15-2

Question 1

what are the advantages and disadvantages of marine creatures?

Answer 1

advantages: lots of water
disadvantages: harder to move

Question 2

what are the three categories of ocean organisms?

Answer 2

plankton, nekton, and benthos

Question 3

describe plankton

Answer 3

tiny algae that float in water are carried by currents. photoplankton: do photosynthesis, zooplankton: animal plankton

Question 4

describe nekton

Answer 4

fire-swimming animals that move independently of ocean currents

Question 5

describe benthos

Answer 5

organisms that live on or in the ocean floor, some stay in one location, most live in shallow coastal ocean floor

Question 6

what are hydrothermal vents?

Answer 6

seawater seeps into ocean floor through cracks in the crust
(black smokers)

Question 7

what are the three factors used to divide ocean into distinct marine life zones?

Answer 7

availability of sunlight, distance from shore, and water depth

Question 8

how is availability of sunlight a factor? describe all the zones.

Answer 8

photic zone: part of ocean into which sunlight penetrates
Euphotic zone: near surface where light is strong enough for photosynthesis
Lower photic zone: not enough light for photosynthesis, enough light for animals
Aphotic zone: below photic zone, no light

Question 9

how is distance from shore a factor?

Answer 9

way to subdivide marine life zones.
Physical conditions help determine which organisms can live in that zone
Intertidal zone: narrow area of shoreline covered by high tide and extends out to sea during low tide. Organisms living must tolerate changes.
Neritic zone: extends from low-tide line out to edge of continental shelf. most variety of organisms, shallow water, steady supply of nutrients
Oceanic zone: extends beyond edge of continental shelf, includes deepest and darkest parts of the ocean