Lecture 2: Evolutionary origins

Question 1

Phylogeny

Answer 1

branching tree depicting evolutionary relationships among organisms with common ancestor

Question 2

Key Mechanisms of evolution

Answer 2

1. mutation
2. Genetic Drift
3. natural selection
4. sexual selection
5. gene flow

Question 3

Genetic variation

Answer 3

-occurs in a gene when all individuals are not identical: dont have AA or aa alleles (need heterozygous Aa)

Question 4

Diploid

Answer 4

presence of two complete sets of chromosomes in an organisms cells, with each parent contributing a chromosome to each pair

Question 5

Allele Frequencies

Answer 5

count up the total number of one type of allele and divide by total number of alleles (number of individuals times 2 in diploids)

Question 6

Genetic changes in quantitative traits

Answer 6

Controlled by changes in allele frequecy at multiply genes, controlled by environment

Question 7

Mutation

Answer 7

Changes genetic code, generating new alleles, potentially resulting in phenotypic effects
- most mutations decrease fitness by 2%

Question 8

Genetic Drift

Answer 8

Random change in allele frequency
- ex major disaster kills portion of pop and changes allele frequency

Question 9

natural selection

Answer 9

traits vary among individuals
traits influence survival
traits are heritable
- traits that improve survival should increase in frequency (or size) through time

Question 10

sexual selection

Answer 10

1. intra-sexual: e.g., male v male competition
2. inter-sexual: e.g., female choice

Question 11

Gene flow

Answer 11

• movements of genes among populations
• causes allele frequencies in the two (or more) populations to be more alike