Sponges are very primitive animals. They don't have nerves cells (nor muscles nor eyes nor a lot of other things we commonly associate with animals). So scientists figured sponges split from the tree of life before nerves evolved.
A new study has surprised researchers, however.
"We are pretty confident it was after the sponges split from trunk of the tree of life and sponges went one way and animals developed from the other, that nerves started to form," said Bernie Degnan of the University of Queensland. "What we found in sponges though were the building blocks for nerves, something we never expected to find."
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Gene enhancer in evolution of human opposable thumb
Scientists have discovered a gene enhancer, known as HACNS1, that may have contributed to the evolution of the uniquely opposable human thumb, and possibly also modifications in the ankle or foot that allow humans to walk on two legs, according to a paper published in Science on Sept. 5, 2008.
This study is the first to provide evidence of the existence of human-specific gene enhancers, which are switches near genes in the human genome.
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Molecular evolution is echoed in bat ears
The big-eared horseshoe bat, Rhinolophus macrotis. Credit:
Echolocation may have evolved more than once in bats, according to new research from the University of Bristol published this week in Proceedings of the National Academy of Sciences (PNAS).
Professor Gareth Jones of the University of Bristol and Dr Stephen Rossiter of Queen Mary University of London, in collaboration with colleagues from East China Normal University in Shanghai, investigated the evolution of a gene called Prestin in echolocating bats - mammals with the most sensitive hearing at high frequencies.
Prestin codes for a protein of the outer hair cells - the tiny structures in the inner ear that help to give mammals their sensitive hearing. Important mutations occurred during the emergence of mammals that led to the evolution of Prestin from similar proteins. Since mammals evolved, it has been argued that the Prestin gene has changed little.
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Oldest Gecko Fossil Ever Found, Entombed In Amber
Scientists from Oregon State University and the Natural History Museum in London have announced the discovery of the oldest known fossil of a gecko, with body parts that are forever preserved in life-like form after 100 million years of being entombed in amber.
Due to the remarkable preservative power of being embalmed in amber, the tiny foot of this ancient lizard still shows the tiny "lamellae," or sticky toe hairs, that to this day give modern geckos their unusual ability to cling to surfaces or run across a ceiling. Research programs around the world have tried to mimic this bizarre adhesive capability, with limited success.