The strawberry squid (Histioteuthis heteropsis), also known as the cock-eyed squid, is famous (as you can also tell if you parse the Latin binomial) for the huge disparity in the size and form of its two eyes. That’s evident from this gif:
Now, before you watch the explanatory video below, or read Wire‘s recent piece on its eyes, form an evolutionary hypothesis about the disparity—one that involves natural selection. How could you test it?
Think! (It’s not obvious, and of course the explanations you’ll hear are speculative). The truth is, what the video and article say sounds good, but we have no idea if the form of natural selection they suggest really acted to produce this bizarre morphology.
Okay, watch the video, and then read the piece above.
And remember, folks, squids, like all cephalopods, are molluscs—in the phylum Mollusca.