Claim CB350:
Sex is too complex for its origin to be explained by evolution. Males and
females would have to evolve independently, and any incompatibility in any
of the physical, chemical, or behavioral components would have caused
extinction. Furthermore, evolutionary theory predicts that asexual
reproduction would be favored because asexual species can reproduce
faster.
Source:
Brown, Walt, 1995. In the Beginning: Compelling evidence for creation
and the Flood. Phoenix, AZ: Center for Scientific Creation, pp.
14-15.
Response:
- The variety of life cycles is very great. It is not simply a matter of
being sexual or asexual. There are many intermediate stages. A
gradual origin, with each step favored by natural selection, is
possible (Kondrashov 1997). The earliest steps involve single-celled
organisms exchanging genetic information; they need not be distinct
sexes. Males and females most emphatically would not evolve
independently. Sex, by definition, depends on both male and female
acting together. As sex evolved, there would have been some
incompatibilities causing sterility (just as there are today), but
these would affect individuals, not whole populations, and the genes
that cause such incompatibility would rapidly be selected against.
- Many hypotheses have been proposed for the evolutionary advantage of
sex (Barton and Charlesworth 1998). There is good experimental
support for some of these, including resistance to deleterious
mutation load (Davies et al. 1999; Paland and Lynch 2006) and more
rapid adaptation in a rapidly changing environment, especially to
acquire resistance to parasites (Sá Martins 2000).
References:
- Barton, N. H. and B. Charlesworth, 1998. Why sex and recombination?
Science 281: 1986-1990.
- Davies, E. K., A. D. Peters and P. D. Keightley, 1999. High frequency
of cryptic deleterious mutations in Caenorhabditis elegans.
Science 285: 1748-1751.
- Kondrashov, Alexey S., 1997. Evolutionary genetics of life cycles.
Annual Review of Ecology and Systematics 28: 391-435.
- Paland, Susanne and Michael Lynch. 2006. Transitions to asexuality
result in excess amino acid substitutions. Science 311: 990-992.
See also: Nielsen, Rasmus. 2006. Why sex? Science 311: 960-961.
- Sá Martins, J. S., 2000. Simulated coevolution in a mutating
ecology. Physical Review E 61(3): R2212-R2215.
Further Reading:
Judson, Olivia, 2002. Dr. Tatiana's Sex Advice to All Creation,
New York: Metropolitan Books.
Margulis, Lynn and Dorion Sagan, 1990.
Origins of sex: three billion years of genetic recombination,
New Haven: Yale University Press.
Wuethrich, Bernice, 1998. Why sex? Putting theory to the test.
Science
281: 1980-1982. See also several related articles in the same issue.
created 2001-2-17, modified 2007-6-8
