Evidence of paleontological evolution. History of life on Earth

The doctrine of evolution causes a lot of controversy. Some believe that the world was created by God. Others argue with them, saying that Darwin was right. They cite numerous evidences of paleontological evolution , which most convincingly confirm his theory.

The remains of animals and plants, as a rule, decompose, and then disappear without a trace. However, sometimes mineral substances replace biological tissues, resulting in the formation of fossils. Scientists usually find fossilized shells or bones, that is, skeletons, solid parts of organisms. Sometimes they find traces of the livelihoods of animals or prints of their tracks. Even more rarely you can find animals entirely. They are found in the ice of permafrost, as well as in amber (tar of ancient plants) or in asphalt (natural resin).

Science paleontology

Paleontology is a science that studies fossil remains. Sedimentary rocks usually lie in layers, because of which the deep layers contain information about the past of our planet (the principle of superposition). Scientists are able to determine the relative age of these or other fossils, that is, to understand which organisms inhabited our planet earlier, and which later. This allows us to draw conclusions about the directions of evolution.

Paleontological chronicle

If we look at the paleontological record, we will see that life on the planet has changed significantly, sometimes completely unrecognizable. The first protozoan single-cell (prokaryotes), not possessing a cellular nucleus, arose on Earth about 3.5 billion years ago. About 1.75 billion years ago single-celled eukaryotes appeared. After a billion years, about 635 million years ago, multicellular animals appeared, the first of which were sponges. After a few tens of millions of years, the first mollusks and worms were discovered. After 15 million years after this primitive vertebrates appeared resembling modern lampreys. About 410 million years ago there were chelated fishes, and insects - about 400 million years ago.

Over the next 100 million years, mostly ferns covered the land, which was inhabited by amphibians and insects. From 230 to 65 million years ago, dinosaurs dominated our planet, and the most common plants at that time were cycads, as well as other groups gymnosperms. The closer to our time, the more similarity is observed between fossil fauna and flora with modern ones. This picture confirms the evolutionary theory. She has no other scientific explanations.

There are various evidences of paleontological evolution. One of them is an increase in the survival of families and genera.

Increase in the duration of family and childbirth

According to available data, more than 99% of all species of living organisms that ever lived on the planet are extinct species that have not survived to our time. Scientists have described about 250 thousand fossil species, each of which is found exclusively in one or several adjacent layers. Judging from the data obtained by paleontologists, each of them existed for about 2-3 million years, but some are much longer or much less.

The number of fossil genera described by scientists is about 60 thousand, and families - 7 thousand. Each family and each genus, in turn, has a strictly defined distribution. Scientists have found that the births live for tens of millions of years. As for the families, the duration of their existence is estimated at tens or even hundreds of millions of years.

Analysis of paleontological data shows that the last 550 million years the duration of the existence of families and genera has steadily increased. This fact can perfectly explain the evolutionary doctrine: gradually the most "hardy", stable groups of organisms accumulate in the biosphere. They are less likely to die out because they better tolerate changes in the environment.

There are other evidences of evolution (paleontological). After tracing the spread of organisms, scientists received very interesting data.

Distribution of organisms

The spreading of separate groups of living organisms, as well as all of them taken together, also confirms evolution. Only the teachings of Charles Darwin can explain their resettlement around the planet. For example, in almost any group of fossils, "eu-lolutionary series" are found. So called gradual changes observed in the structure of organisms, which gradually replace each other. These changes often appear directed, in some cases one can speak of more or less random fluctuations.

The presence of intermediate forms

Numerous evidences of paleontological evolution include the existence of intermediate (transitional) forms of organisms. Such organisms combine the signs of different species or genera, families, etc. Speaking of transitional forms, as a rule, means fossil species. However, this does not mean that intermediate species must necessarily die out. The theory of evolution based on the construction of a phylogenetic tree predicts which of the transitional forms actually existed (hence, can be detected), and which ones do not.

Many such predictions have now come true. For example, knowing the structure of birds and reptiles, scientists can determine the features of the intermediate form between them. There is an opportunity to find the remains of animals similar to reptiles, but having wings; Or similar to birds, but with long tails or teeth. It can be predicted that transitional forms between mammals and birds will not be detected. For example, there have never been mammals that have feathers; Or similar to birds, organisms that have bones of the middle ear (this is typical of mammals).

