Evolution of Populations

Question 1

Microevolution:

Answer 1

a change in allele frequency in a population over generations

Question 2

Introns

Answer 2

noncoding segments in a gene that lie between coding regions

Question 3

Exons:

Answer 3

other regions of a gene that are eventually expressed, and typically translated into amino acid sequences

Question 4

Natural selection can only act on variation with a ____ component.

Answer 4

genetic

Question 5

____ variability is not equal to ____ variation

Answer 5

Nucleotide/Genotypic; Phenotypic

Question 6

What are examples of nucleotide variability?

Answer 6

changes in amino acid sequences

Question 7

Which gene regions are affected by natural selection?

Answer 7

Exon regions – this would change the protein

Question 8

Average Heterozygosity

Answer 8

Measures the average percent of loci that are heterozygous in a population

Question 9

At what level does gene variation occur?

Answer 9

the whole gene level

Question 10

Phenotypic Plasticity

Answer 10

Variation that is not the result of genotypic differences among individuals

Question 11

What external changes can lead to phenotypical changes?

Answer 11

Environmental

Question 12

What are the sources of GENETIC variation?

Answer 12

changes in the nucleotide sequence of DNA, particularly in cells that produce gametes (mutations)

Question 13

Mutations

Answer 13

changes in the genetic information (nucleotide sequence) of a cell

Question 14

Population

Answer 14

localized group of individuals capable of interbreeding and producing fertile offspring

Question 15

Gene Pool

Answer 15

consists of all the alleles for all loci in a population

Question 16

In what circumstance would a locus be fixed?

Answer 16

If all individuals in a population are HOMOzygous for the SAME allele

Question 17

Hardy-Weinberg Equilibrium Equation

Answer 17

p2+2pq+q2=1

Question 18

Conditions for Hardy-Weinberg Equilibrium (5):

Answer 18

1. No mutations
2. No natural selection
3. No gene flow: no new individuals
4. Random mating
5. Extremely large population size

Question 19

What major factors alter allele frequency (3)?

Answer 19

1. Natural selection
2. Genetic drift
3. Gene flow

Question 20

Directional Selection

Answer 20

favors individuals at one end of the phenotypic range

Question 21

Disruptive Selection

Answer 21

favors individuals at both extremes of phenotypic range

Question 22

Stabilizing Selection

Answer 22

favors intermediate variants and acts against extreme phenotypes

Question 23

Relative fitness

Answer 23

Contribution an individual makes to the gene pool of the next generation

Question 24

Selection favors certain (geno/phenotypes) by acting on (geno/phenotypes) of certain organisms.

Answer 24

genotypes; phenotypes

Question 25

Genetic Drift

Answer 25

chance events cause allele frequencies to fluctuate unpredictably from generation to generation

Question 26

Genetic drift tends to (de/increase) genetic variation through (gain/loss) of alleles

Answer 26

decrease; loss

Question 27

The Founder Effect

Answer 27

A few individuals become isolated from a larger population

Question 28

The Bottleneck Effect

Answer 28

A sudden reduction in population size due to a change in the environment

Question 29

Gene Flow

Answer 29

The movement of alleles among populations

Question 30

How are alleles transferred/allowed to flow?

Answer 30

Movement of fertile individuals/gametes

Question 31

Gene flow tends to (de/increase) differences between populations

Answer 31

decrease

Question 32

Gene flow leads to the (de/increase) in fitness of a population

Answer 32

increase

Question 33

What dictates notable evolution?

Answer 33

A change in allele frequency

Question 34

Adaptive Evolution

Answer 34

Occurs as the match between an organism and its environment increases

Question 35

Sexual Selection

Answer 35

natural selection for mating that can result in sexual dimorphism

Question 36

Sexual Dimorphism

Answer 36

idea that individuals of different sexes within a population have different physical characteristics

Question 37

Intrasexual Selection

Answer 37

competition within a species between members of the same sex to gain opportunities to mate

Question 38

Evolution is limited by _____ constraints

Answer 38

Historical

Question 39

_____ , natural selection, and the _____ interact

Answer 39

chance; environment