Question 1

The carrying capacity of owls in an Alaskan forest is 8 per square kilometer.What will happen if 12 owls are confined to a 1-square-kilometer area?

Accepted Answer

The carrying capacity of the 1-square-kilometer area is 8 owls, but if 12 are confined to that area, it is over capacity by 4 owls. Resources such as food and nesting habitats will be limited, resulting in malnourishment and reproductive deficiencies, which will ultimately limit the next generation's population to no more than 8 individuals. Option A is unlikely because owls are solitary animals and would not develop ways to share resources. Option C is incorrect because if there are more owls, they will likely consume more prey organisms, not the other way around. Option D is incorrect because exponential growth occurs when unlimited resources are available, and in this case, resources are limited.

Question 2

In 1978,a drought on the Galápagos Islands caused a reduction in the production of seeds that one of the finches,a type of bird,fed upon.This resulted in a decrease from 1,400 to 200 birds.Drought,in this specific situation,

Accepted Answer

In this specific situation, drought on the Galápagos Islands did not depend on the density of the bird population, therefore it should be considered a density-independent factor affecting the population density.

Question 3

Is it reasonable to expect that all habitats suitable for a given organism will have the same carrying capacity for that organism?

Accepted Answer

The carrying capacity of a habitat is determined by the availability of essential resources such as food, water, and shelter. While all habitats suitable for a given organism will have these resources, the amounts may vary, resulting in different carrying capacities. Therefore, it is not reasonable to expect that all habitats suitable for a given organism will have the same carrying capacity.

Question 4

In computing an individual's ecological footprint,which of the following would NOT be included?

Accepted Answer

Education level is not directly related to an individual's ecological footprint. The ecological footprint is a measure of human impact on the environment, including the use of resources and production of waste, which are directly affected by energy demand, food use, and goods and services use.

Question 5

Bald eagle populations reached such low numbers in the 1960s that some biologists predicted their extinction in the continental United States;what action appears to have been most significant in reversing their decline?

Accepted Answer

The use of DDT was the most significant action in reversing the decline of bald eagle populations. DDT caused eggshell thinning, which led to high rates of reproductive failure in nesting pairs. Bounties on predators and eagle sanctuaries likely provided some protection for eagles, but without addressing the primary cause of their decline, their populations would not have recovered. While reintroduction efforts may have contributed to the recovery of some small populations, it was not the most significant factor in reversing the decline.

Question 6

Density-dependent factors are more likely to limit population growth when

Accepted Answer

Density-dependent factors include competition for resources such as food and territory, disease transmission, and predation. When there are many individuals living in a fixed amount of space, the competition for resources becomes more intense, increasing the impact of these factors on population growth. The other options suggest conditions that are less likely to limit population growth.

Question 7

The amount of productive land and water that individuals or populations require to provide their required resources and dispose of its wastes is called the

Accepted Answer

The term "ecological footprint" refers to the amount of land and water resources that an individual or population needs to sustain their lifestyle and dispose of waste. This includes resources used for food production, energy consumption, and other daily activities. This term is widely used in the field of sustainability to measure the impact of human activities on the environment. The other options (A, C, and D) are not commonly used terms in environmental science to refer to this concept.

Question 8

Which of the following statements about carrying capacity is true?

Accepted Answer

The carrying capacity is established by the factor with the most limited availability, such as food, water, or space. This factor will ultimately limit the size of the population, and the carrying capacity will fluctuate depending on changes in the availability of that factor. The other statements are incorrect. An S-shaped curve represents a population that reaches its carrying capacity and levels off, not one that exceeds it. J-shaped curves show exponential growth, not the effects of carrying capacity. The carrying capacity can vary between different species in the same area.

Question 9

Examine the following graph,which shows the relationship between planting density and seeds produced per individual plant for Plantago major,also known as plantain weed.

What statement best describes the relationship?

Accepted Answer

The graph shows a negative relationship between planting density and seed production per plant, as the density increases, the seed production per plant decreases. However, the total seeds produced remain relatively constant, meaning that the decrease in seed production per plant is compensated by an increase in the number of plants at higher densities. Therefore, option B is the correct statement that best describes the relationship.

