community structure

Question 1

define keystone species

Answer 1

species that has a disproportionate impact on the community relative to its abundance

Question 2

what happens if you remove a keystone species?

Answer 2

it initiates changes in community structure and often results in loss of diversity

Question 3

what happens as you move across a landscape?

Answer 3

biological and physical structure of the community changes AND as you travel farther, the more pronounce changes become

Question 4

what happens as you move across a landscape?

Answer 4

biological and physical structure of the community changes AND as you travel farther, the more pronounced changes become

Question 5

define zonation

Answer 5

changes in physical and biological structure of communities as one moves across the landscape

Question 6

define community

Answer 6

group of species that occupy to a given area and interact either directly or indirectly

Question 7

what is species richness

Answer 7

number of species in the community

Question 8

what is species diversity

Answer 8

species richness and species evenness

Question 9

ecological succession is?

Answer 9

process by which an ecosystem matures and develops. it is gradual, sequential and predictable change

Question 10

define succession

Answer 10

gradual change in plant and animals communities in an area following disturbance

Question 11

primary succession on ___ exposed geological substrates

Answer 11

newly

Question 12

secondary succession following ____ that ____ destroy soil

Answer 12

disturbances, do not

Question 13

define climax community

Answer 13

late-successional community that remains stable until disrupted by disturbance

Question 14

define primary succession

Answer 14

development of a new ecosystem in an area previously devoid of organisms

Question 15

define secondary succession

Answer 15

regrowth of an ecosystem after a disturbance and it is more rapid than primary because soil building is not required

Question 16

example of primary?

Answer 16

bare rock to climax forest
stage 1: lichen pioneer community
stage 2: moss community
stage 3: herbaceous community
stage 4: shrub community
stage 5: tree community
stage 5: climax forest or equilibrium community - association of organisms best adapted to the physical conditions of a defined area

Question 17

example of secondary succession?

Answer 17

old field succession
1y: dominant; crabgrass
2y: dominant; asters
3rd-18thy: grass shrub community
19th-30thy: young pine forest
30th-70th: mature pine forest
70th-100thy: pine to hardwood transition
100thy+ climax oak-hickory forest

Question 18

define intermediate disturbance hypothesis

Answer 18

highest diversity will occur at levels of moderate disturbance

Question 19

(t/f) as succession occurs, overlap will occur

Answer 19

true

Question 20

what other community changes as plant community changes

Answer 20

animal

Question 21

zonation vs succession

Answer 21

succession is temporal change and zonation is spatial change

Question 22

define early successional species

Answer 22

plant species with high dispersal rates, ability to colonize disturbed sites, short life span, shade-intolerant “pioneer species”

Question 23

define late successional species

Answer 23

long-lived, shade tolerant, plant species that supplant early successional species, low rates of dispersal colonization

Question 24

primary vs secondary succession

Answer 24

primary occurs on a site previously unoccupied by a community and secondary occurs on previously occupied sites after a disturbance

Question 25

define chronosequence

Answer 25

group of sites within same area that are in different stages of succession

Question 26

what happens under high frequency of disturbance?

Answer 26

absence of later successional species reduces overall diversity

Question 27

what happens at intermediate frequency of disturbance?

Answer 27

all species coexist and diversity is at maximum

Question 28

what happens when disturbance is absent?

Answer 28

later successional species eventually displace earlier ones and diversity is now low

Question 29

what is a food web?

Answer 29

looks at movement of matter and energy throughout a community

Question 30

define keystone predation

Answer 30

predation that is central to the organization of a community

Question 31

environmental changes can be?

Answer 31

allogenic or autogenic

Question 32

define autogenic

Answer 32

direct result of the activities of organisms in the community (biotic)

Question 33

define allogenic

Answer 33

successional change brought about by a change in the physical environment (abiotic)

Question 34

species colonization ___ species richness

Answer 34

increases

Question 35

species replacement ___ number of species present

Answer 35

decreases