Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Evolution > Exam II - Chapter 6 > Flashcards

Exam II - Chapter 6 Flashcards

1
Q

a situation in which allele and genotype frequencies in an ideal population do not change from one generation to the next

A

the hardy-weinberg equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

hardy-weinberg theorem relies on these 5 assumptions:

A 
No selection
No mutation
No migration
No genetic drift (chance events)
When random mating occurs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

when alleles are not in equilibrium

A

evolution is occurring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Hardy-weinberg is violated (evolution occurs) when

A

there is: selection

there are: mutations, migration, chance events, mates are not chosen at random

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

serves as the fundamental null model of population genetics

A

hardy-weinberg theorem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

when all alternative alleles have disappeared

A

fixed allele

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

when does fixation occur

A

when all individuals are genetically identical at a locus - happens in small populations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

differential reproductive success that happens for a reason

A

selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

differential reproductive success that just happens; non-selection, random form of evolution; does not lead to adaptation

A

genetic drift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

change in frequencies of allele copies in populations resulting from sampling error in drawing error in drawing gametes from gene pool to make zygotes and from chance variation in the survival and/or reproductive success of individuals; resulting in non-adaptive evolution

A

genetic drift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

genetic drift results in a loss of heterozygosity- how is this for evolution?

A

heterozygosity –> good for evolution

homozygosity –> bad for evolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

M&M example

A

sampling error

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

(Graphs in book pg. 162 and quiz question) the smaller the population the _________ the genetic drift and the more variable the ______ frequency

A

stronger, more variable allele frequency (all over chart) where as a larger pop stays more steady

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

example of population bottleneck

A

northern elephant seals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

events in which the number of individuals in a population is reduced drastically, even if the dip in numbers is temporary, it can have lasting effects on the genetic variation of a population

A

genetic bottleneck

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

could be a big problem for bottlenecks that lack genetic diversity

A

disease - could wipe out entire species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

___ alleles are most likely to be lost during population bottle neck

A

rare (figure 6.9 page 164)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

a type of genetic drift describing the loss of allelic variation that accompanies founding of a new population from a very small number of individuals

A

founder effect

can cause the new population to differ considerable from the source population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

the success of an organism at surviving and reproducing and thus contributing offspring to future generations

A

fitness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

the success of the genotype at producing new individuals (its fitness) standardized by the success of other genotypes in the population

A

relative fitness (of a genotype)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

example of founder effect

A

silvereye birds: started in mainland Australia and then traveled from island to island and lastly ended in Norfolk island. the most diversity and genetic alleles on the mainland and the least on norfolk island (where they are most likely to go extinct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

selection that decreases the frequency of alleles within a population; occurs whenever the average excess for fitness of an allele is less than zero

A

negative selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

selection that increases the frequency of alleles within a population; occurs whenever the average excess for fitness of an allele is greater than zero

A

positive selection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

the condition when a mutation in a single gene affect the expression of many different phenotypic traits

A

pleiotropy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

occurs when the effects of an allele at one genetic locus are modified by alleles at one or more other loci

A

epistasis

26
Q

alleles that yield twice the phenotypic effect when two copies are present

A

additive allele

27
Q

rare genotypes have higher fitness than common genotypes; this process can maintain genetic variation within populations

A

negative-frequency dependent selection

28
Q

quiz question a type of genetic drift describing the loss of allelic variation that accompanies formation of a new population

A

founder effect

29
Q

quiz question occurs when the effects of an allele at on locus are modified by alleles at one or more other loci

A

epistasis

30
Q

quiz question selection that favors more than one allele; it acts to maintain genetic diversity

A

balancing selection

31
Q

quiz question this is when rare genotypes have higher fitness than common genotypes; this process can maintain genetic variation in a population

A

negative frequency-dependant selection

32
Q

quiz question an allele that yields twice the phenotypic effect when 2 copies are present at a given locus than when only a single copy is present is known as an

A

additive allele

33
Q

example of negative frequency-dependent selection

A

elderflower orchid: some dark purple, some yellow; produce no nectar but trick bees- when bees land they take orchids pollen with them; risk-bees that visit orchids with no pollen (reward) can learn to avoid them

34
Q

what does it mean when elderflower orchids “leapfrog” color frequencies

A

when purple color is low and yellow high - bees learn to avoid yellow b/c no pollen and go to purple more often
then purple become more predominant and the opposite happens. keeps going back and fourth
fitness is better when more rare color

35
Q

selection that favors more than one allele; it acts to maintain genetic diversity in a population by keeping alleles at frequencies higher than would be expected by chance or mutation alone

A

balancing selection

36
Q

examples of balancing selection

A

negative frequency-dependant selection, heterozygous advantage

37
Q

what effect does natural selection have on deleterious mutations

A

it eliminates them

38
Q

fox and gray squirrel polymorphism example

A

color difference; wanted white squirrels so killed gray squirrels but this was bad because it was reducing genetic diversity and thus increasing the chance of extinction

39
Q

in the fox and gray squirrel example what was the big disadvantage of being white

A

many tumors found on white squirrels - UV damage

40
Q

describe differences of being heterozygous and homozygous when it comes to sickle cell anemia?

A

AA - homo dominant; susceptible to getting malaria
AS - hetero - ADVANTAGE b/c you don’t have health problems from sickle cell and you also have protection from malaria
SS - homo recessive - health problems/lower fitness; suffer from sickle cell anemia

41
Q

the probability that the two alleles at any locus in an individual will be identical by descent

A

inbreeding coefficient (F)

42
Q

as inbreeding increases

A

survival decreases, deleterious genes increase

43
Q

a reduction in the average fitness of inbred individuals relative to that of outbred individuals; it arises because rare, recessive alleles become expressed in a homozygous state where they can detrimentally affect the performance of individuals

A

inbreeding depression

44
Q

what was the significance of the collard lizard example healthy vs actual populations and what were some ways to possibly fix it

A

healthy population should have many different genes, but it is found that separate populations have mostly only one or 2 genes each.
could bring outside females in, remove barriers, mix lizards around to other populations to mix genes, etc.

45
Q

Genetic drift is non-selection, _____ form of evolution

A

Random

46
Q

_____ are more greatly influenced by genetic drift than _____ populations.

A

Small populations; large

47
Q

Genetic drift results in loss of

A

Heterozygosity

48
Q

Genetic drift does NOT lead to _____, selection does.

A

Adaptation

49
Q

A _____ population goes extinct more readily.

A

Small population

50
Q

_____ is higher with a smaller sample

A

Sampling error

51
Q

Genetic drift results from random _____

A

Sampling error

52
Q

In a small population, there is a higher chance all alleles _____, despite how common.

A

All alleles lost

53
Q

_____ will be more likely to occur on mainland

A

Evolution

54
Q

Population more likely to _____ on norfolk

A

Go extinct

55
Q

When a gene has a frequency higher than normal, that indicates

A

Sampling error (founder effect)

56
Q

Recessive will be slower to fix. Why?

A

Heterozygotes will not show phenotype and will take a while for homozygotes to appear. Once they do, seelction will quickly carry it to fixation

57
Q

Some forms of selection maintain diversity in populations. For example?

A

Negative frequency-dependent selection

58
Q

Drift more powerful in _____ population. Selection more powerful in _____ population.

A

Drift - small

Selection - large

59
Q

Inbreeding depression results in _____

A

Reduced fitness

60
Q

As F increases, survival _____ and deleterious genes _____

A

Survival decreases, deleterious genes increase

Evolution (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions