Smo has seven TM α helices, is a member of the GPCR superfamily, and is related in sequence to the Fz.

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#Unit 11. Evolution and Behavior

Evolution might favor traits that benefit the population or species, When one individual’s behavior benefits another, the behavior is cooperative.

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#Unit 11. Evolution and Behavior

When the fitness interests of two individuals are different, they are in conflict.

The evolution of cooperation and conflict depends on when these kinds of behaviors are favored by natural selection.

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#Unit 11. Evolution and Behavior

Selfish (cheater) genotypes are expected to increase within populations, a trait that benefits the group would have to evolve by selection among groups, rather than by selection among individual organisms within the groups.

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#Unit 11. Evolution and Behavior

Some cells carry a cheater mutation that makes spores but that avoids contributing to the stalk.

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#Unit 11. Evolution and Behavior

Reciprocity

When one individual provides a fitness benefit to another, as long as the second individual is likely to return the favor later.

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#Unit 11. Evolution and Behavior

Altruism

Altruistic acts serve to benefit the individual’s close relatives, or kin. They enhance the fitness of other individuals—their offspring—at a cost to themselves.