PSYO 2160 Lecture Notes - Lecture 5: Ovoviviparity, Viviparity, Asexual Reproduction
21 May 2018
School
Department
Course
Professor
Sexual Selection
Modes of reproduction
Classification according to:
1) production of Gamete: egg, sperm, or both.
2) Method of fertilization: internal or external.
3) Method of production of the young: viviparity, ovoviviparity, oviparity, etc…
Gonochoristic (dioecious) mode: separate male and female individual.
Hermaphroditic (monoecious) mode: individuals have both eggs and sperm.
Parthenogenetic mode: all individuals have ovaries. No fertilization necessary.
Parthenogenesis
- Development of embryo from unfertilized egg cell.
- Asexual reproduction.
Why sex?
Selfish gene theory: each sex attempting to maximize own success at propagating genes.
find more resources at oneclass.com
find more resources at oneclass.com
Why choosy females (not all the cases)
Parental investment theory (trivers, 1972)
- Males can potentially fertilize eggs at a faster rate than they are produced.
- Ovulating females are limited resources for males (there are exceptions).
Bateman’s principle
1) Females should be the choosier sex because eggs are expensive to produce and because a
female’s potential reproductive success is limited compared with that of a male.
2) Female’s greater choosiness in mate selection should translate into greater variance in the
reproductive success.
ITRAsexual selection
- Males compete with other males and females compete with other females.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Classification according to: production of gamete: egg, sperm, or both, method of fertilization: internal or external, method of production of the young: viviparity, ovoviviparity, oviparity, etc . Gonochoristic (dioecious) mode: separate male and female individual. Hermaphroditic (monoecious) mode: individuals have both eggs and sperm. Development of embryo from unfertilized egg cell. Selfish gene theory: each sex attempting to maximize own success at propagating genes. Males can potentially fertilize eggs at a faster rate than they are produced. Ovulating females are limited resources for males (there are exceptions). Males compete with other males and females compete with other females. Ex: male lion infanticides previous dominant male"s cubs to make his own. In other cases (mostly insects) they a male would damage the other male"s genitals to prevent them for mating or the male would inject his own sperm into the other"s male reproductive system so the offspring would be his.
