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BIOL 208 > lecture 06 - how organisms adapt and evolve > Flashcards

lecture 06 - how organisms adapt and evolve Flashcards

1
Q

what is evolution?

A

process driven by natural selection that changes populations of organisms of organisms over time, leading to speciation

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2
Q

what are the 4 things for natural selection to occur?

A

heredity, reproduction, physical traits that differ, and variation in the number of offspring produced by each individual

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3
Q

define alleles

A

different forms of a gene (M, m)

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4
Q

define gene pool

A

the sum of all the alleles in a population

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5
Q

define evolution

A

change in allele (or gene) frequencies within a gene pool over time (within a population)

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6
Q

why are individuals variable

A

they have a genotype and a phenotype

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7
Q

define a phenotype

A

an attribute of an organism that is observed such as its behaviour, morphology or physiology (how the gene is expressed)

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8
Q

define a genotype

A

the set of genes an organism has

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9
Q

what does evolution require?

A

phenotypic variation among individuals that is heritable

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10
Q

what are the results of phenotype variation?

A

the combined effects of genes and environment (how the gene is expressed and how that gets passed down to offspring)

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11
Q

what is phenotypic plasticity?

A

variation we see in a phenotype that is the result of environmental variation

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12
Q

what are genetic differences?

A

phenotypic differences we see that are due to differences in genetic material

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13
Q

what are the mechanisms of evolution?

A

natural selection
genetic drift

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14
Q

natural selection

A
  1. more offspring are produced than can survive
  2. traits vary among individuals within a population and may be heritable
  3. some heritable traits give individuals an advantage
  4. advantageous traits that provide higher fitness, become more common
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15
Q

what is direction selection?

A

an extreme phenotype becomes more frequent

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16
Q

what is stabilizing selection?

A

a type of natural selection in which an average phenotype increases in frequency and extreme phenotypes decrease in frequency

17
Q

what is disruptive selection?

A

a type of natural selection in which two or more extreme phenotypes become more frequent and the average phenotype becomes less frequent

18
Q

what is adaptation?

A

traits that have been selected for through natural selection

19
Q

what is adaptive radiation?

A

the diversification of a group of organisms into forms filling different ecological niches

20
Q

what is speciation?

A

physical and ecological processes interact with selection and random processes such as drift to produce new species

21
Q

what is a species?

A

a name and classification humans give to living things

22
Q

how are they grouped based on different criteria?

A

morphological species concept
biological species concept
phylogenetic species concept

23
Q

what is morphological species concept?

A

species grouped by morphological similarities?

24
Q

what is biological species concept?

A

groups of actually or potentially interbreeding populations which are reproductively isolated from other such groups (they HAVE to be reproductively isolated)

25
Q

what is reproductive isolation?

A

separation of environment based on prezygotic and postzygotic

26
Q

what are the prezygotic reproductive isolations?

A

prevents a zygote from beind formed:
finding a mate
both being fertile
give and receive mating cues
mate and form zygote

27
Q

what are the isolating mechanisms for the prezygotic isolation?

A

ecological, temporal, behavioural, mechanical

28
Q

what are the postzygotic reproductive isolations?

A

zygote formed but offspring cannot reproduce
zygote and embryo don’t develop properly
production of grandchild

29
Q

what are the isolating mechanisms for the postzygotic isolation?

A

hybrid unviability and hybrid sterility (grandchildren cannot produce their own offspring)

30
Q

what is the phylogenetics species concept?

A

species grouped together using phylogeny

31
Q

how are new species formed?

A

allopatric speciation
parapatric speciation
sympatric speciation

32
Q

what is allopatric speciation?

A

geographically isolated populations
occurs when a single population becomes spatially subdivded into multiple subpopulations

33
Q

what is parapatric speciation?

A

continiously distributed population
occurs when a population is not spatially subdivded and interbreeding fails due to spatial distances

34
Q

what is sympatric speciation?

A

within the range of the ancestral population
occurs when a population is not spatially subdivded and interbreeding fails due to non-spatial isolating mechanisms, such as positive assortative mating

BIOL 208 (16 decks)

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