Biol 1102 Exam 4

Front 1

Microevolutionary Forces

Back 1

forces that cause biological evolution

Front 2

5 microevolutionary forces

Back 2

mutation

nonrandom mating (sexual selection)

genetic drift

gene flow

natural selection

Front 3

mutations

Back 3

the source of all genetic variation

Front 4

non-random mating

Back 4

sexual selection. individuals choose their mates.

Front 5

types of nonrandom mating

Back 5

male-male competition to mate with females

males display to attract females

both sexes choose mates

Front 6

lek

Back 6

an area where males gather to display for females

Front 7

negative assortative mating

Back 7

choosing a mate UNLIKE yourself.

increases heterozygotes, decreases homozygotes

Front 8

stabilizing selection

Back 8

selection favors heterozygotes.

negative assortative mating can produce a pattern of stabilizing selection.

preserves genetic variation

Front 9

positive assortative mating

Back 9

choosing a mate who is LIKE yourself.

increases homozygotes, decreases heterozygotes.

Front 10

disruptive selection

Back 10

selection that favors both homozygotes.

leads to genetic divergence/speciation.

positive assortative mating always leads to a pattern of disruptive selection.

preserves genetic vartiation

Front 11

directional selection

Back 11

selection that favors one homozygote.

eliminates genetic variation

Front 12

what determines the fate of the heterozygote in directional selection?

Back 12

if there is a dominance relationship between alleles.

Front 13

predicted genotype frequencies:

Back 13

use test for evolutionary change

Front 14

what is the hardy-weinberg equlibrium theory?

Back 14

mathematical theory

predicts genotype frequencies from observed allele frequency.

Front 15

what are assumptions of the hw theory

Back 15

no microevolutionary forces operating

Front 16

how do we measure genetic variation in a population

Back 16

when you have more than 1 allele at a high frequency

ex: 2 alleles each at 50% frequency max variation

ex: 4 alleles each at 25% frequency max variation

Front 17

which 2 patterns of selection preserve genetic variation

Back 17

stabilizing, disruptive

Front 18

which pattern of selection eliminates genetic variation

Back 18

directional

Front 19

which pattern of selection can lead to speciation

Back 19

disruptive

Front 20

biological evolution

Back 20

nonrandom changes in genotype or allele frequencies across generations

Front 21

natural selection

Back 21

differential fitness among individuals based on inherited characteristics

Front 22

adaptation

Back 22

a trait that is or has been a target of selection

Front 23

fitness

Back 23

the ability to survive and reproduce

Front 24

biological species concept

Back 24

species are groups of interbreeding natural populations that are reproductively isolated from other groups

Front 25

galapagos finches

Back 25

example of directional selection.

during drought, directional selection favored birds with long beaks

Front 26

sickle cell anemia

Back 26

example of stabilizing selection

in malaria regions, heterozygotes have advantage. yes, get "half" sickle-cell disease, but also has resistance to malaria.

Front 27

african finches

Back 27

example of disruptive selection

favors either birds with long beaks or birds with small beaks

should lead to pos. assortative mating

Front 28

sexual dimorphism

Back 28

males and females are different

Front 29

why is sexual dimorphism a thing

Back 29

because males and females invest differently in reproduction

Front 30

fitness indicator theory

Back 30

darwin and ra fisher.

sexual ornaments in males evolve so that females can judge the quality of potential male mates

Front 31

why doesnt natural selection completely eliminate harmful alleles/mutation

Back 31

-recessive alleles hide in heterozygoes

-selection varies. can be good in one place and bad in another.

-some alleles do not affect u until after reproduction

Front 32

frequency-dependent selection

Back 32

the fitness of the genotype depends on its frequency in the population

Front 33

positive frequency dependent selection

Back 33

phenotypes are favored only when it is common.

ex: warning coloration

Front 34

negative frequency dependent selection

Back 34

phenotypes are favored only when it is rare or uncommon

ex: lef handed fighters

Front 35

artificial selection

Back 35

selection for specific trait by humans (aka selective breeding/domestication)

Front 36

co-evolution

Back 36

reciprocal adaptation in different species. evolutionary arms race.

ex: predator-prey coevolution, flower-pollinator coevolution, host-parasite coevolution

Front 37

adaptive radiation

Back 37

one species evolves into many species in a short time period.

ex: hawaiian honeycreepers, galapagos finches, north american wood warblers.

