b. Over 50% of the marked individuals were trapped during the recapture phase.c. There is a 50:50 ratio of males to females in the population before and after trapping and recapture.d. Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase.

To measure the population density of monarch butterflies occupying a particular park, 100 butterflies are captured, marked with a small dot on a wing, and then released. The next day, another 100 butterflies are captured, including the recapture of 20 marked butterflies. One would correctly estimate the population to bea. 1,000b. 10,000c. 500d. 200e. 900,000

To measure the population of lake trout in a 250-hectare lake, 400 individual trout were netted and marked with a fin clip, then returned to the lake. The next week, the lake was netted again, and out of the 200 lake trout that were caught, 50 had fin clips. Using the mark-recapture estimate, the lake trout population size could be closest to which of the following?
a. 200
b. 400
c. 1,600
d. 80,000

Which of the following groups would be most likely to exhibit uniform dispersion?a. red squirrels, who actively defend territoriesb. cattails, which grow primarily at edges of lakes and streamsc. dwarf mistletoes, which parasitize particular species of forest treed. lake trout, which seek out cold, deep water high in dissolved oxygen

Use the survivorship curves in the figure to answer the following question.
Which statement best explains survivorship curve B?
a. It is likely a species that provides little postnatal care, but lots of care for offspring during midlife as indicated by increased survivorship.
b. This curve is likely for a species that produces lots of offspring, only a few of which are expected to survive.
c. It is likely a species where no individuals in the cohort die when they are at 60-70% relative age.
d. Survivorship can only decrease; therefore, this curve could not happen in nature.

Use the graph to answer the following question.Which of the following examples are plausible explanations for a population that would produce curve A in the figure?I. Ongoing predation of rabbits throughout their livesII. Susceptibility of older humans to heart diseaseIII. High seedling mortality in sunflowersa. I onlyb. II onlyc. I and IId. II and III

Which of the following graphs illustrates the population growth curve starting with a single bacterium growing in a flask of ideal medium at optimum temperature over a two-hour period? Assume resources do not become limiting over this time frame.

Which of the following causes populations to shift most quickly from an exponential to a logistic population growth?a. favorable climatic conditionsb. removal of predatorsc. decreased death rated. competition for resources

According to the logistic growth equation, dN/dt = rN (K-N)/K, ________.a. the number of individuals added per unit time is greatest when N is close to zerob. the per capita growth rate (r) increases as N approaches Kc. population growth is zero when N equals Kd. the population grows exponentially when K is small

Use the graph to answer the following question.Looking at the data in the figure, what can be said about survival and clutch size?a. Animals with low survival tend to have smaller clutch sizes.b. Large clutch size correlates with low survival.c. Animals with high survival tend to have medium-sized clutches.d. Probability of survivorship does not correlate with clutch size.

Which of the following traits is characteristic of K-selected populations?a. offspring with good chances of survivalb. many offspring per reproductive episodec. small offspringd. a high intrinsic rate of increase

As N approaches K for a certain population, which of the following is predicted by the logistic equation?a. The growth rate will not change.b. The growth rate will approach 0.c. The carrying capacity of the environment will increase.d. The population will increase exponentially.

In models of sigmoidal (logistic) population growth, _____.
a. density-dependent factors affect population growth rate
b. new individuals are added to the population most rapidly at intermediate population sizes
c. population growth rate slows dramatically as N approaches K
d. all of the above are true
e. a and c

Which of the following is a density-independent factor limiting human population growth?
a. pollution
b. social pressure for birth control
c. earthquakes
d. famines
e. plagues

The following question refer to the figure below, which depicts the age structure of three populations.Which population is in the process of decreasing?a. Ib. IIc. IIId. I and IIe. II and III

Population ecologists follow the fate of same-age cohorts toa. determine a population's carrying capacity.b. determine the birth rate and death rate of each group in a population.c. determine if a population is regulated by density-dependent processes.d. determine the factors that affect the size of a population.

A population's carrying capacity
a. may change as environmental conditions change.
b. increases as the per capita population growth rate decreases.
c. can never be exceeded.

