LOL cnidarians

Read LOL Cnidarians on Tangled Up in Blue Guy. He describes two new discoveries in evolution:

  1. Light sensitivity developed in hydras, a group that includes tiny water animals (pictured) and jellyfish.
  2. The proteins for a nervous system occur in sponges (who don’t have one). The first nervous system evolved in cnidarians.

Sponges separated from cnidarians about 600 million years ago, so that puts a time estimate on both those developments.

2 Responses to “LOL cnidarians”

  1. Why My Blogging Has Tailed Off | Tangled Up in Blue Guy Says:

    […] I thought I was on my way about five years ago when I wrote a post about the genetic trace of opsins in  fossil hydra.  It was based on a peer-reviewed paper, and the chief author was Dr. Todd Oakley of the University of California in Santa Barbara.  He noticed my post and wrote that it was the clearest explanation of this work he had read in a non-scientific forum.  PZ Myers linked to the story and the traffic crashed my server until I was able to allocate more space.  (The post is gone now, lost to a database import error, but at least there are one or two links to it here and there.) […]

  2. monado Says:

    As I’ve read more about single-celled organisms, I found that they too have light sensitivity. At the base of their flagella are pigmented oil drops that detect light–perhaps only by providing shade in one direction but not another. This light reaction stimulates the flagellum to move and either evade or seek light. The roots of our evolutionary heritage are deep indeed.

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