Dynamic Ecosystems and Their Populations

Dynamic Ecosystems and Their Populations

Multiple Choice

Which of the following is an example of a biotic limiting factor in an ecosystem?

• New predators move into an ecosystem

• A drought occurs for several months

• A hurricane passes through an ecosystem

• Living space is lost due to deforestation

Multiple Choice

Which of the following events would lead to an increase in the population of squirrels?

• Birth rate > Death rate

• Emmigration > Immigration

• Increase of predator

• Death rate increases due to a forest fire

Multiple Choice

Which statement describes ecosystems?

• They can never change once they are established.

• They constantly change in different ways over time.

• Ecosystems always revert back to their original state.

• Each ecosystem can exist for only a specific length of time.

Multiple Choice

The Nile crocodile is well-known for being hyper-aggressive whenever an uninvited visitor steps into their territory. However, there is one creature that the reptile not only tolerates, but practically welcomes into their aquatic domain. Incredibly, the Egyptian Plover aka “Crocodile Bird” will fly into the crocodile’s open mouth and feed upon the decomposing meat stuck between their teeth. The plover gets a not so scrumptious meal while the crocodile gets a little free dental work! What type of symbiotic relationship is this?

• predation

• commensalism

• mutualism

• parasitism

Multiple Choice

Look at the graph carefully. What type of relationship is this showing between the two species?

• parasitism

• predation

• commensalism

• competition

Multiple Choice

Which organism in this relationship is the tertiary or top consumer? Why?

• gazelle - smaller population, so higher up in food web/ energy pyramid

• lion - smaller population, so higher up in food web/ energy pyramid

• gazelle - larger population, so higher up in food web / energy pyramid

• lion - larger population, so higher up in food web / energy pyramid

Multiple Choice

How is secondary succession different from primary succession?

• Secondary occurs after a disturbance in an area that was previously uninhabited.

• Secondary occurs after a disturbance in an area in which the soil has remained intact.

• Secondary occurs over a longer period of time than primary succession.

• Secondary occurs when animals are introduced to an area that had only plants.

Multiple Choice

The diagram shows ecological succession. How can you tell from the diagram that this is primary succession rather than secondary?

• No producers exist when the process begins.

• Soil is present at the beginning of the process.

• The process ends with the growth of large trees.

• The sizes of the plants generally increase over time.

Multiple Choice

Which term describes the number and variety of organisms in a given area during a specific period of time.

• eutrophication

• succession

• carrying capacity

• limiting factor

Multiple Choice

How do pioneer species make succession possible on an island following a volcanic eruption?

• establishing homes in which animals can live

• using chemicals to produce food

• breaking down rocks into soil for plants to grow

• adjusting the climate by altering the average temperature in a region

Multiple Choice

Bees have a society in which different members have different responsibilities. Which term describes this behavior among bees?

• commensalism

• consumerism

• competition

• cooperation

Multiple Choice

The picture shows a land ecosystem that experienced a violent flood several months ago. Is the ecosystem experiencing primary or secondary succession?

• primary

• secondary

• not enough information is given

Fill in the Blank

A _______________ is something that occurs in an ecosystem that lowers the carrying capacity for a population dwelling in it.

Multiple Choice

Choose the limiting factor that is abiotic

• competition among two organisms over necessary resources

• more predators of a prey

• a tornado destroying an ecosystem

• an invasive parasite attacks ash trees

Multiple Choice

During the 1930's, a large region of the Great Plains experienced a drought that turned grasslands into dust. How did this change most likly affect populations of insects living among the grasslands?

• they adapted to eat dust instead of grass

• they were not affected because population size can't change over time

• they decreased because the resources they needed were not available

• they increased because other populations were eliminated from the environment

Multiple Choice

What causes competition to occur in an environment?

• a population falls below the environment's carrying capacity

• members of a population have different roles

• organisms struggle for a limited resource

• good conditions make resources plentiful