17: Species Abundance & Diversity-Community Structure

Question 1

community composition

Answer 1

mix of species, including their number and relative abundance, within a set area

Question 2

attributes of diversity

Answer 2

species richness and relative abundance

Question 3

What pattern do most communities illustrate?

Answer 3

few common species with many rare ones

Question 4

Relative abundance

Answer 4

the percentage each species contributes to the total number of individuals

Question 5

how can we graphically compare two community diversity?

Answer 5

rank-abundance curves

Question 6

step one of rank-abundance curve

Answer 6

sort table based on rank from high to low

Question 7

step two of rank-abundance curve

Answer 7

calculate relative abundance of each species in the community

Question 8

step three of rank-abundance curve

Answer 8

draw graph with rank on x-axis and relative proportion on y-axis

Question 9

step four of rank-abundance curve

Answer 9

repeat for control group

Question 10

gradual slope on rank-abundance curve

Answer 10

greater species evenness

Question 11

species evenness

Answer 11

equitable distribution of individuals among species. highest when all species have the same abundance

Question 12

problems with graphically comparing two communities

Answer 12

graphs represent qualitate comparison, but often requires a quantitative comparison

Question 13

Diversity Indices

Answer 13

Shannon-Wiener Index. The higher the number, the higher the diversity

Question 14

types of diversity

Answer 14

alpha, beta, and gamma

Question 15

alpha diversity

Answer 15

within-habitat diversity

Question 16

beta diversity

Answer 16

between-habitat diversity (changes along an environmental gradient)

Question 17

gamma diversity

Answer 17

large-scale landscape diversity (combines alpha and beta diversity)

Question 18

How is Species Diversity related to Ecosystem Services

Answer 18

directly proportional

Question 19

where in the globe is diversity typically highest? lowest?

Answer 19

highest in tropics, lowest at poles

Question 20

factors that influence diversity

Answer 20

habitat complexity, environmental complexity, disturbances

Question 21

disturbance

Answer 21

A discrete punctuated killing, displacement, or damaging of one or more individuals that directly or indirectly creates opportunities for others

Question 22

Intermediate Disturbance Hypothesis

Answer 22

Predicts that intermediate levels of disturbance promotes higher diversity

Question 23

Biggest disturbance to biodiversity

Answer 23

Humans

Question 24

overall decline in wildlife population between 1970 and 2010

Answer 24

52%

Question 25

species richness

Answer 25

number of species in a community

Question 26

species diversity

Answer 26

combination of number of species and relative abundance of each species in a community; usually described as an index

Question 27

community structure

Answer 27

all the interactions among species

Question 28

food webs

Answer 28

describe trophic interaction between species and thus describe community structure. arrow points from prey to predator

Question 29

food chains

Answer 29

subset of trophic interaction within a food web. simple and linear and often collapse species into trophic levels

Question 30

trophic levels

Answer 30

obtain their energy in a similar manner (primary producers

Question 31

guilds

Answer 31

exploit a common resource in a similar manner

Question 32

Dominants

Answer 32

when one or a few species represent a large relative proportion of the community

Question 33

keystone species

Answer 33

species with a disproportionate impact on the community relative to its abundance. often predators

Question 34

abundances vs. trophic level

Answer 34

high trophic level, low abundance

Question 35

ecosystem engineers (foundation species)

Answer 35

species that modifies, creates, or destroys habitat and directly or indirectly modulates the availability of resources to other species