Chapter 16: Marine Communities

Question 1

what is a community?

Answer 1

group composed of many populations of organisms that interact at a particular location

Question 2

what is a population?

Answer 2

a group of organisms of the same species occupying a specific area

Question 3

where is the largest marine community located?

Answer 3

within the uniform mass of permanently dark water between the sunlit surface and the deep bottom

Question 4

what are communities dependent on?

Answer 4

the availability of energy

Question 5

what is a habitat?

Answer 5

an organism’s “address” within its community, its physical location

Question 6

what is an organism’s niche?

Answer 6

an organism’s “occupation” within its habitat, its relationship to food and enemies, an expression of what the organism is doing

Question 7

what is ecology?

Answer 7

the study of the balance of physical and biological factors and of the relationships of organisms and interactions within communities

Question 8

what is environmental resistance?

Answer 8

the sum of the effects of these limiting factors in the environment

Question 9

what is the carrying capacity?

Answer 9

the population size of each species that a community can support indefinitely under a stable set of environmental conditions

Question 10

what is population density?

Answer 10

the number of individuals per unit area (or volume)

Question 11

what does random distribution mean?

Answer 11

implies that the position of one organism in a community in no way influences the position of other organisms in the same community

Question 12

what is the most common pattern of population distribution?

Answer 12

clumped distribution

Question 13

what is clumped distribution?

Answer 13

occurs when conditions for growth are optimal in small areas because of physical protection, nutrient concentration, initial dispersal, or social interaction

Question 14

what is uniform distribution?

Answer 14

occurs when there is equal space between individuals

Question 15

what is the rarest distribution pattern of them all?

Answer 15

uniform distribution

Question 16

what is a climax community?

Answer 16

a stable, long-established community, self-perpetuating aggregation of species. tends not to change unless disrupted by severe external forces

Question 17

what is succession?

Answer 17

the orderly changes of a community’s species composition from temporary inhabitants to long-term inhabitants

Question 18

what is the intertidal zone?

Answer 18

the band between the highest high tide and lowest low tide

Question 19

what is one of the Earth’s most densely populated areas?

Answer 19

the intertidal zone

Question 20

what is wave shock?

Answer 20

the powerful force of crashing waves

Question 21

what is dessication?

Answer 21

drying out by exposure to air and sunlight

Question 22

what is an estuary?

Answer 22

a broad, shallow, river mouth where freshwater and saltwater mix

Question 23

do estuaries have more or less wave shock?

Answer 23

less

Question 24

what is brackish water?

Answer 24

mixed saltwater and freshwater

Question 25

what are macroplankton?

Answer 25

plankton that are larger than about 1 cm

Question 26

what are holoplankton?

Answer 26

zooplankton that spend their whole lives in the plankton community

Question 27

what are meroplankton?

Answer 27

plankton who are temporary visitors as the juvenile stages of crabs, barnacles, etc.

Question 28

what is one of the ocean's most important zooplankters?

Answer 28

krill

Question 29

where is about 83% of the ocean's total biomass concentrated?

Answer 29

its uppermost 200 meters

Question 30

what is the deep scattering layer (DSL)?

Answer 30

a relatively dense aggregate of fishes, squid, and other animals that usually migrate up and down in synchrony with daylight

Question 31

what is symbiosis?

Answer 31

the co-occurrence of two species in which the life of one is closely interwoven with the life of the other

Question 32

what occurs in mutualism?

Answer 32

both the symbiont and the host benefit from the relationship

Question 33

what occurs in commensalism?

Answer 33

the symbiont benefits from the association while its host neither benefits nor is harmed

Question 34

what occurs in parasitism?

Answer 34

the parasite lives in or on the host for at least part of its life cycle and obtains food at the host's expense

Question 35

what is the most common type of symbiotic relationship?

Answer 35

parasitism

Question 36

what is a species-specific relationship?

Answer 36

an exclusive relationship between two species