Altruism co-operation increases fitness-0
Altruistic Behavior
Altruistic behavior in nature is the unselfish behavior exhibited by an organism for the benefit of another organism or group of organisms (not closely related).
Examples[]
Honey bees stinging attacker, therefore sacrificing their life trying to protect the colony.
Birds giving warning calls, attracting attention (& danger) to themselves to warn the rest.
Cleaning symbiosis of several fish species.
Resorces[]
de Waal, F. (2008). Putting altruism back into altruism: The evolution of empathy. Annual Review of Phycology. 59, 279-300.
Trivers, R. (1971). The evolution of reciprocal altruism. The Quarterly Review of Biology. 46(1), 35-57.