Question

3 apply the skill
directions: study the diagram and information, read each question, and choose the best answer.
flow of nutrients in an ecosystem
diagram of nutrient flow: plants → animals that eat plants → animals that eat animals → living things that break down dead plants and animals → soil, air, and water → plants
matter, or the material that makes up everything around us, is continuously cycled in an ecosystem. organisms get materials they need to live from the environment. they then release waste matter back into the environment. nutrients are one form of matter that cycles through an ecosystem. the diagram shows the flow of nutrients in a land - based ecosystem.

1. based on the diagram, which statement describes a flow of nutrients in this land - based ecosystem?

a. most animals obtain nutrients by eating other animals.
b. plants obtain nutrients from soil, air, and water.
c. animals that eat animals are a source of nutrients for animals that eat plants.
d. living things that break down dead plants and animals contribute no nutrients to the ecosystem.

1. what would happen to the flow of nutrients shown in the diagram if all the plants in the ecosystem died?

a. nutrients would continue to cycle through the ecosystem, skipping the missing step.
b. plant - eating animals would start eating other animals.
c. the nutrients cycle would end.
d. soil, air, and water supplies would decrease and eventually end.
3 apply the skill
directions: study the information and diagram, read each question, and choose the best answer.
flow of energy in an ecosystem
as energy flows through an ecosystem, it is conserved. that is, the amount of energy neither increases nor decreases. plants get energy by making food. animals get energy by eating food in the form of plants or other animals. living things convert the energy stored in food into energy for movement, growth, and repair. a small amount of energy that a living thing takes in is stored in the cells of its body. most of the energy is transferred to the environment as heat, sound, motion, and—in some cases—light. energy pyramids show how energy flows through ecosystems. the diagram shows an energy pyramid for a forest ecosystem.
energy pyramid diagram: ferns (bottom) → caterpillars → birds → foxes (top)

1. what is one way in which energy flows through the forest ecosystem represented by the diagram?

a. from ferns to caterpillars
b. from foxes to ferns
c. from birds to ferns
d. from birds to caterpillars

1. what idea does the shape of an energy pyramid most likely reinforce?

a. in general, smaller animals in an ecosystem eat larger animals in the ecosystem.
b. plants use sunlight to obtain energy and form the basis for all food chains in an ecosystem.
c. organisms at higher levels of a food chain live at higher levels in an environment.
d. the amount of available energy decreases as energy passes from organism to organism.

Explanation:

Question 2

• Option A: The diagram shows two types of animals (eat plants, eat animals), so not most animals eat other animals. Eliminate A.
• Option B: The diagram has an arrow from "Soil, air, and water" to "Plants", so plants get nutrients from them. This matches.
• Option C: The diagram's arrows don't show animals that eat animals as a nutrient source for plant - eaters. Eliminate C.
• Option D: Decomposers (living things that break down dead plants/animals) return nutrients to soil/air/water, so they do contribute. Eliminate D.

• Option A: Nutrient cycling relies on plants to take in nutrients from the environment and start the cycle. If plants die, the cycle can't skip this step. Eliminate A.
• Option B: Plant - eating animals' diets are adapted to plants; they won't suddenly start eating other animals. Eliminate B.
• Option C: Plants are the start of the nutrient cycle (take in from environment, then passed to animals, then decomposed back). If plants die, the cycle ends as there's no source to start it. This is correct.
• Option D: Soil, air, and water supplies are not dependent on plants for their existence (they are part of the environment). Eliminate D.

• Option A: In the energy pyramid, ferns are producers at the bottom, caterpillars are primary consumers (eat plants). So energy flows from ferns to caterpillars. This is correct.
• Option B: Foxes are top consumers, ferns are producers. Energy flows from producers to consumers, not the reverse. Eliminate B.
• Option C: Birds are consumers (eat caterpillars), ferns are producers. Energy flows from producers to consumers, not the reverse. Eliminate C.
• Option D: Birds are higher up in the pyramid (eat caterpillars), caterpillars are lower. Energy flows from lower to higher levels (caterpillars to birds), not the reverse. Eliminate D.

Answer:

B. Plants obtain nutrients from soil, air, and water.

Question 3