Study of sea creatures suggests nervous system evolved independently multiple times

Xenacoelomorpha
Proporus sp., a xenacoelomorph. Credit: Wikipedia/CC BY 2.5

(Phys.org)—A team of researchers from Norway, Sweden and Denmark has found evidence that suggests the nervous system evolved independently in multiple creatures over time—not just once, as has been previously thought. In their paper published in the journal Nature, the group describes their study of tiny sea creatures they collected from fjords in Norway and Sweden, from various sea floor locations, and from a site off the coast of Washington state, and what they found. Caroline Albertin and Clifton Ragsdale, with the University of Chicago, offer a News & Views piece on the work done by the team in the same journal issue.

Because the central nervous system similar looks so similar across species, it has been assumed for some time that it likely evolved just once in a very early common ancestor. But recent studies have shown that may not be the case. In this new effort, the researchers sought to gather more evidence of multiple instances of nervous system development by studying invertebrates scattered across the evolutionary tree with different types of central nervous system architectures. To that end, they collected tiny specimens from multiple locations and studied their lineage. They report that some of them belong to an ancient lineage called Xenacoelomorpha, which had a wide variety of nervous system types. Some had no central cord, they note, while others, such as modern jellyfish, have multiple cords—and one species has a cord running along its back reminiscent of vertebrates.

The team also looked at a gene called bmp, believed to be the gene that is responsible for kicking off the development of the nervous system. But another team had shown that in the acorn worm, it became active before the formation of the nervous system, suggesting other were also at play. After looking at the invertebrates they had collected, the team found other instances of the bmp gene becoming activated before the formation of nerve cords. They also found that blocking the protein that is produced when bmp becomes active did not prevent formation of the cord in some species. The group also found that other genes that have been associated with development of the nervous cord became active in some that had no nervous cord at all.

The researchers claim their findings show that the evolved in different creatures at different times, which means that it evolved more than once.


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More information: José M. Martín-Durán et al. Convergent evolution of bilaterian nerve cords, Nature (2017). DOI: 10.1038/nature25030

Abstract
It has been hypothesized that a condensed nervous system with a medial ventral nerve cord is an ancestral character of Bilateria. The presence of similar dorsoventral molecular patterns along the nerve cords of vertebrates, flies, and an annelid has been interpreted as support for this scenario. Whether these similarities are generally found across the diversity of bilaterian neuroanatomies is unclear, and thus the evolutionary history of the nervous system is still contentious. Here we study representatives of Xenacoelomorpha, Rotifera, Nemertea, Brachiopoda, and Annelida to assess the conservation of the dorsoventral nerve cord patterning. None of the studied species show a conserved dorsoventral molecular regionalization of their nerve cords, not even the annelid Owenia fusiformis, whose trunk neuroanatomy parallels that of vertebrates and flies. Our findings restrict the use of molecular patterns to explain nervous system evolution, and suggest that the similarities in dorsoventral patterning and trunk neuroanatomies evolved independently in Bilateria.

Journal information: Nature

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Dec 14, 2017
Evidence: central nervous systems looks similar across species

Hypothesis: it likely evolved just once in a very early common ancestor.

Testing of the Hypothesis: studies have shown that may not be the case

Conclusion: the evidence is inconsistent with a evolution from a common ancestor but is totally consistent with a Common Creator

Dec 14, 2017
#B: Or simply 'Convergent Evolution' ??

Dec 14, 2017
Organisms, generally, evolve along similar pathways. With changes being dependent on environmental constraint requirements of the moment...
See Mother Nature's cookbook...

Dec 14, 2017
Evidence: central nervous systems looks similar across species

Hypothesis: it likely evolved just once in a very early common ancestor.

Testing of the Hypothesis: studies have shown that may not be the case

Conclusion: the evidence is inconsistent with a evolution from a common ancestor but is totally consistent with a Common Creator
Religionists actually think science is this easy. Why? Because god wouldn't insult them by making the universe too hard for them to understand.

Hint: gods will is not the only thing you will NEVER be capable of understanding. And that's just the way it is.

Dec 15, 2017
@GhostOfOtto:
Perhaps you'd like to investigate where the foundations of today's science came from:
Mostly a whole bunch of so-called "religionists" of which to name but a few:
Isaac Newton
Albert Einstein (not Christian)
Michael Faraday
James C Maxwell
Leonhard Euler
Johannes Kepler
Galileo Gallilei
Blaise Pascal
Robert Boyle
John Ray
Carl Linnaeus
James Joule
Louis Pasteur
Joseph Lister
Robert Millikan
John Eccles
Roger Bacon
Nicolaus Copernicus
Gottfried Wilhelm Leibnitz
William Herschel
John Dalton
Lord Kelvin

Need I go on????
By the way , Otto, just where does your LIFE come from again? Please remind me of the definitive rational scientific explanation that shows how life arises from lifeless materials all by itself via purely random chemical and physical processes. Show how it overcomes the chiral problem, the coding and decoding problem, the creation of abstract entities from materialistic processes, the repair issue, and start of life itself.

