We see eye in planaria , insect , octopus and verebrates. Can eyes be grouped as to establish a common ebolutionary origin. ? Why ?
The eye seen in planaria, insects, octopus and vertebrates varies greatly in their structure. These groups can be used for the studying of evolution of eye as the eye in planaria is simple without lens, insects have compound eyes, vertebrates have highly specialized eyes. But all of them perform same function that is vision. Thus common evolutionary origin can be established on the basis of eye.