BIOL-UA 11 Chapter : C46 - Animal Reproduction
Document Summary
Sexual reproduction - fusion of haploid gametes; forms a diploid zygote. Egg - female gamete; large, non-motile; created by meiosis. Sperm - male gamete; smaller, motile; created by meiosis. Asexual reproduction - generation of new individuals without the fusion of egg and sperm; dependent on mitosis. Fission - the separation of a parent organism into two individuals of approximately equal size. Budding - new individuals arise from outgrowths of existing ones. Regeneration - regrowth of lost body parts; some animals can regrow an entire animal from a fragment (sponges, some annelids, cnidarians) Parthenogenesis - an egg develops without being fertilized (bees, wasps, ants, Sexual reproduction is more costly (produces fewer females capable of producing more organisms) but provides more variation (favorable in changing environments) Beneficial gene combinations might speed up adaptation; significant only when rate of beneficial mutation is high and population size is small.
