BIOL 208 (January 29, 2014)
• Mating systems and sexual selections
o Sexual reproduction
Classical male/female gender the combine gametes to produce
offspring (typical of vertebrates)
• Cost of having “male” subsection:
o You need a new classification of organism (not just a
o Coefficient of offspring is half of asexual reproduction
(female just reduced her fitness by half)
o Evolution doesn’t favour this type of reproduction yet
it still happens. Why?
It’s not pure cost… there are huge benefits
• There is the potential of choosing mates
Lots of organisms can reproduce both asexually and sexually.
• Hermaphrodism: is common in plants (~75% are
hermaphrodites) and uncommon in animals…
o “Uncommon in animals”. Why?
Because animals can move and seek mates
o Mating systems
• Exclusive relationship between male and female sex types
o Not over the course of their whole life (monogamous
not synonymous with lifetime mating)
• Historically believed to be common in birds
• One mate per breeding cycle • Social monogamy vs. genetic monogamy