Altruism and Kin Selection

Altruism and Kin Selection

Altruism Defined

• Altruism is a form of behaviour where an individual acts in a way that is detrimental to itself (the donor) but beneficial to another individual (the recipient). It represents unselfish acts that contribute to the welfare of others.

Kin Selection and Altruism

• Altruism is often observed in situations where individuals are genetically related, such as among family members or close relatives.
• In these cases, the donor may engage in altruistic behaviour because it benefits their shared genes present in the recipient. This increases the chances of the genes being passed on to the recipient's offspring or future generations.
• Kin selection theory suggests that altruistic behaviour is more likely to occur among genetically related individuals due to the shared genetic interests.

Reciprocal Altruism

• In some cases, altruistic behaviour is not a one-time act but involves a reciprocal relationship where the roles of the donor and recipient are later reversed.
• Reciprocal altruism is commonly observed in social animals where individuals form mutually beneficial partnerships.
• An example of this is seen in vampire bats, which feed exclusively on blood. Bats that have successfully fed will often regurgitate part of their blood meal into the mouth of a bat that has not fed.
• Research has shown that this behaviour is reciprocal, meaning that bats are more likely to provide a meal for a bat that has previously helped them in the same way.

---

Altruism and Kin Selection

Summary

• Altruism refers to unselfish behaviour that benefits others at the donor's expense.
• Kin selection is a theory that explains altruistic behaviour by highlighting the role of genetic relatedness, where donors act altruistically to increase the chances of their shared genes being passed on.
• Reciprocal altruism is observed in social animals and involves a give-and-take relationship where individuals help each other in a mutually beneficial manner.