Chapter 20 Quiz

How have warmer-than-normal climatic conditions affected moose populations on Isle Royale?

- Moose escaped the heat by resting in the shade, but then had less time for eating, which resulted in thinner moose that were not as prepared to survive winter temperatures. - Tick populations have grown and they have fed on the moose, which resulted in blood loss and higher death rates for moose. - An increase in the tick population has resulted in weight loss for the moose, which increased their death rate.

The island of Guam traditionally has not had any snakes that prey on birds; however, brown tree snakes that prey upon birds were introduced. Use your knowledge of wolf-moose population dynamics to determine what happened to the population dynamics of birds and the new snakes on Guam. Which statement is probably one of the results of the snake introduction?

- Snake populations increased exponentially as they preyed upon birds that had no defenses against the predators. - Because prey was abundant and few predators existed, snakes spread throughout the island - .As snake populations became very large, they reached the carrying capacity of Guam and caused bird populations to crash. - Because bird populations crashed, one of the birds' main prey items, spiders, increased their population size.

By studying the data collected from Isle Royale, ecologists have discovered that a large wolf population correlates to vigorous tree growth. Which statement best explains this pattern?

- Wolves decrease the moose population, which consumes trees as its main diet. - The remains of moose carcasses fertilize the soil, which allows for increased tree growth - .When there is a large wolf population on the island, the moose swim to the mainland. The decrease in moose allows for more tree growth.

When moose first arrived on Isle Royale and found a habitat without predators, the moose population _____.

- re-grew after a starvation period that allowed the vegetation to recover. - was not regulated by predator-prey interactions. - could be categorized as going through a cycle of "boom and bust" population dynamics. - grew exponentially, and then crashed due to lack of food.

Which ecological definition is incorrect?

A community is made up of biotic and nonliving components.

Why are truly random distributions rare in nature?

Individuals of a particular species often need certain types of conditions to survive and grow, so more individuals are found in these areas.

Which statement is true of distribution patterns in nature?

Uniform distribution allows individual organisms to maximize space between them.

Ecologists often study the spatial distribution of animals. Which of these descriptions of common distribution patterns is incorrect?

Uniform: moose are highly territorial creatures and move around an island habitat in large groups.

Which event or condition is a density-independent factor that could influence population growth?

a volcanic eruption that covers an island in a layer of lava

Once the carrying capacity of an environment is reached, the population generally _____.

cannot continue growing exponentially

Imagine a system where a finch feeds on thistle seeds and the finch population size is linked to the productivity of the thistle, and the thistle population size is related to foraging pressure of the finch population. This is an example of population dynamics at the _____ level.

community

Which of these is NOT an example of something that ecologists would generally study?

how the mitochondria of a mouse function in its cells

Ecologists study organisms at a number of levels with different numbers of components. Which sequence correctly orders these levels, from smallest to largest?

individual, population, community, ecosystem

All of these statements can be advantages of a clumped distribution pattern EXCEPT _____

it allows individuals to maximize space between them

Which phrase is NOT a biotic factor affecting population growth of moose on Isle Royale?

summer temperatures

All of these statements regarding ecosystems are correct EXCEPT _____.

sunlight and water are good examples of living components of an ecosystem

Growth rates are _____.

the difference between birth and death rates in a populatio

Population dynamics are influenced by birth and death rates. Which situation is NOT a factor that can cause early death for wolves on Isle Royale?

warmer temperatures causing tick populations that feed on wolves to increase dramatically, which causes wolves to lose blood and decreases their hunting abilities

Carrying capacity is NOT the point _____.

where additional resources are available only to individuals that immigrate into the population