The water flea –– Daphnia pulex –– has the largest inventory of genes ever recorded for a sequenced animal, according to a new study in the journal Science by 69 co-authors. An international team effort to sequence the genome of the water flea included work by UC Santa Barbara biologists.

Daphnia is the first crustacean to have its genome sequenced. The study found that it contains more than 31,000 genes. By comparison, humans have only about 23,000 genes.

By studying the hydra, a member of an ancient group of sea creatures that is still flourishing, scientists at UC Santa Barbara have made a discovery in understanding the origins of human vision. The finding is published in this week's issue of the Proceedings of the Royal Society B, a British journal of biology.

Hydra are simple animals that, along with jellyfish, belong to the phylum cnidaria. Cnidarians first emerged 600 million years ago.

The Earth is in the midst of the sixth mass extinction of both plants and animals, with nearly 50 percent of all species disappearing, scientists say.

Because of the current crisis, biologists at UC Santa Barbara are working day and night to determine which species must be saved. Their international study of grassland ecosystems, with flowering plants, is published this week in the Proceedings of the National Academy of Sciences.

Scientists at the University of California, Santa Barbara have discovered significant clues to the evolutionary origins of the nervous system by studying the genome of a sea sponge, a member of a group considered to be among the most ancient of all animals.

The findings are published in the June 6 issue of the journal PLoS ONE, a Public Library of Science journal. The article can be found at http://www.plosone.org/article/info:doi/10.1371/journal.pone.0000506.