New and well-preserved fossils from Latvia testify to key events in our evolutionary history, when our ancient ancestors migrated out of the water and onto land
It has long been known that the first land animals with four limbs - tetrapods, on the weight of tetra - four and pods - limbs - were the ancestors of reptiles, amphibians, birds and mammals, including ourselves. They evolved from a group of fish in the Devonian era, about 370 million years ago - about a hundred million years before the dinosaurs ruled the earth. Scientists managed to find fossils of tetrapod-like fish and fish-like tetrapods from the same era, but they were very different from each other and it was not possible to obtain a complete picture of the intermediate stages in the transition from fish to tetrapods.
In 2006, the picture changed dramatically with the discovery of a fossilized tetrapod fish, almost completely preserved and called Tictalic. Despite this fossil, a gap still remains between this animal and the earliest true tetrapods, which have true limbs and no fins. New fossils of a particularly primitive tetrapod from the Devonian era have now been discovered in Latvia. The fossilized tetrapod is called Ventastega, and it sheds light on the key event that brought fish to land.
"Wentastega was first described from fragments of material in 1994. Excavations that have taken place since then have yielded many new fossils that are well preserved, allowing us to reconstruct the entire head, shoulder girdle and part of the pelvis," says Professor Per Ahlberg from the Department of Physiology and Developmental Biology at Uppsala University.
The reassembly was carried out by Professor Ahlberg and Assistant Professor Henning Bloom, together with their British and Latvian colleagues. The joint work shows that Huntastega was more fish-like than any of its predecessors. The shape of its skull and the pattern of teeth in its jaws correspond exactly to an intermediate stage between the Tictalic and later tetrapods such as the Acanthostega.
"The shoulder girdle and pelvis are almost completely identical to those of the Acanthostega, and the shoulder girdle is very different from that of the Tictalic. This evidence suggests that the change from fins to limbs had already occurred. It seems that different parts of the body evolved at a different rate during the transition from water to land," says Per Ahlberg.
Although the new fossil reveals another step in the evolution from fish to tetrapods, scientists do not believe that Huntastega is one of our earliest ancestors. According to Ahlberg, it is more likely that this creature is an evolutionary 'dead end', and that the origin of the tetrapods that exist today is in another ancient ancestor from a similar group.
20 תגובות
emir,
Sorry for the delay in replying, I've been on standby for the past week.
First of all, I would appreciate it if you could elaborate on the mice that became whales. From your description, I don't see how it weakens evolution.
And now for your questions.
Let's start by saying that evolution as a worldview is indeed irrefutable. That is, absolutely in principle, every finding can be explained in a way that fits the theory, even if the rules of logic have to be bent for this. For example, if we find a few hundred skeletons of rabbits that will be dated with certainty to 4 billion years BC (a time when there were supposed to be only single-celled creatures), even this will not be a refutation of evolution, because it can be said that a time machine brought the rabbits there from the future.
Well, of course it's stupid. But in this way you can refer to any theory and say that it cannot be disproved.
What can be done to theories is to weaken them. If we discover some such skeletons of rabbits, which will be dated with certainty to the distant past, then there is a very great weakness of the theory of evolution, to the point of de facto refutation of a large part of the knowledge we thought we had about the development of organisms from each other.
And simply put, the theory of evolution can certainly be disproved, by gathering evidence that contradicts it. If enough such evidence accumulates, then eventually another theory will emerge that can explain this evidence in a better way. It is important to emphasize, however, that there is countless empirical evidence for the evolution of single-celled organisms under laboratory conditions, and multicellular organisms under laboratory conditions and under natural conditions. Any theory that tries to replace evolution will also have to explain the proven variation of organisms according to environmental conditions.
As for Popper himself, his sentence is usually quoted by creationists, who 'forget' to quote the rest of his words:
And yet, the theory is invaluable. I do not see how, without it, our knowledge could have grown as it has done since Darwin. In trying to explain experiments with bacteria which became adapted to, say, penicillin, it is quite clear that we are greatly helped by the theory of natural selection. Although it is metaphysical, it sheds much light upon very concrete and very practical researches. It allows us to study adaptation to a new environment (such as a penicillin-infested environment) in a rational way: it suggests the existence of a mechanism of adaptation, and it allows us even to study in detail the mechanism at work.
Another interesting fact that is forgotten to mention is that Popper's claim was strongly opposed by biologists and evolutionary researchers, who rushed to explain to him exactly what the theory of evolution is and how it changes according to the empirical evidence. Popper had enough honesty and sincerity to announce that he was wrong out of ignorance of the details, and that evolution is a supremely scientific theory. And in full quote:
I have changed my mind about the testability and logical status of the theory of natural selection; and I am glad to have an opportunity to make a recantation
I hope I answered your question, and have a good Saturday,
Roy.
Hugin:
I don't know what new definition you propose to give to the word smart, but according to the accepted meaning of this word, even a wise sage is made of an oak tree.
Darwin's theory of evolution is indeed true.
Only one thing confuses all the minds here, and that is the lack of insight, which is the swelling of life
That was in the water dwellers is found with all creatures today.
In terms of the intelligence of the universe, that intelligence is shared among everyone in all stages of evolution.
The illusion of man, that he is wiser than an oak tree, arouses ridicule in all the inhabitants of the heavens.
Friend, look at yourselves for a moment. Don't you feel a little ridiculed??
Progress is very necessary, to the extent that it does not recognize the value of its originality... but go on, the nature of the universe
Requests that you investigate until "Tom".
