BCOR 102: Exam 3

Question 1

S-hat equation (for species rank/abundance)

Answer 1

S(v)obs + S(v)undetected

Question 2

s(v)undetected equation

Answer 2

a^2 / 2b

Question 3

Hypothesis 1: Habitat diversity hypothesis

Answer 3

more habitats -> more different niches -> more species can coexist

Question 4

H2: productivity hypothesis

Answer 4

increasing biomass and richness of species at the bottom of the food chain increases diversity at higher levels

Question 5

H3: Keystone predator hypothesis

Answer 5

rocky intertidal seastar stuff

Question 6

keystone predator (from H3)

Answer 6

increases prey species diversity by preferentially eating the competitive dominant

Question 7

Keystone predator (foraging strategies)

Answer 7

specializes on competitive dominant prey species (richness goes up)

Question 8

random predator

Answer 8

consumes prey in proportions in which it encounters it (richness goes down)

Question 9

switching predator

Answer 9

prefers the most common species in an assemblage (richness goes up)

Question 10

rare species specialist

Answer 10

prefers rare species (richness goes down)

Question 11

keystone species

Answer 11

a species whose presence or absence leads to cascading effects on diversity

Question 12

trophic cascade

Answer 12

reciprocal changes in abundance at different levels of a food chain

Question 13

H4: Niche Overlap Hypothesis (3)

Answer 13

a. expand resource axis
b. increase resource specialization
c. increased tolerance of overlap

Question 14

Expand resource axis (H4a)

Answer 14

when the resounce x-axis line is stretched out, fitting more species

Question 15

Expand resource axis (H4a)

Answer 15

when the resource x-axis line is stretched out, fitting more species

Question 16

Increase resource specialization (H4b)

Answer 16

species specialize in specific resources, narrowing their parameters

Question 17

Increased tolerance of overlap (H4c)

Answer 17

more overlap with other species, just tolerate it more

Question 18

H5: intermediate disturbance hypothesis

Answer 18

coral reefs pre and post hurricane, make bell shaped curve

Question 19

non-equilibrium hypothesis

Answer 19

a. in early years, species are good colonizers, poor space competitiors (r-selected)
b. in later years, poor colonizers, good space competitors (k-selected)
c. in the middle, both a and b species

Question 20

darlington’s rule

Answer 20

for oceanic islands, 10x increase in island area leads to a doubling of species number

Question 21

random sampling hypothesis

Answer 21

a. number of individuals that accumulate on an island is proportionate to island area
b. number of species detected increases as more individuals are sampled

Question 22

equilibrium theory of island biogeography

Answer 22

MW eqilibrium model, the island stuff

Question 23

immigration rate

Answer 23

number of “new” species colonizing island / time

Question 24

extinction rate

Answer 24

number of island species going extinct / time

Question 25

Assumptions of MW model

Answer 25

1. source pool of P mainland species with persistent populations
2. Probability of colonization is inversely related to distance or isolation of island
3. probability of an extinction for a population is inversely related to population size
4. population size is proportional to island area
5. colonizations and extinctions of different species are independent of each other (species interactions aren’t important)

Question 26

predictions of MW model

Answer 26

1. s-hat is a stable equilibrium point
2. s-hat = f(A,D) -> area and distance
3. frequent extinctions + recolonizations on island
4. lack of strong species interactions

Question 27

evolution (general)

Answer 27

sustained change in the phenotype of a system through time

Question 28

evolution (biological)

Answer 28

change in allele frequencies of a population through time (adaptation and speciation)

Question 29

genotype

Answer 29

underlying genetic composition of individual

Question 30

phenotype

Answer 30

physical appearance (observed traits)

Question 31

gene

Answer 31

section of DNA on a chromosome that codes for a particular trait

Question 32

alleles

Answer 32

one of two or more alternate states for a gene

Question 33

homozygote

Answer 33

individual with 2 identical alleles at a gene

Question 34

heterozygote

Answer 34

2 different alleles for a gene

Question 35

dominant allele

Answer 35

one whose phenotype is expressed in heterozygous or homozygous individuals

Question 36

recessive allele

Answer 36

phenotype is only expressed in homozygous individuals

Question 37

discrete traits

Answer 37

color, hair type

Question 38

continuous traits

Answer 38

size, mass, protein expression

Question 39

pleiotropy

Answer 39

a single gene affects more than one trait

Question 40

epistasis

Answer 40

gene-gene interactions where the expression of one gene affect the expression of another gene

Question 41

polygenic

Answer 41

small additive effects of many genes on one trait

Question 42

hardy-weinberg model

Answer 42

expected allelic + genotypic frequencies arising only from random mating

Question 43

gene pool

Answer 43

set of all allele copies in a population

Question 44

HW (hardy-weinberg) assumptions

Answer 44

1. no mutations
2. no migration
3. random mating
4. no natural selection
5. large population size
6. random segregation of alleles at meiosis

Question 45

predictions of HW

Answer 45

1. genotype frequencies will change for only 1 generation from initial values
2. no further changes in genotype frequency
3. HW never changes allele frequencies

Question 46

s-hat equation (H5)

Answer 46

(PxI) / (I + E)

Question 47

t-hat equation (H5)

Answer 47

(IxE) / (I + E)