Possible advantages of sex:

• Faster evolutionSexually reproducing populations will evolve faster than a set of asexual clones, provided that the rate of favorable mutation is high enough.

• Lower extinction ratesThe taxonomic distribution of asexual reproduction suggests that asexual forms have a higher extinction rate than sexual forms. Thus sex may be maintained by group selection.

• Deleterious mutationsThe large numbers of deleterious mutations are more efficiently removed by sexual than asexual reproduction.

• Host-parasite arms raceThe coevolutionary arms race of parasites and hosts produces rapid environmental change, making sexual reproduction advantageous.

Figure: the taxonomic distribution of asexual reproduction is spindly; it is found in odd, isolated groups.