Home » Evolution, pre-Cambrian » Animal that stages light display is 600 million years old?

Animal that stages light display is 600 million years old?

In “Ancient Jelly Simplifies Animal Tree?” (The Scientist , September 9, 2011 Sabrina Richards reports “A newly discovered fossil of a nearly 600-million-year-old comb jelly ancestor may call for scientists to rethink early animal evolution.” Just think: 600 million years old. Well,

Like vertebrates, cnidarians exhibit bilateral or biradial symmetry—meaning they can be bisected into two mirror images. The ancestors of comb jellies, however, were not. The current version of the animal tree, which has the comb jelly lineage arising after bilateral cnidarians but before bilateral flatworms suggests that bilateral symmetry must have evolved twice—once in the cnidarian lineage, and again in animals that evolved after the comb jellies branched away. The new fossil, however, may shake up that view. According to the paper published recently in Evolution and Development, the new fossils of Eoandromeda would place comb jellies lower down on the tree than cnidarians, meaning bilateral symmetry would only have evolved once in the animal lineage—after comb jellies evolved.

Chalk one up for convergent evolution, whether anyone admits it or not, and that is more likely due to law or design than chance.

Comb jelly lights:

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2 Responses to Animal that stages light display is 600 million years old?

  1. Law and not chance…wow, that’s a great description of natural selection, actually.

  2. Chalk one up for convergent evolution, whether anyone admits it or not, and that is more likely due to law or design than chance.

    I must be reading this wrong. To me, it seems to be saying that the ordering before this discovery required convergent evolution, the development of bilateral symmetry twice – once before comb jellies branched off, and again afterwards.

    But this new finding means that comb jellies branched off before bilateral symmetry appeared in cnidarians, meaning it only evolved once. No convergent evolution required. This does sound a bit more parsimonious.

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