Walking fish reveal how our ancestors evolved onto land

[Edge Guerrero]

[color=#000000]Date: August 27, 2014
Source: McGill University[/color]

Summary: About 400 million years ago a group of fish began exploring land and evolved into tetrapods – today's amphibians, reptiles, birds, and mammals. But just how these ancient fish used their fishy bodies and fins in a terrestrial environment and what evolutionary processes were at play remain scientific mysteries.


Polypterus senegalus

About 400 million years ago a group of fish began exploring land and evolved into tetrapods -- today's amphibians, reptiles, birds, and mammals. But just how these ancient fish used their fishy bodies and fins in a terrestrial environment and what evolutionary processes were at play remain scientific mysteries.

Researchers at McGill University published in the journal Nature, turned to a living fish, called Polypterus, to help show what might have happened when fish first attempted to walk out of the water. Polypterus is an African fish that can breathe air, 'walk' on land, and looks much like those ancient fishes that evolved into tetrapods. The team of researchers raised juvenile Polypterus on land for nearly a year, with an aim to revealing how these 'terrestrialized' fish looked and moved differently.

"Stressful environmental conditions can often reveal otherwise cryptic anatomical and behavioural variation, a form of developmental plasticity," says Emily Standen, a former McGill post-doctoral student who led the project, now at the University of Ottawa. "We wanted to use this mechanism to see what new anatomies and behaviours we could trigger in these fish and see if they match what we know of the fossil record."

Remarkable anatomical changes The fish showed significant anatomical and behavioural changes. The terrestrialized fish walked more effectively by placing their fins closer to their bodies, lifted their heads higher, and kept their fins from slipping as much as fish that were raised in water. "Anatomically, their pectoral skeleton changed to became more elongate with stronger attachments across their chest, possibly to increase support during walking, and a reduced contact with the skull to potentially allow greater head/neck motion," says Trina Du, a McGill Ph.D. student and study collaborator.

"Because many of the anatomical changes mirror the fossil record, we can hypothesize that the behavioural changes we see also reflect what may have occurred when fossil fish first walked with their fins on land,"says Hans Larsson, Canada Research Chair in Macroevolution at McGill and an Associate Professor at the Redpath Museum

Unique experiment The terrestrialized Polypterus experiment is unique and provides new ideas for how fossil fishes may have used their fins in a terrestrial environment and what evolutionary processes were at play.

Larsson adds, "This is the first example we know of that demonstrates developmental plasticity may have facilitated a large-scale evolutionary transition, by first accessing new anatomies and behaviours that could later be genetically fixed by natural selection."

The study was conducted by Emily Standen, University of Ottawa, and Hans Larsson, Trina Du at McGill University.

This study was supported by the Canada Research Chairs Program, Natural Sciences and Engineering Research Council of Canada (NSERC) and Tomlinson Post-doctoral fellowship.



Source:http://www.sciencedaily.com/releases/2014/08/140827131547.htm

[Masato]

This is huge

I have had a lot of 'evolution' discussions lately with people spontaneously. If this is true it knows a lot of holes in some anti-darwinian folks' debates.

[Edge Guerrero]

This is huge

I have had a lot of 'evolution' discussions lately with people spontaneously. If this is true it knows a lot of holes in some anti-darwinian folks' debates.

- The evolutions thery got more holes than a cheese:

[Masato]

^ I agree, but until I read your article I had never heard ANY explanation/evidence of 'vertical evolution' - that is, the appearance of a NEW species or attribute. HORIZONTAL evolution talks about the changes in EXISTING features of a species... that the shape of beaks etc will slowly adapt to the needs of the environment... creatures with less functional features will die off, and creatures with more suited features will continue to pro-create, thus changing MINOR things over time...

But VERTICAL evolution (until I read this article) I thought had never been proven or even demonstrated or explained; How can eyes form from the eye-less? How can a brain and nervous system 'evolve' from creatures who have none previously? How can wings develop out of the wing-less? How can something so complex as lungs or a nervous system be formed from one-celled organisms, without some kind of intelligent design?

So far the only explanation I'd heard was 'genetic mutation', meaning that sometimes the cells/DNA get randomly scrambled up... but the arguments I've heard against this say that when something gets mutated, the chances of arriving at a place that is SUPERIOR to where it started, or somehow arranging in a fluke formation of something that actually WORKS are basically nil. When you drop a glass on the floor, the pieces won't arrange in a BETTER glass.. nor will they luckily assemble themselves into a working machine. They are broken; the 'law of increasing randomness'. When something gets mutated, this usually means it is broken, damaged, etc - this isn't X-men

This article is the first I've seen that disputes this, and suggests that biology actually CAN make new things.

