U2) KA2) EVOLUTION - fitness and hardy weinberg and co evolution

Question 1

fitness is an indication of…

fitness is a measure of…

Answer 1

• fitness is an indication of an individuals ability to be successful at surviving and reproducing
• fitness is a measure of the tendency of some organisms to produce more surviving offspring than competing members of the same species

Question 2

what is absolute fitness

Answer 2

• absolute fitness is the ratio between the frequency of individuals of a particular genotype after selection and those before selection
  absolute fitness = frequency of a particular genotype after selection / frequency of a particular genotype before selection

Question 3

absolute fitness : what indicates an increase / decrease in a particular genotype

Answer 3

if AF = 1 - the genotype is stable
if AF > 1 increase in genotype
if AF < 1 decrease in phenotype

Question 4

what is relative fitness

Answer 4

relative fitness is the ratio of the number of surviving offspring per individual of a particular genotype and the number of surviving offspring per individual of the most successful genotype
- relative fitness = number of surviving offspring per individual of a particular genotype / number of surviving offspring per individual of the most successful genotype

Question 5

what does the hardy weinberg principle state

Answer 5

• states that in the absence of evolutionary influences , allele and genotype frequencies in a population will remain constant over the generations. This stability is called the Hardy Weinberg equilibrium

Question 6

what are the conditions for maintaining the Hw equilibrium are :

Answer 6

• no natural selection : differences in survival chances or reproductive success will alter allele frequencies
• random mating - if there is inbreeding then random mixing of gametes does not occur , so genotype frequencies will change
• no mutations - the production of new alleles and the duplication or deletion of existing alleles will alter allele frequencies
• extremely large population size - smaller populations are more susceptible to the effects og genetic drift altering the allele frequencies

Question 7

what can the HW be used to calculate

- what are the equations

Answer 7

• used to calculate allele, genotype and phenotype frequencies in the population
  p2 + 2pq + q2 = 1
  p + q = 1

p = frequency of dominant allele
q = frequency of recessive allele
p2 = frequency of homozygous dominant
genotype
2pq = frequency of heterozygous genotype
q2 = frequency of homozygous recessive
genotype

Question 8

what is co evolution , when is it shown

Answer 8

• if there are two species which have frequent or close interactions , they may show co evolution
• co evolution is the process by which two or more species evolve in response to selection pressures imposed by each other

Question 9

in co evolution : a change in the traits of one species acts as a selection pressure on the ___ ____

Answer 9

other species

Question 10

what is the red queen hypothesis

Answer 10

• ## states that in a co evolutionary relationship , change in the traits of one species can act as a selection pressure on the other species , and that species must adapt to avoid extinction

Question 11

what is symbiosis

- what can the impacts of these relationships be

Answer 11

• symbiosis is the co-evolved intimate relationship between members of two different species
• the impacts of these relationships can be positive (+) negative ,(-) or neutral (0) for the individuals involved

Question 12

what are some types of symbiotic relationships

Answer 12

Mutualism: both organisms in the interaction
are interdependent on each other for
resources or other services. As both
organisms gain from the relationship, the
interaction is (+/+).
Commensalism: only one of the organisms
benefits (+/0).
Parasitism: the parasite benefits in terms of
energy or nutrients and the host is harmed as
the result of the loss of these resources (+/-).

Question 13

what increases rate of evolution

Answer 13

• higher temp
• higher rate of mutation
• higher selection pressures