Topic 4- Microevolution

Question 1

Microevolution

Answer 1

A change in allele frequency in a population or species generations; focus is on variation within populations/species

-requires genetic variation (more than one allele sesgregating at a locus in a population)

Question 2

Macroevolution

Answer 2

Evolution above species level- Focuses on variation among species and on questions related to diversification (e.g. origin of new species and higher order groups) across relatively long periods of time.

Question 3

What four processes can cause microevolution

Answer 3

Mutation, Gene flow, genetic drift and natural selection

Question 4

Random-mating

Answer 4

HW requires that individuals mate randomly with respect to their genotype at the locus of interest- random mating in a population is termed panmixa

Question 5

Non-random mating

Question 6

Inbreeding

Answer 6

Mating takes place between related individuals and the resulting offspring are inbred. Inbreeding causes an increase in the frequency of homozygotes

Question 7

What decreases fitness and as consequence causes inbreeding depression

Answer 7

increase in homozygosity as a result of inbreeding

Question 8

Outbreeding

Answer 8

Mating between indivudals less related than would be expected by random mating within the population.

Question 9

What increases fitness causing heterosis or hybrid vigoour

Answer 9

increase in heterozygosity as a result of outbreeding

Question 10

Positive/assortative vs Negative/disassortative

Answer 10

Assortive- tendency for individuals to choose mates that are more similiar in phenotype than expected by chance- increasing homozygosity

Dissasortative- tendency for individuals to choose mates that are dissimilar in phenotype than expected by chance- increasing heterozygosity

Question 11

Mutation

Answer 11

a change in the genetic information (nucleotide sequence) of an organisms DNA (and the process by which this occurs)
-utimate source of genetic variation
-random occurences
-can alter allele/genotype frequencies
-its effect on allele frequency on its own is weak as mutation rates are low

Question 12

Gene flow (aka migration)

Answer 12

Is the movement of alleles between populations (occuring via the migration of individuals or gametes)
-introduces and removes alleles from a population
-effect of gene flow on alleles frequencies is much greater than those of mutation because its rates are higher

Question 13

Genetic drift

Answer 13

Finite populations are subject, to varying degrees, to random changes in allele frequencies across generations
-It occurs due to sampling variation: the difference between the value in a finite sample compared to the true value of a population
-reduces genetic variations because alleles are lost

Question 14

Population bottlenecks

Answer 14

decreases population size which reduces genetic variation and enhances genetic drift

Question 15

Mutation drift

Answer 15

human health implications

Question 16

Natural selection

Answer 16

a process that occurs when certain conditons are met:

1) individual vary in a trait
2) There is a non-random association between the trait and their reproductive success
3) the trait is heritable
then the trait will evolve.
1&2 for natural selection to occur
1,2,3 for natural selection to produce evoloutionary change.

Question 17

Fitness

Answer 17

its reproductive success measured as the number of offspring it produces