In the era known as the 'Perm Age', 251 million years ago, an extinction event so massive, overwhelming and breathtaking that scientists call it the 'Great Death'
Animals and plants become extinct all the time, for a variety of reasons: sometimes it is a competition with another creature for the same ecological niche, and sometimes the sources of food in a certain area dwindle. Other animals and plants rush to take the place of the extinct and the world as usual. But every now and then an 'extinction event' occurs: a huge number of different and unrelated species and types of creatures disappear at once. The period of time in which extinction occurs can range from a few years to hundreds of thousands of years. This and this are considered short periods of time in geological terms.
Five major extinctions have occurred in the last five hundred million years. The extinction of the dinosaurs, the most famous of them all, is not the biggest of them. In the era known as the 'Perm Age' an extinction event took place so massive, sweeping and breathtaking that scientists call it 'The Great Dying'.
Over a long period of time, several million years at least, many species died out one after another. Some factor stressed the ecosystem and brought the animals and plants to the limit of their ability to deal with reality. Over a long period of time this mysterious pressure gradually increased, and the rate of extinction increased accordingly. Then, 251 million years ago, the unbelievable happened: almost all the creatures on Earth became extinct, at once. Ninety-five percent of all types of animals in the sea - disappeared. Seventy percent of land creatures - disappeared. This is an extinction on an unimaginable scale: never before has a catastrophe of this magnitude occurred on Earth. The Great Death dwarfs all the most dramatic Hollywood scripts. It is hard to even imagine a disaster on such a scale: the earth is almost completely desolate, bald of plants and animals. All the forests are gone. The plankton in the sea is dead. Even the insects, which were always immune to extinction, died in droves.
The world after the Great Death was very different from the world we know today. The few species that survived the catastrophe were free to dominate the living spaces without any competition, and for millions of years the terrestrial and marine landscape was dominated by a very limited number of species.
The animals that were most severely affected were those whose respiratory system was not sufficiently developed and the rate of metabolism in their bodies was low. This fact points to a lack of oxygen as the immediate suspect - but the pattern of extinction across the globe and the wide variety of species affected do not support this hypothesis. Another possibility is a dramatic increase in carbon dioxide levels in the atmosphere, which may explain why the aquatic animals were hit the hardest. Carbon dioxide is 28 times more soluble in water than oxygen, so any change in its amount in the air will be quickly reflected in the oceans as well. But these two theories are only part of the general mystery: what is the basic factor that brought about the great changes in the gas relations in the atmosphere?
Siberia is known to all of us as a rather frozen and desolate region in the north of Asia. 250 million years ago the Siberian landscape was far from frozen, and closer to Dante's Inferno. A series of massive volcanic eruptions that lasted over 600 years spilled one and a half million cubic kilometers of lava across the Siberian plain. Such a volcanic eruption, and especially one that stretches over hundreds of thousands of years, has a very noticeable climatic effect. The sulfurous gases that are emitted from the bowels of the earth fall back to the ground as acid rain that eats away at the terrestrial plants and the marine plankton, thereby damaging the entire food chain above them. The volcanic dust fills the air, blocking sunlight and preventing photosynthesis in plants: this is a phenomenon known as 'nuclear winter', as this is also what we expect in the event of an all-out nuclear war. It is possible that the Siberian eruption is the source of the continuous pressure that overwhelmed life in the Permian era.
Another possibility is the impact of a foreign body on Earth. Computer models show that to create the level of destruction of the Great Death, an asteroid impact with a diameter of 250 km is required. It is likely that such an impact would have left a very large mark on the surface of the earth, and so far no evidence has been discovered to support it although it cannot be completely ruled out.
