Why Cnidaria swim?

[ManBearPig89]

Why Cnidaria swim?

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Post by ManBearPig89 » Wed Mar 24, 2010 2:47 pm

Hello, I'm working on some questions in zoology, and this is one of them:

What is "The use" of a swimming stadium among Cnidaria (and also swamps) ?

I think the answear is that becouse of a polyp- colony is single- sexual, they have to produse medusa, if they want to get some kind of gentic variation.

Am i getting this right, or can somone point me in the right direction?

Thanks!

[JackBean]

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Post by JackBean » Wed Mar 24, 2010 3:18 pm

I don't know their life cycle, but that could be reason.
But also, imagine, they would be on one place all the time. They will divide and all of them will stay on one spot. That's not much good for it, is it?

[ManBearPig89]

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Post by ManBearPig89 » Wed Mar 24, 2010 3:20 pm

No, i dont think so ^^ thanks!

[skeptic]

Re: Why Cnidaria swim?

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Post by skeptic » Wed Mar 24, 2010 8:41 pm

There are many different forms of cnidaria, ranging from sessile corals to mobile jellyfish. The main reason for their mobile forms (including the medusa stage of anthozoans) is dispersal. Sometimes they swim towards the light for other reasons. There is a jellyfish living in a lake in Palau that has symbiotic green single celled plants in its tissue. it has to keep swimming upwards to stay in the sunlight for photosynthesis. Other jellyfish are predators and swim to increase the numbers of prey they encounter.

[ManBearPig89]

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Post by ManBearPig89 » Thu Mar 25, 2010 12:05 am

Ahhh.. Nice!