Question 1

The figure below 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 to the development of agriculture, human populations were limited by the carrying capacity of their local ecosystems. However, in the past few hundred years, advancements in technology have increased the carrying capacity and allowed for the rapid expansion of the human population. This includes advancements in agriculture, medicine, and transportation, among other things.

Question 2

For most populations, irregular fluctuations in size or density

Accepted Answer

Irregular fluctuations in size or density commonly occur before populations reach their carrying capacity. These fluctuations can be caused by factors such as changes in environmental conditions, predation, or disease. The J-shaped growth curve represents exponential growth without any limiting factors, which is less common in natural populations. Density-independent factors can also contribute to irregular fluctuations, but they are not the only cause.

Question 3

The graph below 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 answer of The graph below shows the growth of...

Question 4

Studies of the population-size cycles seen between the snowshoe hare and the Canadian lynx showed that

Accepted Answer

The population sizes of the lynx and the hare are closely linked; when hare populations decrease, lynx populations also decrease due to a lack of food.

Question 5

Examine the graph below. 
What statement best describes the relationship between planting density and seed production per individual plant?

Accepted Answer

The answer of Examine the graph below. 
What statement best...

Question 6

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 the density-independent factor that affects the entire population of deer, regardless of its size. However, the survival of the smaller herd suggests that there may have been some density-dependent factors that were also at play, such as competition for resources. Therefore, both types of factors could have contributed to the outcome for the population of deer.

Question 7

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 Alaskan forest for owls is 8 per square kilometer. If we try to confine 12 owls in a 1-square-kilometer area, then it will exceed the carrying capacity of the environment. Thus, the owls might survive as malnourished adults but the next generation will have no more than eight individuals. This means that the population will undergo a correction through natural selection, and the weaker individuals will not survive to reproduce.

Question 8

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

Accepted Answer

The top of the "S" curve represents the carrying capacity of the environment, meaning that the population has reached its maximum sustainable level. At this point, the population growth rate slows down as resources become limited. Therefore, the correct choice is (C) has reached its carrying capacity.

Question 9

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 required to support an individual or population's resource consumption and waste production, and is therefore the best match to the given definition. A sustainable area, biological acreage, and environmental measure are not commonly used terms in reference to this concept.

Question 10

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 and therefore is not typically included in calculations.

Question 11

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

Accepted Answer

Pollution affects organisms regardless of their population density, as the level of contamination is not influenced by how many organisms are present.

Question 12

When an isolated population reaches its carrying capacity

Accepted Answer

When a population reaches its carrying capacity, the number of individuals in the population stabilizes. At this point, the birth rate is equal to the death rate, resulting in zero population growth. This is because resources are limited and can no longer support an increase in population size. Therefore, the best choice is B)the birth rate = the death rate.

Question 13

In 1978, a drought on the Galapagos Islands caused a reduction in the production of seeds that one of Darwin's finches, a kind of bird, fed upon. This caused a decrease from 1,400 to 200 birds. This population change factor

Accepted Answer

The answer of In 1978, a drought on the Galapagos...

Question 14

What was the effect of the pesticide DDT on bald eagles?

Accepted Answer

DDT caused thinning of the eggshells of bald eagles, leading to a high rate of egg breakage before the chicks could fully develop. This severely impacted the reproductive success of bald eagles, causing their population to decline.

Question 15

The Rapanui people created an environmental disaster on Easter Island by

Accepted Answer

The Rapanui people cut down too many of the island's palm trees, which were a crucial resource for their survival. The palm trees were used for building houses, boats, and for food and medicine. The loss of the trees led to deforestation, soil erosion, and a reduction in the availability of resources. This, in turn, had a devastating impact on the Rapanui people's ability to sustain themselves on the island.

Question 16

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

Accepted Answer

Different habitats for the same organism may have varying amounts of resources available, leading to differences in carrying capacity. Even if the organism is able to survive in multiple locations, the carrying capacity may still differ depending on the availability of resources. Therefore, it is not reasonable to expect that all habitats suitable for a given organism will have the same carrying capacity.

Question 17

Under the one-child policy, China's population is expected to peak and then decline in the year

Accepted Answer

China's population is expected to peak around 2030 due to the effects of the one-child policy and subsequent demographic trends.

Question 18

Lynx feed on rabbits, and the growth curves for these two species fluctuate together. This relationship is an example of a(n)

Accepted Answer

The fact that the growth curve of lynx and rabbits fluctuate together suggests a tightly linked cycle. This means that the populations of these two species are interdependent and directly influence each other. A and B are types of growth curves that describe population growth in the absence of any limiting factors or competition, while C describes fluctuations that may not be directly influenced by another species.

Question 19

Which of the following statements about carrying capacity is true?

Accepted Answer

The carrying capacity is determined by the factor that is most limiting to a population, such as food, water, or shelter. Once this limit is reached, the population will stabilize and may even decline if resources continue to be scarce. Therefore, D is the correct answer. A, B, and C are incorrect because they do not accurately describe the concept of carrying capacity.

Question 20

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

Accepted Answer

Density-dependent factors, such as competition for resources, predation, and disease, become more intense as the population size increases. Therefore, when there are more individuals living in the same amount of space, these factors are more likely to limit population growth. The other options do not necessarily affect the intensity of density-dependent factors.

Quiz 22: Growth of Populations

The figure below 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?