Our eyes that scan the farthest reaches of the universe had their origin in water, in the simple hydra, a members ancient group of sea creatures that along with jellyfish, belong to the phylum cnidaria that first emerged 600 million years ago and are still flourishing.
“We determined which genetic ‘gateway,’ or ion channel, in the hydra is involved in light sensitivity,” said Todd H. Oakley, assistant professor in UCSB’s Department of Ecology, Evolution and Marine Biology author of a 2010 UC Santa Barbara study. “This is the same gateway that is used in human vision.”
Oakley explained that there are many genes involved in vision, and that there is an ion channel gene responsible for starting the neural impulse of vision. This gene controls the entrance and exit of ions; i.e., it acts as a gateway. The gene, called opsin, is present in vision among vertebrate animals, and is responsible for a different way of seeing than that of animals like flies. The vision of insects emerged later than the visual machinery found in hydra and vertebrate animals.
The research challenged the misunderstanding that evolution represents a ladder-like march of progress, with humans at the pinnacle. “Instead, it illustrates how all organisms — humans included — are a complex mix of ancient and new characteristics, said Oakley.”
Fast forward to today: zoologists from Cologne and Lyon announced that they have succeeded in reconstructing the structure of the eye of a predatory crustacean from the time of the dinosaurs –the internal structure of an approximately 160 million year old compound eye (sown below Dollocaris ingens van Straelen, 1923, Thylacocephala) from the Middle Jurassic period. It was discovered at the La Voulte deposit in southeastern France.