Thursday, December 8, 2022

A New Branch Of The Tree Of Life

It is not every day that a new branch of organism at a level even higher than that of kingdoms is discovered.
The tree of life is a useful diagram for understanding the relationships between different forms of life, present and extinct. The trunks are made up of three broad groups called domains – Bacteria, Archaea and Eukaryota – which then branch into kingdoms such as animals and fungi. From there the branches become more and more specific until you reach individual species.

The new discovery adds quite a major bough to the tree – Provora. These lifeforms make up a category informally called a “supergroup,” which sits below domains and can contain multiple kingdoms.

This is an ancient branch of the tree of life that is roughly as diverse as the animal and fungi kingdoms combined, and no one knew it was there,” said Dr. Patrick Keeling, senior author of the study.

Members of the Provora supergroup are tiny organisms that the team describes as the “lions of the microbial world.” That’s because they prey upon other microbes, and within their ecosystem they’re relatively rare. The supergroup is further divided into two clades – the “nibblerids,” which use tooth-like structures to nibble chunks off their prey, and the “nebulids,” which engulf their prey whole.

The team discovered this new kind of life in samples taken from around the world, including the coral reefs in CuraƧao, sediment from the Black and Red seas and water from the Pacific and Arctic oceans. . . .

“In the taxonomy of living organisms, we often use the gene ‘18S rRNA’ to describe genetic difference,” said Dr. Denis Tikhonenkov, first author of the study. “For example, humans differ from guinea pigs in this gene by only six nucleotides. We were surprised to find that these predatory microbes differ by 170 to 180 nucleotides in the 18S rRNA gene from every other living thing on Earth. It became clear that we had discovered something completely new and amazing.”
From New Atlas.
Molecular phylogenetics of microbial eukaryotes has reshaped the tree of life by establishing broad taxonomic divisions, termed supergroups, that supersede the traditional kingdoms of animals, fungi and plants, and encompass a much greater breadth of eukaryotic diversity. The vast majority of newly discovered species fall into a small number of known supergroups. 
Recently, however, a handful of species with no clear relationship to other supergroups have been described, raising questions about the nature and degree of undiscovered diversity, and exposing the limitations of strictly molecular-based exploration. 
Here we report ten previously undescribed strains of microbial predators isolated through culture that collectively form a diverse new supergroup of eukaryotes, termed Provora. The Provora supergroup is genetically, morphologically and behaviourally distinct from other eukaryotes, and comprises two divergent clades of predators—Nebulidia and Nibbleridia—that are superficially similar to each other, but differ fundamentally in ultrastructure, behaviour and gene content. 
These predators are globally distributed in marine and freshwater environments, but are numerically rare and have consequently been overlooked by molecular-diversity surveys. In the age of high-throughput analyses, investigation of eukaryotic diversity through culture remains indispensable for the discovery of rare but ecologically and evolutionarily important eukaryotes.
Denis V. Tikhonenkov, et al., "Microbial predators form a new supergroup of eukaryotes" Nature (December 7, 2022).

9 comments:

neo said...

i recall you support this claims

No one in physics dares say so, but the race to invent new particles is pointless
This article is more than 2 months old
Sabine Hossenfelder

Imagine you go to a zoology conference. The first speaker talks about her 3D model of a 12-legged purple spider that lives in the Arctic. There’s no evidence it exists, she admits, but it’s a testable hypothesis, and she argues that a mission should be sent off to search the Arctic for spiders.

The second speaker has a model for a flying earthworm, but it flies only in caves. There’s no evidence for that either, but he petitions to search the world’s caves. The third one has a model for octopuses on Mars. It’s testable, he stresses.

Kudos to zoologists, I’ve never heard of such a conference. But almost every particle physics conference has sessions just like this, except they do it with more maths. It has become common among physicists to invent new particles for which there is no evidence, publish papers about them, write more papers about these particles’ properties, and demand the hypothesis be experimentally tested. Many of these tests have actually been done, and more are being commissioned as we speak. It is wasting time and money.

neo said...

sabine claims are refuted by

A New Branch Of The Tree Of Life
It is not every day that a new branch of organism at a level even higher than that of kingdoms is discovered.

andrew said...

Zoology found the new organisms first (when they had not been hypothesized) when doing microbiological organism surveys, and the learned upon further examination of them that the already newly discovered organisms that didn't fit any of the existing categories second. It is not analogous in terms of research method. It is evidence driven, not a hypothesis chasing evidence that the hypothesis might have support in the first place.

neo said...

It is not analogous in terms of research method. It is evidence driven, not a hypothesis chasing evidence that the hypothesis might have support in the first place.

the 750 gev lhc bump and x17 were or are evidence driven


and new composite particles are discovered in the lhc

glue balls are purely theoretical

also helped there are more organic things than fundamental particles

neo said...

how should HEP find new BSM fundamental particles ?

you seem to reject the proposal for a new $30 billion + 100 tev collider and x17

Guy said...

The world (especially the developed world) is pretty damn rich and can afford whatever it wants. It's just counters in game.

andrew said...

"the 750 gev lhc bump and x17 were or are evidence driven"

These are indeed evidence driven, unlike, for example, SUSY or two Higgs doublet theories.

The issue in those cases is not hypothesis chasing but jumping to a new particle explanation before making an adequate effort to explain the phenomena with existing physics or simple experimental error or uncertainty, which is ultimately what has largely ruled out both the 750 GeV hump and X17.

andrew said...

"how should HEP find new BSM fundamental particles?

you seem to reject the proposal for a new $30 billion + 100 tev collider and x17"

A new HEP collider isn't a great investment at this time. Our money is better spent, for example, on Lattice QCD computing capability and astrophysics observations.

Much lower energy colliders (which are also much less expensive), like Belle, are also perfectly adequate for investigating hadronic physics that is still producing lots of never before seen resonances and firmly establishing their properties.

The experiments in the neutrino physics pipeline are likewise far less expensive and chasing well defined problems that have great, low risk, scientific value (pinning down the parameters of the SM neutrinos, excluding BSM neutrinos, exploring if neutrinoless beta decay exists).

neo said...

ultimately what has largely ruled out both the 750 GeV hump and X17.

i'll revisit this by 2024