Chapter 5 Populations Test Review

An expert in demography is asked to predict changes to the population size of a small country. Which data about the country would be most useful for the expert to analyze? Select three answers.

1. percentages of males and females 2. birthrate and death rate 3. age structure

Scientists have observed the exponential growth of lionfish in the Caribbean Sea. Which of these predictions about the future of the lionfish population is the most likely to occur?

A limiting factor will cause the growth of the lionfish population to slow down, forming a pattern of logistic growth.

A rabbit population is affected by parasitism and disease, both of which are density-dependent limiting factors. Which statement describes the effects of parasitism and disease on the rabbits?

As the density of the rabbit population increases, parasites and disease weaken or kill a greater percentage of rabbits.

How does each graph indicate the growth rate of the country? Explain the relationship between the structure of the graph and the growth rate. **Short Answer**

Country 1: when a population is growing (there are more babies being born than there are people dying), the graphic forms the shape of a triangle. Country 2: These population pyramids are wider in the middle of the graph as the population has high numbers of middle aged and elderly people, but fewer young people. is when there is a lower death rate with the birthrate remaining constant (same). Country 3: is a population with low death rates and low birthrates. These population pyramids represent a stable population that will not change significantly

In the eighteenth century, the population of sea otters decreased significantly along the California coast. Scientists cite the hunting of sea otters by humans as the cause of this decrease. Today, the population of invasive lionfish is growing rapidly in the Caribbean Sea. However, scientists argue that human hunting or harvesting of lionfish will not affect the population. Which comparison of sea otters and lionfish is most useful for explaining the potential impact of human hunting on their populations?

Lionfish have a much higher birthrate.

Lake Tefillin is a large freshwater lake that is popular for recreation. One year, the managers of the lake introduce a population of rainbow trout to the lake. The graph shows the growth of the population over several years. Which best describes the growth pattern of the rainbow trout?

LogiStic growth, because the effect of limiting factors increases with the population size

Population data show that the growth rate of the world human population has been decreasing. Which statement is most useful for explaining this trend?

Many large, populous countries have been passing through the demographic transition.

The graph shows the changing populations of wolves and moose in Isle Royale National Park. Wolves are predators, and moose are their prey. Which of the following pairs of populations is most likely to increase and decrease in a similar pattern to the wolves and moose?

Moose and balsam fir, which are the favorite food plants of moose

Describe the changes that a country undergoes as it passes through the three stages of the demographic transition. Use the United States as an example. **Short Answer**

Stage I: the birthrate and death rate are equally high (population growth = 0) Stage II: the birthrate is high, while the death rate is decreasing (population growth is increasing because more people are being born and none are dying) Stage III: the birth rate is falling, so that it eventually equals the number of deaths (population is decreasing)

Murray is observing a bacterial colony that is growing in agar in a Petri dish. Agar is processed seaweed. Murray calculates that the population doubles in size every 32 hours. Which conclusion is supported by Murray's observations?

The agar and air in the Petri dish are providing all of the resources needed by the bacteria.

Bamboo is a type of grass. In the wild, pandas eat bamboo almost exclusively. For this reason, the availability of bamboo is a significant limiting factor on the panda population. Which statement describes how pandas could become extinct in the wild?

The bamboo population decreases so low that the carrying capacity for pandas becomes zero.

In a forest ecosystem, a variety of predators compete with one another for the same prey. The predators include wolves, coyotes, foxes, and hawks. Their prey include deer, rabbits, mice, and the chickens that live outdoors on nearby farms and backyards. Suppose that human activities, such as hunting, drastically reduce the populations of the wolves, coyotes, and foxes. Which statement best explains a likely change to the hawk population?

The hawk population increases to a new carrying capacity that is determined by one or more limiting factors, such as the availability of food.

The human population has changed in ways that are similar to other populations. How has the human population changed since it first appeared on Earth?

The population has generally increased at a relatively constant rate.

The graphs show the age structure for each of three countries. The horizontal bars show the percentages of the population in each age group, by gender. Note that for Country 1, about 20 percent of the population is between the ages of 0 and 4. This is the greatest percentage of any 4-year age span in all three countries. Which conclusion about Country 1 does its age structure support?

