Shedding new light on the evolution of the squid

February 28, 2017
Belemnoteuthis antiquus NHM OR25966, a 166 million year old exceptionally preserved extinct squid-relative was found near Bristol (Christian Malford). These ancient cephalopods with their large internal shell were not as fast as their recently evolved relatives, which survived until today's squid and cuttlefish. Credit: Jonathan Jackson and Zoë Hughes, NHMUK

Octopus, cuttlefish and squid are well known in the invertebrate world. With their ink-squirting decoy technique, ability to change colour, bizarre body plan and remarkable intelligence they highlight that lacking a back-bone doesn't always mean lacking sophistication.

Examining their deep evolutionary past, researchers have been spoiled by their generous fossil record, as demonstrated by drawer after drawer of ammonites and belemnites in every shop. But, the mostly shell-less modern cephalopods have been less easy to understand.

Now a new study, led by researchers from the University of Bristol, has found out how these remarkable creatures evolved by comparing their fossil records with the evolutionary history chronicled in their gene sequences to shed light on their origins.

Published today in Proceedings of the Royal Society B, it shows that the cephalopods diversified into the familiar modern octopuses, cuttlefish and squid during a time of great change in the marine world, known as the Mesozoic Marine Revolution, 160 to 100 million years in the past.

Lead author, Al Tanner, a PhD student at the University of Bristol's School of Biological Sciences, is a molecular biologist and bioinformatician at the Bristol Palaeobiology Research Group—a world leading evolutionary research group.

He said: "On land this was the time of the dinosaurs, but beneath the seas, ecologies were changing rapidly. Fish, squid and their predators were locked in evolutionary 'arms-races', leading to increasingly speedy and agile predators and prey.

"The cephalopods are now known to have also been caught up in this major transition, evolving to lose the shells of their ancestors and develop as dynamic and uniquely adapted marine animals."

The researchers used a technique called molecular clocks to investigate the timing of when the groups split from each other. Bristol co-author, Professor Davide Pisani, added: "Complex Bayesian models take all sorts of information into account to build a tree of evolutionary time.

"The key element of molecular clocks though is the fact that mutations steadily accumulate in genetic material over time - so by figuring out how many mutations per million years you find, and how it may vary between different groups, we can estimate ."

Al Tanner said: "The molecular clock results can be compared to the fossil record. What we see is that while there is some uncertainty in molecular clock estimates, octopuses and squid appear during the Mesozoic Marine Revolution and the two lines of evidence come together to tell the tale of evolution".

Co-author Dr Jakob Vinther said: "By having a reduced internal skeleton compared to their ancient relatives, the modern squids and octopuses could compress their body and more efficiently jet away leaving a baffling cloud of ink with the attacking predator. Before the predator realises what has happened and gains clear view again, the is far out of sight."

Al Tanner added: "The research exemplifies why evolutionary biologists are increasingly seeking to understand deep history from the combined study of both living organisms and the geological record. Through this synoptic view, so called molecular palaeontologists are transforming our understanding of how life became so complex and diverse."

Explore further: Despite multicolor camouflage, cuttlefish, squid and octopus are colorblind

More information: Molecular clocks indicate turnover and diversification of modern coleoid cephalopods during the Mesozoic Marine Revolution, Proceedings of the Royal Society B, rspb.royalsocietypublishing.or … .1098/rspb.2016.2818

Related Stories

The best way to include fossils in the 'tree of life'

January 10, 2017

The researchers from the Bristol Palaeobiology Group, part of the School of Earth Sciences, studied the best way to understand relationships of extinct animals to other extinct species as well as those alive today.

Recommended for you

Water striders illustrate evolutionary processes

October 19, 2017

How do new species arise and diversify in nature? Natural selection offers an explanation, but the genetic and environmental conditions behind this mechanism are still poorly understood. A team led by Abderrahman Khila at ...

Gene editing in the brain gets a major upgrade

October 19, 2017

Genome editing technologies have revolutionized biomedical science, providing a fast and easy way to modify genes. However, the technique allowing scientists to carryout the most precise edits, doesn't work in cells that ...

11 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

FredJose
1 / 5 (5) Mar 01, 2017
He said: "On land this was the time of the dinosaurs, but beneath the seas, ecologies were changing rapidly. Fish, squid and their predators were locked in evolutionary 'arms-races', leading to increasingly speedy and agile predators and prey.
"The cephalopods are now known to have also been caught up in this major transition, evolving to lose the shells of their ancestors and develop as dynamic and uniquely adapted marine animals."


Yet another evolutionary fairy-tale to explain away the emperor's invisible gown.

It's strange that otherwise highly intelligent people are so blinded by a commitment to naturalism that they cannot or just plainly refuse to see the commonsense that points to the fact that abstract entities like information, signalling and coding cannot arise from purely materialistic processes alone. Those entities require an existing outside intelligent agent to affect the required outcomes. Hence darwinian evolution is a dead-end road. The Creator made life.
TheGhostofOtto1923
3.7 / 5 (3) Mar 01, 2017
the commonsense that points to the fact that abstract entities like information, signalling and coding cannot arise from purely materialistic processes alone
'Commonsense' usually tells us to look for evidence and believe what it tells us. Evidence tells us that evolution is a fact.
The Creator made life
Science cant say whether some higher power created evolution or not. But it can tell us conclusively that it was not the creature that wrote a book full of lies about things that never happened and people who never existed.

