Co-operation (evolution)
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Co-operation or co-operative behaviours are terms used to describe behaviours by biological organisms which a beneficial to other members of the same species. There are several competing theories which help to explain why natural selection favours some types of co-operative behaviour. It is worth noting that more than one of the below theories can contribute to the true reason for the selection of these behaviours.
Contents
Kin Selection
One well accepted theory for why co-operative behaviours occur is the theory of Kin selection. This theory suggests that individuals act co-operatively in order to help others which are genetically similar. Genes for such co-operative behaviour are preserved, because they help to perpetuate their own existence. The classic example is the social insects, such as bees and ants. Worker insects never reproduce, but instead, they work to allow the (genetically similar) queen to reproduce.Reciprocity
The theory of reciprocity suggests that individuals carry out co-operative behaviours because they get something in return. In order for such behaviours to be favoured, there needs to be some perception of external physical markers that the other indidual will recognise (otherwise, there is no selective pressure to maintain the behaviour).Multi-level selection
Multi-level selection theory suggests that selection operates on more than one level: for example, it may operate at the level of cells in the body, and then again at the whole organism level, and the community level, and the species level. Any level which is not competitive with others of the same level will be eliminated, even if the level below is highly competitive. A classic example is that of genes which prevent cancer. Cancer cells divide uncontrollably, and at the cellular level, they are very successful, because they are (in the short term) reproducing very well and outcompeting other cells in the body. However, at the whole organism level, cancer is often fatal, and so may prevent reproduction. Therefore, changes to the genome which prevent cancer (for example, by causing damaged cells to act co-operatively by destroying themselves) are favoured. Multi-level selection theory contents that similar effects can occur, for example, to cause individuals to co-operate to avoid behaviours which favour themselves short-term, but destroy the community (and their descendants) long term.Cultural group selection
References
- Mikhail Burtsev and Peter Turchin: Evolution of cooperative strategies from first principles, Nature 440, 1041-1044 (20 April 2006)
| Topics in evolutionary ecology
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| Patterns of evolution: Convergent evolution | Evolutionary relay | Parallel evolution |
| Colour and shape: Aposematism | Mimicry | Crypsis |
| Interactions between species: Mutualism | Cooperation | Predation | Parasitism |
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