The recent find of a probable new kingdom of life in a routine dirt sample in Nova Scotia (an east coast province of Canada) raises an obvious question: How much more is there out there that is underfoot, so to speak, that does not fit our tidy categories?
Just yesterday, we were looking at the vast newly discovered array of subterranean microorganisms, many of which won’t turn out to be very tidy either, including those that live for millennia rather than twenty minutes.
One writer describes the hemimastigotes above as the latest (and most profound) of additions quietly and routinely added to the “tree of life,” (as if nothing is changing?):
To understand how evolutionarily distinct the hemimastigote lineage is, imagine the eukaryotic tree splayed out before you on the ground as a narrowing set of paths, which begin with places for all living groups of eukaryotes near your toes and converge far in the distance at our common ancestor. Starting at our mammalian tip, walk down the path and back into history, past the fork where our lineage diverged from reptiles and birds, past the turnoffs for fishes, for starfish and for insects, and then farther still, beyond the split that separates us from fungi. If you turn around and look back, all the diverse organisms you passed fall within just one of the six eukaryote supergroups. Hemimastigotes are still up ahead, in a supergroup of their own, on a path that nothing else occupies.Jonathan Lambert, “What a Newfound Kingdom Means for the Tree of Life” at Quanta
Yes, yes, we can picture it. But we are not picturing a tree. Maybe two separate trees. Maybe just a path. Lambert continues:
Burki, Simpson, Eglit and many others also think we have much more of the tree of life to uncover, largely because of how quickly it’s changing. “The tree of life is being reshaped by new data. It is really quite different than even what it was 15 or 20 years ago,” Burki said. “We’re seeing a tree with many more branches than we thought.” Jonathan Lambert, “What a Newfound Kingdom Means for the Tree of Life” at Quanta
Jonathan, it’s totally absorbing. But it might be better pictured as a grove than as an individual tree.
As scientists continue to fill out the tree, the algorithms used to add branches will only get more efficient, according to Eme. This will help researchers resolve deeper, more ancient splits in the history of life. “Our understanding of how life unfolded is still very much incomplete,” said Burki. Questions like why eukaryotes emerged or how photosynthesis evolved remain unanswered because “we don’t have a tree that is stable enough to pinpoint where these key events happened,” he said. What a Newfound Kingdom Means for the Tree of Life” at Quanta
Great discoveries await. But we might find that, for example, photosynthesis arose at different times in response to different groups of life forms’ needs. Let’s hope that the need to see the Tree of Life doesn’t cause us to shoehorn life forms into classifications that are more convenient than accurate.
Part of the underlying problem here is the need to think that all life originated from a single cell. As we’ve noted elsewhere, claims for ordinary common ancestry rest on evidence of similarities; a claim, for example, that today’s cattle and bison come from a common ancestor is made on the basis of detailed evidence from the history, biology, and behavior of those animals. The claim for universal common ancestry is a leap of faith, faith in That One First Cell.
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See also: New life form more different from others “than animals are from fungi”
Soil microorganisms are twice the estimated volume of oceans, raise question Presumably, these millennia-old subsurface organisms don’t reproduce much, as it is more economical to just stay alive and do nothing. What then of evolution? If the millennial organism changes a fair bit over the centuries, is that evolution?
Biologist Wayne Rossiter on non-religious doubts about universal common ancestry