Researchers may have found the answer to why humans walk.
We came from the primordial seas. Our water-dwelling fish ancestors came before our land-dwelling ape ancestors. The prevailing theory on why our fish ancestors came to land 385 million years ago is that they developed limbs. If this were true, then the next logical move for them would have been to use their new limbs in a more suitable environment. However, researchers are offering a new alternative to this theory.
Malcolm MacIver and his colleagues think that improved vision may have had something to do with the shift from water to land. “We found a huge increase in visual capability in vertebrates just before the transition from water to land,” says MacIver. His team's study explains what exactly our fish ancestors may have seen that motivated them to leave the water.
During the course of their research, the team studied the fossil record of the ancient aquatic vertebrates. They measured eye sockets on the fossils and came up with a very telling discovery. The eyes on the vertebrates had tripled in size before the migration to land. The eyes also shifted from their position on the sides of the head to the top of the head.
The eye enlargement is indicative of a significant improvement of vision in our aquatic ancestors. However, this improvement doesn't mean much in the water. Our ancestors were able to see almost 70 times better out of the water than in it.
With much better vision, the vertebrates can now see what's on land. From an evolutionary perspective, the effort it takes to enlarge eyes points to an important reward or benefit. The researchers think that these ancient vertebrates might have seen a wealth of food on land. There must have been insects upon insects that enticed the vertebrates out of the water. With their new and improved vision, the vertebrates must have clearly seen a better food source.
The researchers think that seeing entirely new sources of food might have propelled the fins to evolve into limbs. After all, chasing after prey on land with fins must not have been a very good idea. The vertebrates needed to develop limbs in order to access more food.
Of course, the evolution from fins to land-walking limbs didn't happen overnight. The researchers theorize that the vertebrates must have first made short forays into land to hunt prey. Eventually, the vertebrates evolved into permanent land dwellers.
The search for new sources of nutrients is one of the greatest motivators for living things on Earth. It therefore comes as no surprise that food probably motivated an ancient, less complex species to develop into bipedaled humans. It's a drive that we can still see in ourselves and other living things today, albeit it in smaller, more diluted forms. People move to where better opportunities are, and other living things migrate the world over for better sources of sustenance. The research offers intriguing insights on what powers evolution and why humans walk.
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