Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!tdatirv!sarima
From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: sci.bio
Subject: Re: jellyfish classification
Message-ID: <15@tdatirv.UUCP>
Date: 31 May 91 20:00:37 GMT
References: <91150.145201U33695@uicvm.uic.edu>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
Lines: 24

In article <91150.145201U33695@uicvm.uic.edu> U33695@uicvm.uic.edu (John Walsh) writes:
>
>This question came up in conversation recently (don't ask how):  Are jellyfish
>animals, or are they colonies of plants or animals, like coral or sponges?

They are animals, but so are corals, or rather corals are colonies of animals.
[In fact corals are colonies of forms closely related to jellyfish].
Sponges are *not* considered colonies, they are considered individual animals.

> We
>checked some textbooks but couldn't seem to get a satisfactory answer.  What
>is the definitional distinction between an animal and a colony?

This is difficult to answer. There are different definitions among different
groups of biologists.  One frequently cited definition is a form with cell
differentiation and specialization  (except that just distinguishes between
colonies of protists on the one hand and animals and plants on the other).
Also, generalizing this to apply to component parts would treat the Portugese
Man-of-War as a single individual rather than a colony, since the component
polyps (hydra-like forms) are quite differentiated, and are all specialized
for different functions.
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uunet!tdatirv!sarima				(Stanley Friesen)