Ecosystem lesson 1 review

How are bacteria classified in a forest ecosystem?

• A. as consumers

• B. as decomposers

• C. as herbivores

• D. as producers

Decomposers are important to the flow of energy in an ecosystem because they

• A. are at the top of every food chain.

• B. eat things other organisms do not eat.

• C. make up a large portion of the top layer of the soil.

• D. break organic material into parts that can be reused.

An ecosystem is a community of organisms interacting with their physical environment. Why are decomposers an important part of ecosystems?

• A. They break down dead organisms to return nutrients to the soil.

• B. They produce their own food for survival.

• C. They play a role in preventing weathering and erosion.

• D. They provide most of the energy to consumers.

A brown bear eats a variety of foods including berries, insects, and small animals. Which BEST describes a brown bear?

• A. producer

• B. herbivore

• C. carnivore

• D.omnivore

Meadow voles are small mouse-like animals that eat plants and insects. Their niche in an ecosystem is a

• A. omnivore

• .B. herbivore.

• C. carnivore

• D. scavenger

Plants in a forest need to obtain nutrients from the soil to survive. How do MOST of the nutrients get back in the soil once the forest plants have used them for growth?

• A. Organic matter is recycled from dead organisms.

• B. Commercial fertilizers are applied by humans.

• C. Solar radiation reaches the ground surface.

• D. Rainwater drips off of living organisms.

Decaying plants and animals are important to an ecosystem because they

• A. cause disease in living organisms.

• B. reduce soil erosion.

• C. recycle oxygen to the air.

• D. return nutrients to the soil

Rolanda is growing tomato plants in her garden. She has created a compost pile and has been adding compost around her tomato plants to help fertilize them. Compost is solid waste in which organic material is broken down by microorganisms in the presence of oxygen to where it can be safely stored, handled, and applied to the environment. On what does Rolanda primarily rely in order for composting to work?

• A. producers

• B. consumers

• C. scavengers

• D. decomposers

Living organisms have a role in weathering and erosion in the ecosystem. Which statement describes the role of bacteria and fungi?

• A. They hold soil in place during high winds.

• B. They decompose organic matter in the soil.

• C. They increase water access and flow and help aerate the soil.

• D. They grow within cracks of rocks, breaking the rock into small pieces.

An organism that breaks down dead plants and animals, returning matter back into the soil, is called a

• A. herbivore.

• B. producer.

• C. competitor.

• D. decomposer.