Energy Transfer in Ecosystems

Food webs consist of many intersecting food chains and represents the different things an organism can eat and be eaten by. What is the function of the decomposers in this meadow environment?

• Splitting of water into hydrogen and oxygen.

• Recycling of nutrients from dead organisms back into the soil.

• Conversion of light energy into chemical energy.

• Synthesis of organic molecules from inorganic raw materials.

The diagrams show a marine food web and an incomplete terrestrial food web. The organism in the terrestrial food web that corresponds to the krill in the marine food web is labeled X. Which of the following organisms is most likely organism X?

• 
• 
• 
• 

The diagram shown represents a portion of a food web in a Florida ecosystem. What effect would the removal of the cormorant population have on the state of dynamic balance present in the food web?

• Populations of eels and ospreys would decrease.

• Populations of fluke fish and eels would increase.

• Populations of mud snails and blowfish would increase.

• Populations of ospreys and mergansers would decrease.

A food chain provides details about the food relationships among organisms in an ecosystem. 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

• Sunlight

• Green plants

Ecosystems have producers, decomposers, and consumers. Carnivores and scavengers are both types of consumers in an ecosystem. Which of the following is a characteristic of scavengers that makes them different from carnivores?

• Scavengers eat only plant materials.

• Scavengers are omnivores that always eat live animals.

• Scavengers are omnivores that eat dead plants and animals.

• Scavengers are able to produce their own food when no other food is available.

This food web shows some of the relationships found in a mangrove ecosystem. This ecosystem consists of a grove of trees with an extensive root system and the organisms that use the grove for food or shelter. Materials cycle through the ecosystem as organisms consume one another. What do the arrows in the food web represent?

• The relative location of organisms in the ecosystem.

• The flow of energy from one organism in the ecosystem to another.

• The relative sizes of organisms in the ecosystem from smallest to largest.

• The increase in complexity of organisms from producer through consumer.

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.

The food web shows some of the feeding relationships among organisms in Arctic waters. A change in the population of one organism can affect the entire food web. Based on the information in the food web, which organism would be least affected by overfishing for cod in Arctic waters?

• Seals

• Shrimp

• Baleen whales

• Toothed whales

The food web shows some of the feeding relationships among organisms in Arctic waters. Near the surface of polar oceans, phytoplankton convert solar energy into chemical energy that fuels a complex ecosystem. The food web above illustrates some relationships among organisms in the Arctic. According to the food web, how would cod be classified?

• Producer

• Top predator

• Primary consumer

• Secondary consumer

Which statement describes a difference between decomposers and consumers in an ecosystem?

• Decomposers are types of plants, and consumers are types of animals.

• Decomposers remain in one place, but consumers move around within the ecosystem.

• Decomposers get energy only from plant materials, and consumers eat both plants and animals.

• Decomposers can obtain energy by digesting chemical compounds that consumers cannot digest.