Front 38

remember about evolution

Back 38

-populations evolve, not individuals

-there is no selection w/o genetic variation

-selection acts on alleles and genotypes thru phenotypes

Front 39

gene flow

Back 39

movement of individuals rom one population to another with mating

Front 40

what happens with lots of gene flow?

Back 40

populations cant be genetically different

gene flow prevents speciation

Front 41

what happens with no gene flow?

Back 41

populations become genetically different.

most common way new species form

Front 42

migration

Back 42

seasonal movement of a population from one geographic area to another

Front 43

dispersal

Back 43

movement of a population from their birth areas to their breeding areas

Front 44

genetic drift

Back 44

random changes in allele and genotype frequencies due to sudden, random events.

Front 45

genetic drift (bullets)

Back 45

-big problem in small populations

-decreases heterozygotes, increases homozygotes

-reduces genetic variation

-not adaptive, can prevent selection.

Front 46

effect of genetic drift on allele frequencies

Back 46

allele frequencies are more stable in larger populations

Front 47

population bottleneck and founder effects

Back 47

severe reduction in population size, loss of genetic variation.

much less genetic variation than in the original population.

Front 48

effective population size (Ne)

Back 48

average number of individuals in a population that contribute genes equally to the next gen.

usually smaller than actual (census) pop size

Front 49

example of when census size does not equal effective population size

Back 49

when male elephant seals form harems

Front 50

molecular evolution

Back 50

evolution at the level of DNA sequences

Front 51

allele mutation is "fixed"...

Back 51

means that allele is the ONLY allele in the population, having replaced all others

Front 52

fixed mutations are...

Back 52

used as genetic markers to identify human ancestors, dog breeds

Front 53

positive selection (directional selection at the DNA level)

Back 53

best allele increases in frequency until it becomes fixed

Front 54

selective sweep

Back 54

loss of genetic variation following positive selection

positive selection sweeps away genetic variation

Front 55

purifying selection

Back 55

selection favors only one best allele. new alleles are worse and selected against.

Front 56

balancing selection (stabilizing or disruptive selection at level of dna)

Back 56

2 different alleles are favored by selection

Front 57

diversifying selection

Back 57

selection that favors as much genetic variation as possible.

ex. mhc1 and mhc2 genes

Front 58

neutral allele

Back 58

an allele that has no effect on the phenotype. frequencies in the population change randomly (genetic drift) across generations.

example: silent 3rd codon position mutation)

Front 59

neutral molecular evolution

Back 59

allele frequencies are controlled by mutation and genetic drift, not by selection

Front 60

genetic variation

Back 60

refers to genetic differences w/in a species (me v u)

Front 61

genetic divergence

Back 61

refers to genetic differences between species (species 1 v species 2)

Front 62

molecular clock hypothesis

Back 62

if the neutral mutation rate is constant, populations should accumulate fixed neutral differences (divergence) at a constant rate per generation. that rate can be estimated and used to estimate the divergence between species.

ex: cyt-b gene evolves @ abt 2% sequence divergence per mil years in small birds.

Front 63

epigenetics

Back 63

variation in organisms that is not controlled by differences in dna sequences. such changes are often controlled by changing how genes are transcribed, but w/o changing DNA sequences.

Front 64

maternal effects

Back 64

phenotype of offspring partly determined by genotype and environment of the mother. occurs bc mom has added something to egg (methylated dna, mrna, protein, hormones, etc)

Front 65

female canaries put _____ in eggs so offspring growth can catch up to older sibs

Back 65

androgen

Front 66

during transcription, dna is transcribed into

Back 66

mrna

Front 67

does transcription occur on both strands of the dna molecule

Back 67

yes, but in opp directions

Front 68

where does transcription occur

Back 68

nucleus

Front 69

what enzyme makes mrna molecule

Back 69

rna polymerase

Front 70

translation occurs in the

Back 70

cytoplasm

Front 71

what is the actual site of translation

Back 71

on the ribosome

Front 72

what is a codon

Back 72

group of 3 mrna bases

Front 73

what does trna do

Back 73

carries amino acids to ribosome

Front 74

what is an anticodon

Back 74

trna complement to mrna codon

Front 75

why do many dna mutations have no effect on phenotype

Back 75

the 3rd codon position can often be any base and still make same amino acid. this is neutral genetic variation (silent variation)

Front 76

what does gene expression mean

Back 76

the gene has gone thru transcription and translation to make a protein

Front 77

does transcription require a primer

Back 77

no, rna polymerase starts it.

