Selection

Question 1

Natural Selection

Answer 1

Phenotypic variation occurring on a trait due to survival and reproduction of particular traits

Question 2

What are the four forms of selection?

Answer 2

Directional selection
Disruptive selection
Stabilizing selection
Frequency-dependent selection

Question 3

Is heritability negative or positive for phenotypes under selection?

Answer 3

Positive

Question 4

What is directional selection?

Answer 4

Selection occurring in a single directions altering the mean but not changing the variance

Question 5

What is disruptive selection?

Answer 5

No change in the mean

Increases the variance

Question 6

What is stabalizing selection?

Answer 6

No change in mean, decrease in variance

Question 7

Frequency dependent selection?

Answer 7

Survival of one trait depends on who you are around

Question 8

Negative frequency dependent selection:

Answer 8

If the trait is rare it does really well creating a super dynamic system

Question 9

Positive frequency dependent selection:

Answer 9

The more common the trait is, the better it does (eventually becomes fixed)

Question 10

How does gene flow effect natural selection?

Answer 10

NEED TO ASK FRANCO

Question 11

How does genetic drift effect natural selection?

Answer 11

if you have a small population, genetic drift has large effect and causes alleles to go to fixation so no selection is occuring

Question 12

what does (s) represent?

Answer 12

the selection coefficient

Question 13

What does evolution depend on?

Answer 13

The size of the population relative to the selection coefficient

Question 14

In what case does selection overcome drift?

Answer 14

s>1/4Ne

Question 15

How are advantageous alleles lost?

Answer 15

Due to drift if small population because drift is random! This is also how deleterious alleles can become fixed

Question 16

Does adaptation happen through mutations of large or small effect?

Answer 16

Small effect

Question 17

Fishers model

Answer 17

Displays why it is easier to get adaptations of small effect mutations because the path to “the best trait” is more controlled

Question 18

What does a selective sweep do to variation?

Answer 18

reduce genetic variation near the locus under selection

Question 19

What is a selective sweep?

Answer 19

reduction or elimination of variation among the nucleotides in neighboring DNA of a mutation as the result of recent and strong positive natural selection.

Question 20

Candidate Genes

Answer 20

those loci hypothesized to be under selection.

Question 21

MC1R: melanocortin-1 receptor

Answer 21

The gene that controls skin color. Evolved 1.2 million years ago

Question 22

UVA

Answer 22

Degrades folate
Neural tube disorders
Spermatogenesis
Skin cancer

Question 23

UVB

Answer 23

Cholesterol -> vitamin D
Calcium absorption
Immune function
Reduces inflammation
Modulation of cell growth

Question 24

What form of selection is controlling melanin?

Answer 24

Directional? 
Cholesterol -> vitamin D
Calcium absorption
Immune function
Reduces inflammation
Modulation of cell growth

Question 25

How many genes affect skin pigmentation?

Answer 25

six

Question 26

Meme

Answer 26

an element of a culture that may be passed from one individual to another by nongenetic means, especially imitation.

Question 27

Cultural evolution determine by:

Answer 27

Transmission errors (mutation)
Statistical effects in small populations (drift)
Differential transmission of variants depending upon their utility (selection)
Transmission of variants between populations (migration)

Question 28

Dual Inheritance System

Answer 28

The phenotype is determined by genetic and cultural traits

These inheritance systems interact to influence the transmission of genes and memes

Question 29

Niche Construction

Answer 29

Cultural evolution alters the environment
Natural selection favors genetic mutations that facilitate the adoption of adaptive cultural practices
Cultural evolution may also constrain genetic evolution, and vice versa

Question 30

Neolithic Transition

Answer 30

Farming produces 10-100 times more human-consumable calories per acre than hunter-gathering
Salivary amylase gene (AMY1) CNV

Question 31

Lactose Persistence

Answer 31

Prior to the domestication of animals, only mothers provided milk
Lactase is not expressed in adults in other primates and varies among human populations.
Lactase persistence has been proposed to have evolved in response to selection generated by the advent of dairying practices during the Neolithic transition.

Question 32

Which came first – lactase persistence (LP) or dairying?

Answer 32

Dairy but only populations with LP can dairy

Question 33

Lactase

Answer 33

Enzyme expressed in small intestine

Breaks down lactose into glucose & galactose