The extinction of the dinosaurs 65 million years ago did not affect the evolution of mammals that began 93 million years ago, but its jump was not 65 million years ago with the extinction of the dinosaurs but several million years later. This is according to a study recently published in Nature
One of the popular theories claims that the rise of mammals was directly related to the disappearance of the dinosaurs. Challenging evidence for this connection has recently come from the development of the mammalian family tree. The tree shows how different groups such as the primates and rodents are related to each other and when they diverged. An international team of researchers developed the mammal supertree from fossil data and genetic analyses.
During the Cretocene, when the dinosaurs walked the earth, mammals were very few in number and were prevented from branching out and developing in the ecological niches occupied by the ancient reptiles.
According to the accepted argument, the extinction of the dinosaurs released these constraints and allowed mammals to branch out and flourish until they reached the current state where they dominate the earth. According to this, the cetacean mammals split into a number of main subgroups, which split rapidly after the mass extinction event - apparently caused by a large asteroid impacting the Earth 65 million years ago - a point in time recorded in rocks and known by geologists as the KT boundary).
Kate Jones, one of the partners in the study, from the Zoological Society of London says that it is commonly thought that the meteor impact that killed the dinosaurs is what gave the mammals the boost they needed. However, the supertree shows that the chilian mammals already split into these subgroups 93 million years ago, long before the impact from space, and at a time when the dinosaurs still ruled the planet.
After this split, the rate of mammalian evolution plummeted and remained low until the Eocene epoch, 55 million years ago. The beginning of the Eocene period is marked by rapid warming and the explosion of the diversity of the evolutionary lines of mammals.
"The supertree is a new way to show that all species on Earth started from one common ancestor. You can infer the kinship between them from morphological characteristics and genetic sequences," explains Jones.
"If we had done the job from scratch we would have had to collect molecular and morphological data from 4,000 different species. Instead, we used information that had already been published by hundreds of researchers around the world. We used a new technique known as tree generation that allowed us to access the information, recode it and reanalyze it Like he was part of our data set."
straw man theoryThe composition of the marine and terrestrial rock sediments found in the boundary layer between the Pleistocene and Eocene eras showed that the average temperature rose by six degrees Celsius in less than a thousand years - an event known as the thermal maximum. Dr Rob Asher, an expert in mammalian phylogeny from the University of Cambridge said: "Paleoanthologists have known for over a century that not all modern placental mammal groups emerged immediately after the KT boundary. Most of the groups of placental mammals that led to cats, rats, whales and humans appeared during the Eocene. And vice versa, not all dinosaurs went extinct at the end of the Cretaceous period. There was a period of several million years when several species of non-flying dinosaurs became extinct (and the flying ones evolved into modern-day birds AB), so the idea that at the KT boundary the dinosaurs disappeared and the mammals appeared seems like a straw man. However, the idea that the Cretaceous mammal fossils represent today's mammals was a controversial question," says Dr. Asher.
The evolutionary tree of mammals - PDF file
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Adam Russo is right - Avi Blizovsky is a jealous amateur. Archaeopteryx was not a "flying dinosaur", Maximus jumped between branches similar to today's Hoacin, and on it is placed the tree of the "evolution" of birds. But he had feathers (as well as many large dinosaurs), which the flying ones of that time - the pterosaurs - did not have.
Have to send my father to see Harry Potter to relax.
Did flying dinosaurs evolve into birds?
This is not true!
Other dinosaurs with a lizard-like pelvis evolved into birds, if I'm not mistaken.
odd……..
It seems to me that there is a fixed mindset when it comes to the disappearance of the dinosaurs - the theory that states that the dinosaurs became extinct due to a meteor impact on the earth has many holes: for example, the fact that animals such as elephants, rhinoceroses, and medium and small-sized animals did not become extinct, and only mega-sized animals became extinct? Why did giant mammals like whales and animals like alligators survive?
Has anyone checked the bone densities of dinosaurs from different eras to estimate their true weight? In my opinion, a change in gravity that could have been caused by a huge meteor hitting the moon and deviating it from its orbit could have caused a change in the Earth's orbit and the speed of its rotation and as a result a substantial change in its gravity and as a result the weight of the dinosaurs and flying animals (and the minutes that gave birth) increased significantly too much for their children to be able to support their bodies or at least significantly worsen their ability to eat and breed.
Just a new way of thinking - according to Occam's Razor.
The climate at the time of the extinction of the dinosaurs did not allow life to thrive and only after it stabilized did the mammals take the place of the reptiles that had disappeared in the meantime. Therefore, it is not clear to me how this theory refutes what has been said.
Go ask the rabbis for the same level of precision in the small details. They don't have that problem. They invented something and they are consistent with it. Science takes asymptotic steps to truth. If we find out everything down to the last detail now, what will be left for those who study science today to discover when they become researchers?
seriously. This is how science progresses. There are other external factors besides niche vacancies - sometimes new niches are created. For example, during the time of the dinosaurs there was no grass at all. They fed on leaves and ferns. A niche became available in this area as well, and it took another twenty million years until it was filled with grass - and if you notice, most mammals feed on grass, so it's clear that the picture is not one-dimensional as you describe it.
to my dear father
A. When a scientific proposition, which was presented as a fait accompli, fails even before it has been proven and gives way to another proposition that is different from it and which has also not been proven yet - this is not "progress" but stepping on the spot or even starting from scratch.
B. A "fact" is an event in the material world, which has been proven to have occurred at some past time, using methods and tools accepted in the relevant field in which we are dealing (science or law, for example), as distinguished from "hypothesis", "theory", "presumption", "suspicion", etc. .
A. Science is always advancing and does not stand still.
B. I do not understand how the fact that the divergence of the mammals began 55 million years ago and not 65 million years ago proves the theory of creation.
First of all, I didn't understand the analogy to "straw man", as far as I know it usually refers to a person who is used as a cover for the real person.
Secondly, the dizzying pace of the evolution of the "theory of evolution", only shows that it was appropriate, for the sake of fairness, before jumping with these theories, to emphasize that these are only speculations and hypotheses that have not yet been adequately proven. Although on the face of it they are more logical than the "creation" theory, but they are still speculations.