Evolutionary Forces Drift and Migration

Question 1

melanocytes

Answer 1

produce pigment melanin to be transported to surrounding keratinocytes

Question 2

keratinocytes

Answer 2

exposed to UV radiation and secrete signals that bind to MC1R molecules on the surface of melanocytes

Question 3

MC1R location

Answer 3

surface of melanocytes

Question 4

skin color is determined by (3)

Answer 4

1. MC1R allele type: eumelanin or pheomelanin
2. amount of melanin produced
3. proportions of eumelanin and pheomelanin

Question 5

MC1R type of receptor

Answer 5

GPCR transmembrane snake

Question 6

high UV on folate and vitamin D

Answer 6

decrease folate- babies
increase vitamin d

Question 7

low UV on folate and vitamin D

Answer 7

more folate
less vitamin D-rickets

Question 8

evolution

Answer 8

change in allele frequencies of a population across generations

Question 9

type of natural selection refers to

Answer 9

HOW allele frequencies change over time

Question 10

4 types of natural selection

Answer 10

1. directional
2. stabilizing
3. disruptive/diversifying
4. frequency-dependent

Question 11

directional selection

Answer 11

shifts the mean to a side

Question 12

stabilizing selection

Answer 12

maintains the middle and acts against extremes

Question 13

directional selection

Answer 13

finches beaks keep getting larger over time

Question 14

stabilizing selection with human birth weight

Answer 14

too small-die, too big-complications for mother and child, so needs to be in the middle of the extremes

Question 15

disruptive selection

Answer 15

acts against the mean phenotype

Question 16

example of disruptive selection with flies feeding on hawthorn and apple fruits

Answer 16

life cycle for flies that coordinate with a specific tree, not both, would make them more advantageous

Question 17

frequency-dependent selection

Answer 17

fitness value of a specific trait depends on how common/rare it is in a population

Question 18

positive frequency dependent selection

Answer 18

more common phenotypes have higher fitness

Question 19

negative frequency-dependent selection

Answer 19

more rare phenotypes have higher fitness

Question 20

negative selection can maintain

Answer 20

diversity for phenotypes within a population

Question 21

positive frequency-dependent selection example with heliconius butterfly

Answer 21

morph that is common is less likely to die because birds know that they are poisonous
if a morph is rare, the bird might not think it is poisonous and it gets killed

Question 22

negative frequency dependent selection example with grove snails

Answer 22

more common shell types are eaten more often as they become the search image for birds than rare shell types

Question 23

genetic drift

Answer 23

allele frequencies within a population change by chance alone

Question 24

genetic drift is an evolutionary force that does not

Answer 24

lead to adaptation

Question 25

genetic drift sampling error

Answer 25

is higher with a smaller sample

Question 26

genetic drift random change in allele frequency is due to

Answer 26

imperfect sampling from one generation to the next

Question 27

factors that cause genetic drift(2)

Answer 27

survival events in nature
random reproduction

Question 28

genetic drift occurs in all

Answer 28

real populations

Question 29

genetic drift is especially important in

Answer 29

small populations

Question 30

consequences of genetic drift (2)

Answer 30

harmful alleles may increase and advantagous ones lost
large effect in small populations

Question 31

bottleneck effect

Answer 31

size of population is decreased signficantly for at least one generation

Question 32

founder effect

Answer 32

loss of. genetic variation when a new colony is formed by a very small number of individuals from a larger population

Question 33

founder effect example

Answer 33

amish–changes allele frequencies
-ellis-van creveld syndrome

Question 34

gene flow

Answer 34

migration in population genetics from one population to another

Question 35

gene flow can (2)

Answer 35

add new alleles
change frequencies of existing alleles

Question 36

gene flow often constrains

Answer 36

local adaptation

Question 37

gene flow prevents

Answer 37

populations from genetically diversing

Question 38

factors affecting gene flow(3)

Answer 38

habitat fragmentation-highway bridge
species mobility-plants
location-islands