#3/15 What is evolution?
How does planet Earth work?
Evolution is what stops ecosystems from collapsing. It is all about energy. Animals and plants evolved to capture the Sun’s energy, so Earth could stay cool. Too much energy leads to chaos. Like a youngster who has drunk too many cans of soft drink!
For billions of years, Earth was dangerous and life as we know it could not have existed. Soon after bacteria evolved though, these primitive animals consumed energy on a massive scale.
Things would stabilise for a time and the best adapted bacteria would become the most likely to survive and reproduce. But the waste they produced would overthrow the world’s ecosystems again and again.
After every mass extinction a new and different and more diverse set of organisms would start to dominate. That is what we call ‘natural selection’ – the survival of the likeliest.
Once multi-celled plants and animals had evolved, they were able to become incredibly diverse and eventually occupy every living space on Earth – land and sea. By then, animals had the capability to work together.
Their abundance and diversity were now enough to withstand natural variations in the Sun’s energy and stop one animal or plant from becoming too powerful.
Still today, as one species is challenged and disappears, another will evolve in its place.
