Group selection

Definition

Group selection is a concept in evolutionary biology that proposes that natural selection can act not only on individuals but also on groups, favoring traits that benefit the group as a whole. This idea challenges traditional views of evolution, which often focus solely on individual fitness and competition. Group selection can help explain how certain cooperative behaviors and social structures emerge in animal populations, as groups exhibiting beneficial traits may outcompete other groups.

5 Must Know Facts For Your Next Test

1. Group selection suggests that traits beneficial for group survival can evolve even if they are not advantageous for individuals within the group.
2. This concept was controversial and debated among scientists, particularly due to its implications for understanding social behavior and cooperation in species.
3. Group selection is often invoked to explain behaviors like altruism and cooperation, which seem counterintuitive when viewed through the lens of individual selection.
4. Empirical studies have shown that groups with more cooperative individuals can outperform less cooperative groups, supporting the idea of group selection.
5. Critics of group selection argue that it can be difficult to distinguish between the effects of individual selection and group selection in natural populations.

Review Questions

• How does group selection differ from individual selection, and what implications does this have for understanding social behaviors in animals?
  • Group selection differs from individual selection in that it posits natural selection can act on groups rather than just individuals. This means traits that benefit the group as a whole, like cooperation or altruism, can evolve even if they reduce an individual's personal fitness. Understanding this difference helps explain why some species exhibit complex social behaviors that promote group survival and success, even when those behaviors might seem disadvantageous at the individual level.
• Evaluate the evidence supporting group selection as a mechanism for evolutionary change in social species.
  • Evidence supporting group selection includes observations in various species where groups with higher levels of cooperation outcompete less cooperative groups. Studies of social insects, like ants and bees, demonstrate how cooperative behaviors enhance colony survival. Additionally, mathematical models show that under certain conditions, group benefits can outweigh individual costs. However, while there is supportive evidence, critics argue that many examples can also be explained through individual selection or kin selection.
• Synthesize the key arguments for and against group selection in the context of evolutionary theory and social behavior.
  • Proponents of group selection argue that it provides a framework for understanding altruistic behaviors and complex social structures that can't be easily explained by individual selection alone. They emphasize that traits benefiting the group can lead to better overall survival rates. Conversely, critics assert that natural selection primarily operates at the level of the individual or gene, arguing that any cooperative behavior can also be explained through kin selection or direct benefits to individuals. This debate highlights ongoing discussions about the dynamics of evolution and the varying scales at which it can occur.

Related terms

kin selection: A form of natural selection where individuals are more likely to help relatives, increasing the survival of shared genes.

altruism: Behavior by an individual that increases the fitness of another individual while decreasing the fitness of the actor.

cooperation: Behavior in which individuals work together for mutual benefit, often seen in social species.