Friday, March 7, 2008

When your mouth is your anus is your vagina: reproduction in phylum Porifera

Orifices are sophisticated inventions. Having a hole for every function is the mark of a recently-evolved animal. More ancient animals like birds and reptiles have a cloaca, which is an opening used for both defecation and reproduction. 

Even having a digestive tract with two ends is a complicated arrangement. Animals like jellyfish, corals and sponges, who were the earliest evolved animals, have a large body cavity with just one opening leading to the outside environment. They eat, shit and have sex using the one hole. 

Sponges reproduce sexually by shooting their sperm into the water. (Copulation is a land animal invention, developed to cope with the lack of a hospitable, moist environment and free transport provided by the ocean. In light of this, a uterus can be thought of as a mini, internal, ocean substitute.) Each sponge hopes (metaphorically, sponges have no brain) that its drifting sperm will be 'eaten' by another sponge. If one's vagina doubles as one's mouth, there is a danger that the sperm will not be used to make baby sponges, and instead be digested as a nutritious food source. Happily, sponge cells are capable of telling the difference between food and the sperm of other sponges. 

6 comments:

Christopher Currie said...

You are disgusting, and so is nature. P.S. Where can I find pictures of cloacas?

problematic said...

best.blog.ever.

Romy said...

imagine, my belly as an ocean in miniature ... surf's up!

problematic said...

encore!

*applauds until hands grow red and swollen*

problematic said...

ahem. i think i know this post off by heat. do you think you could give us the tiniest bit of interesting thing? i mean, its been over a month. like a month and 20 days or something...

ahem.

x your fan

kaney said...

Hemorrhoids are one of the most common issues among individuals world wide affecting approximately fifty percent of all people who are over the age of fifty. Hemorrhoids are defined as the swelling and inflammation of the veins in the lower anus and rectum and can develop internally within the anus or externally just below the skin on the outside of the anus.

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