Changes in Ecosystems

Some grass species need fire in order for their seeds to germinate. Why might this adaptation be useful for grasses?

• Fire allows trees to grow and to provide shade for the grasses.

• The hot temperature of the fire helps the grasses grow faster.

• Seeds can germinate in an area that has been cleared by a fire.

• Fire discourages grazing by large animals so the grasses can grow higher.

How can you tell from the diagram that this is an example of secondary succession rather than of primary succession?

• No plants 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.

Which statement best describes ecosystems?

• They are always evolving

• 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.

Which of these might result from the process of natural eutrophication?

• A lake becomes built up with nutrient rich sediment over time from surrounding land

• A rock breaks down into soil.

• A glacier retreats to expose new land.

• A nonnative species takes resources from native species.

Which type of ecological succession is more likely to occur after a flood?

• Primary Succession

• Secondary Succession

• Tertiary Succession

• None of the above.

Match the following terms with their definitions: 1) Primary Succession 2) Secondary Succession 3) Biodiversity

• The variety of life in a particular habitat

• Primary Succession

• The series of community changes which take place on a previously colonized, but disturbed or damaged habitat.

• Secondary Succession

• The series of community changes which occur on an entirely new habitat

• Biodiversity

What is a major threat to biodiversity?

• Urbanization

• Pollution

• Invasive species

• All of the above

What role do keystone species play in biodiversity?

• They have no impact on biodiversity

• They decrease biodiversity by dominating ecosystems

• They increase biodiversity through their extensive prey species

• They maintain the structure of an ecosystem and influence the diversity and abundance of other species

Which of the following best describes ecosystem services?

• Services provided by the government to protect the environment

• Benefits humans obtain from ecosystems

• Services provided by non-profit organizations for species conservation

• Benefits that ecosystems obtain from humans

When designing technology to solve enviornmental problems, engineers must consider conditions or factors that they must work in. What are these factors called?

• Trade Offs

• Constraints

• Prototypes

• Method Planning