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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
What is hybrid sterility?
Postzygotic barrier and hybrid is infertile
26
What is hybrid inviability?
Postzygotic barrier, offspring (hybrid) does not survive
27
What is hybrid breakdown?
Offspring of hybrids have reduced viability or fertility
28
What is a deme?
A local population of organisms that actively interbreed with each other and share a distinct gene pool
29
What is a cline?
Gradient of variation in a species with an extended geographical range
30
What is gradualism?
Pace of evolution evolving slow and steady change
31
What is a ring species?
A cline that forms a loop around a geographical barrier with the two ends joining each other
32
What is sympatric speciation?
Two or more species evolve from one species but there is no physical barrier to gene flow.
33
What is assortative mating?
Non-random mating (male flies form apples mate with females from apples, males from hawthorn mate with females from hawthorn)
34
What is instant speciation?
A form of sympatric speciation where new species form due to a change in their chromosome number
35
What is polyploidy?
Organisms having more than two copies of all the homologous chromosome pairs in each somatic cell
36
What is nondisjunction?
A failure of spindle fibres to separate the chromosomes during cell division
37
What is allopolyploidy?
Polyploidy resulting from contribution of chromosomes from two or more species
38
What is autopolyploidy?
More than two chromosome sets that are all derived from a single species
39
What is divergent evolution?
The diversification of a common ancestral species into two or more species
40
What is adaptive radiation?
The relatively rapid proliferation of forms of a particular plant or animal to fill a variety of vacant niches
41
What is coevolution?
Where two or more interdependent species reciprocally affect each other’s evolution, each adapting to changes in the other
42
What is stabilising natural selection?
Favours the average phenotype over the extreme
43
What is directional natural selection?
Selection against one of two extremes
44
What is disruptive natural selection?
Where the extremes are advantageous and the average values are selected against
45
What is convergent evolution?
When two or more types of an organism that do not share a common ancestor evolve to resemble each other
46
What is punctuated equilibrium?
Pace of evolution in which long stable periods of stasis are interrupted by brief periods of rapid change
47
What are vestigial structures?
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
What is anagenesis?
Evolution within a lineage. It is a result of rapid evolution of the ancestral form without speciation taking place
49
What is cladogeneisis?
Evolution that results in the splitting of a lineage. This is where the parent species splits into at least two distinct species.
50
What is stratigraphy?
The order and relative position of strata and their relationship to the geological timescale. Useful for dating fossils imbedded in strata
51
What is y chromosome?
Similar to mtDNA, it’s passed on from father to son relatively unchanged and can be used to determine the relatedness of populations
52
What is a molecular clock?
Estimating the timing of evolutionary events based on the known (constant) rate of mutations in certain genes
53
What is mitochondrial DNA (mtDNA)?
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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