4.2 Energy flow in Ecosystems

Rabbits are members of a community in a meadow. The rabbits eat grasses, and clover, as well as roots, seeds, and tree bark. What defines the organisms that share the same trophic level as the rabbits?

• snakes, hawks, and other animals that eat rabbits

• community members that interact with rabbits

• meadow animals that are about the same size as a rabbit

• meadow animals that eat plants and plant products

Juanita is studying the food web of the open ocean. Which step would be most beneficial for her to follow to identify the primary producers of the food web?

• Look for floating plants, such as water lilies

• . Look for tiny phytoplankton that floats on the ocean surface.

• Look for small animal plankton near the ocean surface

• Look for plants or animals that live along the ocean floor

The diagram shows a model of feeding relationships in an ecosystem? What is shown by the arrows that lead to and from the raccoon?

• The raccoon is part of several food chains, but not a food web.

• The raccoon is part of several food chains and several food webs.

• The raccoon is part of one food web but has no food chains.

• The raccoon is part of one food web and several overlapping food chains.

Which of the following BEST describes the flow of energy through a food chain?

• Energy flows between primary producers and consumers, in either direction.

• Energy flows from consumers to primary producers, in one direction only.

• Energy flows from primary producers to consumers, in one direction only

• Energy flows between primary producers and consumers, in an endless cycle

The diagram shows a model of an ecosystem. What does the model represent?

• the total biomass in each trophic level

• the total amount of energy in the ecosystem

• the relative amount of energy available at each trophic level

• the conservation of energy as energy transfers between organisms

Ethan is modeling food chains he observes in his local ecosystem. Which of these models represents possible food chains he might observe? Select all that apply

• primary producer -> consumer -> consumer -> consumer -> consumer

• primary producer -> consumer -> primary producer -> consumer

• consumer -> primary producer -> consumer -> primary producer -> consumer

• consumer -> consumer -> consumer -> consumer

What should an ecologist measure in order to construct a pyramid of biomass for an ecosystem?

• the biomass in each trophic level of the food web

• the total mass of all the organisms in a representative area of the ecosystem

• the total mass of all the organisms in the ecosystem

• d. the number of organisms in each trophic level of the food web

A food web shows feeding relationships in an ecosystem. In this food web, what is represented by the chains of arrows from the grass to the fox?

• the one-way flow of energy through the ecosystem

• the one-way flow of matter through the ecosystem

• the conservation of energy in the ecosystem

• the removal of energy from the ecosystem

Vernon is studying the population of deer in a tract of forest. He gathers the following data. Birth rate: ~50 deer/year Death rate: ~70 deer/year Which additional observation would support the conclusion that the deer population is NOT changing size from year to year, meaning that the net population change is 0?

• About 20 deer per year immigrate to the tract of forest

• About 20 deer per year emigrate from the tract of forest

• The average life span of a member of the deer population is 20 years

• If a deer survives its first year of life, its average life span is 20 years

The graph describes the population of dandelions in a field over the course of one summer. Which statement best describes the growth of the dandelions?

• Linear growth occurs because the field provides abundant but limited resources during the summer

• Logistic growth occurs because the field provides unlimited resources during the summer.

• Exponential growth occurs because the field provides unlimited resources during the summer.

• Fluctuating growth patterns occur because the population reached the carrying capacity of the field during the summer.