Lecture 19 Natural Selection and Adaptation Flashcards

1
Q

What are the two types of selection?

A

Artificial vs natural

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2
Q

What is fitness

A

Ability to contribute genetics to generations compared to others in terms of viability and fertility

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3
Q

What is fitness otherwise known as?

A

Darwinian fitness

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4
Q

What is selective advantage?

A

When some individuals are better adapted to the environment they live in Compared to other organisms

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5
Q

What is an adaptation?

A

Trait that makes an organism better able to survive and reproduce

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6
Q

Is an adaptation that same as an ancestral trait?

A

No

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7
Q

What is the significance of adaptation?

A

Origin of how a trait is maintained in given environment

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8
Q

What is artificial selection?

A

Selection by humans to obtain a goal

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9
Q

What happens under the umbrella of artificial selection? (3) DGV

A

Plants and animals are domesticated

Experiments in genetics regarding selection

Evolving of vaccines

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10
Q

What is natural selection?

A

selection by abiotic or biotic environment

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11
Q

Does natural selection have a goal?

A

No

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12
Q

Does natural selection affect all species?

A

Yes

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13
Q

What are different ways to study adaptation? (3) MAE

A

Monitor connection between alleles and traits with the environment

Analyze genomic diversity. Genes selected on by natural selection would stand out

Experiments in the field and lab

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14
Q

what is positive directional selection?

A

When even the tiniest adaptation can spread throughout and environments

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15
Q

What happens to the graph when the frequency of an allele reaches 1?

A

The graph levels out

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16
Q

What is negative selection?

A

the selective removal of alleles that are deleterious.

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17
Q

How is the mean of distribution shown on a graph?

A

tick below where the hill peaks

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18
Q

What is stabilizing selection?

A

individuals with moderate or average phenotypes are more fit

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19
Q

What is directional selection?

A

single phenotype is favoured, causing the allele frequency to shift in one direction continuously

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20
Q

What is disruptive selection?

A

selects for two or more extreme phenotypes that each have specific advantages over intermediates (very beginning and end of graph)

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21
Q

As seeds became harder to find what happens to beaks on of the finches on the Galápagos Islands?

A

They became bigger

22
Q

What happened to the population of finches as the number of seeds decreased?

A

The population fell

23
Q

What does disruptive selection lead to?

A

Trait divergence

24
Q

What does disruptive selection require?

A

Spatial heterogeneity or discrete resources

25
What is the struggle to determine agents of natural selection?
Thousands of measurements of selection Selection demonstrates differences in fitness and evolutionary traits And yet Few convincing causes can explain the agent of natural selection
26
Is Connecting evolution to ecology is difficult?
Yes
27
In the moth example Dark form was caused by a dominant gene, called the
Cortex gene
28
What happened to the dark moth population when Industrial pollution blacked bark on trees on which they lived
The dark moth increase
29
Where do the moth in light form dominat?
Rural areas
30
After introduction of the UK Clean Air Act what happened to the population of dark moths?
Result in decline of dark moth frequency
31
What does the evolutionary response to changes in pollution levels reflect?
reflects the time it takes for a forest to “go back to natural” as well as the frequency of the melanic allele
32
Which types of areas do light mice live?
In light areas
33
Which types of areas to dark mice live in?
In dark areas
34
Most common enzyme deficiency in humans?
G6PD
35
How does G6PD affect us?
Causes severe anemia
36
What is the benefit of G6PD?
protects against malaria
37
When malaria is absent what is the frequency of A allele, and selection of anemia?
Less frequecy of A allele Selection against anemia
38
When malaria is present what is the frequency of A allele, and selection of anemia?
higher frequency of A allele Selection for resistance
39
What is the benefit of historic genomes?
allow tracking of allele over a long period of time
40
Is Natural selection faster than genetic drift?
Yes
41
How does natural selection affect alleles compared to random chance?
Natural selection causes a higher frequency of alleles than random chance
42
What is Evidence of natural selection on vitamin D deficiency that is ancient to modern genomes in the UK?
Vitamin D requires UV radiation which is very little in the UK
43
What is the benefit of DHRC7 genes?
Aids in vitamin D metabolism
44
What was Long term experimental evolutionary study done on?
E coli
45
How many flask were populated when studying Ecoli
24
46
Over how many generations was Ecoli studied for?
75,000
46
What liquid of Ecoli propagated in?
Propagated in minimal glucose citrate medium
47
What was the population of Ecoli like in the first 10,000 years?
populations rapidly increased in fitness, then decreased in their fitness over time
48
What does the thawing out of frozen samples of Ecoli allow?
Thawing out allows comparison of fitness between new and old generations
49
What was Novel key innovation in one population after 33, 000 generations?
One strain evolve ability to grow on citrate
50
What are open questions about adaptation?
What is the importance of pre existing genetic variation in populations vs new mutations? Do the same vs different genes contribute to convergent adaptations in unrelated species? How much of the genome is subject to ongoing adaptations?