Altrusim and Hamilton rule

HAMILTON RULE rb>c
Altruism, Kin selection, CSIR NET qs

1. Hamilton rule
●Predicts if natural selection will favour altruistic acts
●It is favoured when the Hamilton's rule is satisfied

c= cost incurred by altruist
b= benefit received by recipients of altruism
r= coefficient of relatedness between donor & recipient

1
rb >c

2. 2
Altruistic behaviour- When its behaviour benefits other organism,
at a cost to itself

3. Coefficient of relatedness
Grandmother

Mother

You
3
1/2
1/2
1/4

4. KIN SELECTION
4
Natural selection that favours altruistic
behaviour by enhancing reproductive success
of relatives is called kin selection
Condition- Benefit received the altruistic act
is way more than the cost incurred
Kin selection theory predicts
-More likely to behave altruistically
towards relatives

5. 5

6. 6

7. 7
Half siblings → r=0.25. rb>c 0.25 x b> 30 b>30/0.25 b>120

8. 8
In an altruistic act, if a donor sacrifices ‘C’ offspring
which helps the recipient to gain ‘B’ offspring and
the donor is related to the recipient by a coefficient
γ, under which condition would kin selection favour
this altruistic act

a.B>C b. B> γC c. γB-C=0 d. γB-C>0