Adaptation via Natural Selection

Question 0

Name the 4 evolutionary forces that can disrupt HWE

Answer 0

Mutation
Random Genetic Drift
Migration
Natural Selection

Question 1

Describe Hardy Weinberg Equilibrium theory

Answer 1

Allele frequencies and genotypes remain constant over generations. Methods other than Mendelian segregation and recombination may alter frequencies!

Question 2

A force that disrupts HWE which can be good or bad, is random and can create new variation?

Answer 2

Mutation

Question 3

I am more likely to occur in smaller populations and create random change in allele frequencies..
I am a force that disrupts HWE..what am I?

Answer 3

Random genetic drift

Question 4

Another force that disrupts HWE: cause change, counteracts divergence and movement between populations

Answer 4

Migration/Gene flow

Question 5

Natural selection is a force that disrupts HWE .. Change may not occur or may not be at the individual level, but what other factors can be associated with natural selection?

Answer 5

Adaptations that make the species stronger (?)
Lower heterozygotes
Divergence in isolated populations

Question 6

Define fitness…

Answer 6

Everything that affects survival - probability of survival X average number of lifetime offspring

Question 7

Define natural selection…

Answer 7

Any consistent difference in fitness among phenotypically different classes of genes, cell, populations or species

Question 8

1. Correlations between trait and environment
2. Response to experimental change in environment
3. Correlation between trait and fitness
   If all 3 of these factors exist, what force is at work?

Answer 8

Natural selection

Question 9

When an entire chunk of DNA is under selection rather than just a selected allele, what is the process?

Answer 9

Hitch hiking

Question 10

When alleles have hitch hiked, how has selection worked?

Answer 10

The alleles have responded to selection, they haven’t been selected for

Question 11

Does hitch hiking sweeps occur in higher mammals?

Answer 11

Yes but it is rare

Question 12

How does selection work?

Answer 12

It may act to keep a strict proportion of genotypes within the population - balancing selection. It may also act to keep populations the same rather than to change them

Question 13

Traits aren’t always adaptations, they may be useful but weren’t adapted for the selection purpose. What else could they be?

Answer 13

Consequence of physics/chemistry
Consequence of genetic drift
Consequence of linkage (hitch hiking)
Consequence of ancestral state eg exaptation

Question 14

Define preadaptation…

Answer 14

Adaptation that serves a new purpose eg feathers on a running dinosaur

Question 15

Feathers that are unchanged on a modern day bird are classed as:

Answer 15

An exaptation - the process by which hell the feature acquired a new purpose

Question 16

Do many populations remain in Hardy Weinberg Equilibrium?

Answer 16

We don’t expect many to remain in HWE