Changing Ecosystem

Glaciers melted and exposed a new area of land. What kind of succession would occur?

• primary

• secondary

• biological

• eutrophication

Answer explanation

Primary succession occurs when new land is formed, such as when glaciers melt and expose bare rock. This process starts with pioneer species colonizing the area, making it the correct choice.

What is the role of lichen in ecological succession?

• It helps break down rock to make soil

• It allows trees to grow

• It creates new land to increase the size of the ecosystem

• It provides food for larger mammals

Answer explanation

Lichen plays a crucial role in ecological succession by breaking down rock surfaces, which contributes to soil formation. This process allows for the establishment of other plant life, facilitating further ecological development.

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What is the role of algae in eutrophication?

• It uses up a large amount of the oxygen available

• It provides food for the fish to eat

• It cleans the water to improve the quality

• It provides habitat for additional species to grow.

Answer explanation

In eutrophication, algae proliferate due to excess nutrients, leading to oxygen depletion as they decompose. This process uses up a large amount of the oxygen available, harming aquatic life.

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Which is an example of secondary succession?

• A lava flow creates new land

• A lava flow covers an existing portion of land

Answer explanation

Secondary succession occurs in areas where a disturbance has destroyed an existing ecosystem but left the soil intact. A lava flow covering existing land fits this definition, as it disrupts the ecosystem but not the soil.

Which is an example of primary succession?

• A lava flow creates new land

• A lava flow covers an existing portion of land

Answer explanation

Primary succession occurs on newly formed land, such as that created by a lava flow. This process starts with bare rock, allowing pioneer species to colonize and gradually build an ecosystem, unlike covering existing land.

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Trees are chopped down by loggers for new building materials. Over time, the trees begin to grow again. What type of succession would this represent?

• primary

• secondary

• eutrophication

• climax

Answer explanation

This scenario represents secondary succession because the area was previously occupied by trees. After logging, the ecosystem can recover and regrow, unlike primary succession, which occurs on barren land.

An old parking lot has been abandoned. Over time, soil builds up and grasses start growing. What type of succession has occurred?

• primary

• secondary

• eutrophication

• climax

Answer explanation

The succession described is primary succession, as it occurs in a previously uninhabited area where soil has formed over time, allowing grasses to grow. This contrasts with secondary succession, which happens in areas where life previously existed.

What happens to populations after major events such as fires and floods?

• The populations increase because there is more food available

• Many populations decrease because food and habitats are destroyed

• Populations increase at first and then slowly decrease.

• Populations decrease and don't recover from the devastation

Answer explanation

After major events like fires and floods, many populations decrease because food sources and habitats are destroyed, leading to a decline in species that rely on those resources for survival.

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Why does primary succession take longer to reach a climax community?

• Because trees do not perform photosynthesis.

• Because climax community is in a forest.

• Because primary succession already has soil.

• Because primary succession does not have soil.

Answer explanation

Primary succession takes longer to reach a climax community because it starts on bare rock or surfaces without soil. The formation of soil is a slow process, delaying the establishment of plant life and the eventual climax community.

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What type of succession is shown going from Figure A to Figure B?

• primary succession

• ecological succession

• secondary succession

• intermediate

Answer explanation

The transition from figure A to figure B indicates secondary succession, which occurs in areas where a disturbance has cleared an ecosystem but left the soil intact, allowing for the regrowth of vegetation.

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