EVOLUTION OF SEX

EVOLUTION OF SEX - origin of sexual reproduction (cellular...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
EVOLUTION OF SEX Why is there sex? We assume, anthropocentrically, that reproduction requires two individuals. But in many organisms that is not true. Life originated without sex (as best we can tell) so sexual reproduction is something that had to evolve. First what is sexual reproduction? 1) production of haploid gametes by meiosis, a reduction division , 2) fusion of these gametes produces a zygote and restores the full diploid complement of chromosomes. There are thus two parts to the evolution of sex: 1) the
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: origin of sexual reproduction (cellular evolution) and 2) the evolution and maintenance of sexual reproduction and recombination (recombination is like sex in that it reassorts genetic material) Recombination probably evolved ~ 3 billion years ago as a mechanism of DNA repair ; sex evolved ~ 1-2 billion years ago in the early eukaryotes; the reason is unclear but it its likely that it is maintained in the current day by selection....
View Full Document

Ask a homework question - tutors are online