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biology > speciation > Flashcards

speciation Flashcards

1
Q

What is a mutation?

A

A sudden and permanent, random and rare change in the genetic material of an organism

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2
Q

What are somatic mutations?

A

Occur in non-reproductive cells and are not passed on to offspring

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3
Q

What are gametic mutations?

A

Occur in reproductive cells eg egg, sperm and can be passed onto offspring

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4
Q

What is gene flow?

A

The movement of individuals into or out of a defined population

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5
Q

What is microevolution?

A

A change in allele frequency in the gene pool of a population from generation to generation

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6
Q

What is genetic drift?

A

The change in allele frequency in a gene pool due to chance

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7
Q

What is the founder effect?

A

Effect on allele frequencies when only a few individuals colonise a new area and so population is small

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8
Q

What is the bottleneck effect?

A

Effect on allele frequency when a population decreases in number to become a small population

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9
Q

What is natural selection?

A

The differential survival and differential reproductive success in individuals whose characteristics are best suited to the environment at a given time

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10
Q

What are analogous structures?

A

Structures with similar appearance and/or function that have different origins, eg wings of a moth and wings of a bird

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11
Q

What are homologous structures?

A

Structures derived from a common ancestor that may or may not be used for the same function, eg bat wings and dolphin fins

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12
Q

What is a species?

A

A group or organisms that can interbreed and reproduce successfully to produce viable, fertile offspring

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13
Q

What is a clade?

A

A group of species that includes an ancestral species and all of its descendants

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14
Q

What are allopatric populations?

A

Populations of a species separated by a geographical barrier

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15
Q

What is vicariance?

A

Splitting of a population into two smaller, isolated populations by a geographical barrier

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16
Q

What is dispersal?

A

Splitting of a population when some individuals move to a new area

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17
Q

What is speciation?

A

The formation of two or more species from a single species

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18
Q

What is allopatric speciation?

A

Speciation involving a period of geographical isolation

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19
Q

What are reproductive isolating mechanisms?

A

Any barrier (environmental, behavioural, mechanical, physiological) that prevents two individuals of different populations from producing viable, fertile offspring

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20
Q

What are prezygotic reproductive isolating mechanisms?

A

Mechanisms of isolation before or during fertilization

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21
Q

What is temporal isolation?

A

Reproductive isolation where two or more species reproduce at different times

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22
Q

What is gamete incompatibility?

A

Male gamete cannot fertilize female gamete

23
Q

What are structural differences?

A

Species cannot mate because reproductive structures are incompatible

24
Q

What are postzygotic reproductive isolating mechanisms?

A

Prevent zygote from developing into a viable, fertile adult

25
Q

What is hybrid sterility?

A

Postzygotic barrier and hybrid is infertile

26
Q

What is hybrid inviability?

A

Postzygotic barrier, offspring (hybrid) does not survive

27
Q

What is hybrid breakdown?

A

Offspring of hybrids have reduced viability or fertility

28
Q

What is a deme?

A

A local population of organisms that actively interbreed with each other and share a distinct gene pool

29
Q

What is a cline?

A

Gradient of variation in a species with an extended geographical range

30
Q

What is gradualism?

A

Pace of evolution evolving slow and steady change

31
Q

What is a ring species?

A

A cline that forms a loop around a geographical barrier with the two ends joining each other

32
Q

What is sympatric speciation?

A

Two or more species evolve from one species but there is no physical barrier to gene flow.

33
Q

What is assortative mating?

A

Non-random mating (male flies form apples mate with females from apples, males from hawthorn mate with females from hawthorn)

34
Q

What is instant speciation?

A

A form of sympatric speciation where new species form due to a change in their chromosome number

35
Q

What is polyploidy?

A

Organisms having more than two copies of all the homologous chromosome pairs in each somatic cell

36
Q

What is nondisjunction?

A

A failure of spindle fibres to separate the chromosomes during cell division

37
Q

What is allopolyploidy?

A

Polyploidy resulting from contribution of chromosomes from two or more species

38
Q

What is autopolyploidy?

A

More than two chromosome sets that are all derived from a single species

39
Q

What is divergent evolution?

A

The diversification of a common ancestral species into two or more species

40
Q

What is adaptive radiation?

A

The relatively rapid proliferation of forms of a particular plant or animal to fill a variety of vacant niches

41
Q

What is coevolution?

A

Where two or more interdependent species reciprocally affect each other’s evolution, each adapting to changes in the other

42
Q

What is stabilising natural selection?

A

Favours the average phenotype over the extreme

43
Q

What is directional natural selection?

A

Selection against one of two extremes

44
Q

What is disruptive natural selection?

A

Where the extremes are advantageous and the average values are selected against

45
Q

What is convergent evolution?

A

When two or more types of an organism that do not share a common ancestor evolve to resemble each other

46
Q

What is punctuated equilibrium?

A

Pace of evolution in which long stable periods of stasis are interrupted by brief periods of rapid change

47
Q

What are vestigial structures?

A

An unused feature that is a historical remnant of a structure that served a purpose in the organism’s ancestor, for example the tailbone in humans

48
Q

What is anagenesis?

A

Evolution within a lineage. It is a result of rapid evolution of the ancestral form without speciation taking place

49
Q

What is cladogeneisis?

A

Evolution that results in the splitting of a lineage. This is where the parent species splits into at least two distinct species.

50
Q

What is stratigraphy?

A

The order and relative position of strata and their relationship to the geological timescale. Useful for dating fossils imbedded in strata

51
Q

What is y chromosome?

A

Similar to mtDNA, it’s passed on from father to son relatively unchanged and can be used to determine the relatedness of populations

52
Q

What is a molecular clock?

A

Estimating the timing of evolutionary events based on the known (constant) rate of mutations in certain genes

53
Q

What is mitochondrial DNA (mtDNA)?

A

Unaffected by recombination, it’s inherited from mother to offspring relatively unchanged. For this reason, it is useful for studying evolutionary biology

biology (4 decks)

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