Lecture 021 - Let's Talk About Sex

Lecture 021 - Let's Talk About Sex - Lecture outline: sex,...

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1 Bio1222 Lecture outline: sex, sex, and more sex Lecture outline: sex, sex, and more sex Nonrandom mating Why sex? Sexual selection Why are females usually the choosier sex? Can BOTH sexes be picky? Bio1222 Sex Sex reproduction reproduction • Earliest life forms were asexual – fission, vegetative propagation, parthenogenesis… • Now, most species reproduce sexually at least some of the time
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2 Bio1222 Different ways of being sexual Different ways of being sexual • Sexual species can be – dioecious (separate sexes) – monoecious (hermaphroditic) •sequential • simultaneous Bio1222 Why reproduce sexually? Why reproduce sexually? • “You only have to think of sex to see how absurd it is. The ‘sexual’ method of reading a book would be to buy two copies, rip the pages out, and make a new copy by combining half the pages from one and half from the other, tossing a coin at each page to decide which original to take the page from and which to throw away.”- Mark Ridley, The Cooperative Gene
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Bio1222 Why reproduce sexually? Why reproduce sexually? • Sex is inefficient and costly – Finding and competing for mates – Transmitting only half your alleles to your offspring Bio1222 So why do so many species do it? So why do so many species do it?
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Lecture 021 - Let's Talk About Sex - Lecture outline: sex,...

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