A third possibility is the 'methane gun' hypothesis. In certain land areas, especially near ocean shores, there are rocks that contain pockets of methane gas. The methane is wrapped in water molecules that close it and prevent it from being released. The water mantle holds the methane, but only if certain conditions of pressure and temperature are met. If for some reason, for example the retreat of the sea level or the volcanic eruption I described earlier, these conditions change - the methane can break free from its prison and escape like a bullet from a rifle. Methane is much more effective than carbon dioxide in creating a greenhouse effect, which as mentioned may cause very dramatic changes in the climate. Some evidence shows that the average temperature at the end of the Permian period rose by a full six degrees.
And maybe it was Pangaea, the supercontinent, responsible for the whole thing. The formation of a huge landmass, most of it far from the moderating climatic effects of the coast, could have disrupted weather patterns. A large land mass also means less coastal area, less animals and shallow water reefs and therefore less food available for predators.
Bottom line, all of these reasons are possible - as well as any combination of them. It's hard to know for sure because only a few fossils have survived the ravages of time and those that have may not tell the full picture. The earliest fossils contain mostly animal parts: mouth bone, stem there. The scientists are trying to piece together this ancient puzzle as best they can, but it is not impossible that fossils identified as dozens of different species actually belong to a single animal. These virtual species disappear, of course, from the fossil record because they never existed - but we count them as extinct animals. Other animals, for example, appear in fossils until the extinction event, disappear during it - and then reappear a few million years after the extinction with almost no evolutionary change. This is the 'Lazarus effect', named after Eleazar, a village that the Christian Jesus brought back from the dead in the New Testament. Are these animals that managed to escape from the clutches of extinction, or maybe it's an 'Elvis effect': they really went extinct, and those who appeared later are nothing more than imitators that evolution created by chance. We may never know.
The article is taken from Making history!', a podcast about science, technology and history.
Previous articles on the subject on the science website:
25 תגובות
big on me…
Bacteria process information they don't need a nervous system for that.
Nervous system does what other cells in the body do at a different rate and without similar organization and that is to sort out chemicals that change gene expression from place to place.
The bacteria can process information at a relatively complex level, remember that these are coils less than a micrometer long, so that together they transmit chemical signals to each other and do all kinds of things, among other things, exchange genetic information between species, which eukaryotic creatures cannot do.
pit:
Eyal and B.Z. They gave you a correct answer.
You seem confused and it is not clear if you understood that, contrary to your assertion in response 18 - this is indeed well known.
I suggest that if you still think so you tell us so we can fill in the blanks.
Thank you very much for the article! Very interesting and written in a way that makes you want to read and know more.
More articles in this style will be gladly accepted 🙂
to the guest,
BZ continued me well. In simple organisms like bacteria (and you can go even further "back" to viruses and organic molecules even) there is no such thing as a survival instinct. A survivor is the one who survives. And he survives because he had the appropriate features for his environment in his time. That is, the properties it had were those that did not cause its disintegration (whatever the reason for disintegration) before it multiplied/created a duplicate containing similar properties. As organisms became more complex, let's take a creator with a primitive central nervous system-brain that already reacts to the environment and to various events by instincts, we can say that he has a survival instinct. This is simply a name for a system that has reached such a high level of complexity that we humans give it a name. A survival creature." A system that produces many and varied responses depending on the situation, with the result being the maintenance of the creature's function as it was before the situation and thus the possibility of the reproduction of the creature -> reproduction and the transfer of the features to the next generation, the same features that contain this input-processing-output system, "creature survival".
If there is software, it does not mean that there is someone who programmed it. There is no problem writing software A that writes software B.
It is not possible to say about software in that someone programmed it.
In the same way there is no problem to say that there is a software that someone did not program it. The problem is in the limited thinking of those who cannot think that it is possible.
To the guest:
You stated exactly what I meant
But I guess it's actually not really known
We are so used to the "personification" that sometimes we don't notice it.
There is actually nothing that wants to "survive" there are only factors that survive and reproduce and undergo mutations (or multiply in any other way). Bacteria that do not have the properties that allow them to survive simply will not survive. Bacteria that have the traits that allow them to survive will survive and pass on those traits.
