Protostomes and Deuterostomes

[thewax]

Do deuterostomes and protostomes have to have coelems (they are coelemates) or can they be any animal????????

Progress on this question: THIS IS NOT A HOMEWORK QUESTION. I looked in books but they avoided giving definitions of protostomes and deuterostomes with coelems, although they included coeloms the descriptions. Please help!

[plasmodesmata11]

Protostomes and deuterostomes usually are coelomates.... Not to say there aren't any exceptions.... flatworms are acoelomates. The reason they are classified so, however, is because they may have a distant ancestor that links radially symmetric animals with bilateral ones. They share similar ribosomal RNA. It is thought that evolution simplified their body plan as time progressed.

I am not sure if this is answering yor second question, but...
Protostomes--> first, the mouth
Deuterostomes--> second, the mouth
The blastopore, during embryonic development, will be the mouth first in protostomes, and the anus first in deuterostomes. There are other differences as well. Google the patterns of cleavage each does (spiral in protostomes and radial in deuterostomes).
Hope that helps!

[thewax]

Thanks!

So are acoelomates and pseudocoelemates (nematodes, etc.) also protostomes or are they not (they're definitely NOT deuterostomes)???????

[plasmodesmata11]

Glad I could help. Pseudocoelomates are protostomes. I will have to assume that there are very few acoelomates, and if not they may be separately classified, but I am not sure. Acoelomates are present in protostomes, but not deuterostomes.

[thewax]

ohh...

So deuterostomes and protostomes can be any animal, right????

Thanks very much!!!!!!!!