New evidence of ancient multicellular life sets evolutionary timeline back 60 million years

September 25, 2014, Virginia Tech

A multicelled specimen with dividing dyads. Specimen about 0.7 mm in diameter. Credit: Lei Chen and Shuhai Xiao
(Phys.org) —A Virginia Tech geobiologist with collaborators from the Chinese Academy of Sciences have found evidence in the fossil record that complex multicellularity appeared in living things about 600 million years ago – nearly 60 million years before skeletal animals appeared during a huge growth spurt of new life on Earth known as the Cambrian Explosion.

The discovery published online Wednesday in the journal Nature contradicts several longstanding interpretations of multicellular fossils from at least 600 million years ago.

"This opens up a new door for us to shine some light on the timing and evolutionary steps that were taken by that would eventually go on to dominate the Earth in a very visible way," said Shuhai Xiao, a professor of geobiology in the Virginia Tech College of Science. "Fossils similar to these have been interpreted as bacteria, single-cell eukaryotes, algae, and transitional forms related to modern animals such as sponges, sea anemones, or bilaterally symmetrical animals. This paper lets us put aside some of those interpretations."

In an effort to determine how, why, and when arose from single-celled ancestors, Xiao and his looked at phosphorite rocks from the Doushantuo Formation in central Guizhou Province of South China, recovering three-dimensionally preserved multicellular fossils that showed signs of cell-to-cell adhesion, differentiation, and programmed cell death—qualities of complex multicellular eukaryotes such as animals and plants.

The discovery sheds light on how and when solo cells began to cooperate with other cells to make a single, cohesive life form. The complex multicellularity evident in the fossils is inconsistent with the simpler forms such as bacteria and single-celled life typically expected 600 million years ago.

A multicelled specimen with dividing dyads in the interior and slightly elongate cells in the periphery. Specimen about 0.8 mm in diameter. Credit: Lei Chen and Shuhai Xiao

While some hypotheses can now be discarded, several interpretations may still exist, including the multicellular fossils being transitional forms related to animals or multicellular algae. Xiao said future research will focus on a broader paleontological search to reconstruct the complete life cycle of the fossils.

A multicelled specimen with a matryoshka, which is a growing ellipsoidal structure within the specimen. Specimen about 0.7 mm in diameter. Credit: Lei Chen and Shuhai Xiao
A multicelled specimen with a large matryoshka, which is a growing ellipsoidal structure within the specimen. Specimen about 0.7 mm in diameter. Credit: Lei Chen and Shuhai Xiao

Explore further: Geometry, programmed death might have enabled evolution of multicellularity

More information: "Cell differentiation and germ–soma separation in Ediacaran animal embryo-like fossils" Lei Chen, Shuhai Xiao, Ke Pang, Chuanming Zhou & Xunlai Yuan Nature (2014) DOI: 10.1038/nature13766

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Jaeherys
5 / 5 (12) Sep 25, 2014
The use of the phrase "transitional form" is slightly misleading. I understand the reasoning behind using it as we try to find evidence of species that are snapshots of organisms along the path from species A to species F but it can be easily misinterpreted. The word transition implies changing from one form to another but in the case of "transitional species" there is no end point. It's only in retrospect that we can see, ahh yes, species B is the species between A and C in the evolutionary timeline. Another word, maybe interpolant, would be more apt. "Species B is the interpolant of species A and C."

But these are some amazing specimens! Those photos show very well, especially cell-cell contact, some of the aspects of multicellular life. To see how they may be stuck together, imagine each dyad is a fixed shape. Without adhesion, they would be more or less the same shape. But clearly, the outer cell layer possibly cuboidal and interior cell tight contact. Remarkable.
OZGuy
5 / 5 (17) Sep 25, 2014
@verkle - Still pouting drivel.Honestly why do you bother?
Anda
5 / 5 (5) Sep 25, 2014
Verkle: science has always been confused with magic by non-illustrated people... just saying.

I recall reading the same conclusion in another article a few weeks ago.
vaire
4.5 / 5 (15) Sep 25, 2014
@verkle - Still pouting drivel.Honestly why do you bother?


