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NC16: how sharks copulate

08 Sep

GT: so do sharks have penis??

me: hmmm… ya… ive never seen one man… oh… maybe they release sperm and the female releases eggs which gets fertilised in the ocean..

GT: oh…

me: but then, sharks give birth to young alive… and the young comes from inside, so fertilisation has to be inside the female

GT: so, do sharks have penis??

yes, sharks have something that represents a penis. infact, they dont just have one. they have 2!

and its not a penis. its called claspers. its the back part of the male’s pelvic fin, modified to become an organ that delivers the sperm into the female vent (opening for the sperm). only one of the claspers are used to deliver the sperms and i dont know what the other one is used for. the male even bites the female to hold on while copulating. “ouch”

did you know that some in some sharks, when the young hatch from the egg, they eat the other unhatched egg’s yolk. its called intrauterine cannibalism it seems. as gross as that sounds, its a natural survival need for some sharks. and the grey nurse sharks are one of those culprits.

btw! seems that there have been reports of a female delivering a young when it had no contact with a male! do you know what that means??? “asexual reproduction!” says wikipedia. its called parthogenesis.

parthogenesis appears to occur in many species. the females produce eggs that can develop without fertilisation.

and then this whole paragraph comes in, which i dont think i write in another better way. so just read.

“Parthenogenesis is distinct from artificial animal cloning, a process where the new organism is necessarily genetically identical to the cell donor. In cloning, the nucleus of a diploid cell from a donor organism is inserted into an enucleated egg cell and the cell is then stimulated to undergo continued mitosis, resulting in an organism that is genetically identical to the donor. Parthenogenesis is different, in that it originates from the genetic material contained within an egg cell. Egg cells may be produced via meiosis or mitosis oogenesis.[5] If by mitosis, the egg that undergoes parthenogenesis can be either haploid or diploid, leading to a number of possible outcomes in terms of the genetic fingerprint of the parthenogen. Whether the parthenogen is haploid or diploid, because meiosis was involved in forming the gamete that subsequently underwent parthenogenesis, incidence of crossing over would effectively create a new genetic fingerprint; this would be of particular importance in the case of a haploid parthenogen, in which crossing over would drastically alter its single chromosome genotype.[clarification needed] Because there are so many variables in parthenogenesis, there is little that can be said for sure unless the specific methods of the particular parthenogenetic tendencies of an organism are known.”

and thats why google and wiki are so good…

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Posted by on September 8, 2009 in i-Bio, i-Marvel

 

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