Question 10

The following figure shows that the human population was small and relatively stable for nearly 12,000 years but has increased dramatically in the past 200 years.

How might this increase in population growth be explained?

Accepted Answer

Prior human populations were at existing carrying capacities, but newly developed technologies such as advancements in medicine, agriculture, and industry have raised the carrying capacity and permitted the recent expansion in human population growth.

Question 11

Factors such as the age of reproductive maturity,maximum litter size,and the gestation period combine to produce an upper limit for the growth rate of any population;under what circumstances is that rate most likely to be seen?

Accepted Answer

When there are very few individuals in the population, for example, the initial colonists in a new habitat, or the first few individuals of an introduced species, the growth rate is most likely to be seen. This is because the population will have low competition for resources and will not yet have reached its carrying capacity. As the population grows, competition for resources will increase, which will put pressure on the population to slow its growth rate.

Question 12

As a component of its solution for overpopulation,China has imposed a policy that legally limits families to one child;China's government is attempting to manipulate which population factor?

Accepted Answer

The government is attempting to manipulate the population growth rate (r) by limiting the number of children per family. The other options are not directly related to this policy.

Question 13

For most populations,irregular fluctuations in size or density

Accepted Answer

Irregular fluctuations in size or density are more common than the smooth J-shaped growth curve because real-world populations are influenced by a variety of unpredictable environmental factors, interactions within and between species, and changes in carrying capacity, making smooth, predictable growth patterns less common.

Question 14

The Rapanui people initiated the environmental disasters on Easter Island by first

Accepted Answer

The Rapanui people cleared the vegetation on the island, which exposed the soil to erosion and decreased its ability to hold nutrients. This caused a negative impact on the soil quality, making it more difficult to grow crops and support animal and human life.

Question 15

When an isolated population reaches its carrying capacity

Accepted Answer

When a population reaches its carrying capacity, the birth rate equals the death rate, as the resources available to sustain the population are unable to meet the needs of any additional individuals. Therefore, the population stabilizes and there is no net increase in the number of individuals.

Question 16

Which of the following situations illustrates a link between the effects of density-dependent and density-independent factors?

Accepted Answer

In this situation, the drought is a density-independent factor that affects both the small and large herd of deer. However, the larger herd is also impacted by density-dependent factors, as the competition for resources becomes more intense as the population size increases. This illustrates the interaction between both types of factors.

Question 17

Biologists estimate that the human population on Easter Island declined by 90 percent during the 200-year period between AD 1400 and 1600;what accounts for the crash of this population?

Accepted Answer

The depletion of resources, deforestation, and soil erosion are the most widely accepted explanations for the population decline on Easter Island. The Rapa Nui people, who lived on the island, relied heavily on resources such as trees, which they used to build canoes, homes, and transport their large statues. The overuse of resources resulted in deforestation, which led to soil erosion, loss of farmland, and a decrease in crop yields. This, in turn, made it difficult to sustain a large population, leading to their decline over time.

Question 18

The top of the "S" in an S-shaped curve indicates that the population

Accepted Answer

The top of an S-shaped curve represents the carrying capacity of the environment, which is the maximum population size that the environment can support sustainably. Once the population reaches this level, it is no longer able to sustain further growth and will stabilize. Therefore, the correct choice is C.

Question 19

The effects of pollution are generally considered to be density independent because

Accepted Answer

Pollution affects organisms regardless of population density because the level of contamination is not dependent on how many individuals are present. Pollutants in the environment can accumulate and persist, potentially harming all organisms that come into contact with them.

Question 20

The following graph shows the growth of a Paramecium population.

The greatest amount of daily growth occurred when the population was at approximately ________ percent of its carrying capacity.

Accepted Answer

The greatest amount of daily growth occurred at approximately 50% of the carrying capacity, which is the point where the growth rate is steepest.

Quiz 21: Growth of Populations