Mechanisms (Evolution) Flashcards

1
Q

traits

A

can be preferentially selected for or against which can cause rise of a new species

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2
Q

disruptive selection

A

two extreme traits are preferentially selected for

moderate traits slowly become less common and then disappear

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3
Q

stabilizing selection

A

extreme traits are preferentially selected against

moderate traits become more common and extreme traits become less common and slowly disappear

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4
Q

directional selection

A

when a trait moves slowly over time towards one extreme

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5
Q

4 ways of evolving

A

divergent, convergent, parallel, coevolution

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6
Q

divergent evolution

A

when two or more related species become more and more dissimilar
ex. red fox and kit fox

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7
Q

red fox and kit fox

A

example of divergent evolution
evolved differently because of their environments
red fox- farmland and forests
kit fox- deserts

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8
Q

convergent evolution

A

unrelated species become more and more similar

adapting to the same environment

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9
Q

American cactus and African euphorbia

A

example of convergent evolution

adaptations help to store water and protect themselves from predators

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10
Q

parallel evolution

A

2 species with similar characteristics evolve similar traits in a similar timeframe
might be due to being exposed to similar/identical selective pressures
aren’t necessarily interacting with each other

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11
Q

coevolution

A

joint evolution of 2 or more species in close interaction

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12
Q

evolution of predators and their prey

A

example of coevolution

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13
Q

bats and the flowers they pollenate

A

example of coevolution
bats adapt to be better at retrieving pollen
flowers adapt to be lighter in colour so the bats can see them better

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14
Q

species

A

the event by which a new species arises

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15
Q

Ernst W. Mayr’s definition of a species

A
  1. can breed or reproduce with one another
  2. produces offspring of both sexes that are capable of reproducing offspring of both sexes
  3. do not ordinarily breed with organisms from another group
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16
Q

requirements for a mating

A

have to be in physical contact

17
Q

mechanism for speciation

A

geography

natural selection leads to speciation

18
Q

requirements for the rise of a new species

A
  1. must arise independently from an existing species

2. cannot breed with cousins in the same species

19
Q

reproductive barriers

A
  1. pre-zygotic
  2. post-zygotic
    ensure that inbreeding doesn’t happen- essential in the rise of a new species
20
Q

pre-zygotic barriers

A

all the things that can prevent mating

21
Q

examples of pre-zygotic barriers

A

geographical isolation
ecological isolation
ethological isolation

22
Q

geographical isolation

A

cannot mate because they are not in the same geographical area

23
Q

ecological isolation

A

can be in the same geographical are but different niches

24
Q

ethological isolation

A

behaviour based

not sexually attracted

25
post-zygotic barriers
only in hybrid species | ex. mules- cannot successfully have offspring
26
4 types of speciation
1. allopatric 2. peripatric 3. parapatric 4. sympatric
27
allopatric speciation
when a geographical location is physically divided selective pressures in different geographical locations cause sub-populations to evolve differently earthquake, moving glaciers, drifting continents
28
peripatric speciation
no geographical division a new colony is established new colony cannot go back (for some reason) and therefore don't mate with initial population
29
parapatric speciation
new colony in continuous or adjacent to the population it divided from ex. mountain goats that moved farther up the mountaine
30
sympatric speciation
ethological pre-zygotic barriers based on mating rituals no geographical barriers ex. bowerbird that builds nests to attract females new species within the existing population