I have to ask Roi to answer you, he is busy in the next few days but I hope at the end of the week. I will try to find in which book this argument of the non-popery of evolution came up and was easily refuted. Just can't remember right now.
Evolution is a proven scientific theory and has been working for 150 years. If there was a problem with her, even the slightest, she would have been abandoned a long time ago.
I think you attribute too much power to the Batathites, and too little to healthy skepticism.
I am not influenced by rabbis, I am influenced by the desire to find a real answer.
Your example is instructive, but it doesn't fully meet Popper's criteria for me.
For me, evolution includes two main assumptions:
1) Natural selection
2) a single common ancestor
I think I figured out how to answer (1), but not (2).
I am looking for an experiment that will unequivocally and completely disprove evolution, thereby showing that it is scientific (just as the theory of general relativity could have been completely disproved if the sun's gravitational field had not deflected the light rays passing near the sun in the 1919 solar eclipse, but the gravitational field did deflect and therefore the Newtonian theory of gravity was disproved).
Any help will be appreciated.
You are probably too influenced by bacteria that any answer you give them will not put their minds to rest. Let's try another direction. The best example of evolution is the adaptation of bacteria to antibiotics. Very simply, the bacteria that were sensitive to antibiotics died and the others survived and from them the following bacteria were born. Note that even if one in a billion A bacteria survives because it happened to get a slightly different version of the gene that is allergic to antibiotics, it can produce offspring and easily reach millions of bacteria.
Why does this contradict evolution? It just contradicts our current dating of when there were dinosaurs and when there were humans.
Just as they found mouse-like creatures that were on the trees and from which today's cetaceans evolved (not making this up, you heard it from National Geographic), so they also found a human-like (or dinosaur-like) creature that is next to the dinosaur (or next to man).
Although this is unlikely, and although it certainly weakens the theory, it is not a contradiction.
They still all came from an ancestor, it's just that along the way we had something that resembled something that existed in another time (just like the mouse-like creatures that have already been found).
There is no problem disproving evolution, consider an experiment for example, finding humans and dinosaurs of the same age (according to the same criterion of carbon 14) and thereby disproving evolution. Therefore it meets the Popper criterion and the whole tower you built collapsed.
We do not have the possibility to measure millions of years on Earth as well as millions of light years in space directly (that is, wait for time to pass, or travel the distance in the case of space) but we have indirect means that are good enough to know what it is about.
Can someone please explain to me how evolution fits with the Popper criterion (a scientific theory must be sufficiently defined in its predictions that it can be disproved).
As far as I understand, every living creature that can be observed today can be explained its development from a common ancestor by finding fossils, which will testify to an intermediate stage. But finding or not finding fossils cannot disprove the theory of evolution, because if we found an "unsuitable" fossil then It may be that we simply haven't found the fossils that are missing yet, or some other explanations. And if we found a fossil - how good! We have a reinforcement for the theory. Since we don't have millions of years to sit and watch a continuous experiment that will prove (or disprove) evolution, we also don't have the tool that proves evolution (small changes of a certain species over several decades do not prove, only strengthen, and certainly the theory cannot be disproved with the help of such an observation, because if the same species has not changed, you can always say that there was not enough time).
The only way I can think of to disprove evolution is to be from "God" ourselves, observe billions of stars with suitable conditions for billions of years, and see how life develops there and if the process does not resemble evolution, then we were able to disprove it.
Does anyone have any other ideas?
ravine:
We are not talking here about the first terrestrial animals on land but about the first crustaceans on land (actually tetrapods but I think it is permissible to generalize to crustaceans).
Kazakh:
These are the fossils they found. There may have been earlier creatures whose fossils have not been found.
Anyway, in 10 million years you can get quite a lot done. I don't know if you have read on this site about evolution observed in a 36-year follow-up of lizards moved from island to island (yes! Only 36 years!)
Between the different schools..there are other rational bridges..related to cycles
bigger in nature..
The contradiction arises, from a linear reference, in the sequence of time..
I thought that the reptiles began to develop 360 m.s. ago and here it is written that only ten million years before that the amphibians began to develop.
Didn't they already know the evolutionary process of amphibians?
It seems to me that invertebrates are the first animals on land.
someone,
Thanks for the correction and the detailed explanation of where Latvia is not.
September,
I'm glad you enjoyed the article.
good week,
Roy.
A country called Latvia - is written only in one way in Hebrew - Latvia - and not Latvia and Latvia - as it appears in the article - as if it is some kind of land outside the earth that is written differently every time!
Moshe Levi, in general; All forms of life today are nothing but transitional stages between some feature and another (or a collection of features to a collection of other features).
But you're right that some examples of transitional stages are much more prominent.
(And I don't think this will convince any creationists).
Good Day!
This is an important discovery that shows a missing link between different stages of evolution.
It might also convince creationists, although these people will turn a blind eye to any discovery.
In any case, even today we see before our eyes creatures that there is no other way but to explain them as evolutionary transitional stages: bat (from the ground to air), penguin (from the air to the ground), hippopotamus (from land to water), marine mammals (a more advanced stage from land to water), man, Or actually only some of the people 🙂 (from the trees to the ground) and on and on.
wonderful news. It's always fun to hear about such intermediate fossils of such critical stages.
Thanks!
It can not be. It is written in the Torah:
And God created man in his image, in the image of God he created him: male and female he created them.
And the Lord God created the man from the ground, and he opened his mouth with the breath of life; And the man, the soul of life.