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biodiversity & biogeographhy > evolution and natural selection > Flashcards

evolution and natural selection Flashcards

1
Q

4 aspects of biological evolution

A
  1. heritable (descent w/ modification)
  2. genetic change (common ancestry)
  3. over generations (time)
  4. at population-level
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2
Q

natural selection

A

1 mechanism that drives biological evolution

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3
Q

phenotypic plasticity

A

phenotypic ability to acclimate to environments (NOT evolution)
- ex: over time adjust to high elevation

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4
Q

3 types of selection

A

directional, stabilizing, disruptive

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5
Q

directional selection

A

favors 1 extreme range of variation
- either favors left or right

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6
Q

stabilizing selection

A

favors moderate/middle range trait

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7
Q

disruptive selection

A

favors both extremes
- right and left but NOT center

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8
Q

homologous traits

A

similar appearance due to common ancestry; shared genotype
- not caused by environmental pressure

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9
Q

analogous traits

A

similar appearance due to independent evolution but similar environmental pressures; shared phenotype
- brought about by convergent evolution

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10
Q

convergent evolution

A

process that brings about analogous traits
- species develop similar appearances due to similar environmental pressures NOT common ancestry

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11
Q

mechanisms for evolution (4)

A
  1. natural selection
  2. genetic drift
  3. sexual selection
  4. horizontal gene transfer
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12
Q

genetic drift

A

change in allele frequency due to chance
- common in small populations
- ↓ diversity

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13
Q

2 types of genetic drift

A

founder and bottleneck effects

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14
Q

founder effect

A

small portion of population leaves and starts a new population
- ↓ genetic variation = ↓ genetic diversity

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15
Q

bottleneck effect

A

extreme reduction in population size due to bottleneck event (environmental disasters)
- ↓ genetic variation = ↓ genetic diversity

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16
Q

genetic drift always causes…

A

↓ genetic variation = ↓ genetic diversity

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17
Q

extirpation

A

localized extinction
- at least 1 population goes extinct

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18
Q

sexual selection

A

1 sex chooses partner based on specific traits

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19
Q

2 types of sexual selection

A

intErsexual, intrAsexual

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20
Q

intErsexual selection

A

members of 1 sex choose a mate by preference
- usually females selecting males
- “female mate choice”

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21
Q

intrAsexual selection

A

members of same sex compete w/ others for sexual access to members of other sex
- (usually competition b/w males)

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22
Q

why do females usually choose (intErsexual selection)?

A

they have a larger investment (pregnancy) and have to choose most successful male (males don’t even always know whose their offspring)

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23
Q

sexual dimorphism

A

difference in appearance b/w females and males in secondary sex characteristics (related to sex; ex: puberty changes)

24
Q

sexual dimorphism is a result of ____

A

intrAsexual selection

25
Q

example of sexual dimorphism

A

males are larger than females

26
Q

sexual dichromatism

A

difference in coloration or plumage b/w males and females

27
Q

sexual dichromatism is a result of ___

A

intErsexual selection

28
Q

example of sexual dichromatism

A

male peacock feathers/colors

29
Q

horizontal gene transfer

A

non-sexual movement/transfer of genes b/w genomes
- 2 organisms “swap” genetic material through cell walls
- material replaces/introduces new genes

30
Q

horizontal gene transfer can occur between…

A

members of related AND unrelated species

31
Q

rotifers

A

example of horizontal gene transfer; take up genetic info (DNA) from bacteria in new location before un-hibernating

32
Q

microevolution

A

genetic changes w/in a population; mechanisms for evolution

33
Q

macroevolution

A

evolution leading to speciation
- population becomes new species
- lots of micro- leads to macro-

34
Q

3 drivers/types of speciation

A

allopatric, parametric, sympatric

35
Q

allopatric speciation

A

speciation due to vicariance (geo isolation)

36
Q

vicariance

A

geographic separation (isolation) driven by continental drift (Pangea separating)

37
Q

parapatric speciation

A

(similar to allopatric) but has a narrow overlap of land
- inter-mating occurs but ↓ fitness
- drives isolation

38
Q

which drivers of speciation are the slowest/fastest?

A

(slowest): sympatric > parapatric > allopatric (fastest)

39
Q

sympatric speciation

A

speciation occurs w/in larger population; occupy the new range
- random mutations = new behaviors = behavioral isolation –> 2 diff species
- no geographic isolation = most hybridization

40
Q

which driver of speciation leads to the most hybridization?

A

sympatric speciation

41
Q

species concepts

A

ways species are defined

42
Q

morphological species concept

A

morphometrics- measuring and comparing appearances

43
Q

which species concept was the most dominant historically?

A

morphological

44
Q

pros of morphological species concept

A

fossils records and asexual species

45
Q

cons/downfalls of morphological species concept

A

natural variation, sub-species, subjective (human observed), convergent evolution

46
Q

biological species concept

A

“lumpers”; if 2 individuals from 2 populations can mate and have viable offspring (can reproduce) = same species

47
Q

which species concept is most used today?

A

phylogenetic species concept

48
Q

cons of biological species concept

A

doesn’t consider asexual selection (no mate for reproduction), what if two populations are so isolate they will never meet?

49
Q

phylogenetic species concept

A

“splitters”; uses DNA and genetic code to determine species
- species should be “diagnosably similar” w/ __ % DNA in common

50
Q

which species concept is generally used for sub-species?

A

biological species concept

51
Q

cons of phylogenetic species concept

A

vague, how much % similar DNA = enough to be same species?
- taxonomic inflation?

52
Q

taxonomic inflation

A

inflating too many species; over speciation- can be good for awareness (less there are, more important it feels to save them)

53
Q

adaptive radiation

A

lineage rapidly diversifies w/ new lineages w/ new adaptations
- short period of time = ↑ diversity = ↑ # of species in 1 population

54
Q

3 instances/causes of adaptive radiation

A
  1. mass extinctions (new/empty niches)
  2. invasion of under-used/un-used land and resources
  3. development of key innovations to a species (ex: bird wings)
55
Q
A

biodiversity & biogeographhy (12 decks)

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