Front 78

how are genes regulated

Back 78

a) dna methylation: shuts genes off. methyl groups added to c and a nucleotides. present in all cells and dna except housekeeping genes. major form of tissue specific gene regulation

b) in pos regultion, transcriptional activator protein binds to dna at 5' end of gene to start transcription. w/o activator protein, ther eis no transcription and the gene is off.

c) in neg regulation, a repressor protein binds the dna to block transcription. gene remains off until repressor protein is removed. (ex. SRY protein)

Front 79

positive selection

Back 79

best allele increases in frequency until it is fixed

Front 80

ex of positive selection

Back 80

lct gene

lactose gene makes lactase enzyme. the allele that allows lactose tolerance was under positive selections in some human populations.

Front 81

diversifying selection

Back 81

selection that favors as much genetic variation as possible

Front 82

example of diversifying selection

Back 82

mhc genes. selection favors many low-freq alleles so that many dif heterozygotes can be formed.

genetic variation is good, so you can recognize many different antigens.

Front 83

balancing selection

Back 83

2 or more alleles are favored by selection

Front 84

example of balancing selection

Back 84

sickle cell anemia.

Front 85

domain of humans

Back 85

eukarya

Front 86

kingdom of humans

Back 86

animalia

Front 87

phylum of humans

Back 87

chordata

Front 88

class of humans

Back 88

mammalia

Front 89

order of humans

Back 89

primates

Front 90

family of humans

Back 90

hominidae

Front 91

genus of humans

Back 91

homo

Front 92

species of humans

Back 92

sapiens

Front 93

linnean hierarchical classification system

Back 93

organisms in same group are more related to each other than to organisms in different groups

Front 94

phylogeny (cladogram)

Back 94

tree showing evolutionary relationships.

close branches=close evolutionary relationships

Front 95

melanism

Back 95

does not help build trees.

overproduction of pigment melanin leads to development of different color morph

Front 96

leucism

Back 96

underproduction of melanin and other pigments produces patchy pale color morph w/in a species

Front 97

albinism

Back 97

complete absense of melanin produces entirely pale color morph

Front 98

convergent evolution (analogy)

Back 98

does not help build trees.

organisms evolve to look alike, but are not closely related.

example: american and african vultures; monarchs and viceroys

Front 99

vestigal structures

Back 99

structures that have lost their original function

ex: appendix, leg bone in whales

Front 100

atarisms

Back 100

"throwbacks"--genes present but normally turned off

ex: teeth in chickens, anal fin in dolphin, extra toes in horses.

Front 101

homology

Back 101

does help us build trees

organisms are similar bc they are closely related

ex: blue jay, stellar jay

Front 102

dna sequence characters

Back 102

must be neutral alleles. must be fixed differences if comparing different species.

Front 103

ingroup

Back 103

the groups of closely related species u are studying

Front 104

outgroup

Back 104

a closely related species, but not part of the group u are studying.

Front 105

why do we use an outgroup

Back 105

character state in outgroup assumed to be ancestral. allows us to infer direction of evolutionary change.

Front 106

shared-derived character

Back 106

character shared by 2 or more "sister" species in the ingroup, but not the outgroup.

Front 107

apomorphy

Back 107

a character found in only one species

Front 108

ancestral character

Back 108

character found in ingroup and outgroup, or in outgroup

Front 109

what does each tick mark on the tree represent?

Back 109

evolutionary change from one character state to another.