Scientific study of the population cycles of the snowshoe hare and its predator, the lynx, has revealed that
a. predation is the dominant factor affecting prey population cycling.
b. hares and lynx are so mutually dependent that each species cannot survive without the other.
c. both hare and lynx population sizes are affected mainly by abiotic factors.
d. the hare population is r-selected and the lynx population is K-selected.

Analyzing ecological footprints reveals thata. Earth's carrying capacity would increase if per capita meat consumption increased.b. current demand by industrialized countries for resources is much smaller than the ecological footprint of those countries.c. it is not possible for technological improvements to increase Earth's carrying capacity for humans.d. the ecological footprint of the United States is large because per capita resource use is high.

The observation that members of a population are uniformly distributed suggests that
a. resources are distributed unevenly.
b. the members of the population are competing for access to a resource.
c. the members of the population are neither attracted to nor repelled by one another.
d. the density of the population is low.

What is meant by the term “doubling time” and how did changing values for N0 affect the doubling time of a population?a) Doubling time is the amount of time needed for a population to double in size; increasing N0 did not change the doubling time.b) Doubling time is the amount of time needed for a population to double in size; increasing N0 increased the doubling time.c) Doubling time is the time needed for an individual in the population to reproduce itself; increasing N0 did not change the doubling time.d) Doubling time is the time needed for an individual in the population to reproduce itself; increasing N0 decreased the doubling time.

A(n) _____ is a group of interbreeding members of the same species in a particular areaA. frequency B. incidence C. populationD. equilibriumE. gene pool

How do changing values for r affect the growth rate of a population?a) Populations grow when r is negative, remain constant when r is positive, and shrink when r is zero.b) Populations grow when r is negative, remain constant when r is zero, and shrink when r is positive.c) Populations grow when r is positive, remain constant when r is negative, and shrink when r is zero.d) Populations grow when r is positive, remain constant when r is zero, and shrink when r is negative.

How long will it take a population of 550 moose to double if 25 offspring are born and 14 moose die on average per year?a) 26.9 yearsb) 34.5 yearsc) 52.3 yearsd) 79.0 years

The equations used in the tutorial apply to populations over short time intervals. Why can they not be applied to populations over very long time periods?a) The equations only apply to small populations and so populations become disqualified over long time periods as they get larger.b) Real populations are affected by resource limitations that are not accounted for in the equations.c) Large values for time cannot be used in the equations without generating error.d) The equations are meant for theoretical applications only and cannot be used in the study of real populations.

What is Symbiosis? Distinguish between and describe the various types.

An asexual population consists of N = 2 individuals. Each individual has 2 offspring and dies. The probability that each offspring dies before next yearis 1/3. The probability the population goes extinct by the next year is _____. If the population were larger, the probability of extinction would _____.A. 1/27; increaseB. 1/9; increaseC. 1/9; decreaseD. 1/81; increaseE. 1/81; decrease

Carrying capacity is influenced by all of the following except ____. (NOTE: the species for which the K is calculated is in parentheses.)A. Nesting sites (bald eagle)B. Squirrel abundance (fox)C. Milkweed plants (Monarch butterflies)D. Soil nitrogen content (maple tree)E. Fox abundance (squirrel)

What is a carrying capacity? Why is understanding the carrying capacity important in understanding population growth?

Predator-prey populations provide a good example for "Co-evolution". Explain what you understand as "co- evolution".

Explain why cane toads were effective ecological invaders. Include at least three factors.

In some habitats with few species, the food web may become closer to a food chain: only a couple of herbivore species and even fewer carnivores. Compare the effects of losing one species in more typical food webs. Which is more stable? Generally speaking, how are stability and number of species related, and why does this relationship exist?

Distinguish between mutualistic and parasitic symbioses. Give examples of each.

Describe the difference between exponential growth and logistic growth.

Ecological interactions can be divided into categories based on whether only one of the interacting parties benefits (+/-) or both benefit (+/+) or neither benefit (-). Provide an example of each of these and explain the effects each interacting partner has on the other.

Epidemiology is the study of _____.A. the historical diseases that impacted societyB. the epidermis of the skinC. pathogens and their counterpartsD. transmission and control of a disease

What is meant by ecological fallacy?

Compare and contrast commensalism, predation, competition, mutualism, and parasitism. Give an example of each, naming the species involved and briefly describing their interaction.

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