Chapter 3: Genetic Drift

Question 1

Natural Selection
-Under natural selection, we see _______________

Answer 1

predictable changes

Question 2

Mechanisms of evolution
There are other mechanisms of evolution with Natural Selection being just one of them:
1. Natural Selection
2. Genetic Mutations
3. Gene Flow (___________)
4. _____________ Mating
5. Genetic Drift

Answer 2

-migration
-nonrandom

Question 3

Mechanisms of evolution
1. Natural Selection: process where organisms that better __________ to their environment (____________) tend to survive and produce more offspring
2. Genetic Mutations: a change (error) in the ________________
3. Gene Flow (migration): Movement of individuals from one __________ to another
4. Nonrandom mating: mate selection

Answer 3

-adapted
-higher fitness
-DNA of a gene
-population

Question 4

5. Genetic Drift
   -Changes in allele frequencies due to __________________
   -RANDOM rather than survival of the fittest
   -In effect is an example of __________________
   *lightning, hurricane

Answer 4

-random chance events
-sampling error

Question 5

Sampling Error
-occurs when a ______ subset (sample) does not represent the population as a whole
-in science we fix this by taking ________ or _______ samples
-in nature, sampling error results in populations with drastically different allele frequencies.

Answer 5

-small
- more
-bigger

Question 6

How to Get Sampling Error
-Genetic Drift is the result of ________________ drops in population size.
-2 special cases of genetic drift:
1. Population bottleneck
2. Founder Effect

Answer 6

-rapid, random

Question 7

1. Population Bottleneck
   -when a major disaster causes a ________ in population size
   -can cause reduced ______________
   -can be caused by natural disasters, disease, droughts, fire, etc.

Answer 7

-sharp drop
-genetic variation

Question 8

2. Founder Effect
   -when a _____ individuals from an original population start a new population in an isolated ___________
   -can cause reduced genetic variation **

Answer 8

-few
-new area

Question 9

Changes in Allele Frequencies
-Both natural selection and genetic drift are measured by looking at changes in _______________
-described as *MICROEVOLUTION

Answer 9

-allele frequencies

Question 10

The null hypothesis of evolution
-__________________ describes a set of theoretical circumstances where allele frequencies do not change

Answer 10

-Hardy-Weinberg Equilibrium

Question 11

Hardy-Weinberg Equilibrium

ALL 5 assumptions must be met in order to say that a population is in equilibrium (not evolving):
1. NO _________
2. NO gene flow (migration)
3. __________ mating
4. Very ________ population
5. No natural selection

Answer 11

-mutation
-random
-large