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general biology I > test 2: evidence for evolution > Flashcards

test 2: evidence for evolution Flashcards

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1
Q

convergent evolution

A

different ancestor, same solution to a problem (not true homology)
- ancestors are not related, similar morphology or lifestyle (often same habitat)

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2
Q

how does convergent evolution occur?

A
  • similar environmental pressure = similar adaptation
  • ex: birds and bats
  • ex: marsupials vs placentals
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3
Q

divergent evolution

A

same ancestor, different morphologies based on habitat (true homology)
- common ancestor, different morphology or lifestyle (different habitats)

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4
Q

how does divergent evolution occur?

A
  • changing environment of different area
  • also called adaptative radiation
  • ex: pentadactyl limbs (snakes, birds, lizards)
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5
Q

microevolution

A

how adaptations evolve in a particular gene pool/population (ex: particular bird on a particular island)

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6
Q

macroevolution

A

how adaptations evolve above the species level (ex: feathers in birds from dinosaurs)

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7
Q

methods for examining evolution

A

1- fossil record
2- comparitive anatomy
3- molecular biology

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8
Q

fossil record

A
  • 99% of species are extinct
  • hard parts fossilized (ex: bone)
  • parts of organisms are protected from bacterial decay
  • certain periods have more fossils than others
  • carbon dating
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9
Q

radiometric dating (fossils)

A

rate of decay expressed by half-life of parent isotopes

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10
Q

half-life

A

time required for 50% of parent isotope to decay

  • unique for each isotope
  • not affected by environmental factor
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11
Q

half-life of Carbon14

A

5730 years (+- 4000 years)

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12
Q

oldest known fossils

A
  1. 5 billion year old stromatolites:

- rocklike structures composed of layers of bacteria and sediment

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13
Q

biogeography

A

studying the distribution of organisms (species on one island hopping to another and evolving)

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14
Q

continental drift

A
  • ancestral groups found only in africa
  • new world vertebrates didn’t migrate (spread to SA, when two continents were connected)
  • movement of continents caused mountain building, drainage changes, changes in the shallows = big effect on evolution
  • organism distribution, fossil magnetism, coastline shape, present movements
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15
Q

islands

A
  • often inhabited by endemic species
  • nearest relatives on mainland
  • idea of a bird getting blown off course, landing on an island and adapting (galapagos finches)
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16
Q

radiative adaptation

A

australia never had the same type of competition between placentals and marsupials, so marsupials under went radiative adaption (ex: 5 species to 25 species)

17
Q

niche

A

ecological role of an organism, how it fits into it’s habitat and resource partitioning
- for biogeography and radiative adaption: selective pressure of environment dictates a particular solution

18
Q

how do two species survive in same area?

A

different niche, avoid conflict (don’t overlap niches)

19
Q

comparative anatomy

A
  • compare one structure in a number of organisms
  • many limbs have minimal modifications
  • had they evolved separately, they would have been better suited
    therefore, must have common ancestor
    ex: pentadactyl limb
20
Q

pentadactyl limb

A

humerus, radius, ulna, carpals, metacarpals, phalanges

21
Q

ex of comparative anatomy

A
  • pentadactyl limb
  • all extant vertebrates have 4 limbs
  • all vertebrates have pharyngeal pouches at some point
    therefore, must have evolved from ancestor with gill pouches and 4 limbs
22
Q

comparative embryology

A

“ontogeny recapitulates phylogeny”

  • development of embryo follows steps during evolution of a species (evolutionary development follows evolution of your species)
  • process itself is evolving and provides clues to phylogeny
23
Q

vestigial structure

A

remnants of structures in ancestors not important now (ex: tailbone)

24
Q

molecular biology

A
  • DNA/proteins of different species comparared
  • closely related varies less than distantly related
  • lots of variation, short amount of time
  • rate of evolution for these proteins found can estimate time since common ancestor
  • difference between 2 species depends on length of time since their common ancestor
25
Q

molecular biology ex

A

cytochrome (all eukaryotes), histone IV (dna, chromatin), hemoglobin, fribrinopeptides

26
Q

dna-dna comparisons

A
  • base sequences of different species compared
  • most similarities = more closely related
  • used with other methods to confirm findings
27
Q

example: pepper moth

A
  • british peppered moth
  • polymorphic light/dark forms
  • clean vs dirty city areas
  • light morphs in clean areas, dark in dirty
  • camouflage from birds
28
Q

antibiotic resistance

A

bacteria mutate to resist, forms a resistant pop

- also HIV, tuberculosis

29
Q

pesticide resistance

A

DDT - stable flies

- artificial selection (think livestock, salmon, dogs, cats)

30
Q

causes of microevolution

A 
1- mutations
2- genetic drift
3- founder effect
4- bottleneck effect
5- geneflow
6- assortative mating
7- natural selection
31
Q

mutations

A

new alleles

32
Q

genetic drift

A

random change in allele frequency due to chance alone (usually small pop for this to occur)

33
Q

founder effect

A

few individuals colonize new area and their alleles are what form new pop (islands)

34
Q

bottleneck effect

A

few individuals survive natural disaster (earthquake, flood, drought)

35
Q

founder and bottleneck effect on population

A

reduces pop and alleles to choose from

36
Q

genetic drift effects on pop

A

changes alleles in population

37
Q

geneflow

A

change in allele frequencies due to migration

38
Q

assortative mating

A

near by populations tend to mate together more often, only go so far to find a mate
- organisms tend to choose mates with similar phenotypes (match each other in size)

39
Q

natural selection

A

only cause of microevolution that is adaptive

  • individuals with more fitness leave more offspring
  • only cause that is a judgement on your traits

general biology I (20 decks)

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