Parasites prevent their hosts from passing genes by either a) killing them before they breed or b) making them unable to breed (by say, weakening or sterilizing them, or simply making them undesirable mates for conspecifics--a bird ravaged by mites, missing display feathers, may not be able to attract a mate).
I can't comment on the effect of your ex on sex, and thank goodness for that.
The text goes on a 9 page explanation for the quote you excised. The gist of it is that sex, with its scrambling of genetic material (as opposed to other kinds of reproduction that result in exact copies) helps creatures to defend against parasites. It adds that a parasite that can reproduce either asexually or sexually, will tend to reproduce sexually more often in a host that has a stronger immune system. It's genetic adversity in general (I think) not just parasitism, that reinforces the usefulness of sexual reproduction. (pp. 162-171)
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timeasmymeasure
"chapter 2"
Date: 2005-07-13 01:19 am (UTC)I can't comment on the effect of your ex on sex, and thank goodness for that.
The text goes on a 9 page explanation for the quote you excised. The gist of it is that sex, with its scrambling of genetic material (as opposed to other kinds of reproduction that result in exact copies) helps creatures to defend against parasites. It adds that a parasite that can reproduce either asexually or sexually, will tend to reproduce sexually more often in a host that has a stronger immune system. It's genetic adversity in general (I think) not just parasitism, that reinforces the usefulness of sexual reproduction. (pp. 162-171)
Does that make sense? I'm a little tired.