Why are there creatures on Earth? How did life on Earth come about?

The conditions under which life arises:

1) There are necessary constituent substances that can synthesize organic matter such as carbon, hydrogen, oxygen, nitrogen and other elements.

2) life requires moderate light and heat, the temperature is too high, and the chemical bonds of carbon atoms are broken; If the temperature is too low, the biological process will come to a standstill.

3) There is liquid water, which is an absolutely indispensable component of living organisms.

4) There is an atmosphere, and the atmosphere has three functions, one is that the atmosphere synthesizes organic matter through ultraviolet irradiation and electric sparks; the second is to protect life safety from meteorites and cosmic rays; The third is to protect the heat of the earth's surface.

5) The above conditions can be maintained for a long time, so that life has a process of generation, development and evolution.

The above conditions are fully met only on Earth, and the hope that was pinned on Mars in the past is now almost disappointed. Some people think that life is possible in Titan, where there is a primitive atmosphere like the Earth, close to one atmosphere, but it has not been confirmed so far, and it seems that the possibility of finding life in the solar system is unlikely.

Liquid water, between 0 and 100 degrees, is necessary for the existence of all life.

The proper greenhouse effect is at least a necessary condition for the existence of higher life.

Air is a necessary condition for the existence of life.

The necessary conditions for the existence of life are external energy and the environment that guarantees the transformation of energy.

Life on Earth depends mainly on the sun and water, but there are also those that rely solely on geothermal heat and seawater to survive.

The means of delivery you are talking about to complete immigration are unlikely to be possible at the current level of technology.

But we can imagine that at some point in the future, the earth will be destroyed. Earthlings will launch delivery machines called "life eggs", which contain equipment and databases that can replicate life on Earth, and record all the scientific civilizations created by humans at that time. These "life eggs" have been in the universe for tens of thousands or hundreds of thousands of years, and as soon as they find a planet suitable for life on Earth, they will land and begin to hatch life on Earth, and replicate the ancestors of humans on that planet.

The origin of all things is water, and where there is water, there may be living things. Under the current technology, people can detect the existence of extraterrestrial creatures, which is also based on water.

Because there is an environment suitable for living organisms.

Did life on Earth originate from land or ocean, or was it carried by asteroids from some distant part of the universe? To this day, the question of the origin of life on Earth remains a mystery for scientists. They often have different opinions.

The planet we live on was formed about 4.6 billion years ago, and in some ways something must have happened at an uncertain time, as this lifeless celestial body began to accept something very different from rock and water. Nitrogen and carbon molecules evolved into DNA, a microorganism that travels between the stars of the universe ......It is an indisputable fact that millions of years after the appearance of this tiny molecule, primitive single-celled bodies were born, and then more and more complex aquatic organisms slowly appeared, and they eventually landed on land, and since then various organisms have multiplied and spread on a large scale on the earth.

Today, there are about 2 million different species of organisms on Earth. But all kinds of organisms originate from the same substance—a substance that, to some extent, initiates the course of life. What kind of substance is it?

This article will elaborate on the latest theories and research results on life on Earth.

The fragments of some celestial bodies cruising in space are like a gang of "robbers" in the universe, and sooner or later they will collide with a certain celestial body. But some of the comets and asteroids that collided with the Earth may thus become the creators of life on Earth. It is very likely that a comet (a celestial body made of rock and ice) brought a large amount of water to Earth, and without it, the Earth would have been a dry planet forever.

"Comets and asteroids certainly played a crucial role in the birth and evolution of life," said Cristiano Kosmovic, coordinator of 27 Italian research groups engaged in outer space biology. Organic molecules, the molecules that make up living things, have recently been discovered in asteroids.

These recent discoveries have led to a reconsideration of the embryo hypothesis proposed by Achenis in 1907, which holds that it is objects such as comets and asteroids that sow the seeds of life on Earth, and that these celestial bodies are a bit like buses, transporting organic and sometimes complex matter from one planet in the solar system to another, and some believe that they also bring bacteria. ”

However, the space biologist added that the gigantic meteorite also caused a real natural catastrophe, and it was really a disaster from the sky. "On the one hand, these phenomena led to the extinction of many biological species, such as the dinosaurs, but they also contributed to the development of life forms, such as the extinction of the dinosaurs, which led to the faster reproduction of mammals, and then the flourishing of humans. ”

About 3 billion years ago, after the heavy rains stopped, the Earth entered another stage of development. The earth's primitive atmosphere contains ammonia, methane, hydrogen cyanide, hydrogen sulfide, carbon dioxide, hydrogen, water and other components, but there is no free oxygen, some gases in the atmosphere and some soluble substances on the surface of the earth's crust are dissolved in water, and a series of small molecule organic compounds, such as amino acids, nucleotides, monosaccharides, fatty acids, etc., are naturally synthesized under the action of cosmic rays, solar ultraviolet rays, lightning, high temperatures, etc., which are gathered in the primordial ocean to form the so-called "primordial soup" of Haldane. Thus preparing the necessary conditions for the birth of life.

