Scientists call it the Tree of Life: a diagram that shows all the many forms of life on this planet and how they’ve all branched out from each other over millions of years. The only thing is the picture has just changed radically thanks to latest discoveries about the dominant life form on Planet Earth: bacteria.
Biologists have long known that the tree has three main trunks:
* Eukaryotes, which includes animals, plants and fungi);
* Archaea (some of the more ancient life forms);
* and Bacteria.
And the one that includes us animals (Eukaryotes) was generally accepted as the biggest. As recently as last September, the picture was generally being drawn like this, with Metazoa (multicellular animals) and other branches of Eukaryotes taking up the most space:
But thanks to a new study that’s just been published, the tree is now looking like this, with Eukariotes a much smaller part of the pictures and us Metazoans just a twig on that branch:
What the new study shows is that we’re all totally dwarfed by what is now understood to be far and away the main trunk of the Tree of Life: Bacteria. We Metazoans are maybe five percent of what’s really going on in terms of life on this planet.
It’s a bit like when astronomers discovered, just a few years ago, that everything we can observe in the Universe, from tiny subatomic particles to huge galaxies, makes up only five percent of what’s actually there. The other 95 percent – what they call “dark matter – is all around us, yet completely invisible. No one has a clue what it is or what it’s doing, except that it’s there.
In the same way, we’re now seeing that while we animals and plants and the like are all going about our lives like we’re some kind of dominant life form, we’re actually maybe five percent of what’s really going on in terms of life on this planet.
So, all hail the dominant life form on Planet Earth! And we can feel reassured by the likelihood that since many kinds of bacteria thrive in what are, for us, some of the most inhospitable conditions on Earth, they will likely survive the mass extinctions that we humans have set in motion. And perhaps, millions of years from now, they’ll have given birth to amazing new branches on the Tree of Life – life forms that we Metazoans can’t even imagine.