'Cause he's sky daddy's knight in shining armour, defending his name and fighting his battles on the heathen interwebz? I'm guessing the more inane the post, the bigger the star he gets in sky daddy's book. Verkle - earning his place in heaven, one stupid post at a time.

Returners
1.4 / 5 (11) Sep 25, 2014
Calling it a "Transitional Form" is fallacious without a viable decendent fossil to compare it to.

For all you know, this line or organisms went extinct and has no significant line decendents.

Also, Symbiosis and Differentiation are two different things which may be difficult to distinguish when looking at something so old that DNA has degraded.

The discovery sheds light on how and when solo cells began to cooperate with other cells to make a single, cohesive life form.


This statement is a little out of place given the context, as it mistakenly implies two unrelated cells working together, which is symbiosis, which as pointed out is not the same thing as differentiation within the same species. This language needs to be clarified.

Differentiation would be if all cells have the same germ parent: one cell is good at collecting and making food, another other cell is good at storing food, and maybe a third cell is good at reproducing new cells and new organisms.
JVK
1.3 / 5 (14) Sep 25, 2014
Re: "...recovering three-dimensionally preserved multicellular fossils that showed signs of cell-to-cell adhesion, differentiation, and programmed cell death—qualities of complex multicellular eukaryotes such as animals and plants."

The physiology of reproduction is nutrient-dependent and pheromone-controlled in species from microbes to man via RNA-directed DNA methylation that leads from nutrient uptake to RNA-mediated amino acid substitutions. The amino acid substitutions stabilize the DNA in the organized genomes and differentiate cell types of cells in individuals of ecologically-adapted organisms.

Does anyone know what evolutionary events lead from mutations that perturb protein folding to increasing organismal complexity manifested in the morphological and the behavioral phenotypes of all species? If not, does anyone know how the evolutionary time frame, which changes frequently, was first established in terms that link it to biologically-based cause and effect?
Captain Stumpy
4.7 / 5 (16) Sep 25, 2014
Too bad there aren't the transitional species in the fossil record like there should be. We should discard such magical thinking as evolution.
@verkle
too bad you've never heard of http://www.talkor...nal.html
or
http://www.talkor...comdesc/
dont forget to also read
http://www.talkor...ion.html

perhaps you should read more, eh verk?
as for the jk crap above
what evolutionary events lead from mutations
your model CREATES MUTATIONS per your own admission, therefore you are the only idiot minion on PO
ever read this site? http://myxo.css.m...dex.html
completely DEBUNKS your creationist bull posts like above

Jeppe
Sep 25, 2014
This comment has been removed by a moderator.
JVK
1.3 / 5 (13) Sep 25, 2014
"ever read this site? http://myxo.css.m...ex.html"

60991.7 generations of e. coli evolution and counting.

When does he predict the E. coli will become a different species? How?

In my model, ecological variation is linked to RNA-mediated events via amino acid substitutions that stabilize the DNA in organized genomes of species from microbes to man, The amino acid substitutions do not arise in the context of mutations, which perturb organization. Thus, repeating your idiotic claim that
your model CREATES MUTATIONS per your own admission
exemplifies the intelligence common among evolutionary theorists.

For comparison see: http://www.nature...306.html
"We cannot conceive of a global external factor that could cause, during this time, parallel evolution of amino acid compositions of proteins in 15 diverse taxa that represent all three domains of life..."

Adding 60 million years doesn't help. It makes theorists seem more foolish.
Torbjorn_Larsson_OM
4.6 / 5 (9) Sep 26, 2014
Wow. "fossils that showed signs of cell-to-cell adhesion, differentiation, and programmed cell death", plus rather obvious matryoshka cloning.

If this stands, it is _huge_! It may even fence in the origin of animals. Which seems most likely from the traits and dating, even though the abstract give plants a shout out as well: "an affinity with cellularly differentiated multicellular eukaryotes, including stem-group animals or algae, is likely".
Torbjorn_Larsson_OM
4.6 / 5 (11) Sep 26, 2014
Never mind the trolls, especially when both creationists are obviously lying about the biology and the article both (these transitional forms were expected, and they are not fossil "species"; pheromones are not the evolutionary mechanisms as such].

@Jaeherys: I assume you know this, but for illustration.
"A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group."

"Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. Therefore, we can't assume transitional fossils are direct ancestors of more recent groups, though they are frequently used as models for such ancestors."

"Thus, with cladistics there is no longer a transition between established groups, and the term "transitional fossils" is a misnomer. "

[ http://en.wikiped...l_fossil ]
Torbjorn_Larsson_OM
4.6 / 5 (10) Sep 26, 2014
@Returners: This is a transitional form, see above and the article. More specifically between unicellular eukaryotes and multicellular plants/animals that are seen today. Your description of the concept is completely erroneous, as seen by the quotes I give.

Differentiation is when cells are specialized, not that they share germ lineage (say as non-differentiated clones).

Re language, they are clearly not discussing symbiosis.
JVK
1.4 / 5 (10) Sep 26, 2014
Never mind the trolls...


Today's Science Magazine includes an IN DEPTH perspective on three articles that collectively link the epigenetic landscape to the physical landscape of DNA in organized genomes via RNA-directed DNA methylation and RNA-mediated events that link nutrient-dependent amino acid substitutions to cell type differentiation in viruses and all extant living genera or extinct genera. See: http://www.scienc...50.short

See also: "We cannot conceive of a global external factor that could cause, during this time, parallel evolution of amino acid compositions of proteins in 15 diverse taxa that represent all three domains of life and span a wide range of lifestyles and environments. Thus, currently, the most plausible hypothesis is that we are observing a universal, intrinsic trend that emerged before the last universal common ancestor of all extant organisms." http://www.nature...306.html
JVK
1.7 / 5 (11) Sep 26, 2014
A series of articles in Science Magazine attests to the foolishness of those still touting their pseudoscientific nonsense about evolution.

See: Combating Evolution to Fight Disease
http://comments.s....1247472

RNA and dynamic nuclear organization http://comments.s....1252966

H3K27me and PRC2 transmit a memory of repression across generations and during development
http://comments.s....1255023

Anyone who finds a link from a biologically-based evolutionary event to the nutrient-dependent METABOLIC SHIFT that may train immune cells, should describe the event.

It can be compared to what is known about HOW ecological variation leads from nutrient-dependent RNA-mediated events and amino acid substitutions, which differentiate cell types, to recognition of self vs non-self differences in cell types and to behavior that leads to differences in morphological phenotypes via adaptations.
Captain Stumpy
4.6 / 5 (9) Sep 26, 2014
The amino acid substitutions do not arise in the context of mutations, which perturb organization. Thus, repeating your idiotic claim that

your model CREATES MUTATIONS per your own admission

exemplifies the intelligence common among evolutionary theorists
so now you say you are doubly-idiotic?
perhaps I should post the whole thing AGAIN?I asked
DOES your model make any changes to the nucleotide sequence of the genome of an organism, virus, or extrachromosomal genetic element?
This is a yes or no answer
THIS IS THE DEFINITION OF MUTATION AS ACCEPTED BY BIOLOGISTS AND GENETICISTS IN THEIR LEXICON - to which you answered
YES!
--Thanks for asking
Therefore your comment above is simply your backpedaling way of saying that "YEP" you got found out that you are stupid, sou are a glorified lab tech who is actually a perfumer and NOT a diagnostician (reported).

sorry jk - you are the idiot
still
Captain Stumpy
4.6 / 5 (9) Sep 26, 2014
When does he predict the E. coli will become a different species? How?
POST SCRIPT

this argument is about MUTATIONS (not speciation - which is hotly debated still) &
the fact that you cannot comprehend the MUTATIONS your own model creates which makes you a idiot

now - BECAUSE your model causes MUTATIONS it is actually a small supporting argument FOR EVOLUTION, not against it as you think, moron

by the way- for those looking to comprehend the idiocy of jk
see this link: http://freethough...s-place/

Myers defines the tactics of jk then explains WHY he is wrong
mostly I would say it is because he is a self-described college drop-out who couldn't comprehend the basics, so went into a self delusional state, as evidenced by his comment that he is a diagnostician (practicing without a license as it were)

nice try jk
but you've already been shown to be a crackpot
anonymous_9001
5 / 5 (9) Sep 26, 2014
See also: "We cannot conceive of a global external factor that could cause, during this time, parallel evolution of amino acid compositions of proteins in 15 diverse taxa that represent all three domains of life and span a wide range of lifestyles and environments. Thus, currently, the most plausible hypothesis is that we are observing a universal, intrinsic trend that emerged before the last universal common ancestor of all extant organisms." http://www.nature...306.html


