LUCA

Há cerca de 3 mil milhões de anos atrás, vivia na Terra um super-organismo. Era enorme em comparação com os seus antepassados, e estava espalhado virtualmente por todo o lado em que existia água.
O grande oceano foi uma incubadora planetária para o desenvolvimento da vida na Terra durante centenas de milhões de anos.
Eventualmente, esse organismo desenvolveu-se para 3 organismos diferentes e deu origem a toda a vida que existe actualmente na Terra.
A esse organismo chamamos LUCA – Last Universal Common Ancestor, o último antepassado comum a toda a vida na Terra.

Leiam o interessante artigo na New Scientist, aqui.

“ONCE upon a time, 3 billion years ago, there lived a single organism called LUCA. It was enormous: a mega-organism like none seen since, it filled the planet’s oceans before splitting into three and giving birth to the ancestors of all living things on Earth today.
This strange picture is emerging from efforts to pin down the last universal common ancestor – not the first life that emerged on Earth but the life form that gave rise to all others.
The latest results suggest LUCA was the result of early life’s fight to survive, attempts at which turned the ocean into a global genetic swap shop for hundreds of millions of years. Cells struggling to survive on their own exchanged useful parts with each other without competition – effectively creating a global mega-organism.
It was around 2.9 billion years ago that LUCA split into the three domains of life: the single-celled bacteria and archaea, and the more complex eukaryotes that gave rise to animals and plants. It’s hard to know what happened before the split. Hardly any fossil evidence remains from this time, and any genes that date that far back are likely to have mutated beyond recognition.”