Biology Chp. 23 The Evolution Of Populations

Front 1

Prerequisite

Back 1

Variation in heritable traits is a ______ for evolution

Front 2

Genetic Component

Back 2

Natural Selection can only act on variation within a _____, not on acquired traits.

Front 3

Mutation

Back 3

Heritable variation only comes from?

Front 4

- Discrete

- Quantitative

Back 4

2 Types of characters that contribute to variation within a population

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Discrete Characters

Back 5

- Characters that can be classified as either/or basis

- Ex: Pink or white, red or sepia

Front 6

Quantitative Characters

Back 6

- Character that varies along a continuum within a population

- Ex: Speed, beauty, Multiple-allele gene, most of everything in nature

Front 7

Deletion (H)

Disruption (H)

Rearrangement (H)

Duplication (Less)

Back 7

4 Ways that Chromosomal Mutations alter gene numbers or position

- Which are typically harmful? Less harmful?

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Duplication

Back 8

- Increases genome size

- Type of chromosomal mutation that can allow taking on of new functions by further mutation

- Ex: Ancestral odor-detecting gene

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c. Recombines existing alleles
d. Creates more variation in phenotypes
e. Gives natural selection broader subject matter

Back 9

Sexual Reproduction

a. is a Force of evolution

b. Provides genetic differences for adaptation

c. Recombines existing alleles

d. Creates more variation in phenotypes

e. Gives natural selection broader subject matter

Select all that are true.

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Emergent Traits

Back 10

- states that with rising levels of complexity in living things, new patterns will emerge

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Population

Back 11

- Group of individuals (in the same area) capable of interbreeding and producing fertile offspring

- Defined based on interbreeding > physical location

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Gene Pool

Back 12

Consists of all the alleles for all loci (genes) in a population

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p + q = 1

p: Dominant allele FREQUENCY

q: Recessive allele FREQUENCY

Back 13

Allele frequencies in a population will add up to 1. What is the equation? What does p and q stand for?

Front 14

Is not

Back 14

Hardy-Weinberg principle/equilibrium [Allele frequency does not change over generations] describes a population that (is/is not) evolving.

This can also be considered our NULL hypothesis.

Front 15

- Natural selection

- Genetic Drift

- Gene flow

- Mutation

Back 15

4 Mechanisms of Allele Frequency change(=Microevolution)

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Natural Selection

Back 16

- Involves both chance and "sorting"

- Consistently results in adaptive evolution (non-random)

- Does not introduce variations, sorts random variations into complex, harmonious structures

- Ex: Eyeball

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Natural Selection

Genetic Drift

Back 17

2 Mechanisms of Microevolution that gets rid of diversity by removing alleles from the population

Front 18

Gene Flow

Mutation

Back 18

2 Mechanisms of microevolution that introduces diversity by spreading new alleles into a population or introducing new alleles into a gene pool

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p2 + 2pq + q2 = 1

p2 = homozygous dominant FREQUENCY

2pq = heterozygous FREQUENCY

q2 = homozygous recessive FREQUENCY

Back 19

Frequency of different genotypes should add up to 1. What is the equation? What do the individual components stand for?

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1. No mutation

2. Random mating

3. No Natural Selection

4. Extremely large population size

5. No gene flow

Back 20

5 Conditions of Hardy-Weinberg Equilibrium

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1. Mutation

2. Local mating (inbreeding)

3. Natural Selection

4. Small population size

5. Gene flow

Back 21

5 Causes of Evolution (compared to Hardy-Weinberg)

Front 22

Natural Selection

Genetic Drift

Gene Flow

Back 22

3 Causes of Evolution [alter allele frequencies] that cause the most evolutionary change

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Genetic Drift

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- Unpredictable mechanism, RANDOM fluctuations

- Significant in smaller populations

- Takes away allele frequencies and thus reduces genetic variation

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Founder Effect (Decrease pop. size from isolation)

Bottleneck Effect (Decrease pop. size from environmental change)

Back 24

2 Non-standard "Pre-Requisite" Cases of Genetic Drift

& the difference between the two

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Gene Flow

Back 25

- Consists of the movement of alleles among populations

- Can be transferred through the movement of fertile individuals or gametes (ex: pollen)

- Tends to reduce differences between populations over time

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Relative fitness

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- Contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals

- =/= "Struggle for existence" or "Survival of the fittest"

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Directional

Disruptive

Stablizing

Back 27

3 Modes of Selection

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Directional Selection

Back 28

- Favors individuals at one end of the phenotypic range

Front 29

Disruptive Selection

Back 29

- Favors individuals at both extremes of the phenotypic range

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Stabilizing selection

Back 30

Favors intermediate variants and acts against extreme phenotypes

Front 31

Sexual Selection

Back 31

Natural selection for mating success

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Sexual dimorphism

Back 32

Marked differences between the sexes in secondary sexual characteristics

Ex: Peacocks

Ex: Can attract opposite sex but decrease change of survival

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Intrasexual Selection

Back 33

Competition among individuals of one sex (often males) for mates of the opposite sex

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Intersexual Selection

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- "Mate Choice"

- Occurs when individuals of one sex (usually females) are choosy in selecting their mates

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1. Selection can only act on existing variations

2. Evolution is limited by historical constraints

3. Adaptations are often compromises

4. Chance, natural selection, and the environment interact

Back 35

4 Reasons for Non-Perfect Natural Selection

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Mutation (New)

Gene Flow (New)

Genetic Drift (Removes)

Back 36

- 3 RANDOM mechanisms of evolution

- Which brings new variations?, Which removes?