mechanisms of evolutionary change

Question 1

what is evolutionary change

Answer 1

changes in the allele frequency (micro)

Question 2

explain mutation

Answer 2

provides the raw variation that selection acts on. its a change in allele frequency by by itself, mutation does not affect significant changes in allele frequency (requires natural selection too). they can pop in and pop out. they must also be in gerline cells

Question 3

what is non random mating

Answer 3

changes the likelihood that alleles are in heterozygous or homozygous form. it changes genotype frequency. it produces excess of homozygotes. it can lead to allele frequency. its self fertilisation. an example of assortative mating- mating with another individual like yourself. diassortative mating: mating with someone not like you.

Question 4

explain meiotic drive

Answer 4

its an overpresentation of an allele. theres usually a 50 50 change because of mom and dad but anything that causes deviations fro this, it will be considered a meiotic drive-

Question 5

explain gene flow or evolution by migration

Answer 5

may introduce alleles or change existing allele frequency. could occur because of:
- is the source population different compared to destination
- number of migrants (and their alelles) coming in

Question 6

explain evolution by genetic drift

Answer 6

changes in allele frequency caused by chance. natural selection is NOT involved. its most potent in small populations. can happen through bottleneck or founder effect.
we use the term fix (when the allele is now dominating the population) and lost (if allele is no longer found)

Question 7

explain genetic bottlenecks

Answer 7

an event occurred in the future that changed the genetic diversity. it leads to loss of genetic diversity and generally an increase in homozygous individual

Question 8

explain the founder effect

Answer 8

small populations. another key is what allele is left on the island or the starting allele frequency.

Question 9

explain evolution by natural selection

Answer 9

non random survival of alleles in the population. different genotypes differ in their fitness and make different contributions to the gene pool. one is reaching the age of being able to reproduce and how many offspring of yours can reproduce

Question 10

how do we classify different types of evolution (exam question)

Answer 10

• directional selection
• stabilising selection
• disruptive (diversifying selection)

Question 11

explain directional selection

Answer 11

selective force that favours the dark coloured moths and after selection, it shifts in one particular direction. eg. white moths turn to dark moths mostly.

Question 12

explain stabilising selection

Answer 12

selective pressure where the population will tend to move to the middle of the curve. eg. too little or too many eggs.

Question 13

explain diversifying selection

Answer 13

different selective forces that create a change resulting in both traits of two individuals blending as one. eg, two spiders that are both male that’s from the same species but have different phenotype and therefore genotype grow to be different. one is chosen by females because of size and the other will get chosen based on who can dance the best.

Question 14

explain sexual selection

Answer 14

a type of natural selection that favours traits that improve chances pf mating and reproduction. does not always mean they have the favourable traits.

Question 15

real life examples that genetic frequency is used for

Answer 15

• conservation and breeding: quantify and mane interbreeding. determine if populations can interbreed. when and where to release populations from conservation programs
• ancestry: how similar or different are you from a. certain ascent
• biosecurity and forensics
• Disease: proportion of people that can have recessive disease
  demographic inference: populations demographics of extinct species

Question 16

why is there genetic variation left after natural selection

Answer 16

• heterozygotę advantage: allow normal alleles that usually gets selected against to be maintained in the population
• frequency dependant selection: selection may favour rare ale. selective benefit vary with season, location or year.
• natural variation: many polymorphisms in DNA have no affect on phenotype. neutral polymorphisms are maintained by a combination of mutation and genetic drive. they are useful to population geneticists and phylogenetic as they provide measures of gene flow.