Dec 15, 2017
Nicholas of Cusa resolved the ontological paradox by demonstrating the principle of continuing creation. The necessary existence of the universal process of becoming provides a mission for mankind to increasing discover its ever evolving underlying lawfulness. This is the only basis for successive scientific revolutions via hypothesis or what Cusa called learned ignorance.

Dec 15, 2017
Freddy the god lover...
Mostly a whole bunch of so-called "religionists" of which to name but a few
But Freddie most people know that in the past if you didn't believe in god you didn't get work. No, you often died in jail or at the stake.

A notable name not on your list: Giordano Bruno.

"He is known for his cosmological theories, which conceptually extended the then-novel Copernican model. He proposed that the stars were just distant suns surrounded by their own exoplanets and raised the possibility that these planets could even foster life of their own... Starting in 1593, Bruno was tried for heresy by the Roman Inquisition on charges of denial of several core Catholic doctrines... The Inquisition found him guilty, and he was burned at the stake in Rome's Campo de' Fiori in 1600."

Simpleton believers also tell simpleton lies. Of course they don't seem simple to THEM.

Dec 15, 2017
By the way , Otto, just where does your LIFE come from again?
Science will eventually figure this out because nothing about it is unphysical. Who knows? It might well have been created by some advanced being.

But we do know that it was not created by the god in your book. THAT omniscient, omnipotent, morally impeccable and perfect creature nevertheless wrote a book about events we know never happened and people we know never existed.

THAT god is either incompetent or a liar... ie he's not who and what he claims to be; ie he doesn't exist.
Need I go on????

-Sure. I never tire of repeating this.

Dec 16, 2017
Intriguing. The evolution of the neural system is iffy with its migrating cells under early development and what not.

@Beginning, FJ, sascoflame: Irrelevant and wrong. You cannot - socially or scientifically - use yet another successful test of evolution or secular science to argue that it has failed or is based on religion.

Historically society was religious at the time modern science developed. But ancient Greek science was not but was destroyed by religion, as was ancient Arabian science. Modern science succeeded due to the secular development of liberal democracy and the best scientists is irreligious today according to statistics. Likely that happens since known facts continously replace myths while religion tries to replace facts with myth, two totally conflicting human endeavors.

[tbctd]

Dec 16, 2017
Moreover evolution of the universal common ancestor or its lineage has nothing to do with evolution of later neural systems. It was recently established by evolutionary science that the universal common ancestor lineage evolved in hydrothermal vent systems; that is where we came from and that is the explanation and the description of the start of life you ask for.

To end on this display of insanity of religious extremists dabbling in facts they do not understand, despite being a bioinformatician I have no idea what "the chiral problem, the coding and decoding problem, the creation of abstract entities from materialistic processes, the repair issue" refers to.

[tbctd]

Dec 16, 2017
Cells evolved to be self repairing. They evolved to have genomes code for evolved genes and are transcribed and translated - coding for proteins, not "decoding" - by a genetic machinery which evolution we know lots (but of course not all) about. And cells have evolved to be chiral as attested by chiral filters in said process.

If you *really* are interested in that evolution, which obviously are no problems either for evolution - since it both could happen and did happen - or for our understanding despite some parts evolved in deep, poorly resolved time, I can dig them up. There is plenty of such research, obviously, it is a central part of the universal common ancestor lineage evolution (hard,but not impossible it seems, to resolve) and of the current evolution in central functions of genetic and metabolic machinery of modern cells (that we resolve much more easily).

But it appears you are taught to drone on Gish gallop proclaimed 'problems' by your religious tutors.

Dec 16, 2017
@sascoflame - dude. You cannot avoid the need for spontaneous creation by suggesting that instead of a few simple molecules combining to form life gradually, an entire omnipotent being instead was spontaneously created just to solve the problem.

In other words, if God created life, who created God? You can't wave away the origin question by claiming it all started with a giant turtle. What is the origin of the giant turtle?

I fully understand that you lack the cognitive ability to even contemplate this question, so I will bid you and your comments goodbye.

Dec 18, 2017
Evidence: central nervous systems looks similar across species

Hypothesis: it likely evolved just once in a very early common ancestor.

Testing of the Hypothesis: studies have shown that may not be the case

Conclusion: the evidence is inconsistent with a evolution from a common ancestor but is totally consistent with a Common Creator
Erm..whut?
What you just said is akin to:

Evidence: The sky is blue
Evidence: The sea is blue
Testing reveals the sky not to be the the sea
Conclusion: The evidence is consistent with unicorns having black stripes.

Is that how logic works on your planet? Really? Maybe you should start over with school. You seem to have failed there from the word 'go'.

(hint: look up the term 'convergent evolution')

Dec 18, 2017
Evidence: Two rocks fall off different sides of a mountain.

Hypothesis: All rocks are the same.

Testing of the hypothesis: The rocks are differently shaped and colored.

Conclusion: The evidence is inconsistent with all rocks being the same. Therefore rocks don't exist.

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