Talk:Ecdysozoa

From Wikipedia, the free encyclopedia

Could we get some examples of classes/orders/species of ecdysozoa, so us less biologically aware folk have some idea which animals are being discussed here? -- JohnOwens 18:14 Mar 21, 2003 (UTC)

[edit] Removed PoV

I've taken out a lot of material which was not properly verified or written in a neutral manner. It appeared to have all been inserted by a single editor in an attempt to push a PoV. Jefffire 21:16, 23 September 2006 (UTC)

I was that author. Strongly disagree. I provided all necessary references to the peer-revieved sources, so there was no original research involved. The references, by the way, are still visible in the current revision in the References section. If the controversy is still open, the one-sided Wikipedia article strongly supporting Ecdysosoa hypothesis is a POV-pushing ebterprise. AGF, please. I'll go take a lunch and come back to revert. Alexei Kouprianov 11:28, 30 November 2006 (UTC)

Well, here I am. Just to prove that the controversy really exists (bold added):

Discussions about the phylogenetic placements of acoels and nemertodermatids (basal-most extant bilaterians or derived lophotrochozoans?), brachiopods and phoronids (lophotrochozoan protostomes or deuterostomes?), and arthropods and annelids (monophyly of Ecdysozoa or Articulata?) are among the more conspicuous of the current debates (e.g., Luter and Bartolomaeus, 1997; Ruiz-Trillo et al., 1999; Baguna et al., 2001; Wagele et al., 1999; Wagele and Misof, 2001; Zrzavy, 2001; De Rosa, 2001). The resolution of these debates will eventually be dependent upon the reconciliation of molecular and morphological phylogenetic evidence. However, before we can hope for such an overarching consensus, we first have to secure a more modest goal: to establish the contribution of a decade of morphological cladistic research towards our current understanding of metazoan relationships. (Unleashing the force of cladistics? Metazoan phylogenetics and hypothesis testing. Integrative and Comparative Biology, Feb 2003 by Jenner, Ronald A.)

Other references are provided in the article. Alexei Kouprianov 12:26, 30 November 2006 (UTC)

I've removed the ciliated sperm argument because ciliated sperm are now considered to be an acceptable part of the group ecdysozoa (much like humans can be primates despite lacking a tail).

I've also removed the "moulting" argument as it doesn't actually address any important issues. It's roughly equivalent to pointing out that snakes moult to. Jefffire 10:30, 15 December 2006 (UTC)

Your comments reveal some deep misunderstanding of the argument, and I feel I need to explain it more thoroughly.

Humans surely can be primates lacking a tail. Moreover, the reduction of the tail is a synapomorphy humans share with some but not all primates. The case you are discussing is far more complicated and the better illustration is as follows. Imagine that there is a whole new order of mammals lacking tails 'Acauditheria.' Then imagine that someone claims that this group is a sister group of 'Primates' because the latter lack tails too. Someone else objects: not all Primates lack tails, just the subordinate group of human-like apes; therefore, the absence of the tail can not be used in our classification as a shared derived character supporting the monophyly of 'Acauditheria' and 'Primates,' and, even though the two groups may be monophyletic, the lack of the tail renders no support for this hypothesis and the synapomorphies are to be sought elsewhere. The latter point is mine. If the arthropods vary with respect to this character displaying both the plesiomorphic (flagellate sperm) and apomorphic (amoeboid sperm) condition, one can not argue that amoeboid sperm is a synapomorphy of arthropods and roundworms unless this someone claims that arthropods are indeed paraphyletic to roundworms or that there is a major character reversal in all but few arthropods from amoeboid to the flagellate sperm.

Moulting arument is relevant because it is not the position of snakes what makes us worry, bit the position of the annelids. It is the monopyly of annelida and arthropoda or paraphyly of annelida to arthropoda that is challenged by the ecdysosoa hypothesis, so this would be simply unfair to disregard the paper claiming that the two groups are not so much different in this crucial aspect. Alexei Kouprianov 16:09, 28 December 2006 (UTC)