3.3-3.4

Question 1

Food chain

Answer 1

Series of steps in an ecosystem in which organisms transfer energy by eating and being eaten

Question 2

Phytoplankton

Answer 2

Photosynthetic algae found near the surface of the ocean

Question 3

Food web

Answer 3

Network of complex intersections formed by the feeding relationships among the various organisms in an ecosystem

Question 4

Zooplankton

Answer 4

Small free-floating animals that form part of plankton

Question 5

Trophic level

Answer 5

Each step in a food chain or food web

Question 6

Ecological pyramid

Answer 6

Illustration of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web

Question 7

Biomass

Answer 7

Total amount of living tissue within a given trophic level

Question 8

Biogeochemical cycle

Answer 8

Process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another

Question 9

Nutrient

Answer 9

Chemical substance that organisms need to substance life

Question 10

Nitrogen fixation

Answer 10

Process of converting nitrogen gas into nitrogen compounds that plants can absorb and use

Question 11

Denitrification

Answer 11

Process by which bacteria converts nitrates into nitrogen gas

Question 12

Limiting nutrient

Answer 12

Single essential nutrient that limits productivity in an ecosystem