What is the evolution of living things? About the evolution of living things

Changes in gene frequencies in populations are evolutionary manifestations and are multidirectional. However, because of natural selection, the evolution we see has been on the favorable side. Time is a tool to test whether evolution is perfect, and at the same time it is a necessary condition for evolution.

For example, there is a moth that is much whiter when the bark is white; When polluted, the bark turns black and the brown moths increase. Because white moths are not suitable for survival on brown bark (easy to spot).

The path of biological evolution is tortuous and exhibits a variety of special complications. In addition to progressive development, there are also specializations and degradations in the biological world. Specialization is different from the perfection of comprehensive biology, it is the specific adaptation of organisms to certain environmental conditions.

This evolutionary direction favors the development of one aspect but reduces the adaptability of others, such as the evolution of horses from multi-toed to single-hoofed suitable for running. When environmental conditions change, highly specialized organisms often become extinct because they cannot adapt, such as the Irish deer, which eventually becomes extinct because its overdeveloped horns do more harm than good to survival. Adaptation to a parasitic or sessile lifestyle can also lead to the deterioration of certain organs and physiological functions of the body.

For example, there is a deep-sea parasitic fish, the male parasitizes on the female, and the male's digestive organs are degenerated, and only the sperm nest is particularly enlarged to ensure the reproduction of the race.

Survival of the fittest There is a low level that evolves into a high one.

Let me be more detailed with you:

From the perspective of the process and law of evolution, vertebrates should have evolved from invertebrates.

There must be many intermediate types of stages in between.

Since invertebrates are not hard.

bones, so evolution can only be found from the material of comparative anatomy and comparative embryology.

Clue. Vertebrate ontogeny has a zytochord, pharyngeal cleft parotal and dorsal neural canal, hence the ridge.

Vertebrates share a common ancestor, the primitive headless, which may have occurred in the form of protochordates.

Cambrian. The primitive headless class evolved into the primitive head class with a brain, senses, and skull at the front, that is, it became the ancestor of vertebrates.

Whereas caudal chordates and cephalic chordates may be the two proto-headless.

specialized branches.

The evolution of vertebrates can be divided into three stages:

evolution in water;

From water to land.

the evolution of the high bucket - the evolution of amphibians and reptiles; Evolution of birds and mammals.

If you want to think about it, vertebrates are gone, and they will slowly evolve again after hundreds of thousands of years, and if invertebrates are gone, the foundation of life will be broken.

Life on Earth evolved from the most primitive state of cellless structure to prokaryotes with cellular structures, from prokaryotes to eukaryotic single-celled organisms, and then developed in different directions, and the kingdom of fungi, plants and animals appeared.

The plant kingdom ranged from algae to gymnoferns to ferns, gymnosperms, and finally angiosperms.

The animal kingdom evolved from primitive flagellates to multicellular animals, from primitive multicellular animals to the emergence of chordates, and then evolved into higher chordates vertebrates. Fish in vertebrates evolved into amphibians and then reptiles, from which mammals and birds were differentiated, and one of the mammals further developed into higher intelligent creatures, which is man.

As for the topic of how modern science explains how organisms evolve, I have learned about the latest explanations of biological evolution at the forefront of science, and on the whole, there are the following characteristics:

On the one hand, the cellular organisms on the earth (including the three major types of animals, plants and fungi) are all composed of single-celled microorganisms that continuously gather and symbiosis and form multicellular living organisms.

The greater the number of proliferation and accumulation of biological gene assemblages, the more functional cell tissues that constitute the living organism, the more functional cell tissues that reproduce the memory of the offspring, and the greater the progeny proliferation and deterioration.

In three aspects, the accumulation of proliferative mutation in biological evolution is obtained by the phenomenon of proliferation and mutation of survival function adaptability based on the number of genetic combinations formed by organisms in each generation and the method of survival exercise and learning that each generation acquires to continuously adapt to the environment.

In terms of internal factors, it depends on the pattern of genetic inheritance of organisms (sexual reproduction and asexual reproduction); It depends on the adaptability of organisms to survive in the natural environment; It depends on the degree of learning and exercise acquired by each generation.

In terms of external factors: It is the change of the living environment, and the change that is adapted to the environment. It is the continuous use of survival function, which will make the continuous improvement of functional ability and the continuous growth of functional cell tissue.

It is the frequent use of the brain that will make the brain volume continue to increase. It is the competition between species for survival, which will lead to the phenomenon of multiplication and mutation of their survival function. Different regions, different foods and different amounts of food will cause different organisms to multiply and mutate and so on.

The above-mentioned internal and external factors of biological evolution will cause organisms to produce the phenomenon of proliferation and mutation, and the accumulation and transmission of this phenomenon of abnormality from generation to generation will make the accumulation and embodiment of functional multiplication and abnormality of biological species in the individual, and the accumulation of this functional multiplication and abnormality will make the biological individual continue to occur generation by generation and gradually become larger, which is essentially the specific manifestation of biological evolution. This is the main content of the latest explanation of biological evolution synthesis in modern science, and I would like to share it with the readers of the headlines.

What is the evolutionary process of living things.

The evolution of living things is a very complex process, all of which have gone through a long evolutionary process from simple to complex, from aquatic to terrestrial, from low to high. But this evolutionary process is not smooth sailing, straight up, but zigzag and spiraling, and each of its cycles is a leap forward in the history of biology.

Over the course of history, all animals have changed over time, and this change is a very slow and gradual process, which is called evolution in biology.

Nowadays, many animals no longer exist, because their offspring often mutate under the influence of natural conditions, animals that adapt to natural conditions can survive and develop, while animals that are not suitable for natural conditions are eliminated, this process of survival of the fittest is called natural selection. The remains of those eliminated animals are preserved in the form of stones under the action of the natural environment, and fossils are formed. Fossils are now the main basis for scientists to study paleontology.

Organisms evolve gradually, from low to high, from simple to complex, and from few to many species. There was no life on Earth, and about 3 billion years ago, primitive life began to form under certain conditions. Later, due to variation, heredity, and natural selection, organisms continued to evolve until today.

There are currently 2 million species in the world. Primitive life that appeared 3 billion years ago did not have a cellular structure, and some single-celled organisms gradually appeared later. This organism continued to diverge and develop, some of which evolved into plants, others into animals, and it was not until about 3 million years ago that humans appeared.

At present, about 2 million species have been discovered and recorded, including more than 1.5 million species of animals and more than 400,000 species of plants. However, there may be a big gap between the above figures and the actual number of species that exist. Biological evolution is manifested not only in the increase in species and numbers, but also in the continuous improvement of structures and adaptation to the environment.

The main direction of biological evolution is forward, upward, and perfect. In the process of evolution, the relationship between living things and their surroundings has become more and more harmonious. However, there are also types of degradation in the biological world, which is caused by some special environmental factors, such as the sensory degradation of some internal parasites, some birds inhabiting Australia have lost their ability to fly due to the threat of predators for a long time, and the vision of burrowing animals such as moles has also deteriorated due to the effect of the law of use and waste.

Scientists tell us that these dinosaurs lived about 100 million years ago, when the climate was generally warmer than it is now, with lush gymnosperm forests growing everywhere, and the average annual temperature was about 9 in the polar regions and about 28 near the equator.

How do scientists know all this? There are two secrets, one is that the paleontological fossils were excavated from the ground, and the other is the geological chronology that determines the age of these fossils.

Since the 19th century, scientists have gradually learned that the earth has undergone an extremely long evolutionary process since its birth by examining geological structures, the formation of minerals, the material composition of rocks, the layers of sedimentary rocks, and the paleontological fossils in strata. The underground rock formations have gradually accumulated from ancient times to the present day, like a thick history book, recording the evolution of the earth page by page. The "page number" that determines the order of the book is the fossil paleontology in the strata, because the evolution of organisms is an orderly process, from nothing, from simple to complex, from low to high, and multicellular complex organisms must have evolved from single-celled lower organisms.

Based on paleontological fossils, scientists divide stratigraphic units and time units representing different geological periods, and on this basis, establish geological chronology that can reflect the relative age order of the earth. The oldest age on Earth is called Archean, and the time is from the birth of the Earth to 2.4 billion years ago. At that time, primitive lithosphere, hydrosphere and atmosphere had formed on the surface of the earth, but the earth's crust was unstable, volcanic activity was frequent, and later a vast area of primitive oceans appeared, from which primitive life was born, mainly bacteria and cyanobacteria and other lowest-grade microorganisms.

The second is the Proterozoic Zoic, 2.4 billion to 100 million years ago, when most of the earth was still covered by oceans, and large areas of land appeared in the late period, and single-celled life began to appear in the oceans, and gradually evolved into invertebrates.

From 100 million to 100 million years ago, the Paleozoic Era, including the Cambrian, Ordovician, Silurian Period, Devonian, Carboniferous and Permian periods, was the era of great biological evolution. At this time, the earth underwent strong plate tectonic movements, and the land area expanded further and there was a violent orogeny. During this period, the climate is warmer, and the chemical composition of the sea changes.

Since the Cambrian period, the number of many marine invertebrates has increased explosively, and later fish and amphibians have appeared; One of these fish crawled onto land with fins and became the ancestor of terrestrial vertebrates. After the arrival of primitive algae, the previously bare land gradually turned green.

The Earth's environment in the Carboniferous period.