Vision Might Have Kickstarted Evolution on Land – Popular Mechanics

According to some scientists, it was vision, rather than mobility, that let fish evolve to land-dwelling creatures. A team of researchers examined old fossil data and are arguing that vision was the primary reason that fish made the jump to land hundreds of millions of years ago.

Researchers Malcolm A. MacIver of Northwestern University and Lars Schmitz of Claremont McKenna, Scripps, and Pitzer colleges analyzed fossilized fish before and after they made the transition to land. They found that the size of eyes nearly tripled prior to moving onto land, suggesting that eyesight played a strong role in this stage of evolution.

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Their reasoning is that light can travel much further on land than in the water. Larger eyes would have been almost useless underwater, but the large increase in eye size suggests a significant evolutionary drive. MacIver and Schmitz account for this by suggesting that pre-terrestrial fish used their eyes to spot food on the shore.

Insects and other invertebrates made the jump to land around 50 million years before fish did, so for a prehistoric fish, the shores would have been teeming with food just out of reach. Over millions of years, many fish species evolved better eyes as well as limbs to reach more of it.

This increased vision may have also led to increased brain size. In the water, where vision is minimal, the majority of brainpower is devoted to quick reflexes. But on land, being able to see further lends itself well to planning and strategy, and could have fostered what is known as prospective cognition, the ability to consider multiple outcomes and plan for the future.

Source: Northwestern University

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Vision Might Have Kickstarted Evolution on Land - Popular Mechanics