Originally posted by Shakyamunison
Sure it does. The problem with asexuality is that the offspring are genetically the same as the parents. Bacteria that were asexual started swapping genetic material. This swapping gave some an advantage, and they passed it on. Aphids us both asexuality and sexuality, as an example.
"The production of males is a "cost" that lowers the fitness of species in a competitive world. In many species, the males does nothing for the species other than providing sperm. For example, the male lion does not hunt for food or take any part in the rearing of young. However, males must be fed by the females, which uses up half of their food resources with no benefit produced in return. The male lion reduces the "fitness" of the species by two-fold. Here is another example of how sexual reproduction costs a species. Let us say that there are a million members of a species of sexually reproducing snails. At some point, there arises one female that is able to reproduce asexually. This female produces two females while her sexual cousins produce one male and one female. Therefore, for each generation, the asexual snails produce twice as many reproducing members as the sexually reproducing species. According to population dynamics, the asexual mutants would completely replace the original population within 52 generations.2 Despite the increased cost of sexual reproduction, it persists over asexual reproduction."
http://www.godandscience.org/evolution/reproduction.html