BIOL10004 Lecture Notes - Lecture 19: Asexual Reproduction, Egg Cell, Gamete
14 Jun 2018
School
Department
Course
Professor
Semester 1, 2018 Sam Midler
BIOL – Lecture 19
Reproduction I
Asexual reproduction
• mitotic cell division
• offspring genetically identical to parents
o no exchange of genetic material
• allows a single individual to produce a colony
o corals, hydra (budding), sea stars (fragmentation)
• common among invertebrates but also some vertebrates
o stream fish, some geckos, snakes and sharks
parthenogenesis
• advantageous for animals living in constant, stable environments
• parthenogenesis occurs through use of ova and the female reproductive system
o process where an egg develops without being fertilised
• also occurs in fluctuating environments
• facultative parthenogenesis – use asexual or sexual reproduction depending on
environment, food resources and mate availability
sexual reproduction
• exchange of genetic information
• common strategy among both invertebrates and vertebrates
• needs two sexes – female / male
o female: produce a few large gametes (eggs) – non-motile, contribute all
cytoplasm and DNA → embryo
o male: produce many small gametes (Sperm) – motile, usually only contribute
DNA
mitosis and meiosis
• mitosis
o somatic cell division
o no exchange or genetic material
o asexual reproduction
• meiosis
o specialised form of cell division
o haploid (1n) gametes fuse to
form a new diploid (2n) individual
o sexual reproduction
• sexual reproduction requires
mechanisms to get sperm and egg
together → fertilisation
o offspring a combination of
genetics
find more resources at oneclass.com
find more resources at oneclass.com