Front 110

principle of parsimony

Back 110

the least complicated explanation is prob the best explanation

Front 111

macroevolution

Back 111

evolution above the level of population (species and above. ex, horse evolution, bird feet)

Front 112

phyletic gradualism

Back 112

new species evolve by accumulating many small changes over long periods of time

Front 113

punctuated equilibrium

Back 113

speciation is rapid and followed by long period of no change (stasis)

Front 114

genetic variation

Back 114

genetic differences within a population or species

Front 115

genetic divergence

Back 115

genetic differences between species

Front 116

interbreeding depression

Back 116

decreased fitness breeding. individuals too closely related. offspring homozygous at many genes

Front 117

heterosis

Back 117

hybrid vigor. increased fitness breeding. genetically different individuals. mutts are healthier than purebreds

Front 118

outbreeding depression

Back 118

decreased fitness breeding individuals too genetically different from each other.

epistasis and pleiotropy cause poor gene interactions.

Front 119

reproductive isolation

Back 119

no gene flow

individuals cannot breed, and produce sterile or no offspring

occurs as a by product of genetic change

Front 120

____between different chicken breeds produce the fastest growing rates and most meet

Back 120

hybrids

broilers- gain 10 lbs in 10 weeks

Front 121

the ____wolf (coywolf) and the southeastern _____wolf are hybrids between the ____ and _____. both grow larger than coyote

Back 121

eastern

red

gray wolf

coyote

Front 122

pre-zygotic isolation

Back 122

mating and fertilization prevented, no zygote forms.

Front 123

temporal pre-zygotic isolation

Back 123

species dont breed at same time

Front 124

behavioral pre-zygotic isolation

Back 124

dif mating behaviors prevent dif species from mating

Front 125

ecological/habitat pre-zygotic isolation

Back 125

if species live in different environments, they never meet each other.

Front 126

mechanical pre-zygotic isolation

Back 126

some parts do not fit.

Front 127

post-zygotic isolation

Back 127

mating occurs and zygote forms, but offspring is sterile or dies early.

Front 128

haldane's rule

Back 128

if in the offspring of 2 different animal species one sex is absent, rare, or sterile, that sex is the heterogametic sex.

Front 129

geographic separation models

Back 129

how geography can block gene flow and lead to speciation

Front 130

allopatric speciation

Back 130

geographic ranges do not touch or overlap significantly.

no gene flow between populations.

prob most common form of speciation

example: northern spotted owl vs mexican

Front 131

parapatric speciation

Back 131

ranges touch, but do not overlap significantly. hybrid zone forms where overlap is.

small gene flow.

example: northern oriole vs baltimore

Front 132

sympatric speciation

Back 132

ranges overlap significantly. geography does not prevent gene flow.

Front 133

microallopatric speciation

Back 133

sympatric speciation is prob just allopatric at a smaller spacial scale.

Front 134

speciation by polyploidy

Back 134

new species formed when chromosome number in hybrids doubles, allowing polyploid hybrids to mate with other polyploid hybrids, but not with either parent species.

creates new hybrid species that is reproductively isolated from either parent species.

Front 135

artificial polyploidy

Back 135

used to overcome inbreeding in plant breeding experiments

Front 136

example of artificial polyploidy

Back 136

wheat and rye together make triticate, which has traits of both parents but 1st gen is sterile.

colchicine chemicals are used to block microtubule formation during cell division, causing nondisjunction and polyploidy in gametes.

Front 137

extinction

Back 137

a) fossil records show at least 20 large scale extinction events

b) loss of species diversity

c) loss of diversity followed by adaptive radiation

Front 138

permian-triassic extinction

Back 138

about 250 mil year ago

biggest extinction

prob comet/asteroid impact

about 95% of marine and 70% of land species went extinct.

Front 139

K-T extinction

Back 139

about 65 mil year ago

asteroid impact in gulf of mexico

52% of marine life and 18% of land vertibrates, including dinos, went extinct.

Front 140

primary cause of mass extinction

Back 140

extraterrestrial impacts, changes in global ecology

Front 141

what strikes earth more frequently, asteroids or comets

Back 141

asteroids (70%)

Front 142

extinction occurs at a natural "background" rate of ________. scientists estimate we are now losing species at _______x background rate

Back 142

1-5 species per year

1000x

Front 143

as many as _____% of all species could be extinct by the end of the century, including most big animals

Back 143

20-50%

Front 144

behavior

Back 144

what an animal does and how it does it

Front 145

innate behaviors

Back 145

developmentatlly fixed, not modified by environmental factors.

instinctive

no opportunities for learning

ex- cliff-edge avoidance in kittiwake gulls.

