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A Startling Microbe Discovery Just Revealed a Whole New Branch of Our Tree of Life
Microscopic organisms found in dirt collected from a hike through Nova Scotia mean we're going to have to add another branch to the tree of life. The strange organisms simply don't fit into the plant kingdom, the animal kingdom, or any other kingdom we've classified up until now. The tiny critters in question represent two species of the group of microbes called hemimastigotes, and based on a detailed genetic analysis, one of them has never been spotted before.
According to the team of researchers from Dalhousie University in Canada, the two species are eukaryotes (with complex cells, like humans), and protists (outside the animal, plant, and fungi kingdoms). But they don't fit the patterns of the existing 10 kingdoms that make up the Eukaryota domain. "This discovery literally redraws our branch of the tree of life at one of its deepest points," says one of the researchers, Alastair Simpson. "It opens a new door to understanding the evolution of complex cells – and their ancient origins – back well before animals and plants emerged on Earth."
Hemimastigophora is a novel supra-kingdom-level lineage of eukaryotes (DOI: 10.1038/s41586-018-0708-8) (DX)
(Score: 4, Interesting) by PartTimeZombie on Monday November 19 2018, @09:57PM (5 children)
These sorts of discoveries raise some questions to me:
Is it possible there are many more undiscovered branches? It certainly seems possible. If these guys only live in the soil of Nova Scotia, it seems possible (or even likely) that the soil of Northumberland or Queensland might have a similar, but non-related microbe.
Could this be some sort of link to the Ediacaran biota? [wikipedia.org] Not that it's likely we will find evidence either way after 575 million years. Still they're fascinating and I want to know more about them.
For those not keeping score, it looks like our ancestors in the Cambrian explosion ate or out-competed a whole type of life that seems to have left no traces other than some soft-bodied fossils.
If these new things are not plants or animals or fungi, what the hell are they? Something else I suppose.
(Score: 2, Interesting) by Anonymous Coward on Monday November 19 2018, @10:28PM
Yes it is possible. With a billions of years of natural selection (or just good fortune) ending up with the survivors we know about, there could be just as many that never got far enough to leave a fossil record we will discover.
The fact that these little buggers are still alive means there could be more to be discovered. It's unknown which supercontinent existed when some of the previous forms of life emerged, so its impossible to guess where in the world (on land, in the Earth's crust, or under water) the fossils might be.
(Score: 3, Interesting) by All Your Lawn Are Belong To Us on Monday November 19 2018, @11:30PM (2 children)
Yeahbut... OK, not Plant, Not Animal, Not Fungus. Why are they not then Protists [wikipedia.org] by definition? Granted, the Protist label is just as confusing [shmoop.com] a label in some ways. And, so I was taught in Microbio, the Protist category itself may be spilt up when the professional microbiological community actually decides how they shall be split.... But for now isn't Protist any eukaryote which is not animal/plant/fungus (the textbook definition in the first sentence of the Wikipedia article).
Wish I had a subscription to Nature to see how they answer that, because I'm sure they must have. Oh, plus the ability to actually understand the answer to that question which may or may not be possible currently.
This sig for rent.
(Score: 2, Interesting) by Anonymous Coward on Tuesday November 20 2018, @03:09AM (1 child)
Protists and "Protista" are a taxonomic classification. Depending on which taxonomic system you use, there are between 4 and 8 kingdoms, with 5 and 6 being most common. Biology is now changing to cladistical analysis. They have stricter standards for what they consider a kingdom, although they don't like that classification due to the baggage it brings. Those systems start at 10 kingdoms and argue there are over 25. This new category is a "Protist" under the old usage, but under cladistics, are not close enough phylogenetically to fit a current classification, therefore they are definitely a new category, regardless of where you lie on the 10-25 classification range (which should now be considered 11-26)
(Score: 0) by Anonymous Coward on Tuesday November 20 2018, @03:23AM
Sorry, one section should have read
Calling one of the classification levels a "kingdom" is frowned upon by many biologists because it brings to much baggage to expert and lay people. For example, you hear "kingdom" you think of the 5 or 6 you learned in school, despite the fact that the general agreement is that there are at least 7 in modern taxonomy and more in cladistic usage.
(Score: 0) by Anonymous Coward on Tuesday November 20 2018, @12:29AM
Branches of life are not "discovered", they are "decided". People can choose to hierarchically cluster things into as many or few groups as is most convenient for them. Even using different systems for different purposes if they want.