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The real reason humans are the dominant species

Science desk || shiningbd

Published: 11:56, 29 March 2021  
The real reason humans are the dominant species

From early humans rubbing sticks together to make a fire to the fossil fuels that drove the industrial revolution, energy has played a central role in our development as a species. But the way we power our societies has also created humanity's biggest challenge. It's one that will take all our ingenuity to solve.

Energy is the key to humanity's world domination.

Not just the jet fuel that allows us to traverse entire continents in a few hours, or the bombs we build that can blow up entire cities, but the vast amounts of energy we all use every day.

Consider this: a resting human being requires about the same amount of energy as an old-fashioned incandescent light bulb to sustain their metabolism - about 90 watts (joules per second).

But the average human being in a developed country uses more than 100 times that amount if you add in the energy needed to get around, build and heat our homes, grow our food and all the other things our species gets up to.

The average American, for example, consumes about 10,000 watts.

That difference explains a lot about us - our biology, our civilisation and the unbelievably affluent lifestyles we all lead - compared, that is, with other animals.

Because unlike virtually every other creature on Earth, we human beings do much more with energy than just power our own metabolism.

We are a creature of fire.

Humanity's exceptional relationship with energy began hundreds of thousands of years ago, with our discovery of fire.

The fire did much more than just keep us warm, protect us from predators and give us a new tool for hunting.

A number of anthropologists believe fire actually refashioned our biology.

"Anything that allows an organism to get energy more efficiently is going to have huge effects on the evolutionary trajectory of that organism," explains Prof Rachel Carmody of Harvard University in Cambridge, Massachusetts.

She believes the decisive development was cooking. Cooking transforms the energy available from food, she argues. The carbohydrates, proteins and lipids that provide our bodies with nutrition are unravelled and exposed when they are heated.

That makes it is easier for our digestive enzymes to do their work effectively, extracting more calories more quickly than if we ate our food raw.

Think of it as a way of "pre-digesting" food.