Fitness

Question 1

what is fitness

Answer 1

the relative probability of survival and reproduction of a given genotype

Question 2

what decides someones fitness

Answer 2

vaires according to environmental condissions

Question 3

sickle cell, differences between those who are homozygotic and those who are hetero zygotic

Answer 3

homo - unwell, more liekly to get anaemia, worse symptoms

heterzygotes - less likely to get malaria so is advantageous in malarial zones

so this is possibly why unfit alleles remain

Question 4

genetic basis of sickle cell?

Answer 4

mutation causing change in amino acid - alters structure of Hb

(CRISPR is a potential treatment for this)

Question 5

levels selection can occur at

Answer 5

• species
• groups
• families
• individuals
• genes

know that there are diff view on what level selection occurs at, with some people taking multi level approach

Question 6

what’s an example of ‘hitchhiking genes’

Answer 6

genes being physically close to each other and on same DNA chain meaning they end up being swept up when another gene is being selected for

e.g. deletrious gene = cancerous gene

Question 7

what is sexual selection

Answer 7

natural selection arising through preference by one sex for certain characteristics in individuals of the other sex.

Question 8

why might some maladaptive charateristics still be selected for?

Answer 8

sexual selection (until natural selection takes over if theres a strong selec pressure)

Question 9

why might animals mate with others with certain charac, even if they seem maladaptive?

Answer 9

may have underlying good genes

e.g. peacock w/ colours
femal may think it shows that it has good health and no parasites
and that it’s male way of showing fitness

Question 10

how did darwin explain neuter insects

Answer 10

insects that are sterile - e.g. in bees only queen bee reproduces

selection on family level

Question 11

what is altruism

Answer 11

beh of an animal that benefits another at its own expense

Question 12

what are the 2 types of fitness

Answer 12

darwinian/direct fitness = survival and production of offspring

inclusive fitness = direct fitness + indirect fitness (fitness of related offspring)
aka kin selection

Question 13

what is hamilton’s rule?

Answer 13

natural selc of genes that lead to social actions via the sharing of these genes between performer and recipient

ie rb>c

Question 14

what is rb>c

Answer 14

c = the cost of being altruistic
b = benefit to someone by recieving altruism
r= degree of relatnedness

as long as rb>c then altruism occurs

Question 15

how might altruistic effects occur between individuals

Answer 15

might respond to individuals with similar genotype e.g. detected by smell

more liekly when relatedness is high e.g. in social insects

Question 16

haplodipolidy

Answer 16

when females are diplod and males are haploid

Question 17

how does haplodiploidy affect altruism

Answer 17

because offspring are more related to each other than to their parents
more liekly to help each other
cuz
genes are more likely to be passed down if helping siblings rather than having offspring

Question 18

what are some problems with the haploidiploid altruism thing

Answer 18

• actual relatedness might be lower
  cuz queen may mate with more than one male

but ancestral form may did only mate with one male

• many hymenoptera (ants bees etc.) are not eusocial

Question 19

diagram on relatedness in haplodiploid hymenoptera

Answer 19

icl idk what it’s on about
something to do with the male has to give all its genes to the offspring cuz males haploid
the female gives half of her genes to each cuz femals are diploid
hence offspring are 0.75 related to each other
so more related to each other than their parents or than they would be to their offspring

only stnads if female mates with one male