Chapter 5 How Ecosystems Work

an atmospheric gas that increases when fossil fuels are burned

evidence of excessive fertilizer use

a final and stable community

a type of succession that occurs on abandoned farmland

a gradual process of change and replacement of the types of species in a community

a common type of succession that occurs on a surface where an ecosystem has previously existed

What is the ultimate source of energy for almost all organisms? a. producers b. consumers c. the sun d. bacteria

Which of these consumers might depend on a rabbit for its energy? a. grasshopper b. coyote c. cow d. horse

What term is used to describe a linear sequence in which energy is transmitted from one organism to the next as each organism eats another organism? a. food web b. food chain c. trophic level d. energy pyramid

What term is used to refer to the many feeding relationships that are possible in an ecosystem? a. food web b. food chain c. energy pyramid d. energy transfer

Which organism would occupy the level on an energy pyramid with the most energy? a. bobcat b. bird c. grasshopper d. carrot

In the carbon cycle, where do the producers get their carbon? a. the atmosphere b. carbohydrates in plants c. fossil fuels d. animal remains

Where are fossil fuels located? a. on the surface of Earth b. deep within Earth c. beneath the ocean floor d. all of the above

How do lichens contribute to primary succession? a. Lichens begin to break down rock to form soil. b. Lichens decompose organic matter from animals and plants. c. Lichens are nitrogen-fixing bacteria. d. Lichens convert carbohydrates into fossil fuels.

Where would you most likely find nitrogen-fixing bacteria? a. in leaves of trees b. on the roots of legumes c. on dust particles in the atmosphere d. in blue-green algae

What type of vegetation would you expect to find on an abandoned farm that has been undisturbed by humans for 150 years? a. short grasses b. shrubs c. young pine trees d. tall, mature oak trees

Consumers are organisms that a. eat only other animal species. b. get their energy by eating other organisms. c. are also known as self-feeders. d. occupy an ecosystem’s lowest energy level.

The energy consumed by organisms a. can be stored in fat and sugar molecules. b. remains constant at all trophic levels. c. undergoes magnification in food chains. d. is not partially lost during digestion.

Which of these is a large reservoir of nitrogen that is unusable by most organisms? a. soil b. atmosphere c. ocean d. space