L3-4

Question 1

What is the effect on variation for mutation, gene flow, drift, natural selection

Answer 1

mut: increases
gf: increase
drift: decrease
ns: up/down

Question 2

is mutation a weak or strong evolutionary force and why

Answer 2

weak

- Mutation alone can change frequencies but only over long period of time

Question 3

what is RGD

Answer 3

• Allele frequ. change due to chance – Sampling variation

Question 4

what does RGD do to 2 populations, compared to gene flow

Answer 4

make them genetically different , gf counteracts and homogenises

Question 5

explain the relationship of RGD between effect magnitude and population number

Answer 5

• Magnitude is inversely proportional to N (Size of pop important)
  o Low pop= larger effect of RGD
  o High pop= less effect of RGD

Question 6

what is the process of natural selection

Answer 6

• The change in allele frequency within a population from one generation to the next, resulting from differences in the ability of different phenotype to produce surviving offspring.

Question 7

what is the measure of natural selction

Answer 7

• Fitness (reproductive success): viability (survival, mortality) and fertility

Question 8

what is the result of natural selection

Answer 8

• Genotypes with higher fitness increase in frequency (changes in allele frequency)

Question 9

components for natural selection to occur

Answer 9

variation
heritablity
compeittion
differential reproduction

Question 10

heritability formula

Answer 10

• Total variation= f (genes, environment)

* H= VarianceG /VarianceG+VarianceE (proportion of the total variance that is due to genetic variation)

Question 11

what is directional change

Answer 11

phenotypic characters shifts in one direction

Question 12

what is the speed of directional change influenced by

Answer 12

• Starting allele freq prior to selective pressure (low= slower than higher)
• Expression (recessive= longer to increase in pop

Question 13

what is stabilising selection

Answer 13

• Outlier phenotypes= disadvantagous // favoured to centre middle
• If higher fitness is centre= removal of outliers or extremes

Question 14

what is balancing selection and what does it promote

Answer 14

Heterozygote advantage

• Promoting polymorphism

Question 15

what does deviation of HW mean

Answer 15

evolutionary forces at play

Question 16

formula for allele freq (from pop number)

Answer 16

[# heterozygotes+ 2(# homozygotes)]/2n

Question 17

Allele Frequency > (Expected) Genotype Frequency

Answer 17

1. Find allele freq via [# heterozygotes+ 2(# homozygotes)]/2n
2. Work out genotypes via: p2=, q2=, 2pq=
   - (Working out P = 1-q)

Question 18

(Expected) Genotype Frequency > # Individuals

Answer 18

• Genotype frequency (i.e. p2) x n

Question 19

Chi- Square Test:

Answer 19

• χ2 = Σ(observed-expected)2/expected

Question 20

most suitable environment for respiratory pathogens

Answer 20

high pop density

Question 21

most suitable environment for fecal-oral pathogens

Answer 21

contaminated water

Question 22

most suitable environment for vector pathogens

Answer 22

temp, conditions suitable for vector

Question 23

what factors have influenced disease over time in humans

Answer 23

agriculture 
trade
migration 
sanitation 
treatment

Question 24

decribe HG vs agriculture in predisposition to disease

Answer 24

• Mobile groups (HGs) = low population density, no domesticated animals (limited vector contact/ animal-human transmission) or likely contaminate water sources

• Increased population density (build-up of waste), particular farming methods (stagnant water), vectors (rodents, mosquitoes)
• Increased pathogen exposure ‘crowd diseases’, transmission from animal reservoirs, vectors

Question 25

Did the onset of agriculture increase the effect of Malaria?

Answer 25

• Some aspects of agriculture likely to have increased vector reservoirs also coinciding with increased human (host) populations in settled areas
• More vector= more likelihood of transmission + increase population= accelerated malaria
• Although already existed before onset of agricultural practices

Question 26

ways disease can impact darwinian fitness

Answer 26

1. Survival
   • Death inutero= (zero fitness for fetus? Parents)
   • Death before reproductive maturity or in reproductive years
2. Growth & Development
   • Competition for resources within body
   • Destruction of parts of body or diminished capacity to use resources effectively
3. Mating
   • Stigma
   • Reduced attractiveness or behaviourally unappealing
   • Social shunning & isolation
4. Child Rearing
   • Infertility
   • Impairment of capacity to raise children successfully