Chapter 50

Question 1

detritus

Answer 1

a layer of dead organic matter accumulates at ground level or on seafloors and lake bottoms

Question 2

turnovers

Answer 2

in lake ecology, the complete mixing of upper and lower layers of water that occurs each spring and fall in temperate zone lakes

Question 3

thermocline

Answer 3

a gradient (cline) in environmental temperature across a large geographic area

Question 4

emergent vegetation

Answer 4

any plants in an aquatic habitat that extend above the surface of the water

Question 5

benthic zone

Answer 5

the area along the bottom of an aquatic environment

Question 6

permafrost

Answer 6

a permanently frozen layer of icy soil found in most tundra and some taiga

Question 7

specific heat

Answer 7

the amount of energy required to raise the temperature of one gram of a substance by one degree Celsius, a measure of the capacity of a substance to absorb energy

Question 8

net primary productivity

Answer 8

in an ecosystem, the total amount of carbon fixed by photosynthesis over a given time period minus the amount oxidized during cellular respiration

Question 9

invasive species

Answer 9

an exotic (nonnative species) that upon introduction to a new area, spreads rapidly and competes successfully with native species

Question 10

epiphytes

Answer 10

a non-parasitic plant that grows on trees or other solid objects and is not rooted in soil