Selection

Question 1

evolution

Answer 1

change in genetic composition of populations over time
observed in lab experiments, natural populations, fossil record
occurs through natural selection

Question 2

Darwin’s Observations

Answer 2

1. if every individual was to successfully reproduce, populations will grow exponentially
2. populations tend to remain stable in size
   - differential reproductive success
3. resources are present in constant amounts in stable environments
4. variation between individuals is present in populations
   - different phenotypes leads to differential fitness
5. some types of variation is heritable
   - passed from parent to offspring
   - type of variation that undergoes evolution

Question 3

What type of traits can evolve?

Answer 3

~ only heritable traits can evolve
~ successive generations will contain an increasing proportion of individuals descended from parents with those helpful variation

Question 4

natural selection

Answer 4

• results in change in frequency of phenotypes
• some phenotypes might help their bearer survive better, so they produce more offspring
• beneficial phenotypes that have a genetic basis will increase in frequency since they are inherited from successful offspring
  THIS is evolution

Question 5

alleles

Answer 5

different forms of a gene formed by mutation

Question 6

diploid

Answer 6

contains two alleles for one gene
two copies of the gene

Question 7

natural selection sees…

Answer 7

phenotype
i.e: which phenotypes produces an advantage?

Question 8

mechanisms of evolution

Answer 8

some act on variability present within the populations, others act to alter the amount of variability

Question 9

null conditions

Answer 9

a large breeding population = no genetic drift
random mating = no sexual selection
no change in allelic frequency due to mutation = no mutation
no change in allelic frequency due to immigration or emigration = no migration
no natural selection

Question 10

null hypothesis

Answer 10

natural selection is NOT occurring
selection is not favoring one phenotype over another
therefore, selection is not favoring one allele or genotype

Question 11

Hardy-Weinberg

Answer 11

describes a population in which evolution is not occurring
only when there are two alleles at a single locus

Question 12

Hardy-Weinberg equations

Answer 12

f(AA) = p^2
f(AB) = 2pq
f(BB) = q^2

Question 13

allele frequency equations

Answer 13

p = f(A) = [2(AA) + AB]/2(T)
q = f(B) = [2(BB) + AB]/2(T)