That creature was most obviously entirely human.
FredJose
1 / 5 (4) Mar 01, 2017
Evidence tells us that evolution is a fact.

Friend, you can believe what you want. Including that life jumped out of the ground or pond scum all by itself. Or that stars can form from clouds of gas all by themselves. Or that planets can form from clouds of dust all by themselves. Or that the universe can jump out of nothing, all by itself. All in violation of the most basic established principles of physics and chemistry.

Just as books cannot write and create themselves or computers jump out of a pile of scrap metal and plastic all by themselves, neither can the biological life as we know it create itself out of the ground or pond scum. And this life is far more complex than any book or computer invented by human beings. You obviously have some magical evolutionary god that can make abstract information, logic, signalling, coding, decoding, repair and replication happen all by itself from purely materialistic processes. Wonderful magic that it.
FredJose
1 / 5 (3) Mar 01, 2017
@TheGhostofOtto1923:
Perhaps you can explain how the evolutionary process supposedly created all that abstract entities I mentioned above? All from purely physical and chemical processes, all by themselves without any intelligent agent being involved whatsoever? I'd like to see that explanation.

How did biological life arise - all by itself? Have you ever really set aside some serious time to think on these things? Have you looked at the make up of the DNA and RNA molecules and read about or personally investigated their biological chemistry? Have you seen how impossible it is that the enzymes required for the chemical transactions are also part of and coded in the DNA itself? How the chirality stacks up - left-handed only for amino acids and right-handed only for sugars? Do you know that the life processes actively BLOCK any other-handed item from gumming up the works? Have you examined replication to see how the chicken and egg situation arises again? The list goes on and on...
FredJose
1 / 5 (3) Mar 02, 2017
But it can tell us conclusively that it was not the creature that wrote a book full of lies about things that never happened and people who never existed.

This simply shows a great ignorance inspired by a strong desire to be free from accountability to a Creator.

The bible is a historical, eye-witnessed record that has stood the test of time and skeptical human beings, again and again. Many a skeptic has set out to prove that it's a pack of lies and after following some very rigorous methodology found it so convincing that they became Christians.
There is no better explanation for why we are here and why there's all the evil in the world. But it goes further and actually tells us where and how it's all going to end up.
Very unlike the evolutionary tale that has to appeal to blind faith in magical physical and chemical processes that created everything. None of which has ever been witnessed or documented by any human being. It's all a case of "maybe", "perhaps" etc.
MarsBars
3.3 / 5 (3) Mar 02, 2017
Please go back to the Discovery Institute, FredJose (and be careful that the door doesn't hit you on the backside as you leave).
FredJose
1 / 5 (3) Mar 02, 2017
MarsBars and GhostofOtto1923, you obviously do not realize that your adherence to the abiogenesis and evolutionary fairy-tale is akin to worship of nature?
Here's a very apt article you might want to read and consider:
http://creation.c...g-nature
And yes, it is indeed the much-maligned creation do com website.
Perhaps you'll learn something about your own religion which you didn't even know about: The fact that you are practicing a religion.
TheGhostofOtto1923
5 / 5 (2) Mar 02, 2017
@TheGhostofOtto1923:
Perhaps you can explain how the evolutionary process supposedly created all that abstract entities I mentioned above?
No, but I can explain how archeology has proven that the bible is full of lies about history. So the god who wrote it was either an incompetent or a liar, or both; ie somewhat less than the omnipotent, omniscient moral paragon he describes himself to be.

So using him and his book to explain or discount anything is a waste of time. Dont you agree?

If your god does exist then you will have to explain how he could be responsible for all the evidence which proves him false.

Do you have the courage to face that little conundrum honestly, or will you instead dismiss it like the good xian that you are?
TheGhostofOtto1923
5 / 5 (2) Mar 02, 2017
Perhaps you'll learn something about your own religion which you didn't even know about: The fact that you are practicing a religion
You misconstrue faith and confidence. Faith is belief despite evidence and is the basis of all religion. Confidence is evidence-based. We have increasing confidence in the scientific method because of its success in explaining the universe. We have decreasing confidence in religion because of its consistent failure to do the same.

Confidence is not faith. Science is not religion.

Religion teaches the systematic rejection of all evidence because its the only way it can survive. But its obvious that disregard for the info we get from our senses and what our reason allows us to make of it, is anti-life.
TheGhostofOtto1923
5 / 5 (2) Mar 02, 2017
Thats right, religion is anti-life.

"25 Large crowds were traveling with Jesus, and turning to them he said: 26 "If anyone comes to me and does not hate father and mother, wife and children, brothers and sisters—yes, even their own life—such a person cannot be my disciple. 27 And whoever does not carry their cross and follow me cannot be my disciple."

-Seems pretty clear to me. I guess this explains why he was so eager to purge the entire planet of it, and why he promises to do the same to proclaim his holy return.

Not enough to just show up - everythings got to die. Except of course for the few who are desperate and selfish enough to be able to ignore just how MONSTEROUS this all is.

Evil incarnate.
TheGhostofOtto1923
5 / 5 (2) Mar 02, 2017
Anyway, re your theories on evolution, i think its pointless to look for explanations as to how life operates from a god who is so eager to destroy it and torture the best of it for all eternity.

Dont you agree?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.