Pre-AP BIO B Units 3-4 Alternate Test

Organisms that obtain nutrients by breaking down dead and decaying plants and animals are called

decomposers

Which are two ways a population can DECREASE in size?

decreased birthrate and emigration

Which of the following is NOT one of the factors that play a role in population growth rate?

demography

Only 10 percent of the energy stored in an organism can be passed on to the next trophic level. Of the remaining energy, some is used for the organism's life processes, and the rest is

eliminated as heat.

Any factor in the environment that causes population growth to decrease is a

limiting factor.

A symbiotic relationship in which both species benefit from the relationship is called

mutualism

The symbiotic relationship between a flower and the insect that feeds on its nectar is an example of

mutualism because the flower provides the insect with food, and the insect pollinates the flower

What is the process by which bacteria convert nitrogen gas in the air to ammonia?

nitrogen fixation

Which is a biotic factor that affects the size of a population in a specific ecosystem?

number and kinds of predators in the ecosystem

A symbiotic relationship in which one organisms lives on or inside another organism and harms it is called

parasitism

Each of the following is an abiotic factor in the environment EXCEPT

plant life.

All of the members of a particular species that live in the same area are called a(an)

population

Green plants are

producers

What is the original source of almost all the energy in most ecosystems?

sunlight

Use Figure 4-1 to answer the question

Producers

According to the figure above, what would happen to the ecosystem if Sessile invertebrates (shown below) were removed from this food web?

Small predatory fish population would decrease

Which of the following descriptions about the organization of an ecosystem is correct?

Species are grouped in populations, which make up communities.

In some ecosystems, wolves have been eliminated due to their threats to humans. How can the reintroduction of wolves benefit the ecosystem?

It can eliminate weak animals from a prey population, thereby decreasing competition for natural resources.

What will most likely happen if a nonnative species is introduced into a stable ecosystem?

The native species will have to compete for resources with the nonnative species, and the ecosystem will become unbalanced

Which of the following BEST explains the difference in the amount of available energy in the trophic levels of the desert ecosystem?

There is less available energy in the fourth trophic level because of the loss of energy through metabolism in each of the lower trophic levels.

An organism that uses energy to produce its own food supply from inorganic compounds is called a(an)

autotroph.

What is the combined portions of Earth called in which all living things exist?

biosphere

A symbiotic relationship in which one member of the association benefits, and the other is neither helped nor harmed is called

commensalism

Which will reduce competition within a species' population?

fewer individuals

If the birth rate becomes higher than the death rate in a population, then the population will ______.

grow

The movement of organisms INTO a given area from another area is called

immigration.

When the birthrate in a population becomes HIGHER than the death rate, the population growth rate

increases

All the interconnected feeding relationships in an ecosystem make up a food

web