Exam 2 Test Questions

Question 1

Describe the Wright Fisher Model

Answer 1

Used as a null hypothesis, similar to Hardy Weingberg but with small populations

Question 2

How do bottlenecks cause fixation or loss of alleles?

Answer 2

By reducing the effective population size

Question 3

Describe Founders Effect

Answer 3

Small subset of a population creates a new population creating new genetic variance

Question 4

Homoplasy

Answer 4

Traits similar in one or more species even though it was not present in their common ancestor

Question 5

What is inbreeding depression caused by?

Answer 5

A reduction in fitness caused by deleterious recessives

Question 6

Why is disassortative mating beneficial?

Answer 6

Reduces the probability of deleterious recessives expressed and maximizes genetic diversity in offspring

Question 7

Consequences of genetic drift (3)

Answer 7

Divergence in allele frequencies among independently evolving finite populations, fixation of one allele, loss of heterozygosity

Question 8

Describe assumptions of Hardy Weinberg model

Answer 8

No one allele has a selective advantage over another, the population is considered infinite, no gene flow between population

Question 9

Genetic Saturation

Answer 9

The maximum amount of divergence rate due to reverse mutations, and other multiple changes happening at the same site

Question 10

Negative Frequency Dependent Selection

Answer 10

Good to have low frequency; i.e. immunity to pathogens or sinistrial fish

Question 11

Positive frequency dependent selection

Answer 11

Good to be common, higher frequency of allele higher the fitness

Question 12

Bootstrap method

Answer 12

Statistical analysis done to estimate the reliability of each node in a phylogenetic tree

Question 13

Synapomorphy

Answer 13

Characters used to establish monophyletic groups

Question 14

Transitional Forms

Answer 14

Fossils that combine traits of two different lineages that are thought to be related

Question 15

Tiktalik

Answer 15

Corresponds to the common ancestor of all tetrapods, shows fish traits and tetrapod traits

Question 16

Reversal

Answer 16

Change of a modified trait back to its ancestral state

Question 17

Genetic drift

Answer 17

random changes in allele frequencies that occur due to chance

Question 18

Parsimony

Answer 18

Explanation requiring the least number of changes is correct

Question 19

Symplasiomorphy

Answer 19

Shared ancestral trait

Question 20

Phylogeography

Answer 20

Study of how populations or species have moved across the globe to their current distribution