Types • Asexual • Sexual Reproduction • Sexual vs. asexual – costs associated with sexual but benefits (“lottery” model) Asexual fission • Fission • budding, • parthenogenesis • Fragmentation- the body of the parent breaks into distinct pieces, each of which can produce an offspring. Planarians exhibit this type of reproduction. • Regeneration- a piece of a parent is detached, it can grow and develop into a completely new individual. Echinoderms exhibit this type of reproduction. budding Parthenogenesis • in females, where growth and development of embryos occurs without fertilization by a male (rotifers, crustaceans, some sharks, nematodes) 1 Sexual reproduction Broadcast spawning • One of the • Broadcast spawning most common • Live birth forms of reproduction • Mating systems in the oceans • Hermaphrodites • Eggs and sperm are – Sequential released into the water – Simultaneous column and are fertilized by neighbors • Often it is synchronous fertilization Live birth in fishes Anadromous fishes 2 Mating systems in sexual smoltification reproduction • Transition to ocean form • Monogamy • Silvering of skin – deposition of purines • Polygamy • Polygyny (the most common polygamous mating such as guanine system in vertebrates so far studied): One male • Parr territorial, smoltification results in has an exclusive relationship with two or more schooling behavior females • Polyandry: One female has an exclusive • Hormonal changes, increased NaK- relationship with two or more males ATPase in gills preparing for salt tolerance • Promiscuity: A member of one sex within the • Body shape changes becoming more social group mates with any member of the streamlined opposite sex. • Coral spawning: • http://www.youtube.com/watch?v=RrMAOBT_Vco&NR=1 • Hermaphrodites • http://www.youtube.com/watch?v=NVqf2geKju4 – Sequential • Barnacle • http://www.youtube.com/watch?v=v1SW-pl2gYs&feature=related – Simultaneous • http://www.youtube.com/watch?v=2TnB4dm3KyM&feature=related • Sea urchin fertilization • http://www.youtube.com/watch?v=T6BtSMerBmw&feature=related • Sea hare hermaphrodite • http://www.youtube.com/watch?v=6lp87hrb-5I • Cuttlefish mating • http://www.youtube.com/watch?v=fR7Dqf0vzzQ&feature=related • Protandry: Simultaneous hermaphrodite Where an organism is born • Hamlet fish as a male, and • Sea hares then changes sex • Barnacles to a female - clownfishes 3 • Protogyny: Where the organism starts as a female, and then changes sex to a male - wrasses 4.