Archeopteryx detection

A lot of interesting finds are related to paleontological evidences of evolution. The first skeleton of a representative of the Archeopteryx species was discovered shortly after the publication of Darwin 's work The Origin of Species. This work contains theoretical evidence of the evolution of animals and plants. Archeopteryx is a form intermediate between reptiles and birds. His feather was developed, which is typical for birds. However, according to the structure of the skeleton, this animal was practically not different from dinosaurs. Archeopteryx had a long bone tail, teeth, on its forelimbs there were claws. As for the features of the skeleton peculiar to birds, he did not have much of them (fork, on the ribs - hook-shaped processes). Later, scientists found other forms intermediate between reptiles and birds.

Detection of the first human skeleton

Paleontological evidences of evolution include the discovery in 1856 of the first human skeleton. This event occurred 3 years before the publication of the "Origin of Species." Scientists at the time of publication of the book did not know of other fossil species that could confirm that the chimpanzee and man originated from a common ancestor. Since then, paleontologists have discovered a large number of skeletons of organisms that are transitional forms between chimpanzees and humans. These are important paleontological evidences. Examples of some of them will be given below.

Transitional forms between chimpanzees and humans

Charles Darwin (his portrait is presented above), unfortunately, did not learn about the many finds found after his death. Probably, he would be interested to know that these evidences of the evolution of the organic world confirm his theory. According to her, as we know, we all descended from monkeys. Since the common ancestor of the chimpanzee and man moved on four limbs, and the size of his brain did not exceed the size of the chimpanzee's brain, in the course of evolution, according to theory, the uprightness should develop over time. In addition, the brain volume had to increase. Thus, there must have been any of the three variants of the transitional form:

• A large brain, an undeveloped uprightness;
• Developed uprightness, the size of the brain as in chimpanzees;
• Developing upright, the volume of the brain is intermediate.

The remains of Australopithecus

In Africa in the 1920's. The remains of the body, which was named Australopithecus, were found. This name was given to him by Raymond Dart. This is another proof of evolution. Biology has accumulated information about many similar findings. Later, scientists discovered other remains of such creatures, including the skull AL 444-2 and the famous Lucy (pictured above).

Australopithecus lived in northern and eastern Africa in the period from 4 to 2 million years ago. They had a somewhat larger brain than chimpanzees. The structure of the bones of their pelvis was close to human. The skull in its structure is characteristic of the animals erect. This can be determined by the opening in the occipital bone, which connects the cavity of the skull to the vertebral canal. Moreover, in the volcanic petrified ash in Tanzania, "human" traces were found that were left about 3.6 million years ago. Australopithecines, thus, are an intermediate form of the second of the above types. The brain they have about the same as a chimpanzee, there is a developed upright.

Ardipithecus remains

Later, scientists discovered new paleontological finds. One of them is the remains of an ardipitek, which lived about 4.5 million years ago. After analyzing his skeleton, they found out that the ardipithecus were moving on the ground on two hind limbs, and also climbing trees on all four. They had poorly developed uprightness compared with subsequent species of hominids (Australopithecines and humans). Ardipithecus could not travel for significant distances. They are a transitional form between the common ancestor of chimpanzee and human and Australopithecus.

Numerous evidence of human evolution has been found . We told only about some of them. Based on the information received, the scientists compiled an idea of how the hominids changed over time.

The evolution of hominids

It should be noted that so far many are not convinced by evidence of evolution. A table with information on the origin of a person, which is presented in every school textbook on biology, does not give rest to people, causing numerous disputes. Is it possible to include this information in the school curriculum? Should children learn Evidence? The table, which is of a fact-finding character, angered those who believe that man was created by God. One way or another, we will present information about the evolution of hominids. And you decide how to treat it.

At hominids during evolution at first the erection was formed, and the volume of their brain was considerably increased much later. In australopithecines that lived 4-2 million years ago, it was about 400 cm³, almost like a chimpanzee. After them on the planet inhabited by a kind of skillful man. Found his bones, whose age is estimated at 2 million years, found more ancient stone tools. About 500-640 cm³ was the size of his brain. Then, in the course of evolution, a Man worked. His brain was even bigger. Its volume was 700-850 cm³. The next look, the Man erect, was even more like a modern man. The volume of his brain is estimated at 850-1100 cm³. Then the Heidelberg man appeared. He had a brain size of 1100-1400 cm3. Then came the Neanderthals, who had a brain with a volume of 1200-1900 cm³. A reasonable man appeared 200 thousand years ago. It is characterized by a brain size of 1000-1850 cm³.

So, we presented the basic evidence of the evolution of the organic world. How to treat this information, you decide. The study of evolution continues to this day. Probably, in the future will be discovered new interesting findings. Indeed, at the present time such a science as paleontology is actively developing. Evidence of evolution, which it provides, is actively discussed both by scientists and people far from science.