The uncertainty of life.

This is a comb jelly, a pelagic marine invertebrate, washed up on Newburgh beach by the recent gales. Comb jellies, or Ctenophores as they are more formally known, have been in the scientific news this week; they have just replaced sponges as the oldest known branch of the animal family tree.

The PhysOrg website broke the news in the following way:

"Sponges are getting squeezed out of a distinctive role in evolution. A new study says they don't represent the oldest branch of the animal family tree after all.

The DNA research gives the spot instead to comb jellies, a group of gelatinous marine animals with names like the sea walnut and the sea gooseberry.

All animals evolved from a single ancestor and scientists want to know more about how that happened. More than half a billion years ago, long before humans appeared, the first split in the tree separated one lineage from all other animals. Traditionally, scientists have thought it was sponges.

The evidence in favour of comb jellies comes from deciphering the first complete genetic code from a member of this group. Scientists were finally able to compare the full DNA codes from all the earliest branches.

The genome of a sea walnut, a plankton-eating creature native to the western Atlantic Ocean, was reported online Thursday in the journal Science by Andreas Baxevanis of the National Human Genome Research Institute with co-authors there and elsewhere. The work supports some earlier indications that comb jellies were the first to branch off."

Isn't life interesting?!