Why are we here??!!
From an interview with an entomologist by the New York Times this week:
Q. SO BIG BRAINS ARE NOT ALWAYS AN ADVANTAGE?As a matter of fact, I suspect strong evolutionary pressures are still at work on our species to downsize our brains. For example, not a week goes by without me stumbling on some individuals who astonish me with how energy efficient they are. Anyway guys, if you thought that you are here to grow big brains, then you were wrong. The insects have shown us this.
A. Bigger is better if you want to produce enormously complicated behavior. But in evolution, brains evolve by selection. There always is pressure on animals to produce behaviors for as little energy as possible. And that means for many animals, smaller brains are better because they won’t waste energy.
You know, there’s this pervasive idea in biology that I think is wrong. It goes: we humans are at the pinnacle of the evolutionary tree, and as you get up that tree, brain size must get bigger. But a fly is just as evolved as a human. It’s just evolved to a different niche.
In fact, in evolution there’s no drive towards bigger brains. It’s perfectly possible that under the right circumstances, you could get animals evolving small brains. Indeed, on some islands, where there’s reduced flora and fauna, you’ll see smaller versions of mainland species. I would argue that their brain size has been reduced because it saves energy, which permits them to survive in situations of scarcity. They also might not need big brains because they don’t have natural predators on the islands—and don’t have to be as smart because there’s nothing to avoid.
Q. SPEAKING OF ISLANDS, WHEN AN APELIKE FOSSIL WAS DISCOVERED ON THE INDONESIAN ISLAND OF FLORES IN 2003, A GREAT CONTROVERSY BROKE OUT AMONG ANTHROPOLOGISTS. SOME SAID THIS THREE-FOOT TALL SMALL- BRAINED CREATURE WAS A NEW SPECIES OF HOMINID — A HUMANLIKE PRIMATE. OTHERS CLAIMED IT WAS AN EARLY HUMAN WITH A BRAIN DEFORMITY. WHY DID YOU JUMP INTO THE FRAY?
A. Because I thought it was a hominid. This thing about its being a human ancestor with a diseased brain never made much sense. The people who insisted it was a deformed early human couldn’t believe that it was possible to have such a huge reduction in brain size in any hominid. Yet, it’s possible to get a reduction in brain size of island animals as long as the selection pressure is there. There’s nothing to stop this from happening, even among hominids.
Q. SO WHY WERE OTHER SCIENTISTS INSISTING THAT FLORES MAN WAS A DEFORMED HUMAN?
A. Because there’s this idea that nature moves inexorably towards bigger brains and some people find it very difficult to imagine why if you evolved a big brain — as ancient hominids had — why you would ever go back to a smaller one. But evolution doesn’t really care. This smaller brain could have helped this species survive better than an energy-consuming bigger one. The insects have shown us this.
Source: Insects as Model Animals
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