Ask a question about the theory of biological evolution

In which book did you find it?

The second sentence should mean that "the same population is geographically isolated and there is no genetic exchange for a sufficient period of time", not that reproductive isolation has occurred.

Under natural conditions, two subspecies cannot be crossed because there is a reproductive isolation mechanism, but if the hybrid is artificially forced, then the hybrid offspring formed are generally fertile, because the subspecies is only a product of the initial stage of isolation

Subspecies (ssp.)) is a group formed in the early stage of geographic and reproductive isolation of intraspecific individuals, with certain morphological characteristics and geographical distribution areas, so it is also called "geographic subspecies".

At the same time, it is a smaller unit, that is, a group formed after the individuals within the species are fully isolated geographically and reproductively; It is a geographical population within a species, or a physiological or ecological population, and is geographically or ecologically different.

But they are able to produce offspring!

The use of biological organs and the Cambrian explosion of life.

Cambrian explosion: Known as one of the great unsolved cases in paleontology and geology, the Cambrian explosion has puzzled academia such as evolution since Darwin. About 600 million years ago, at the beginning of the Cambrian period, the vast majority of invertebrates appeared in a very short period of time over millions of years.

This phenomenon of almost "simultaneous" and "sudden" appearance in the Cambrian strata of a large variety of invertebrate cherry blossoms (arthropods, molluscs, brachiopods, annelids, etc.), while animal fossils have not been found in the more ancient strata before the Cambrian for a long time, is called the "Cambrian explosion of life", referred to as the "Cambrian explosion".Darwin mentions this fact in his work On the Origin of Species and was greatly puzzled. He believed that this fact would be used as strong evidence against his theory of evolution.

But he also explained that the ancestors of Cambrian animals must have come from Precambrian animals, which were produced over a long period of evolution; The "suddenness" of the appearance of Cambrian animal fossils and the lack of Precambrian animal fossils are due to the incomplete geological record or due to the submergence of old strata in the ocean.

From the analysis, it can be seen that in the process of studying the evolution of organisms, fossils are important evidence, scientists have found that the older the strata, the simpler, lower, and more aquatic organisms in the fossil-forming organisms The more recent strata, the more complex, higher, and more terrestrial organisms in the fossil-forming strata, so it proves that the general trend of biological evolution is from simple to complex, from low to high, from aquatic to terrestrial The lowest option is fish, so the fossils of fish organisms appear in relatively ancient strata

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The theory of evolution is the science of the general laws of the historical development of the biological world.

The concept of evolution refers to the evolution or development of things. Its meaning is extremely broad, including the growth and decline of celestial bodies, the evolution of organisms, the development of society, and so on. In a narrow sense, it refers to the evolution of living things.

Biological evolution refers to changes in the diversity and adaptability of biological populations, or changes in the genetic composition of a population over a long period of time. As Stebbins (1974) puts it, "Biological evolution is a series of irreversible changes in the genetic components of a living group, or in whole or in whole, which are essentially based on changes in the interaction of organisms with their environment".

Biological evolution ranges from a species (e.g., horses and elephants), to a group (e.g., birds and mammals), to the historical development of the entire biological world.

Organisms are evolutionary. There was no life on Earth. Life only appeared about 3.4 billion years ago.

Primitive life did not possess a cellular structure, and a few single-celled primitive types appeared later. These organisms are constantly differentiating and developing under the right conditions. Some evolved into plants; Others evolved into animals and even humans.

As a result of long-term efforts, more than 2 million species of organisms have been discovered and recorded. Among them, there are more than 400,000 species of plants, more than 1.5 million species of animals, and more than 200,000 species of microorganisms.

See the bricks? How can it be a house, it is built day by day. Evolution, too, is a long process.

For a long time, scientists have never stopped studying the entire natural world, whether it is the origin of life or the direction of evolution, there are still huge bottlenecks in related aspects, and Darwin's theory of biological evolution can only provide us with certain ideas.

Life is far more complex than we think, and with the continuous development of science and technology, people have discovered more and more mysteries about life, including genes, and there are still some genes that cannot be fully deciphered, and the question of the evolution of life has not been accurately answered.

According to relevant research, human beings have been around for millions of years, and we not only have advanced intelligence, but also created countless tools, and even flew out of the earth to explore in the far reaches of space. In line with this trend, the dinosaur family of hundreds of millions of years ago also had a long evolutionary journey on Earth, so people are curious why they did not evolve into intelligent life.

Scientists say that there is no clear direction for biological evolution, and there are some species in nature that have evolved backwards, and can repeatedly streamline their own structures and functions to meet the needs of survival.

Our current understanding of the evolution of organisms is still superficial, and we simply think that they are constantly changing themselves under the influence of the external environment. In fact, this is only one reason, and more often than not, the factors that affect the direction of biological evolution are still unknown.

In this way, "intelligence" is not necessarily the goal pursued by all living beings, because developing the brain will pay more costs, such as sacrificing a large body, or losing more energy, which is not cost-effective for many living beings.

However, our ancestors won the "gamble", and although we have no way to compete with nature, the power of technology has helped humans to have a larger living space than other living creatures.

For the question of biological evolution, we cannot give a complete conclusion for the time being, and scientists are also trying to conduct more in-depth research. However, we can understand that the wisdom of nature is endless, and even human beings themselves cannot ** the future direction of evolution, and this process is very long, and it is not something that can be observed overnight, only by investing more energy, we can hope to find more clues.