Bums me out, because I was having some fun contemplating that evolution was done, lol

[Canuckster]

^ I agree, but until I read your article I had never heard ANY explanation/evidence of 'vertical evolution' - that is, the appearance of a NEW species or attribute. HORIZONTAL evolution talks about the changes in EXISTING features of a species... that the shape of beaks etc will slowly adapt to the needs of the environment... creatures with less functional features will die off, and creatures with more suited features will continue to pro-create, thus changing MINOR things over time...

But VERTICAL evolution (until I read this article) I thought had never been proven or even demonstrated or explained; How can eyes form from the eye-less? How can a brain and nervous system 'evolve' from creatures who have none previously? How can wings develop out of the wing-less? How can something so complex as lungs or a nervous system be formed from one-celled organisms, without some kind of intelligent design?

So far the only explanation I'd heard was 'genetic mutation', meaning that sometimes the cells/DNA get randomly scrambled up... but the arguments I've heard against this say that when something gets mutated, the chances of arriving at a place that is SUPERIOR to where it started, or somehow arranging in a fluke formation of something that actually WORKS are basically nil. When you drop a glass on the floor, the pieces won't arrange in a BETTER glass.. nor will they luckily assemble themselves into a working machine. They are broken; the 'law of increasing randomness'. When something gets mutated, this usually means it is broken, damaged, etc - this isn't X-men

This article is the first I've seen that disputes this, and suggests that biology actually CAN make new things.

Bums me out, because I was having some fun contemplating that evolution was done, lol

I think a very good question here is if nature is providing the blueprint for new species, then why did old, ugly inefficient animals that seemingly have no place whatsoever in nature come to be in the first place? This would suggest not intelligent design per se, but a self regulating mechanism within life itself that rapidly adapts to outside stimuli that forces evolution in and of itself.

great threads lately btw edge.

[Edge Guerrero]

I think a very good question here is if nature is providing the blueprint for new species, then why did old, ugly inefficient animals that seemingly have no place whatsoever in nature come to be in the first place? This would suggest not intelligent design per se, but a self regulating mechanism within life itself that rapidly adapts to outside stimuli that forces evolution in and of itself.

great threads lately btw edge.

- I don't think we are gonna get the answer to this question.
If we look that way, look's like every main species of today had a concorrent one, we had the neandertall, and even after the giant lizards era, we had some great mammals that got extinct to, for some reason, and this is talking about what is probably a natural selection.

Every big climate change make's some species more dominating.

THank you Canuckster, i am glad you guys appreciet.^^

[Edge Guerrero]

^ I agree, but until I read your article I had never heard ANY explanation/evidence of 'vertical evolution' - that is, the appearance of a NEW species or attribute.

- Maybe there's a btw species, like a species that wasn't found yet?

HORIZONTAL evolution talks about the changes in EXISTING features of a species... that the shape of beaks etc will slowly adapt to the needs of the environment... creatures with less functional features will die off, and creatures with more suited features will continue to pro-create, thus changing MINOR things over time...

But VERTICAL evolution (until I read this article) I thought had never been proven or even demonstrated or explained; How can eyes form from the eye-less? How can a brain and nervous system 'evolve' from creatures who have none previously? How can wings develop out of the wing-less? How can something so complex as lungs or a nervous system be formed from one-celled organisms, without some kind of intelligent design?

- I honestly don't know, just like you, i assumed theres a link specis in the middle of this, making the chain of a ancient one and a more recente one.
The eyes is a thing that makes me lose my mind, because the first species didn't have one, just like some of the abissal creatures of the oceans today. But at some point they started desenving a more sensible nervous system.


So far the only explanation I'd heard was 'genetic mutation', meaning that sometimes the cells/DNA get randomly scrambled up... but the arguments I've heard against this say that when something gets mutated, the chances of arriving at a place that is SUPERIOR to where it started, or somehow arranging in a fluke formation of something that actually WORKS are basically nil. When you drop a glass on the floor, the pieces won't arrange in a BETTER glass.. nor will they luckily assemble themselves into a working machine. They are broken; the 'law of increasing randomness'. When something gets mutated, this usually means it is broken, damaged, etc - this isn't X-men

- Mutantion is a excuse that is used when there's something that we an't explain, but i agree, some mutantions are less adapted to survive on he enviroment.

This article is the first I've seen that disputes this, and suggests that biology actually CAN make new things.

- Mother nature is amazing because of this, just like the old Rod Piper quote, when whe thing we know the answer, mother nature change the questions.

Bums me out, because I was having some fun contemplating that evolution was done, lol

- Same, i used to get headches tryng to figure out, how manny years ago that Littlefoot has lived with his friend's. :mrgreen: