The whole earth is solar powered. The movement of clouds and air and water, the growth of plants and animals, it’s all just a big heat engine driven … - David Walton

All I'm hearing is 'I can't' when I needed that data yesterday. Go bore someone else with your excuses.

"When history looks back on this century," Paul said, "they will see it as an aberration. A bizarre spike on the energy graph when we suddenly realized the Earth had millions of years of the sun's energy stored underground and used it all up in a brief blaze of glory. The worst thing that ever happened to the human race was the invention of the steam engine."
"You're kidding me," I said. "All of modern human advancement and invention, enabling billions of people to survive, that's all nothing? Medicine? Global communication? Modern agriculture?"
"It's a glitch. It's like blowing your whole trust fund in a weekend. When the fund runs out, you've got to live on your income."

Its purpose is the same as every other organism. To survive.