That doesn't mean what you think it means. It doesn't mean evolution doesn't happen in general, it means it's extremely unlikely the scenario they were investigating would happen independently in 15 different taxa, therefore it most likely occurred in a single common ancestor.
Mike_Massen
3.3 / 5 (7) Nov 07, 2014
verkle claimed
Too bad there aren't the transitional species in the fossil record like there should be. We should discard such magical thinking as evolution.
Explain PLEASE verkle, just HOW does your god communicate to us lesser humans ?

And WHY does your god punish so many innocent please - just the same as if they were born subject to the same variants as part of evolutionary diversity such as found in these (god generated) deformities:-

https://www.googl...gQ_AUoAQ

Does verkle think or act like a robot trying so hard to raise doubt when the philosophy of Science based on the same paradigm as "Survival of the fittest" works so well.

It took a while from blind faith to questioning & as such it must be obvious the ideals of the philosophy of Science as a discipline evolved just like nature did with organisms !
JVK
2 / 5 (4) Nov 07, 2014
a universal, intrinsic trend that emerged before the last universal common ancestor of all extant organisms."


How can that mean:

it most likely occurred in a single common ancestor.


Captain Stumpy
4.2 / 5 (5) Nov 07, 2014
How can that mean:
all you did with your post was prove that you have issues with reading and comprehension
and you actually brag about being mensa?
try re-reading what he wrote, moron
That doesn't mean what you think it means. It doesn't mean evolution doesn't happen in general, it means it's extremely unlikely the scenario they were investigating would happen independently in 15 different taxa, therefore it most likely occurred in a single common ancestor.


@anonymous_9001
Thank you Anon
very well stated

but, alas, i think it is a bit much for kohl-slaw to comprehend...
do you have the ability or means to reword this with a monosyllabic vocabulary for jk?

maybe we should all chip in for x-mas and buy him a dictionary that includes the biological/medical/geneticists lexicon as well?

maybe it will help, since tutors are too expensive and he already admitted that he failed out of college?
anonymous_9001
5 / 5 (5) Nov 07, 2014
a universal, intrinsic trend that emerged before the last universal common ancestor of all extant organisms."


How can that mean:

it most likely occurred in a single common ancestor.




Literally all I did was reword it to make it easier to understand.
JVK
2 / 5 (4) Nov 07, 2014
The universal trend that emerged before the last universal common ancestor of all extant organisms linked nutrient uptake and metabolism from metabolic networks to genetic networks via RNA-mediated events that link amino acid substitutions to cell type differentiation in all cells of all individuals of all species via conserved molecular mechanisms.

The conserved molecular mechanisms link the epigenetic landscape to the physical landscape of DNA in the organized genomes of species from microbes to man -- as detailed in our 1996 review. Pheromones link the physiology of reproduction to nutrient-dependent biodiversity manifested in morphological and behavioral phenotypes.

What aspect of my model do you not understand? What do you think you understand about the statement

a universal, intrinsic trend that emerged before the last universal common ancestor of all extant organisms.


How could a trend involving mutations emerge before the last universal common ancestor?
Captain Stumpy
3.7 / 5 (6) Nov 08, 2014
How could a trend involving mutations emerge before the last universal common ancestor?
how can you claim to be a "serious scientists" when you don't understand Lenski's experiments?

how can you claim to be Mensa or even knowledgeable of biology or genetics when you cannot comprehend the definitions used every day in the field and that make communication easier?
Instead, you redefine the words to suit your own purpose and blatantly ignore the chosen communications parameters so that you can obfuscate the science with blatant stupidity

i would ask you to answer but i know you will only provide troll pseudoscience in return
What aspect of my model do you not understand?
YOU do not even understand your OWN model... so how can YOU explain it to ANYONE?

even though you have already admitted that your own model causes mutations, how can you argue against mutations?

kohl=PSEUDOSCIENCE CRACKPOT TROLL

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