01:119:116 Lecture Notes - Lecture 14: Sponge, Bulbourethral Gland, Portal Vein
13 Mar 2016
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L14 reproduction i: intro to animal reproduction, asexual reproduction, single parent 2 or more offspring (100% genetically identical/clones, no meiosis (only mitosis, no fusion of gametes, methods, budding- small part of parent"s body separates, only in invertebrates: ex. Porifera & cnidaria: fission- parent splits into 2 individuals of approx. equal size, only in invertebrates, fragmentation & regeneration- parent body breaks into several pieces, each piece produces missing parts, ex. Sea stars: parthenogenesis- unfertilized egg develops into adult animal(n, certain spp of bees, wasps, ants, advantages of asexual reproduction, don"t need a mate i. ii. # of caribous offspring has declined by ~75: occur in animals that reproduce asexually & sexually, ex. Waterflea- produces 2 types of eggs: one type- requires fertilization (sexual) if env. stress, other type- parthenogenesis (asexual) if conditions favorable, hermaphroditism. 1: some are self-fertilizing (sexual reproduction)- meiosis & fertilization, sequential hermaphroditism- individuals reverse sex during lifetime, protogynous- female 1st, the male, proandrous- male 1st, then female, ex.
