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
Q

post-zygotic barriers

A

only in hybrid species

ex. mules- cannot successfully have offspring

26
Q

4 types of speciation

A
  1. allopatric
  2. peripatric
  3. parapatric
  4. sympatric
27
Q

allopatric speciation

A

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
Q

peripatric speciation

A

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
Q

parapatric speciation

A

new colony in continuous or adjacent to the population it divided from
ex. mountain goats that moved farther up the mountaine

30
Q

sympatric speciation

A

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