Ecology l.17.1

What might most likely happen if an ecosystem lost all its decomposers?

• Consumers would not be able to obtain food and their populations would quickly decrease.

• Nutrients would remain in waste products and remains of dead organisms, and would not be recycled.

• The food web would gain nutrients because there would be no organisms breaking them down or consuming them.

• Producers would multiply until they reached the carrying capacity of the habitat.

Think of all the components that contribute to the flow of energy and matter in a food web. Which of the following groups forms the base of the food web?

• consumers

• decomposers

• producers

• scavengers

This food chain shows some of the plants and animals that could be observed in a meadow ecosystem. What is the source of energy for the snake?

• the toad

• the owl

• the beetle

• green plants

All organisms take energy from their environment. Every organism needs this energy in order to grow and reproduce. How do producers get energy?

• They obtain energy by eating plants, bacteria, and algae.

• They extract chemical energy from decaying organic matter.

• They extract energy from the chemicals in soil, air, and water.

• They capture energy from sunlight and manufacture their own food.

Each organism has its own role in an ecosystem. Organisms can be producers, consumers, or decomposers. Which of these organisms can be classified as a decomposer?

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A healthy ecosystem must have producers, consumers, and decomposers. Most decomposers are either fungi or bacteria. Why are decomposers an essential part of a healthy ecosystem?

• Decomposers are a necessary part of the diet of most consumers.

• Decomposers convert plant material into a form that primary consumers can use.

• Decomposers make resources available to producers by breaking down waste materials.

• Decomposers extract energy from sunlight as they break down plant materials, adding energy to the system.

What is the primary source of energy used by producers during photosynthesis?

• thermal energy from the sun

• light energy from the sun

• chemical energy from food and oxygen

• chemical energy from carbon dioxide and water

What information is included in a food web?

• definitions of producer, consumer, and decomposer

• the amount of food energy available in an ecosystem

• the feeding relationships among organisms in an ecosystem

• the number of different types of organisms in an ecosystem

Some consumers, such as many flying insects, need large amounts of energy to grow and move from one place to another. How do consumers get energy to function?

• Consumers obtain all of their energy by eating other organisms.

• Consumers obtain some energy from other organisms and some from sunlight.

• Consumers obtain most of their energy by absorbing it from their environments.

• Consumers light energy from the sun and convert it into chemical energy stored in food.

What is the primary role of decomposers in an ecosystem?

• to control the population of producers and consumers

• to compete with producers for energy and other resources

• to provide a source of energy for the producers in the ecosystem

• to recycle energy and materials from dead producers and consumers