Re: Cnidaria versus ctenophora

On 2007-06-17 07:31:45 +0100, Lorentz <drosen0000@xxxxxxxxx> said:

Ctenophorians and cnidarians are two separate phyla of biblastic
animals, meaning that they have an early embryo with only two cell
layers. Ctenophora include sea combs, while cnidarians include the
jellyfish, hydra, corals, and sea anenomes. They are supposed to be
separate phyla. I have never seen anyone who classifies ctenophora as
a class witin cnidaria.

My main question
1) How ctenophora and cnidarians differ?

Subquestions
1.1) What distinguishes ctenophors and cnidarians?

Cnidaria are radially symmetric organisms whilst ctenophora are often
considered to be bilateral (or bi-radial at the very least). They also
heavily differ in their nervous system architectures. Cnidaria for
example often have a characteristic nerve ring, and the reamining
architecture is typically then very diffuse.

Ctenophora or comb-jellies also propel themsevles entirely differently,
relying on 'comb cilia' to propel themselves forward . Cnidarian
medusans by comparison rely on the rythmic contraction of the bell to
bring about propulsion.

A quick google search also yielded some further differences. I am
uncertain about your remaining questions :-)

Ben.





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Relevant Pages

  • Re: Cnidaria versus ctenophora
    ... Ctenophora include sea combs, while cnidarians include the ... Are there any animals whose classification within these phyla ...
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  • Cnidaria versus ctenophora
    ... Ctenophorians and cnidarians are two separate phyla of biblastic ... Ctenophora include sea combs, while cnidarians include the ... Are there any animals whose classification within these phyla ...
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