PPt Evolution And Population Genetics (Ex 1)

Question 1

Defining a Population

Answer 1

1. A group of individuals of the same species living in the same place at the same time
2. Evolution acts on POPULATIONS, not on individuals

Question 2

Evolution

Answer 2

1. Change in the inherited traits of a population of organisms from generation to generation
2. Natural Variation, Reproduction, Selection, Genetic Drift, Gene Flow
3. Can be RANDOM (genetic drift)
4. Can be NON-RANDOM (selection)
5. HAS NO GOAL—mutations occur by chance, not when they’re “needed”

Question 3

Micro-evolution

Answer 3

Studies changes within a population (single species)

Question 4

Macro-evolution

Answer 4

Studies changes that divide a population (speciation)

Question 5

Hardy-Weinberg—Test of Evolution

Answer 5

1. Wilhelm Weinberg and G.H. Hardy
2. Null model-“evolution isn’t happening here”
3. Allows us to detect changes in gene flow within a population (“reject null hypothesis”)
4. Test observations to see whether evolution is occurring
5. If evolution IS occurring expect changes in allelic frequencies

Question 6

Hardy-Weinberg 5 Postulates/assumptions

Answer 6

1. Large Population
2. Isolated Population
3. No net mutations
4. Random mating
5. No natural selection

Question 7

Hardy-Weinberg Equilibrium

Answer 7

Q^2+2pq+p^2 = 1
2pq=Aa
Q^2=aa
P^2=AA

Question 8

Gene

Answer 8

A gene is a unit of heredity information that consists of a specific nucleotide sequence. A gene codes for a certain character (usually a protein)

Question 9

Allele

Answer 9

An allele is an alternative form of a gene that codes for a certain variety of that character

Question 10

Phenotype

Answer 10

A phenotype is the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment

Question 11

Genotype

Answer 11

A genotype is the alleles of a gene or genes present in a given individual

Question 12

Genotype vs Phenotype

Answer 12

GENOTYPE
1. The genotype is an organism’s genetic information
2. BB homozygous dominant, Bb heterozygous, bb homozygous recessive
PHENOTYPE
1. The phenotype is the set of observable physical traits
2. Purple, purple, white

Question 13

Rabbits—Allele,Genotype,Phenotype

Answer 13

A: C, G: CC, P:Wild type: Brown fur
A: c^ch, G: c^chc^ch, P:Chinchilla: Black-tipped white fur
A:c^h, G:c^hc^h, P:Himalayan: White fur with black paws, nose, ears, tail
A:c, G:cc, P:Albino:White fur

Question 14

Punnett Squares

Answer 14

R=Red r=yellow individual 1 = Rr Individual 2=rr
Rr,Rr,rr,rr

Question 15

Genotypes & Phenotypes

Answer 15

Genotype:
1. Genetic constitution of a cell
2. Allele Composition
3. Trait we cannot see
Phenotype
1. Trait we can see

Question 16

Alleles (Roses)

Answer 16

R=Red Petals
r=White Petals
Rr x Rr
RR,Rr,rR,rr
Dominant Allele = R = Red Petals
Recessive Allele = r = White Petals
Homozygous Dominant = Red
Homozygous Recessive = White
Heterozygous = Rr = Red

Question 17

Calculating Allele Frequency

Answer 17

1. P+q=1
2. P= frequency of Dominant allele
3. q = frequency of Recessive allele

Question 18

Calculating Genotype Frequency

Answer 18

1. P^2 +2pq +q^2 = 1
2. P^2 = frequency of homozygous dominant type
3. 2pq = frequency of heterozygous type
4. Q^2 = frequency of homozygous recessive type

Question 19

Hardy-Weinberg Practice
If the black fur gene is dominant BB, and the white fur gene is recessive bb, and a grey fur gene is Bb: When there are 122 black mice, 34 grey mice, and 67 white mice, What is q?

Answer 19

B = frequency p
b = frequency q
1 = p^2 + 2pq + q^2
Total allele = 122+122+34+34+67+67=446
B = (122x2) + 34 = 278
b = (67x2) + 34 = 168
q = 168/446 = 0.3766

Question 20

Hardy-Weinberg extra info

Answer 20

1. A population is not evolving and is at equilibrium if HW equation = 1
2. If our observed allelic frequencies match our expected allelic frequencies, the population is not evolving

Question 21

Darwin Requirements

Answer 21

1. Variation: “individuals within species are variable”
2. Inheritance: “some of these variations are passed on to offspring”
3. Differential survival: “in every generation, more offspring are produced than can survive”
4. Extinction: “the survival and reproduction of individuals is not random. Individuals who survive and reproduce are those with the most favorable variation…”

Question 22

***Hardy-Weinberg Requirements

Answer 22

1. No mutation
2. No natural selection (no phenotypes outperform others in the population’s environmental conditions)
3. Extremely large population size (no genetic drift)
4. No gene flow
5. Random mating (all individuals have an equal chance of passing on their alleles, no individual more likely to mate based on their alleles/phenotype)

Question 23

Hardy-Weinberg Practice Hypothesis (mice problem)

Answer 23

Hypothesis: This population is evolving
Null hypothesis: This population is in HW equilibrium and is not evolving