Biology 1001A Lecture Notes - Lecture 14: Asexual Reproduction, Plant Reproductive Morphology, Sequential Hermaphroditism
12 Dec 2017
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Cycle 7 - lecture 14: why sex? (november 1st, 2017) Reproduction doesn"t always mean sex, sex conjures up ideas about copulation, reproduction, males and females, and sex means recombination. Sex can take alleles and it creates new combinations of alleles. Sexual reproduction generates new multilocus combinations of alleles: ab, ab, bb, ab. Offspring genetically distinct from either parent and (usually) from each other. Not all reproduction involves sex; hence asexual: obligately asexual, ex. Amazon molly, cannot reproduce sexually because there are no males: facultatively asexual, ex. aspen trees; can reproduce sexually, and they are different from their parents. It is better to be female; size increases as reproductive success. The first cells, and the first eukaryotes reproduced asexually. Meiosis, specialized gametes and normal" diploid sex first appeared 1. 5 billion years ago. Most living things are asexual; but in plants and especially animals, most species reproduce sexually; not representative in life in general.
