unit 1

Question 1

what is evolution?

Answer 1

descent with modification

change in genetic composition of a pop from gen to gen

change in heritable traits of a pop from gen to gen

Question 2

what is natural selection?

Answer 2

Many offspring are produced, not all survive

Traits vary among individuals within a pop and may be heritable

Some heritable traits give individuals an advantage in their env

Advantageous traits, conferring higher fitness, become more common

Question 3

Aristotle

Answer 3

Scale of nature arranges species in order of lower to higher complexity

Describes species as fixed

Question 4

James Hutton

Answer 4

Earth is old and is shaped by small, slow changes

Gradualism

Question 5

Thomas Robert Malthus

Answer 5

Human pop growth is limited by resources

Question 6

Jean-Baptiste Lamarck

Answer 6

Species drive towards increased complexity

Traits that are used improve and are inherited by offspring
Proposes organisms change due to environment

Ex: giraffe wants more food so stretches its neck to be longer, then giraffe’s baby inherits long neck

Question 7

Georges Cuvier

Answer 7

Fossils exist as evidence of extinction

Question 8

Charles Lyell

Answer 8

Processes that shape the earth have been uniform over time

Question 9

Charles Darwin

Answer 9

Observations of geology, fossils, plants, and animals led Darwin to think about how species arise

Voyage of the Beagle

Question 10

On the Origin of Species

Answer 10

Descent with modification

Species diversity due to branching from common ancestor in response to env

Describes NS as mechanism for evolution

Question 11

what are the principles of natural selection?

Answer 11

Many offspring are produced, not all survive

Traits vary among individuals within a pop and may be heritable

Some heritable traits give individuals an advantage in their env

Advantageous traits, conferring higher fitness, become more common

Question 12

homology

Answer 12

similarity due to ancestry

can be anatomical or molecular; form and func may be very different

suggest descent with modification

Question 13

convergence

Answer 13

similarity of form/func due to similar envs

Question 14

phenotypic plasticity

Answer 14

a genotype that produces different phenotypes in response to the env

the phenotype that results from plasticity is not heritable

Question 15

population

Answer 15

group of individuals of the same species that live in the same area and interbreed, leaving viable offspring

Question 16

alleles

Answer 16

different variants of a gene

Question 17

gene pool

Answer 17

all copies of all alleles at every locus in all members of the pop

Question 18

evolution

Answer 18

change in the gene frequencies of a pop from gen to gen

Question 19

Hardy-Weinberg principle

Answer 19

If alleles are transmitted by meiosis and random mating, frequencies do not change over time

Question 20

Hardy-Weinberg equations and values

Answer 20

p: frequency of alleles A1
q: frequency of alleles A2

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

Question 21

Assumptions of HW equil

Answer 21

1. selection
2. no mutation
3. no migration
4. large pop
5. random mating

Question 22

genetic drift

Answer 22

change in allele frequency due to chance

has larger effect on smaller pops

Question 23

bottleneck effect

Answer 23

something like a natural disaster cause a decrease in population and only a few different phenotypes are most popular when the pop increases

Question 24

founder effect

Answer 24

small number of individuals establish a new pop

daughter pops have lower genetic diversity than source pops

Question 25

intrasexual selection

Answer 25

selection within a sex to compete for mates

Question 26

intersexual selection

Answer 26

selection by one sex for mates; mate choice

Question 27

balancing selection

Answer 27

maintains multiple forms of alleles

Question 28

heterozygote advantage

Answer 28

heterozygotes have greater fitness than either homozygote

Question 29

frequency-dependent selection

Answer 29

fitness depends on how common the phenotype is in the pop

Question 30

constraints of evolution

Answer 30

laws of physics sources of genetic variation adaptation is opportunistic trade-offs environmental change

Question 31

species

Answer 31

groups of actually or potentially interbreeding pops, which are reproductively isolated from other such groups

Question 32

what are some difficulties in defining species?

Answer 32

Local variation Asexual reproducers Hybrids

Question 33

habitat isolation

Answer 33

species mate in different places

Question 34

temporal isolation

Answer 34

species mate at different times

Question 35

behavioral isolation

Answer 35

unique behaviors attract different species

Question 36

mechanical isolation

Answer 36

morphological differences prevent mating

Question 37

gametic isolation

Answer 37

sperm cannot fertilize eggs

Question 38

reduced hybrid viability

Answer 38

hybrids do not live to maturity

Question 39

reduced hybrid fertility

Answer 39

hybrids do not produce viable offspring

Question 40

hybrid breakdown

Answer 40

offspring viability is reduced after several gens

Question 41

allopatric speciation

Answer 41

Species are geographically divided, leading to selection and/or genetic drift in the divided pops

Question 42

sympatric speciation

Answer 42

Polymorphism appears in a pop that members of the pop find attractive, leading to more appearance of the trait; sexual selection, habitat differentiation

Question 43

autoploidy sympatric speciation

Answer 43

Cell division error within a species leads to increase in chromosome number In a diploid, error leads to diploid gametes and tetraploid species New species likely established through self-fertilization

Question 44

alloploidy sympatric speciation

Answer 44

Hybridization between species, chromosomes cannot pair up Error doubles chromosomes, hybrids can now interbreed New species likely established through self-fertilization

Question 45

adaptation

Answer 45

natural selection in response to env leads to increased frequency of phenotype in the pop over time

Question 46

local adaptation

Answer 46

species exhibit phenotypes that differ due to local conditions could lead to speciation over time

Question 47

acclimation

Answer 47

physiological response to env lead to change in individual phenotype during a single gen

Question 48

hybridization

Answer 48

when reproductive isolation between two species breaks down

Question 49

reinforcement

Answer 49

hybrids less fit Individuals that hybridize have fewer offspring Reproductive isolation increases

Question 50

fusion

Answer 50

hybrids more fit Individuals that hybridize have an equal number or more offspring Reproductive isolation decreases

Question 51

what is speciation the result of?

Answer 51

reproductive isolation

Question 52

what reduces reproductive isolation?

Answer 52

gene flow

Question 53

evolutionary processes that lead to reproductive isolation

Answer 53

natural selection genetic drift mutation