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Biology > chapter twenty-two/twenty-three > Flashcards

chapter twenty-two/twenty-three Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

2 examples of evidence for natural selection

A
  1. natural selection of soapberry bugs in response to introduced plant species
  2. evolution of drug-resistant bacteria
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2
Q

natural selection in response to introduced plant species

A
  • soapberry bugs use beak to feed on seeds in fruit
  • Southern Fl - longer beaks, balloon vine w/ larger fruit
  • Central Fl - shorter beaks, golden rain tree w/ smaller fruit
  • beak size has evolved in populations depending on size of fruit
  • Fl - occurred in less than 35 years
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3
Q

evolution of drug-resistant bacteria

A
  • Staphylococcus aureus found on people
  • became resistant to penicillin 1945
  • became resistant to methicillin in 1961 - MRSA (dangerous pathogen)
  • became resistant to vancomycin
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4
Q

how does methicillin work

A

it inhibits protein used by bacteria in cell walls
- MRSA bacteria use dif protein in cell walls
- when exposed to methicillin, MRSA strains more likely to survive and reproduce

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5
Q

what does natural selection edit or select?

A

traits already present in populations

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6
Q

homology

A

similarity resulting from common ancestry

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7
Q

homologous structures

A

anatomical resemblances that represent variations on a structural theme present in a common ancestor

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8
Q

what does comparative embryology reveal?

A

anatomical homilies not visible in adult organisms

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9
Q

vestigial structures

A

remnants of features that served important functions in the organism’s ancestors

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10
Q

examples of homologies at molecular level

A

genes shared among organisms inherited from a common ancestor

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11
Q

evolutionary trees

A

hypotheses about relationships among dif groups
- homologies form nested patterns
- branch points indicate common ancestors

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12
Q

convergent evolution

A

evolution of similar or analogous features in distantly related groups

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13
Q

how to analogous traits arise?

A

when groups independently adapt to similar environments in similar ways

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14
Q

what does convergent evolution not provide information about?

A

ancestry

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15
Q

what do fossil records provide evidence of?

A

extinction of species, origin of new group, changes within groups over time
- documented transition from land to sea in ancestors of cetaceans

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16
Q

biogeography

A

geographic distribution of species, provides evidence of evolution

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17
Q

endemic species

A

species that aren’t found anywhere else in the world

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18
Q

implications of evolution

A
  1. philosophy - no purpose/meaning to existence
  2. religion - no goal, no morality, no ethics
  3. politics - social darwinism, eugenics
  4. psychology - human just another animal and is prisoner of animal urges
  5. biology - links all living things to common ancestor
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19
Q

do organisms evolve during their lifetime?

A

no

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20
Q

natural selection of medium ground finches on Galapagos Islands

A

beak size varied on seeds available

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21
Q

microevolution

A

change in allele frequencies in a population over generations

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22
Q

3 mechanisms that cause allele frequency change

A
  1. natural selection
  2. genetic drift
  3. gene flow
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23
Q

what is the only thing that causes adaptive evolution?

A

natural selection

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24
Q

what is a prerequisite for evolution?

A

variation in hereditable traits

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25
Q

what provided evidence of discrete heritable units/genes?

A

Mendel’s work on pea plants

26
Q

what is genetic variation caused by?

A

differences in genes or other DNA segments

27
Q

what is phenotype the product of

A

inherited genotype and environmental influences

28
Q

discrete characters

A
  • classified on either/or basis
  • typically determined by single gene locus
  • white/purple flowers
29
Q

quantitative characters

A
  • vary along continuum within pop
  • human heigh, intelligence
30
Q

what can genetic variability be measured as?

A

gene variability and nucleotide variability

31
Q

average heterozygosity

A

average percent of loci that are heterozygous in population

32
Q

how is nucleotide variability measured?

A

by comparing DNA sequences of pairs of individuals

33
Q

true or false: most species exhibit geographic variation, which includes differences between gene pools of separate populations

A

true

34
Q

genetic variation at the whole-gene level can be quantified as the average percentage of loci that are _______________

A

heterozygous

35
Q

new genes and alleles can arise by what?

A

mutation or gene duplication

36
Q

true or false: phenotypic variation is not always the result of genetic differences

A

true

37
Q

mutation

A

change in nucleotide sequence of DNA

38
Q

mutations in what type of cells can be passed to offspring?

A

gametes

39
Q

effects of point mutations

A
  • in noncoding regions often harmless
  • can be neutral because of redundancy in genetic code
  • can result in change in protein production (harmful)
  • can result in change in protein production (beneficial)
40
Q

altering gene number/position

A
  • chromosomal mutations that delete or disrupt or rearrange many loci are harmful
  • duplication of small pieces of DNA increases genome size and is usually less harmful
  • duplicated genes can take on new functions by further mutation
41
Q

mutation rates in animals/plants

A

low
- repair systems fix many mutations
- average: 1 mutation per 100,000 genes per generation

42
Q

comparison of mutation rates in prokaryotes and viruses

A

lower in prokaryotes, higher in viruses

43
Q

what can sexual reproduction do to existing alleles?

A

shuffle them into new combinations

44
Q

in organisms that reproduce sexually, what is more important that mutation to produce genetic differences?

A

recombination of alleles
- crossing over

45
Q

population

A

localized group of individuals capable of interbreeding and producing fertile offspring

46
Q

gene pool

A

consists of all the alleles for all loci in a pop

47
Q

when is a locus fixed in a population?

A

if all ind. are homozygous for same allele

48
Q

total number of alleles at locus in diploid organisms

A

total number of individuals x 2

49
Q

p + q =

A

1

50
Q

what does the Hardy-Weinberg principle describe?

A

a population that isn’t evolving
- if pop doesn’t meet criteria, it is evolving

51
Q

what does the Hardy-Weinberg principle state about the frequencies of alleles and genotypes in a pop?

A

they remain constant from generation to generation

52
Q

in a given population where gametes contribute to the next generation randomly, what won’t change?

A

allele frequencies

53
Q

5 conditions for non evolving pops that are rarely met in nature

A
  1. no mutations
  2. random mating
  3. no natural selection
  4. extremely large population size
  5. no gene flow
54
Q

natural selection

A

differential success in reproduction results in certain alleles being passed to the next generation in greater proportions

55
Q

genetic drift

A

allele frequencies fluctuate unpredictably from 1 gen to next
- the smaller a sample, the greater the chance of deviation from a predicted result
- tends to reduce genetic variation through loss of alleles

56
Q

founder effect

A
  • when few individuals become isolate from larger population
  • allele frequencies in dif populations can be dif
57
Q

bottleneck effect

A
  • severe drop in pop size due to change in environment
  • resulting gene pool may no longer reflect original pop’s gene pool
  • if pop remains small, it may further be affected by genetic drift
58
Q

summary of genetic drift

A
  • sig. in small populations
  • causes allele frequencies to change at random
  • can lead to loss of genetic variation within pop
  • can cause harmful alleles to become fixed
59
Q

gene flow

A

movement of alleles among populations
- can be transferred through movement of fertile ind./gametes

60
Q

does gene flow increase or decrease variation over time?

A

decrease

61
Q

does gene flow increase or decrease fitness of pop?

A

decrease - lake erie water snake
increase - insecticide resistance in mosquitos

Biology (35 decks)

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