The population has generally increased, and at rates that have varied over time.

Demographers developed a hypothesis to explain the changes to the populations of countries over time. This hypothesis describes a demographic transition, in which countries change from a combination of high birthrates and high death rates to low birthrates and low death rates. The changes of the demographic transition are summarized in the graph. Which of these events is most likely to occur during Stage II of the demographic transition?

The population increases significantly, due mainly to a decrease in death rate.

Which statement BEST summarizes the effects that the Irish Potato Famine and Dust Bowl had on the respective populations of Ireland and the United States?

The populations of both areas decreased as people died from starvation or moved to other areas.

A scientist concludes that a population of bison has reached the carrying capacity of the prairie where it lives. The birthrate and death rate of the bison population are equal to each other. What can be concluded about the rates of immigration and emigration?

The rates of immigration and emigration are equal to each other.

A hurricane blows across a Caribbean island. The storm flattens trees, and it drowns or washes away a large number of plants and animals. As a result of the storm, the carrying capacity of the island is temporarily reduced for many of the island species. How is the storm classified as a limiting factor?

The storm is a density-independent limiting factor, because population size and density do not alter the storm's effect.

Studies predict that precipitation in California will decrease by up to 15% over the next 20-30 years. Predict two ways that this change in water availability could affect resource availability in the area. Predict how this could affect human activity in the area. Suggest a change that could be made to adapt to or reduce the impacts.

Without necessary water, plants will be unable to undergo photosynthesis. Through this process, oxygen is given off for humans to breathe and food. In addition, to photosynthesis, humans are contributing to carbon toxins in the atmosphere. By burning fossil fuels, humans is causing the temperature to increase: melting icecaps and drying up rivers/ lakes. As a result, no water is available for animas.

The managers decide to introduce rainbow trout to Lake Charles, another lake in the region of similar size and shape to Lake Tefillin. Should the managers expect a similar growth for the rainbow trout in Lake Charles? Explain your reasoning, and identify some of the factors that might affect the population growth. **Short Answer**

Yes. If the environment is similar to the other lake as Lake Charles, then the rainbow trout will grow exponentially with abundant supply of nutrients and fresh ecosystem. However, as the birth rate increase and the death rate decreases (with no predators except humans), the nutrients will lessen and more competition will occur- slowing the population growth. Finally, as food becomes scarce and clean water is limited (due to algae buildup/ oxygen lessens) the trout will reach carrying capacity stabilizing the growth rate.

Identify the type of growth that each of the charts above shows. Write 1 for Country 1, 2 for Country 2, and 3 for Country 3.

__1___ Rapid Growth (Niger) __3___ Negative Growth (Japan) __2___ Slow growth (United States)

A population of mice in a meadow is growing in a pattern of logistic growth. Order the steps below from 1-3 by writing a 1 next to the first step of the growth pattern and a 3 next to the last.

__2___ The rate of population increase begins to slow down. __3___ The population fluctuates near the carrying capacity. __1___ The population increases exponentially.

Label each statement with the phase of population growth that it describes. Write I for Phase I, II for Phase II, and III for Phase III.

___III__ The population reaches carrying capacity. __II___ The growth rate slows down, due to the effect of limiting factors. ___I__ Exponential growth is occurring. __III___ The changes to population size are relatively small, temporary, and difficult to predict. ___I__ Many limiting factors, such as competition for food and nesting grounds, have little or no effect on the population.

Label each statement with the stage of demographic transition it describes. Write I for Stage I, II for Stage II, and III for Stage III.

_____ This stage represents the United States today. _____ Improved health, sanitation, and nutrition help explain this stage. _____ This stage applies to most of human history, though not necessarily the present. _____ The population stops growing during this stage. _____ This stage helps explain why the human population grew very slowly until about 1900.

Brianna is mapping trees in a section of land. She observes that some of the trees are clumped together, some are uniformly separated, and some appear to be spaced randomly. What is she describing?

the population distribution