selection and drift

Question 1

polymorphism

Answer 1

a discontinous genetic variation resulting in the occurance os several different forms of individuals among the same species

Question 2

frequency dependent selection

Answer 2

fitness is dependent upon the frequency of a phenotype or genotype in a population.

negative frequency-dependent selection, whereby fitness of a phenotype or genotype increases as its frequency in a population decreases.

Positive frequency dependent selection occurs when the more common a variant is in a population, the higher its fitness

Question 3

apostatic selection

Answer 3

form of negative frequency-dependent selection.

It describes the survival of individual prey animals that are different (through mutation) from their species in a way that makes it more likely for them to be ignored by their predators

Question 4

red queen hypothesis

Answer 4

a species must adapt and evolve not just for reproductive advantage, but also for survival because competing organisms also are evolving

e.g hosts and parasites : arms race
• constant adapation by the paarsite to overcome the hosts immue defences
• co-evolution among hosts evolving new defences

Question 5

why doesnt selection lead to uniformitiy?

Answer 5

• negative frequency dependent selection
• heterozygote advantage (heterosis)
• spatial selection
• temporal fluctuations
• drift

Question 6

population bottleneck

Answer 6

a drastic reduction of the size of a population due to a catstrophic event

Question 7

founder effect

Answer 7

loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger populations