*Unit 7 Part 5: Mechanisms of Change

Question 1

List 3 mechanisms by which evolution can occur.

Answer 1

~Genetic variation
~Gene flow
~Genetic drif

Question 2

Artificial selection

Answer 2

Intentional reproduction of individuals in a population with desirable traits

Question 3

Gene pool

Answer 3

All the alleles of all the genes in a population

Question 4

Gene (allele) frequency

Answer 4

Proportion of a particular type of alleles in a population

Question 5

Gene flow

Answer 5

New alleles/frequencies from one population enter another due to migration

Question 6

Mutations

Answer 6

Change in DNA that leads to new alleles (harmful or beneficial)

Question 7

Sexual reproduction

Answer 7

Meiosis (recombination of alleles during crossing over) and fertilization

Question 8

Genetic drift

Answer 8

Random changes in allele frequencies of a gene pool

Question 9

Founder effect

Answer 9

A new population started by a small number of indiviuals and their allele frequencies

Question 10

Bottleneck effect

Answer 10

Random event radically decreases population size and allele frequencies
Ex. earthquake

Question 11

List the three types of natural selection.

Answer 11

~Directional selection
~Disruptive selection
~Stabilizing selection

Question 12

Directional selection

Answer 12

One extreme expression of a trait is more fit

Question 13

Disruptive selection

Answer 13

Gets rid of average trait and increase frequency of both extreme traits

Question 14

Stabilizing selection

Answer 14

Gets rid of extreme expressions when average is more fit