Friday, April 23, 2010

The Sea Lily vs. The Sea Urchin

Throughout evolutionary history, animals have been evolving to better adapt to their environments. They have changed in ways that will better allow them to hide from and escape from predators, hide from and attack prey, and ways that have made reproduction more efficient. Marine animals are no exception.

Sea lilies have adapted to the fact that they are preyed on by sea urchins. If they sense a predator in the area, they can “shed their stalk ends like lizards’ tails and scoot away.” This is a very interesting find because it was originally thought that sea lilies were sessile and that they could not move from where they were anchored to the substrate. In studying fossils of crinoids, which is what a sea lily is, researchers found that similar marks from sea urchin “mouths” were found on the fossils that they found in current research. They concluded that this escape mechanism was derived from predation pressures and that it is a development that probably occurred only about 150 million years ago. Evolution is interesting! If you would like to read the full article click here.


  1. Great find. That is very interesting to hear about the sea urchins eating something other than kelp. It is also great that the discovered sea lilies are not sessile.

  2. This is a very interesting article! It is really neat to find evidence of evolution and selection pressures in smaller organisms that we tend to think less about.