Front 146

FAP

Back 146

sequence of innate behaviors that is unchangeable and, once initiated, is carried to completion.

ex: egg rolling behavior in geese.

Front 147

super-normal stimulus

Back 147

when organisms prefer an excessive stimulus to the normal stimulus

ex: bird that wants to incubate the biggest egg it can find, even if "egg" is a rock.

Front 148

learning

Back 148

modification of behavior resulting from specific experiences

Front 149

imprinting

Back 149

recognition, response, and attachment of young to particular adult or object.

usually irreversible.

Front 150

sensitive period

Back 150

limited phase during early dev when imprinting takes place

Front 151

associative learning

Back 151

classical conditioning.

ability of animals to learn to associate one stimulus with another. ex: pavolv dog

Front 152

habituation

Back 152

loss of responsiveness to unimportant stimuli.

Front 153

operant conditioning

Back 153

trial and error learning. animal learns to associate behaviors with reward or punishment.

Front 154

insight learning

Back 154

reasoning. formulating a course of action by understanding the relationships between the parts of the problem. problem solving. well developed in primates.

Front 155

playing

Back 155

may facilitate social dev, practice certain behaviors, and develop coordination and skills that may be important during adult life.

Front 156

anisogamy

Back 156

difference in gamete size in males and females. eggs are large and costly, sperm are small and cheap

Front 157

how does anisogamy influence reproductive behavior in females

Back 157

females should be choose bc they invest more in reproduction. males should fertilize as many females as possible.

Front 158

mating systems

Back 158

evolve bc sometimes males and females have to cooperate in order to successfully raise offspring

Front 159

monogamy

Back 159

one male, one female. bond for life.

Front 160

concealed ovulation in humans

Back 160

few, if any, external signs of ovulation bc females' ability to manipulate behavior of males.

Front 161

mate guarding

Back 161

protecting your investment in reproduction by not allowing your mate to reproduce with other individuals. constant oversight and attention. behaviors may range from vigilance to violence.

Front 162

polygyny

Back 162

one male and many females

harem concept when territories are limiting

showy males and drab females. females cryptic

Front 163

polyandry

Back 163

one female many males

causes reversal of sexual dimorphism patterns

females showy males drab. males cryptic

Front 164

sperm storage

Back 164

females of many species store sperm.

fruit fly= one week

turkey= a few days

Front 165

sperm competition

Back 165

in species where multiple males might inseminate a single female, natural selection favors males with competitive sperm. sperm swimming speed seems to be important.

Front 166

how is testicle size related to mating system

Back 166

polygamous and polyandrous species in which males mate w many females have larger testicles for their body size than species in which males mate w only 1 female bc they need to produce more sperm

Front 167

minimal mate choice criteria

Back 167

female accepts the first male that meets a minimum threshold. usually occurs when males are scarce or are spread out over large geographic area

Front 168

best in show

Back 168

female accepts the best male among those available. usually involves a simultaneous comparison of many males.

Front 169

sibling rivalry

Back 169

competition between siblings for resources that the parents are providing

Front 170

parent-offspring conflicts

Back 170

it is in a parent's best interest to provide parental care only up to a point where the offspring are independent. after that, they only compete for resources

Front 171

siblicide

Back 171

killing ur sib as a way to gain access to all of ur parents resources

Front 172

nest parasitism

Back 172

parents forego all parental duties and force another bird species to raise their young. found in cuckoos and cowbirds.

Front 173

despite all of the conflicts, do animals cooperate

Back 173

yes

Front 174

kin selection

Back 174

behaviors or strategies that help your genetic relatives survive, even if it means reduced fitness for u. sacrifice urself for ur relatives

Front 175

inclusive fitness

Back 175

your fitness plus the fitness of your close relatives. be nice to ur fam, bc they are all carrying some of ur genes too.