Sociobiology and Behavioural Ecology PO Flashcards
What does Sociobiology stand for?
Merge of behaviour (socio) and genetics (biology)
What does Behavioural Ecology stand for?
Stresses way that behavioural contribution to Darwanian fitness depends on ecology (food, enemies, nesting requirements etc)
What is Altruism?
behaviour that increases survival and reproduction of other individuals at a cost to one’s own survival and reproduction
Example of an altruistic act:
A Belding’s ground squirrel produces an alarm call when it detects a predator, this is an altruistic act as it benefits others whilst being costly for itself
How did altruism evolve?
- Kin selection
- Mutualism
- Manipulation
- Reciprocal Altruism
What is Kin selection?
relatives (kin) also have copies of an individual’s genes. Gene proliferation can occur through care for relatives (when they reproduce). Acts may be phenotypically altruistic but genotypically selfish
What is coefficient of relatedness (r)
probability that relatives will share a particular gene
In diploid species, how many percent do each parent contribute to the genes
50% when the egg + sperm fuse
What does Diploid Species have?
Pairs of chromosomes, one from each parent
What is the probability of any one gene being shared by a parent and offspring? r =
r = 0.5
r =
coefficient of relatedness
What is R for identical twins?
1.0
What is R for siblings?
0.5
What is R for grandparents + grandchildren?
0.25
What is R for grandparents + great-grandchildren?
0.125
Relatives contribute to an individuals _______
fitness
Fitness=
measure of genes contributed to next generation
What is direct fitness?
Component from personal reproduction
What is indirect fitness?
Component from reproduction of kin
What is an individuals total fitness called?
inclusive fitness
In what context will the frequency of an altruistic gene increase?
if the fitness benefit to altruist is greater than fitness cost
What does C depend on?
the impact (of altruistic act) on Direct Fitness (personal reproduction)
C =
number of offspring (forgone) in next generation x r
r = 0.5, as they are your offspring
What does B depend on?
the impact (of altruistic act) on indirect fitness (reproduction of kin)
B =
number of kin’s offspring in next generation (as result of altruism) x r
The frequency of an altruistic gene in a population will increase if
B > C
(Nk x r) genetic units > (Ns x 0.5) genetic units
What does Nk and Ns stand for?
Nk= number of kin's offspring resulting Ns= Number of own offspring forgone
What is mutualism?
cooperation may occur because each participant gains survival/reproductive benefit
What is manipulation?
Donors may be ‘tricked’ into behaving altruistically
Example of manipulation? (Cuckoo birds)
‘Brood parasites ‘- lay eggs in nests of other species, Parasites hosts nest during ost’s laying period (one egg per nest), Takes egg from host nest and replaces it with own, young are raised for free
What is Reciprocal Altruism?
individuals gain from repayment of altruistic act at future date
Example of Reciprocal Altruism? (Vampire bats)
Some individuals failed to obtain blood meal during night, beg blood from others in daytime roosts, often successful, regurgitation only occurred between frequent roostmates (or relatives), Preferential regurgitation for roostmates continued in lab, suggests ability to recognise each other.
