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BIO 2 > Ch.23 > Flashcards

Ch.23 Flashcards

1
Q

Define alleles

A

A particular version of a gene

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2
Q

Define genotype

A

 Refers to the genetic material past between generations

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3
Q

Define phenotype

A

The Observable traits of an individual

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4
Q

What does nonrandom mating only change

A

It onlychanges genotype frequencies NOT allele frequencies

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5
Q

What does inbreeding do to alleles

A

Homozygosity of alleles increase but heterozygosity of alleles decrease

Result in less fitness and recessive alleles will represent loss of function in an organism

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6
Q

Define inbreeding depression

A

Is a decline in avg, fitness that takes place when homozygosity decreases in a population

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7
Q

What evolutionary process only produces adaptation?

A

Natural selection

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8
Q

Define directional selection

A

Changes avg. Phenotype in pop. In one direction

Effect on phenotype: cause change in avg phenotype of a pop.

Genetic variation is reduced

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9
Q

Define stabilizing selection

A

Form of natural selection where individuals with moderate or avg phenotypes are more fit

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10
Q

Define disruptive selection

A

A type of natural selection that actively selects against the intermediate in a population favoring both extremes of the spectrum

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11
Q

Define balancing selection

A

This type of natural selection that maintains genetic variation for longer than expected

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12
Q

Define sexual selection

A

Is a form of nonrandom mating that occurs when females choose certain males or males competition

It leads to change in allele frequencies

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13
Q

Define intersexual selection

A

Is a type of sexual selection inwhich an individual of one sex chosen a particular individual of other sex for matching

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14
Q

Define intrasexual selection

A

A type of sexual selection driven by competition among members of one sex (male v male)

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15
Q

Define founder effect

A

Occurs when a group establishes a new pop. In a new area. This change alleles frequencies

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16
Q

Define population Bottle necks

A

Sudden decrease in pop-size in a once large pop., that are caused by disease or natural catastrophes

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17
Q

What does gene flow do?

A

Is the random movement of alleles between pop.

That then equalized allele frequencies

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18
Q

gene flow occurs when

A

Individuals leave one population join another and breed

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19
Q

Define mutation

A

Any permanent change in the hereditary material of an organism and is the only source of new alleles in a population and modifies allele frequencies by continually introducing new alleles

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20
Q

Does a mutation occur by chance?

A

Yes, and only by chance

21
Q

what is the ultimate source of genetic variation ?

A

Mutations

22
Q

Are mutations random?

A

Yes

23
Q

Does genetic drift decrease genetic diversity?

A

Yes, over time

24
Q

Does gene flow increase genetic diversity? Is there any exceptions?

A

Yes it does, but it can also decrease variation of the source of population if alleles leave with the moving population

25
Q

Define point mutation

A

Before chromosome level mutation

26
Q

Key points of genetic drift

A
  • Genetic drift is random with respect to fitness
  • genetic drift is most pronounced in small populations
  • overtime genetic daft can lead to the random loss or fixation of alleles
27
Q

Define sexual dimorphism

A

Refers to any trait that differs between males and females of same species include:

-Weaponry deer ex antlers on males

  • ornamentation and behavior in courtship ex
    peacocks colorful male feathers
  • body size
28
Q

What is heterozygote advantage?

A

Pattern of natural selection that favors heterozygous individuals compared to homozygous individuals.

Promotes genetic variation forming balancing selection

29
Q

Define deleterious alleles

A

Allele that reduces an individuals fitness

30
Q

What does inbreeding increase?

A

Homozygosity which makes offspring have lower fitness

31
Q

The assumptions of the Hardy- Weinberg principle

A
  1. Random mating- no mate choice; gametes combine randomly
  2. No natural selection- all individuals contribute equally to gene pool
  3. No genetic drift- random allele frequency changes)
  4. No gene flow - no new alleles added or lost from gene pool
  5. No mutations - no new alleles introduced into gene pool
32
Q

Define gene pool

A

alleles from all gametes and each generation go into a single group then combine randomly This concept was first brought up by Hardy and Weinberg

33
Q

What four processes is known to drive evolution?

A
  1. natural selection
  2. Genetic drift
  3. Gene flow
  4. Mutation
34
Q

Alleles that reach a frequency of 1.0 are said to be

A

Fixed

35
Q

Deleterious alleles are said to be

A

Lost at a 0.0

36
Q

Natural selection

A

Increases the frequency of alleles that contribute to reproductive success in a particular environment

37
Q

Genetic drift

A

causes allele frequencies to change randomly

38
Q

The 5 important assumptions of the hardy Weinberg principle

A
  1. Random mating- no mate Choice gametes combine randomly
  2.  No natural selections- all individuals contribute equally to gene pool
  3. No genetic drift - (random allele frequency changes) - alleles not picked by chance because it assumes population is large
  4. No gene flow - no new alleles added or lost from gene pool
  5. No mutations- no new alleles introduced into gene pool
39
Q

Given a population Of 100 individuals where 15 AAand 25 Aa and 60 aa what is the frequency of allele “A” and the frequency of alleles ”a”

A
40
Q

The Hardy Weinberg equation

A

P^2+2pq+q^2=1

41
Q

4 processes of evolution

A

Natural selection

Genetic drift

Gene flow

Mutation

42
Q

Natural selection

A

Increases the frequency of alleles that contribute to reproductive success in a environment

43
Q

Genetic drift

A

Causes allele frequencies to change randomly

Can lead to random loss or fixation of alleles

Thy can result to decrease in genetic variation

44
Q

Gene flow

A

Occurs when individuals leave one pop., join another, and breed

45
Q

Mutation

A

Modifies allele frequencies by continually introducing new alleles

46
Q

Natural selection occurs in what 4 patterns?

A
  1. Directional selection
  2. Stabilizing selection

3.disruptive selection

  1. Balancing selection
47
Q
A
48
Q

4 processes of evolution

A
  1. Natural selection
  2. Genetic drift
  3. Gene flow
  4. Mutation

BIO 2 (13 decks)

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