exam 3 ppt 8

Question 1

5 assumptions of HWE

Answer 1

mate at random, no natural selection, no genetic drift, no gene flow, no mutation

Question 2

what was charles darwin’s book on evolution?

Answer 2

On the Origin of Species (about natural selection)

Question 3

what did Darwin and Wallace do?

Answer 3

they independently came to describe natural selection

Question 4

definition of artificial selection

Answer 4

describes how humans have modified species for desired traits over many generations

Question 5

which type of selection is due to human manipulation?

Answer 5

artificial selection

Question 6

what did Darwin base his theory called natural selection on?

Answer 6

he based it on the principles of artificial selection

Question 7

definition of fitness

Answer 7

those best adapted to an environment would be most successful at passing on their genes to the next generation

Question 8

what does natural selection do?

Answer 8

natural selection acts over generations to increase the fitness of a population

Question 9

definition of adaptation

Answer 9

any heritable trait that increases the fitness of an individual relative to those lacking the trait

Question 10

did Darwin and Wallace ultimately publish together?

Answer 10

yes

Question 11

how many postulates does natural selection have?

Answer 11

4

Question 12

4 postulates of natural selection (listed)

Answer 12

1) variation exists in populations, 2) some of the differences in traits are heritable, 3) survival and reproductive success is variable, 4) the individuals that have the highest survival and the highest number of offspring are not random

Question 13

1st postulate of natural selection

Answer 13

variation exists in populations

Question 14

2nd postulate of natural selection

Answer 14

some of the differences in traits are heritable

Question 15

3rd postulate of natural selection

Answer 15

survival and reproductive success is variable

Question 16

4th postulate of natural selection

Answer 16

the individuals that have the highest survival and the highest number of offspring are not random

Question 17

what is another name for natural selection?

Answer 17

survival of the fittest

Question 18

definition of survival of the fittest (natural selection)

Answer 18

the more prolific reproduction of individuals with favorable traits (adaptations) that survive environmental change because of those traits; this leads to evolutionary change

Question 19

what different characteristics can natural selection be?

Answer 19

it can be stabilizing, directional, or diversifying- acting on a phenotype

Question 20

definition of directional selection

Answer 20

changes the average phenotype of a population in one direction (skewing one way or another)

Question 21

definition of stabilizing selection

Answer 21

reduces both extreme phenotypes in a population

Question 22

definition of disruptive selection

Answer 22

eliminates average phenotypes and favors extremes

Question 23

definition of balancing selection

Answer 23

maintains variation in the population; no phenotype is favored; favors variation

Question 24

exp of disruptive selection

Answer 24

beak length in Darwin’s finches- only birds with short or extremely long beaks survived long enough to reproduce (intermediates didn’t have any food to eat in drought, died)

Question 25

could selection lead to the formation of a new species?

Answer 25

yes

Question 26

in directional selection, genetic variation is…

Answer 26

reduced

Question 27

in stabilizing selection, genetic variation is…

Answer 27

reduced

Question 28

in disruptive selection, genetic variation is…

Answer 28

increased (selecting for two different phenotypes, the extremes)

Question 29

in balancing selection, genetic variation is…

Answer 29

maintained

Question 30

natural selection works by acting on ….

Answer 30

genetic variation

Question 31

as a result of natural selection acting on phenotypic variation, the _______ also changes

Answer 31

frequency of alleles

Question 32

exp of how the frequency of alleles changes with natural selection

Answer 32

rock pocket mice- increase for dark fur, decrease for light fur

Question 33

huntington’s disease is caused by a dominant lethal mutation, the allele H. if having the H allele leads to death, what would you expect to see happen to the H allele over time?

Answer 33

the allele is still in human population because it doesn’t show up until age 30-40; if stopped during reproduction, it wouldn’t survive still

Question 34

what may occur in extreme cases of natural selection?

Answer 34

fixation

Question 35

definition of fixation

Answer 35

in natural selection, may occur where a beneficial allele has a frequency of 1 (other allele frequency is 0, only one allele present)

Question 36

definition of positive selection

Answer 36

increases the frequency of a favorable allele

Question 37

exp of positive selection

Answer 37

B allele in lava flow areas- rock pocket mice

Question 38

definition of negative selection

Answer 38

decreases the frequency of a harmful allele

Question 39

exp of negative selection

Answer 39

b allele in lava flow areas

Question 40

definition of balancing selection

Answer 40

observed when two alleles are maintained, and are more successful in different conditions (either allele can be helpful)

Question 41

what can be one explanation for balancing selection?

Answer 41

heterozygote advantage

Question 42

definition of heterozygote advantage

Answer 42

occurs when heterozygotes have a higher fitness than do both homozygotes

Question 43

exp of heterozygote advantage

Answer 43

in tropical Africa, where Malaria is common (parasite attacks red blood cells): 1) homozygous wild type individuals die of malaria (SS), 2) homozygous recessive individuals die of sickle cell anemia (ss), 3) heterozygotes are relatively free of both (Ss)- cancels each other out

Question 44

definition of sexual selection

Answer 44

promotes traits that increase an individual’s reproductive fitness, and may seem to violate natural selection

Question 45

type of sexual selection

Answer 45

sexual dimorphism

Question 46

definition of sexual dimorphism

Answer 46

distinct difference in size or appearance between the sexes of an animal in addition to differences between the sexual organs themselves; leads to them being more relroductively successful

Question 47

exp of sexual dimorphism

Answer 47

birds- color, feathers of males vs females, etc

Question 48

two broad types of sexual selection

Answer 48

intersexual selection, intrasexual selection

Question 49

definition of intersexual selection

Answer 49

(between two sexes) occurs when a mate is chosen by an individual of the opposite sex

Question 50

definition of intrasexual selection

Answer 50

(within a sex) occurs when there is a competition to obtain a mate

Question 51

exp of intrasexual selection

Answer 51

red deer males use weaponry with their antlers to compete for mates

Question 52

exp of intersexual selection

Answer 52

male birds of paradise display their feathers for females

Question 53

what is sexual selection an example of?

Answer 53

natural selection

Question 54

the varied traits we discussed are examples of…

Answer 54

adaptations

Question 55

what is the only “adaptive” type of evolution?

Answer 55

natural selection

Question 56

what types of evolution are non-adaptive?

Answer 56

mutation, genetic drift, and gene flow