The bacteria that have the properties that allow them to survive and reproduce and pass on their properties will compete with each other for resources and in the end the bacteria that have the properties that ensure the best survival/culture will survive more and the other bacteria less to the point of possible extinction.
Eyal, it seems to me that your answer is also incomplete unless you explain the survival instinct because it seems to me that in fact his question was how the survival instinct exists if it does not have the ability to think in order to consciously want to survive. And to say that he wouldn't have existed in the first place if he didn't have the survival instinct doesn't completely answer the question.
Point, I'm amazed at your phrasing "programmed for it". Straight up - and who programmed them?
One should try to explain the idea of natural selection simply: the bacteria (and every other organism including us humans of course) that survive, pass on to the next generation the traits that made them survive. Those that had traits less suited to the environment did not survive and did not pass on those traits to the next generation. That's what happens. No one wants and no one plans. By the way, everything related to the creature of survival stems from this process. If we make the extreme assumption that there is someone who does not have a survival instinct, he will not do everything to survive, and these qualities will die with him. The one who did have a survival instinct, survived, reproduced and thus passed the "instinct" to the next generation.
They are programmed for it. Software that ran on a computer does not want to continue running, it is programmed for that.
I understand that
But what exactly wants to survive? Is it a reaction of the bacterial structure to the environment
Because it is simply a natural reaction to the environment or that bacteria such as AIDS want to continue to exist
A bacterium doesn't have a nervous system, so it doesn't belong for it to think.
Bacteria also have hostile and less hostile environments.
No one knows if animals are self-conscious (although there is indirect evidence that they dream, for example).
All that evolution develops are things that help survival in general, and certainly could have developed differently. In any case, it always gets more and more complicated with development, because it is built on previous developments.
What a person who smokes all his life did not develop will not develop the human species. Today there is no evolutionary process at this level in humans, and certainly not in a time of hundreds of years
Can someone answer me a basic question in Avulzuya
Does a bacterial organism think or feel does it want to continue to exist
What exactly adapts itself to the environment and why is it all bacteria
And do animals have an inner voice
I mean, does a dog think in barking or is it some kind of robot that reacts to the situation
And is it known why evolution made man develop a stomach and all that stuff
And after so many pucks it will be more complicated instead of simpler
And will the human body get used to cigarettes in a few years?
I hope that all of this can be answered in one answer
You are amazing.. What a happy and interesting article I have no words I enjoyed it a lot Thank you very much to whoever brought this interesting article!
The most important question is what will we do when it happens to us? Maybe it's already happening to us?
can someone tell me
Is the earth bigger or smaller?
I mean he started small or big
And evolution also happened if it stopped a few times and had to start again
It is true that not all species are extinct
But the assumption is that the simpler ones remained
ו
exciting!
Thanks.
Why not conclude that the methane that was released from the depths of the oceans was ignited and turned into carbon dioxide and hence the tremendous change in the ratio of oxygen to carbon dioxide in the atmosphere? For your information, each molecule of methane that burns becomes one molecule of carbon dioxide and two molecules of water, that is, it reduces four atoms of free oxygen from the atmosphere.
They did not check the doses that could have been released. Note that this is a chain action because as soon as it turns on, the temperature rises, the sea heats up and immediately more matan is released.
This idea is very important for the current situation on earth where the temperature is rising and a lot of gas may be released into the atmosphere.
It is worthwhile to conduct a survey on the amount of iron trapped in the days and glaciers of the earth.
Good Day
Sabdarmish Yehuda
Since this is before the time of the dinosaurs, what creatures were here?
I know scorpions are very ancient, are they a relic of that time?
And from what was left, what evolved into dinosaurs? And for mammals?
And a point... You are in the movie...
The world has existed for 2000 years or 3000 at most I think
The more nonsense, the more professor
The Russians exterminated them with nuclear weapons
Sort -> million