tunicatesWhen walking the lovely beaches of Amelia Island, Florida, it is not uncommon to find things that you have no clue as to what they are. Recently, we took a boat out into the Atlantic Ocean and stopped at a local beach for lunch on our way home. I stumbled upon this glob of Sea Squirts on the shore line of Cumberland Island, Georgia. Fortunately I was with my brother-in-law, a marine biologist, who gave me quite the education on tunicates.

As it turns out this sea squirt, as it is commonly called, is really a urochordate or tunicate and scientists have known for years that they have a number of physical characteristics that are similar to vertebrates like us!

These barrel shaped adults attach to rocks, boats, piers and the ocean floor and feed on plankton and oxygen by siphoning the seawater through its body using an internal filter.

However, as a juvenile they reveal their kinship to humans. Developing into a tadpole one day after the egg is fertilized, while still in its swimming stage it has a stiffened rod called a notochord running the length of its tail. This notochord is the forerunner of our backbone as well as a primitive nervous system. Eddy Rubin, Director of the Joint Genome Institute said, “Through a comparison of their genomes, we can now understand how these relationships are reflected at the molecular level, and how these similar systems and gene sets evolved in different ways over 500 million years from a common ancestor.”

What did you find on our local beaches?