Chapter 21

Question 0

Populations

Answer 0

Interbreeding members of a species that live in the same area at the same time

Question 1

Species

Answer 1

Members of population that can successfully breed to produce fertile offspring

Question 2

Pleotrophy

Answer 2

Single genotype-multiple phenotypes

Question 3

Source of all genetic variation

Answer 3

Mutations

Question 4

Allele Frequency

Answer 4

of copies of allele/total # of alleles in a population

Question 5

Evolution

Answer 5

• Change in allele or genotype frequency in a population over time
• All living things related through common ancestor and characteristics of living things change over time

Question 6

Hardy Weinberg Principle

Answer 6

• Allele frequencies will remain in equilibrium unless outside forces act to change
• must be a sexually reproducing diploid population

Question 7

Hardy Weinberg conditions

Answer 7

• no differences in survival
• random mating
• no gene flow
• no natural selection
• large population size
• no mutations

Question 8

p and q

Answer 8

p= frequency of dominant allele 
q= frequency of recessive allele

Question 9

Hardy Weinberg equation

Answer 9

p^2+2pq+q^2=1

Question 10

Darwin’s observations

Answer 10

• species of animals and plants different in S. America vs. GB
• In Galápagos Islands each island had unique species
• developed idea of mainland origins

Question 11

Artificial Selection

Answer 11

Selective breeding

Question 12

4 conditions for natural selection

Answer 12

• must be variation
• influence of ability to survive and reproduce
• those who survive have the chance to pass those genes on
• favorable traits will increase in frequency

Question 13

3 clarifications about evolution

Answer 13

1. Individuals don’t evolve, populations do
2. Acquired characteristics can’t be passed down
3. Not goal directed and won’t lead to perfection

Question 14

Fitness

Answer 14

Ability to pass gene on

Question 15

Adaptation

Answer 15

Phenotype shown from gene change

Question 16

2 scales of evolution

Answer 16

Microevolution and Macroevolution

Question 17

Macroevolution

Answer 17

Change in allele frequency in a population over time

Question 18

Mechanisms of evolution

Answer 18

• natural selection
• sexual selection
• genetic drift
• gene flow

Question 19

3 points about natural selection

Answer 19

• editing process
• response to specific time and place
• can occur in a short time

Question 20

Stabilizing selection

Answer 20

Selection for intermediate phenotype

Question 21

Directional selection

Answer 21

Selection for either extreme

Question 22

Disruptive selection

Answer 22

Selection against intermediate

Question 23

Sexual selection

Answer 23

Certain phenotypes influence choice of mate

Question 24

Intersexual competition

Answer 24

Females picking mate because of some characteristics

Question 25

Genetic drift

Answer 25

- How allele frequencies fluctuate unpredictably from one generation to the next - tends to reduce genetic variation

Question 26

2 types of genetic drift

Answer 26

1. Founder effect | 2. Bottleneck effect

Question 27

Founder effect

Answer 27

- Few individuals become isolated from larger population | - don't represent all alleles of larger population

Question 28

Bottleneck effect

Answer 28

- some organisms survive | - different allele frequency

Question 29

Phylogeny

Answer 29

- common ancestry | - involve similarities and differences of DNA sequence

Question 30

Fossils

Answer 30

- Evidence of extinction | - document similarities and differences

Question 31

Transitional Fossils

Answer 31

-track changes in size and shape of skeleton

Question 32

Key Facts about Evolution

Answer 32

- Animal and plant forms change over time - time span change is immense - extinction fate of most species - environments in every location have changed

Question 33

Homology

Answer 33

Link to common ancestor

Question 34

Fixation

Answer 34

Allele frequency = 1

Question 35

Speciation

Answer 35

- lineage splitting event - long term genetic change - bridge between Macroevolution and Microevolution

Question 36

Causes of speciation

Answer 36

Reduction in gene flow - geographic isolation - reproductive isolation

Question 37

Prezygotic barriers

Answer 37

Block fertilization from occurring

Question 38

Postzygotic Barriers

Answer 38

Genetic incompatibility(don't progress to produce fertile offspring)

Question 39

Allopatric speciation

Answer 39

1. Dispersal-group colonized a new habitat | 2. Vicariance-group separated by physical barrier

Question 40

Adaptive Radiation

Answer 40

- Radiation into many different species | - starts with dispersal

Question 41

Sympatric Speciation

Answer 41

-Disruptive selection may lead to sympatric speciation if strong and sustained enough

Question 42

Gene Pool

Answer 42

All alleles present in all individuals in a species

Question 43

Recombination

Answer 43

Shuffles mutations to create new combinations