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Biology 202- Organism Biology > Chapter 23 > Flashcards

Chapter 23 Flashcards

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1
Q

microevolution is defined at

A

a change in the allele frequency of a population from one generation to another

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2
Q

_______________ is evolution at its most fundamental levels. Change within a population.

A

microevolution

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3
Q

evolution operates on __________________

A

genetic variability

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4
Q

the combination of darwinian evolution and mendelian genetics is referred to as the modern synthesis

A

genetic variability

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5
Q

two processes produce the genetic variation on which evolution acts

A
  • mutations

- sexual reproduction

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6
Q

changes in the nucleotide sequences of DNA

A

Mutations

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7
Q

Mutation can

A

be harmful or have no effect

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8
Q

mutation may occasionally confer an advantage and be selected for

A

mutations are responsible for producing new allies, new genes, and ultimately all of the diversity of life.

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9
Q

____________________ rearranges existing alleles into new combinations by way of three mechanisms

A

sexual reproduction

  1. crossing over
  2. independent assortment of chromosomes
  3. random fertilization
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10
Q

___________________ is a larger contributor to genetic variability than are mutations in sexual organisms

A

reproduction

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11
Q

allele are ____________________________ within a population

A

alternative forms of genes

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12
Q

_______________ consists of all of the alleles for all of the genes within all of the individuals in the population

A

populations gene pool

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13
Q

the portion of a population that is dominate is represented by

A

P

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14
Q

the portion of a population that is recessive is represented by

A

q

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15
Q

equation of p and q

A

p + q=1

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16
Q

knowing allele frequency allows us to determine

A

genotype frequency

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17
Q

proportion of homozygous dominant

A

p^2

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18
Q

proportion of heterozygous

A

2pq

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19
Q

the proportion of homozygous recessive

A

q^2

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20
Q

the hardy-weignberg equation

A

p^2+2pq+q^2

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21
Q

if the allele and genotype frequencies remain the same from one generation to the next the population is in Hardy-Weinberg equilibrium

A

it is not evolving

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22
Q

if allele and genotype frequencies do change from generation to another, the population is undergoing

A

microevolution

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23
Q

there mechanisms cause allele frequencies and therefore genotype frequencies to change with in the population

A

genetic drift
gene flow
natural selection

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24
Q

____________ is the change in the allele frequencies of small populations due to ______________

A

genetic drift

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25
Q

_____________ can increase or decrease the proportion of helpful or harmful alleles. tends to reduce genetic variability within a population over time

A

genetic drift

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26
Q

two examples of genetic drift

A
  • bottleneck effect

- founder effect

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27
Q

_______________ occurs when a few individuals become isolated from a larger population thereby colonizing a new smaller population

A

the founder effect

28
Q

_____________________ occurs when a population’s size is significantly reduced often by natural disaster

A

bottleneck effect

29
Q

in both cases, allele frequencies in the new smaller population may by chance ____________________________________________

A

be different from allele frequencies in the original larger population

30
Q

________________ is the transfer of alleles between populations

A

gene flow

31
Q

allele are transferred due to the movement of _______________

A

individuals and their gametes

32
Q

gene flow can increase or decrease the proportion of

A

helpful or harmful alleles

33
Q

gene flow tends to reduce genetic variability

A

between populations over time

-the gene pools of the populations become more similar

34
Q

____________ is unequal reproduction

A

natural selection

35
Q

natural selection is only ___________________ that consistently promotes __________________________

A

microevolutionary mechanism

adaptive evolution

36
Q

populations become better _____________ to their environments over time as advantageous alleles are passed among generations to greater proportions

A

adapted

37
Q

___________ increase the frequency whole harmful allele decrease during ______

A

helpful allele

natural selection

38
Q

for population to be in Hardy Weinberg equilibrium (allele and genotype frequencies remain constant from one generation to the next; the population is not evolving) the population must be

A
  • the population must be very large

- genetic drift as a result would have no effect

39
Q

more qualifications for Hardy Weinberg equilibrium

A
  • there must be no movement of individuals or their gametes into immigration or out of emigration a population
  • natural selection must not occur
  • there must be no mutations
  • mating must have no mutations: individuals within a population cannot preferentially choose mates this would affect the random fertilization
40
Q

how common is Hardy Weinberg equilibrium

A

not very alleal frequencies are changing, microevolution is constantly occurring, populations are constantly evolving

41
Q

two type of balancing selection

A
  • frequency dependent selection

- heterozygote selection

42
Q

__ is being defined as an individuals contribution on the next generations gene pool

A

fitness

43
Q

the number of offspring an individual produces relative to the number of offspring produce by all other individuals in the population

A

fitness

44
Q

natural selection results in competitively superior individuals surviving and reproducing

A

these individuals have the greatest fitness

45
Q

________________________ changes the frequencies of allele and genotypes in a population based on which phenotypes are favored

A

natural selection

46
Q

one extreme of a phenotype is selected for

ex- dark rat

A

directional selection

47
Q

both extremes of a phenotype range are selected for

ex- dark and white rat

A

disruptive selection

48
Q

intermediate phenotype is selected for

ex- brown rat

A

stabilizing selection

49
Q

_____________________ occurs when natural selection maintains two or more phenotypes within a population and helps to preserve the populations genetic diversity

A

balancing selection

50
Q

__________________________ the fitness of a phenotype depends on how common it is in the population

A

frequency dependent selection

51
Q

frequency dependent selection:

the fitness of a phenotype ________________ if the phenotype becomes too common. Selections favor less common

A

decline

52
Q

_______________ occurs when individuals heterozygous for a particular gene have higher fitness than individuals homozygous dominant or homozygous recessive for that gene

A

heterozygous advantage

53
Q

heterozygous advantage maintains

A

both alleles for the gene within a given population

54
Q

In certain regions of africa _______________________ suffer from sickle cell disease

A

4% of the population suffers from sickle sell disease

q^2=0.04

55
Q

sick cell is a __________________

A

a homozygous recessive disorder

56
Q

why is the frequency of sickle cell high wouldn’t the individual die before they can reproduce

A

sick cell has an advantage. resistance to malaria which is supper prevalent in some regions of malaria

57
Q

____________________ individuals are protected against malaria but have sickle cell
____________ individuals are not protected against malaria but do not have malaria
____________________ individuals are protected against malaria and do not have sick cell

A

homozygous recessive
homozygous dominant
heterozygous
example of heterozygous example

58
Q

q^2=0.04
q=0.2
p=0.8
2pq=0.32

A

the sick cell allel is helpful to 32% to population but only harmful to 4% of the population so it permits

59
Q

sexual selection is a form of

A

natural selection

60
Q

______________ if the limited resource for which individuals compete for is

A

mates

61
Q

the “environment” selects for advantageous traits is

A

opposite sex

62
Q

sexual selection frequently results in

A

sexual dimorphism

63
Q

differences in size color ornamentation and behavior of the two sexes

A

sexual dimorphism

64
Q

natural selection can only select for __________________ which may not be the most advantageous traits

A

existing variations

65
Q

natural selection is contracted by

A

descent with modification

66
Q

adaptions are often ___________

A

compromises or trade offs

67
Q

natural selection has to interact with other mechanisms of evolution as well as with a potentially

A

changing environment

Biology 202- Organism Biology (30 decks)

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