By Adrian Galbreth
Eyes may not be the only tools people have used to see throughout history, a new study suggests.
Experts at the University of California have published a new study in the in the journal BMC Biology, which shows how the ability to detect light could have evolved before anything resembling an eye.
By examining the stinging mechanism in the freshwater polyp Hydra magnipapillata, which is essentially a mouth surrounded by tentacles armed with stinging cells, the researchers discovered a simple nervous system linking the stinging cells and nerve cells that detect light using a process similar to that of the human eye.
The experts, including David Plachetzki, now a postdoctoral researcher at UC Davis, noted that the hydra fire their stingers less frequently in bright than in dim light, despite having nothing that resembles an eye.
"This capacity for stinging cell regulation by light-sensitive neurons could have predated the evolution of eyes in cnidarians," Dr Plachetzk explained.
Future studies at the facility will now examine how these findings relate to the evolution of eyes in other animals.
by Adrian Galbreth