>>”Instead, it illustrates how all organisms –– humans included –– are a complex mix of ancient and new characteristics.” <<
Is that statement very scientific. It appears to be a statement of fact about something that, at best, is an hypothesis.
We determined which genetic 'gateway,' or ion channel, in the hydra is involved in light sensitivity...This is the same gateway that is used in human vision... 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 fact that there is a specific gene that establishes the ion channel for neural transmission for vision is a scientifically verifiable fact. That this gene is the same in hydra and in vertebrate animals, including humans, is a scientifically verifiable fact.
In order to make "vision" you need three things. 1. a lens. 2. a bundle of light sensitive neurons onto which the lens focuses light, and 3. the visual processing part of the brain to take the neural response to the images focused on the light sensors (the retina) and extract information from that (the visual cortex).
There is nothing remarkable about human vision. I have a sight-hound who sees many things at far greater distance than I do or can. I cannot even see things that he has seen and is straining at the lease to chase.