BIO120H1 Lecture Notes - Lecture 6: Eichhornia Crassipes, Red Queen Hypothesis, Sexual Reproduction
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BIO120H1 Full Course Notes
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Floating (asexual cloning) vs. not floating (sexual) (water hyacinth) Transmission bias: sexual female contributes only 50% of her genes to the next generation compared with an asexual female (this favours asexuals) Brings together favourable mutations - long term benefit. Benefits of genetic variation in variable environments - short term benefit lottery model". Sexual reproduction more quickly combines favourable mutations than asexual reproduction. Dominant alleles could hide" recessive deleterious genes in sexual selection. Asexuality is sporadic across animal kingdom; more common in invertebrates, but rare in vertebrates. Asexuality is much more common in plants, though a few species are exclusively asexual. Asexual species are likely to go extinct; has less genetic variation thus less evolutionary potential. Outbreeding: mates less closely related than random. Heterozygosity reduced by 50% per generation with self-fertilization. Homozygosity for deleterious recessive alleles results in inbreeding depression. The reduction in fitness of inbred offspring in comparison with outcrossed offspring. Manifested by reductions in viability & fertility.
