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Bio 5C > Unit 3 - Evolutions in Populations > Flashcards

Unit 3 - Evolutions in Populations Flashcards

1
Q

What is a population?

A

A group of individuals of the same species that live in the same area and interbreed.

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2
Q

____ are composed of populations of individuals.

A

Species

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3
Q

What is an allele?

A

Genetic variants on loci.

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4
Q

What is frequency?

A

The proportion of the population with that genotype of allele.

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5
Q

What is a gene pool?

A

It consists of all copies of every allele at the loci of interest in all members of the population.

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6
Q

What are polymorphic populations?

A

When a population or gene pool has more than one allele.

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7
Q

What are monomorphic populations?

A

When a population or gene pool has only one allele. Allele is “fixed”.

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8
Q

What is evolution at the scale of a population defined as?

A

A chance in allele frequency over generations.

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9
Q

What is allele frequency?

A

The proportion of a specific allele out of the total number of alleles in the gene pool.

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10
Q

In a gene pool, there are 20 B alleles and 80 b alleles. What is the frequency of the “b” allele?

A

0.8

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11
Q

What is evolution?

A

The change in allele frequency over generations.

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12
Q

What does the frequency of all alleles add up to?

A

One.

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13
Q

At a locus with two allele, p = 0.65. What is q?

A

0.35

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14
Q

What are the four processes that change allele frequencies?

A

Mutation, drift, migration, and selection.

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15
Q

In a population of 320 red flowers(CRCR), 20 white flowers(CWCW), and 160 pink flowers(CRCW), how many CW alleles are there?

A

200

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16
Q

When can you calculate expected genotype frequencies?

A

When the allele frequency is known in the parental population and when there is random mating in the parental population.

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17
Q

What is random mating?

A

When every individual has as equal and independent chance of mating with every other individual.

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18
Q

What is the rule of probability?

A

If samples are drawn at random, the probability of a given item being included in the samples equals the frequency of that item in the source population.

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19
Q

What does the Hardy-Weinberg equation predict?

A

Genotype frequencies from allele frequencies. (p^2 +2pq + q^2)

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20
Q

What type of population will genotype and allele frequencies will be constant under the Hardy-Weinberg model?

A

A population that is not evolving and randomly mating.

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21
Q

What can the Hardy-Weinberg equation test?

A

Whether a population is evolving or not.

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22
Q

When there is a significant deviation from HWE, what does it suggest?

A

One of the HWE assumptions were violated.

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23
Q

What do we assume with HWE?

A

There is no selection, no mutation, no migration, a large population, and random mating.

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24
Q

Approximately ___ of the US population carry PKU alleles.

A

2%

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25
Q

What are allele frequencies?

A

The proportion that allele makes up of the total.

26
Q

What can genotype frequencies do?

A

They will rapidly achieve HWE for a given set of allele frequencies.

27
Q

What is evolution?

A

A change in allele frequencies in a population over time.

28
Q

What are random processes?

A

Processes that can have different outcomes, but cannot be predicted.

29
Q

What is an example of a random process?

A

Flipping a coin.

30
Q

What is genetic drift?

A

It is the random change of allele frequencies from one generation to the next due to random events.

31
Q

What is a haploid?

A

An individual that has only a single copy of their genes.

32
Q

What causes random sampling in real populations?

A

Any process that has the effect of randomly increasing or decreasing allele frequencies.

33
Q

What is the meiosis lottery?

A

One large source of random sampling.

34
Q

What are the two main facts about drift?

A
  1. It is the main driver of evolution at the genetic level.
  2. It is the null hypothesis when testing for other evolutionary processes.
35
Q

Drift causes _____ changes from generation to generation in smaller populations.

A

Extreme

36
Q

What is fixation?

A

When the allele frequency of one allele reaches 100%, also occurs more rapidly in small populations.

37
Q

What are the two forms are genetic drift?

A

Founder effect and bottleneck effect.

38
Q

What is the found effect?

A

Occurs when a small number of individuals become isolated from a larger population.

39
Q

Island populations have much ____ genetic diversity vs. the mainland.

A

Lower

40
Q

What is the bottleneck effect.

A

A magnification of the effect of genetic drift due to a reduction in size within a population.

41
Q

Where does the bottleneck effect occur?

A

Within a single population.

42
Q

What does genetic drift do to evolution?

A
  • Makes the evolutionary process more random
  • Reduces genetic variation
  • Can result in the fixation of alleles.
43
Q

What is gene flow?

A

The movement of alleles between populations due to migration.

44
Q

What is migration?

A

The movement of an individual from one population to another.

44
Q

Gene flow tends to make populations __________ over time.

A

more genetically similar

44
Q

If all gene flow between two populations suddenly stopped, we would expect them to start becoming ___ different over time.

A

more

44
Q

Isolation by distance is a pattern of _____ genetic differences with ____ geographic distance.

A

increasing; increasing

45
Q

What is genetic swamping?

A

The reduction in a population’s ability to adapt due to gene flow from a maladapted population.

46
Q

What is adaptive introgression?

A

The movement of beneficial alleles between populations, which facilitates adaptation.

47
Q

What is FST?

A

A measure of genetic differences between populations. Ranges between 0 and 1.

48
Q

What is natural selection?

A

The differential survival and reproduction of individuals/genotypes due to differences in phenotype.

49
Q

True/False: No other evolutionary
process causes adaptation.

A

True.

50
Q

What are the basic requirement for evolution via natural selection.

A
  1. There is phenotypic variation in the population.
  2. The variation is at least somewhat heritable.
  3. The variation results in differences in fitness.
51
Q

What is fitness?

A

A quantitative measure of how much an individual with a particular phenotype or genotype will contribute to the next generation on average.

52
Q

True/False: Strength, intelligence,
speed, etc. is not necessarily connected to evolutionary fitness.

A

True.

53
Q

What are the three main forms of selection?

A

Directional selection, disruptive selection, and stabilizing selection.

54
Q

What is directional selection?

A

An increase in the frequency of a trait or allele due to a fitness benefit.

55
Q

Directional selection tends to ____ genetic variation.

A

reduce

56
Q

What is disruptive selection?

A

Changes in population genetics in which extreme values for a trait are favored over intermediate values

57
Q

What is stabilizing selection?

A

The population mean stabilizes on a particular non-extreme trait value.

58
Q

What is balancing selection?

A

Selection that maintains two or more phenotypic forms in a populations.

Bio 5C (4 decks)

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