Chapter 23 - Microevolution

Question 1

Microevolution

Answer 1

Evolutionary changes below the species level. Change in the allele frequencies in a population over generations

Question 2

3 main mechanisms for allele fruequency change

Answer 2

1- Natural selection
2- genetic drift
3- gene flow

Question 3

genetic variation

Answer 3

differences among individuals in the composition of their genes

Question 4

gene pool

Answer 4

The total of all copies of every type of allele at all loci in every individual in a population.

Question 5

Hardy-Weinberg equilibrium

Answer 5

The state of a population in which the frequencies of alleles and genotypes remain constant from genberation to generation, provided that only mendelian segregation and recombination of alleles are at work.

Question 6

adaptive evolution

Answer 6

evolution that results in a better match between organisms and their environment

Question 7

Genetic drift

Answer 7

a process in which chance events (moose stepping on the only 3 white flowers in a population) cause unpredictable fluctuations in allele frequencies from one generation to the next. Effects of genetic drift are most pronounced in small populations.

Question 8

Gene flow

Answer 8

The transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes.

Question 9

Directional selection

Answer 9

Natural selection in which individuals at one end of the phenotypic range survive or reproduce more succesfully than do other individuals

Question 10

Disruptive selection

Answer 10

Natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more succesfully than individuals with intermediate phenotyopes

Question 11

stabilizing selection

Answer 11

Natural selection in which the intermediate phenotypes survive or reproduce more succesfully than do extreme phenotypes

Question 12

Intra- and inter-sexual selection

Answer 12

Intra: selection within the same sex e.g. two males competing for the same female
Inter: selection in which individuals of one sex are selecting mates form the other sex

Question 13

balancing selection

Answer 13

Natural selection that maintaints two or more phenotypic forms in a population

Question 14

Frequency dependent selection

Answer 14

Selection in which the fitness of a phenotype depends on how common the phenotype is in a population

Question 15

Neutral variation

Answer 15

A trait that is neutral in one environment, but may be advantageous in another.

Question 16

Hardy weinberg opdracht waarbij je q2 weet: Approximately 1 out of every 2,500 Caucasians in the United States is born with the recessive disease cystic fibrosis. According to the Hardy-Weinberg equilibrium equation, approximately what percentage of people are carriers?

Answer 16

• q2 is 1/2500 = 0.004.
• van q^2 naar q is wortel van q2 dus: Wortel 0.0004 = 0.02
• als q = 0.02 dan p = 0.98
• heterozygoot is 2xpq dus 2x(0.02x0.98) is 0.039
  =0.04 = 4%