Question 1

Ants should live in _____ populations, and rhinoceroses should live in _____ populations.

Accepted Answer

Ants are social insects that thrive in high-density populations, whereas rhinoceroses are large mammals that require more space and resources, and therefore live in low-density populations.

Question 2

What factors drive the relationship between population density and adult body size?

Accepted Answer

Population density and adult body size are likely linked to the availability of space and resources. In areas with high population densities, there may be more competition for limited resources, such as food and habitat. This may lead to smaller body sizes in some species. Conversely, in areas with lower population densities and more abundant resources, individuals may be able to grow larger. Predation may also play a role, but it is not the main factor driving the relationship. The availability of mates is not directly related to body size.

Question 3

A researcher who counts the number of individuals of a tree species between two fixed points is making a(n) _____ survey.

Accepted Answer

The researcher is counting individuals between two fixed points, which indicates a line transect survey. An area-based survey would involve counting all individuals within a specific area, a volume-based survey would involve measuring the physical dimensions of the trees, and mark-recapture is a technique typically used for studying animal populations.

Question 4

The best way to quantify organisms that are well camouflaged is a(n) _____ survey.

Accepted Answer

Mark-recapture methods are effective for quantifying well-camouflaged organisms because they do not rely on the ability to see or find all individuals in a population during a single observation. Instead, they involve capturing a number of individuals, marking them in a harmless way, releasing them back into their environment, and then recapturing individuals at a later date. The proportion of marked to unmarked individuals in the second capture allows researchers to estimate the total population size, including those that are camouflaged or otherwise difficult to detect.

Question 5

What is the relationship between population density and adult body size?

Accepted Answer

Studies have shown a negative correlation between population density and adult body size, meaning that in populations with high densities, individuals tend to be smaller in size. This could be due to competition for resources and limited space, leading to reduced access to food and an increased risk of predation.

Question 6

Dispersal limitation occurs when

Accepted Answer

Dispersal limitation occurs when there is a barrier preventing a species from dispersing into suitable habitat. This could be a physical barrier such as a mountain range or an ocean, or it could be a biological barrier such as the presence of a competing species. Dispersal limitation can prevent a species from colonizing new areas or from expanding its range in response to changing environmental conditions.

Question 7

During the annual Christmas bird count conducted by the Audubon Society, volunteers count the number of individuals of every bird species they can see or hear along a predetermined path within a 24-kilometer circle. This is an example of a(n) _____ survey.

Accepted Answer

The answer of During the annual Christmas bird count conducted...

Question 8

If the geographic range of a population is decreased, it is generally considered that the

Accepted Answer

When the geographic range of a population is decreased, there is less habitat available for the individuals of that population to live in. This can lead to decreased resources, increased competition for those resources, and a higher likelihood of predation or disease. All of these factors can lead to a decrease in the size of the population.

Question 9

You conduct a mark-recapture survey of eastern fence lizards (Sceloporus undulates) in a 2-hectare plot in eastern Arizona. You mark 250 lizards and are able to recapture 75, of which 24 are marked. What is the estimated size of the population of fence lizards in this plot? Calculate the estimated population size for the plot and the estimated lizard density per hectare and per square meter. Use the following formula: $\frac { M } { N } = \frac { R } { C }$ where M is the number of initially marked individuals, N is the population size, R is the number of recaptured marked individuals, and C is the total number of individuals recaptured.

Accepted Answer

The answer of You conduct a mark-recapture survey of eastern...

Question 10

Which of the following populations would be best estimated by an area-based survey?

Accepted Answer

An area-based survey is appropriate when the population is stationary and can be easily observed by physically sampling a particular area. Therefore, the best choice is flowers in a field, as they are stationary, and their location can be easily observed and sampled in a specific area. The other options involve mobile or elusive populations that would be difficult to accurately estimate through an area-based survey.

Question 11

Why does reduction of a population lead to decreased geographic range?

Accepted Answer

When a population decreases, there will be fewer individuals available to disperse into marginal habitats and maintain their presence. This will cause a reduction in the geographic range of the population. Options A, B, and C do not offer a satisfactory explanation for the phenomenon described in the question.

Question 12

Measuring the lifetime dispersal distance of a species helps scientists to estimate how rapidly a growing population can increase its

Accepted Answer

Measuring the lifetime dispersal distance of a species helps scientists to estimate how rapidly a growing population can increase its geographic range.

Question 13

Populations with high abundance tend to have a _____ range.

Accepted Answer

Populations with high abundance can occupy a larger geographic range compared to populations with lower abundance. This is because high abundance usually means that there are plenty of individuals to colonize new areas and occupy a variety of habitats within their range. Additionally, a larger geographic range can provide more opportunities for resources, such as food and shelter, which can support a larger population size.

Question 14

For a mark-recapture survey, the ratio of the number of marked individuals to the total population is equal to the ratio of the

Accepted Answer

The mark-recapture method involves capturing a sample of individuals from a population, marking them, releasing them, capturing a second sample at a later time, and then comparing the number of marked individuals in the second sample to the total number of individuals in the second sample. The ratio of the number of marked individuals in the second sample to the total population is estimated to be equal to the ratio of marked individuals recaptured in the second sample to the total number of individuals in the second sample. This ratio is used to estimate the size of the total population. Therefore, choice A is the correct answer.

Question 15

Methods such as area-based, volume-based, and line-transect surveys would be best for estimations of _____ populations.

Accepted Answer

The answer of Methods such as area-based, volume-based, and line-transect...

Question 16

The relationship between population density and adult body size is demonstrated in many organisms. Would you expect this relationship to hold true for body size averaged across all developmental stages (juveniles to adults)? Why or why not?

Accepted Answer

The answer of The relationship between population density and adult...

Question 17

A researcher who wants to know how many tree seedlings are in a 1-hectare site counts the number of seedlings within five 2-square-meter subplots and then calculates the average. This method of determining the number of individuals in an area is known as a

Accepted Answer

This method is known as a survey because it involves sampling a portion of the area (the five 2-square-meter subplots) to estimate the total number of individuals (tree seedlings) in the larger area (the 1-hectare site). A census, in contrast, would involve counting every individual in the entire area.

Question 18

Imagine that you are conducting a mark-recapture survey of common pill bugs (Armadillidium vulgare), a terrestrial isopod, in a field. Unbeknownst to you, the majority of the pill bugs molt between marking and recapturing. How does this affect your estimate of the population size? How could you have foreseen this? How could you prevent this in the future?

Accepted Answer

The answer of Imagine that you are conducting a mark-recapture...

Question 19

Based on the relationship between geographic range and population, what would you expect to happen if a large portion of a species' habitat is converted to agriculture?

Accepted Answer

The answer of Based on the relationship between geographic range...

Question 20

Scientists commonly use _____ dispersal distance to quantify an organism's dispersal.

Accepted Answer

The answer of Scientists commonly use _____ dispersal distance to...

Quiz 11: Population Distributions

Ants should live in _ populations, and rhinoceroses should live in _ populations.