Talk:Protostome

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In both protostomes and deuterostomes, the embryo consists of a little ball of cells known as a blastula. Protostomes have their early cell divisions diagonal to the polar axis forming a spiral arrangement of cells; this is called spiral cleavage. A groups of cells move inward to form an opening called the blastophore, which in protostomes develops into the mouth.

Protostomes have a determinate cleavage: the fate of how each embryonic cell will turn out to be or function is typically fixed very early; the first four cells are separate and each will develop into a fixed quarter of the larva. If a cell is removed from the blastula, a limb might not form, for the other cells don't compensate. Protostomes are schizocoely, where the mesoderm splits and the split widens into a cavity that becomes the coelom.

This is because it doesn't seem accurate. Although many protostomes have spiral cleavage, it's not universal to the group, and in particular is rare among the Ecdysozoa. I'm not sure about the rest, but I thought it worth erring on the side of caution. Josh

I am curious to know what evidence there is for the assertion that it appears that the protostomes evolved from the deuterostomes, and that therefore protostomy is the derived condition. ???

 You're correct, protostomes did not evolve from deuterostomes, I will remove this now.

Just a sugestion but could you, perphaps change this page so that the rest of the world can understand it? Now I'm a reasonablly bright person, but this article is like reading a foreign language. I'm all for having accurate and informative pages, but the only person that could read this would be people with degrees in Biology, and people with degrees in Biology do not need to look this stuff up on Wikipedia. Its just a suggesstion but consider it. Antarticstargate 04:56, 18 March 2007 (UTC)AntarticstargateAntarticstargate 04:56, 18 March 2007 (UTC)[reply]

I've looked under both protostome and deuterostome, and there is no mention of the cnidarians. Do they fit under either, or neither? They have a mouth, but some don't have an anus, so they can't be deuterostomes. Even so, what is it called when the blastopore becomes both the mouth and the anus? —The preceding unsigned comment was added by 24.210.91.137 (talk) 17:01:50, August 19, 2007 (UTC)

Cnidarians are Acoelomates, they do not possess a coelom and thus are neither protostomes nor deuterostomes. Platyhelminthes are also Acoelomates so I am not sure they can be categorized as protostomes. —Preceding unsigned comment added by 71.141.2.167 (talk) 21:01, 2 May 2008 (UTC)[reply]

I removed this section, it is not right:

subphylum of protostomes

• spincula
• echiura
• pogonophora
• pentastomida
• onychophora
• tardigrada

--Dj Capricorn (talk) 17:00, 1 January 2008 (UTC)[reply]

some diagrams on the embryonic development of protostomes vs. deuterostomes would be a nice addition. —Preceding unsigned comment added by 66.32.146.72 (talk) 21:44, 23 January 2008 (UTC)[reply]

I agree. It is unclear what the alternative theories are. Picture = 1,000 words. And articles shouldn't be afraid to state the "obvious" general points (relating e.g to germ layers), even if they occur elsewhere - children read wikipedia looking for an introductory orientation to subjects; if they go away feeling they understand, they may, with luck, go on to spend a life studying the subject. They should be given a "good in" rather than put off with unclear explanations. Tsinfandel (talk) 22:29, 1 August 2010 (UTC)[reply]

Please add sources in the appropriate sections:

• See Kimberella and Cambrian explosion for some refs.
• See Evolving a Deuterostome for more.
• Detlev Arendt, Ulrich Technau & Joachim Wittbrodt (Jan 2001) Evolution of the bilaterian larval foregut; Nature 409, 81-85; doi:10.1038/35051075
• University of Leeds Evolutionary Developmental Biology Lecture 10
• Richard A. Kerr (Feb 1998) Pushing Back the Origins of Animals; Science Volume 279, Number 5352, pp. 803 - 804
• Francisco José Ayala, Andrey Rzhetsky, and Francisco J. Ayala Origin of the metazoan phyla: Molecular clocks confirm paleontological estimates; PNAS January 20, 1998 vol. 95 no. 2 606-611 - caution: mol phylo estimates vary widely
• Andrew H. Knoll & Sean B. Carroll Early Animal Evolution: Emerging Views from Comparative Biology and Geology; Science 25 June 1999, Vol. 284. no. 5423, pp. 2129 - 2137 DOI: 10.1126/science.284.5423.2129
• Aguinaldo, Anna Marie A, Lake, James A Evolution of the multicellular animals American Zoologist, Dec 1998
• Guillaume Balavoine and André Adoutte One or Three Cambrian Radiations?; Science 17 April 1998: Vol. 280. no. 5362, pp. 397 - 398; DOI: 10.1126/science.280.5362.397

• Acoelomorph flatworms and precambrian evolution contains a nice summary and cites the peer-reviewed source.

-- Philcha (talk) 15:33, 27 August 2008 (UTC)[reply]

Why does the Protostome article refer to the group as a clade, but the Deuterostome article refers to it's group as a superphylum? --Dante Alighieri | Talk 20:38, 31 March 2009 (UTC)[reply]

Some sources say deuterostome is the original condition of bilaterians, and thus a paraphyletic group that includes protostome. --Philcha (talk) 02:37, 2 August 2010 (UTC)[reply]