3. Natural Selection and Population genetics

Question 1

Metagenome

Answer 1

All genes available in a group of individuals

Question 2

Macroevolution

Answer 2

Evolution over large taxonomic groups over a long period of time
- e.g. Archeopteryx to modern birds

Question 3

Microevolution

Answer 3

Evolutionary changes within a population

Question 4

Population Genetics

Answer 4

The study of genetic differences within and between populations

• Evolution acts on population
• Evolution = change in allele or gene frequency

Question 5

Early belief on gene frequencies

Answer 5

Dominant alleles would take over recessive ones

Question 6

Hardy - Weinberg Principle

Answer 6

Mathematically proved Mendelian inheritance

Question 7

Limitation of Hardy-Weinberg Principle

Answer 7

Only for two alleles and simple dominant-recessive relationship

1. Diploid
2. Sexual reproduction only
3. Generations are non-overlaping
4. mating is random
5. Population size is infinitely large
6. Allele frequencies are equal in sexes
7. No migration, mutation or selection

Question 8

Population

Answer 8

Groups of organisms that share similar genes, that can exchange those genes
*Population in evolutionary theories = gene pool

Question 9

Meta-population

Answer 9

All the individual isolated populations that are still capable of interbreeding but are reproductively isolated
- When put together can interbreed

Question 10

Sub-population

Answer 10

sub-sample from a large population

Question 11

Stratified populations

Answer 11

A single population that can interbreed but is starting to differ in gene frequencies in different parts of shared ranges

Question 12

Unit of selection

Answer 12

The term/level we believe evolution is acting on

Question 13

Unit of Selection in the Modern Synthesis

Answer 13

Genes

Question 14

Natural Selection

Answer 14

The sum of all factors which cause differences in reproduction and survival among individuals in a population

Question 15

Fitness

Answer 15

The extent to which a particular genotype contributes offspring to the next generation

Question 16

Trait

Answer 16

A measurable and visible character in the phenotype of an organism

Question 17

Discrete trait

Answer 17

A trait that consists of a smalle number of distinct alleles which do not vary along a continuous gradient

Question 18

Continuous trait

Answer 18

Trait varies along a gradient

Question 19

Fixed Trait

Answer 19

Determined genetically

- instinct

Question 20

Plastic Trait

Answer 20

Influenced by environment

- learning

Question 21

Stabilizing Selection

Answer 21

Extreme traits eliminated and the average stays

- Continuous or discrete

Question 22

Disruptive Selection

Answer 22

Individuals with extreme variation have greater fitness

- Only continuous

Question 23

Directional

Answer 23

Selection driven towards one genotype at the expense of others
- Continuous or discrete

Question 24

Strength of Selection

Answer 24

Strong - Rapid evolution
- Low fitness will die or not reproduce
Weak - Slow evolution
- Low fitness has a disadvantage but still reproduces

Question 25

Flight in birds - general

Answer 25

Usually stabilizing selection

Question 26

Flight in birds - island

Answer 26

small wings

• strong wind makes harder to fly
• no predators
• less competitors
• directional selection

Question 27

Convergent Evolution

Answer 27

Similar traits appear in vastly different species

• Not evolved from same trait
• e.g. blood

Question 28

Trade-off

Answer 28

Selection of a trait in the cost of others

• Foundry cove worms - tolerance to Ni-Cd
• Dead with lower conc.

Question 29

Gene-centered view of evolution

Answer 29

Gene is trying to survive

Organisms are only a vessel