week 2(ch 26 &27)

Question 1

a group of individuals from the same species that live in the same area at the same time and can interbreed

Answer 1

population

Question 2

a group of all the alleles from all the gametes produced in each generation

Answer 2

gene pool

Question 3

equation for allele frequencies

Answer 3

p + q = 1

Question 4

equation for genotype frequencies

Answer 4

p^2+ 2pq+ q^2 = 1

Question 5

Hardy-Wienberg’s assumptions

Answer 5

1. random mating
2. no natural selection
   3.no genetic drift
   4 no gene flow
   5 no mutation

Question 6

inbreeding causes — to increase, but does not change—-

Answer 6

inbreeding causes homozygosity to increase, but does not change allele frequencies

Question 7

alleles that lower fitness

Answer 7

deleterious alleles

Question 8

inbreeding does not cause evolution, but it can…

Answer 8

increase the rate at which deleterious alleles are eliminated

Question 9

what are two reasons why inbreeding depression occur?

Answer 9

1. many recessive alleles represent loss of function mutations ( are bad)
2. many genes that are involved in fighting disease need heterozygote

Question 10

the number and relative frequency of alleles that are present in a particular population

Answer 10

genetic variation

Question 11

changes the average value of a trait because individuals at one end of the distribution experience low reproductive success

Answer 11

directional selection

Question 12

reduces the variation of a trait, but keeps the average value constant

eg. Weight of baby

Answer 12

stabilizing selection

Question 13

extreme phenotypes are favored. increases the amount of genetic variation

Answer 13

disruptive selection

eg only birds with extremely short or extremely long necks survive

Question 14

disruptive selection sometimes plays a role in…

Answer 14

speciation!

Question 15

when no single phenotype is favored; genetic variation is maintained

Answer 15

balancing selection

Question 16

when an individual of one gender selects for an individual of another gender

Answer 16

intersexual selection

Question 17

when selection occurs within two organisms of the same gender

eg. giraffes fighting or seals fighting

Answer 17

intrasexual selection

Question 18

any trait that differs between males and females

eg. Mallards

Answer 18

sexual dimorphism

Question 19

any change in allele frequency due to chance

Answer 19

genetic drift aka sampling error

Question 20

genetic drift occurs especially in

Answer 20

small populations

Question 21

over time genetic drift can lead to…

Answer 21

the random loss or fixation of alleles

Question 22

a change in allele frequency that occurs when a new population is established

Answer 22

founder effect

Question 23

when a large population experiences a sudden reduction in size

Answer 23

genetic bottleneck

Question 24

occurs when an individual leaves one population, joins another, and breeds

Answer 24

gene flow

Question 25

gene flow is --- with respect to fitness

Answer 25

gene flow is random with respect to fitness

Question 26

an evolutionary process that increases genetic diversity in populations

Answer 26

mutation

Question 27

mutation can have a very large effect when...

Answer 27

combined with genetic drift, gene flow, and selection

Question 28

the ultimate source of genetic variation

Answer 28

mutation

Question 29

a splitting event that creates two or more distinct species from a single ancestral species

Answer 29

speciation

Question 30

an evolutionarily independent population or group of populations

Answer 30

species

Question 31

the main criterion for identifying species is reproductive isolation

Answer 31

biological species concept

Question 32

isolation that prevents individuals from different species from mating ( before)

Answer 32

prezygotic isolation

Question 33

occurs when the offspring of matings between members if different species do not survive or reproduce

Answer 33

postzygotic isolation

Question 34

what is a disadvantage of using the biological species concept?

Answer 34

it doesn't apply to asexual organisms, fossils, or populations that do not overlap geographically

Question 35

identifying different species based on their size, shape, or other features

Answer 35

morphospecies concept

Question 36

the naming of two or more species when there is only one

Answer 36

polymorphic species

Question 37

two species that differ in traits other than morphology

Answer 37

cryptic species eg. eastern meadow larks and western meadow larks are almost identical in morphology, but their hybrid offspring are infertile

Question 38

what is disadvantage of using a morphospecies concept?

Answer 38

it is objective. It miss it misidentifies polymorphic species and misses cryptic species

Question 39

identifies species based on the evolutionary history of populations

Answer 39

phylogenetic species concept

Question 40

consists if a ancestral population, it's descendants, and ONLY those descendants

Answer 40

monophyletic group ( also clade or lineage)

Question 41

what is a disadvantage of phylogenetic species?

Answer 41

relatively few well- estimated phylogenies are currently available

Question 42

populations that are geographically isolated are in

Answer 42

allopatry

Question 43

speciation that begins with geographic isolation

Answer 43

allopatric speciation

Question 44

the physical splitting of a habitat

Answer 44

vicariance

Question 45

when populations or species live close enough that interbreeding is possible

Answer 45

sympatry

Question 46

speciation that occurs even though species live in the same geographical area

Answer 46

sympatric speciation

Question 47

error that creates the doubling of chromosome number

Answer 47

polyploidy

Question 48

when two species that have diverged and there is selection against interbreeding

Answer 48

reinforcement

Question 49

a geographic area where interbreeding occurs and hybrid offspring are common

Answer 49

hybrid zone

Question 50

4 processes that can create evolution

Answer 50

1. Natural selection 2. genetic drift 3 gene flow 4 mutation