When small organic molecules such as amino acids, nucleotides, monosaccharides, and fatty acids are formed, they can further form complex organic substances under the right conditions. For example, proteins, nucleic acids, polysaccharides, lipids and other macromolecular substances. Among them, the formation of proteins and nucleic acids plays a very important role in life phenomena, and there are two main views on their formation.

1) Terrestrial origin: They believe that the polymerization reaction occurs in the local area of the volcano, and the organisms generated by the aggregation are collected into the ocean by the erosion of rainwater, and continue to develop into complex organic matter under certain conditions.

2) Marine origin: It is believed that small organic substances such as amino acids and nucleotides in the primitive ocean can be adsorbed on the active surface of substances such as clay, and polymerization reactions can occur in the presence of appropriate condensation agents.

Biological macromolecules cannot independently express the phenomenon of life, and can only express the germination of life when a numerous, or even million, protein, and nucleic acid-based multimolecular system is formed.

Biological macromolecules aggregate in large quantities in solution, thus forming various independent multimolecular systems, and agglomerates or microspheres appear. Because the multimolecular system can play a catalytic role on the organic surface, and in turn act with the polymerization of various monomers, promote the production of higher proteins and nucleic acids, and then through the long-term process of gradually improving the order, its structure and function will become more complex and perfect, thus giving rise to primitive life.

Let me introduce you to the following view of the origin of life that most people now agree on:

As early as the period when the earth was not formed, the earth's gravitational pull was enough to trap the gas and form the initial atmosphere, but this atmosphere was dominated by carbon dioxide and some toxic gases, and it was impossible to provide the conditions for the survival of organisms. However, with the atmosphere comes the possibility, and the friction between the atmospheres and a series of natural conditions have formed a common natural phenomenon, which is lightning. Officially, due to the continuous occurrence of lightning, the atmosphere in the air is constantly undergoing chemical reactions under the action of ionization, and trace amounts of oxygen, ozone, water and other inorganic substances are formed.

After years of change, the earth has gradually formed oceans, and there are also small amounts of oxygen, nitrogen, etc. However, inorganic substances such as carbon dioxide still account for the vast majority. I don't know how many years have passed, nature is still changing, due to the action of lightning, a small amount of organic matter is produced in the atmosphere and oceans, and gradually formed the most basic organic matter - amino acids, which are the basic units of protein, and the formation of life is inseparable from protein.

With the conditions for the formation of living organisms, life forms gradually formed in the ocean, and these living organisms are said to be the most primitive algae, mainly consuming carbon dioxide to produce oxygen. Later, there was more oxygen in the atmosphere and less carbon dioxide. Later, according to Darwin's theory of evolution, life gradually evolved from those primitive sea creatures

It's all handwritten, I hope it can help you!

It is possible that an asteroid with a life star hit the Earth, and then evolved over hundreds of millions of years to become what it is today.

Life on Earth is constantly evolving!

It has undergone an evolutionary process from "aquatic to terrestrial", "low to high", and "simple to complex"!

The most primitive life originated from the ocean, because there was no ozone layer in the ancient atmosphere, which did not block the ultraviolet rays in the sun, so organisms can only live in the ocean to be protected by the seawater to survive!

In ancient times, there was a large amount of water on the earth, and the atmospheric content was mainly methane, ammonia, hydrogen, and water vapor, and these gases produced chemical reactions when they encountered lightning, producing the most basic substances of life--- amino acids, and life was born, and later due to evolution, from aquatic to terrestrial, from low to high, until today.

Take the example of the evolution of life on Earth:

1. There is a belief that after an alien object hits the Earth, the organic molecules on the object are born to the Earth. The process of organic matter production on this celestial body is roughly the same as the following two mechanisms.

2. Oxygen, nitrogen, hydrogen, carbon and other elements on the earth form proteins under the action of the sun's ultraviolet rays and thunderstorms; It is also a coincidence that the earth is at the right distance from the sun, so there is life. Life then evolves further due to the constraints of the environment.

Then after n billion years of evolution, humans were born.

Three: Billions of years ago, Earth's weather contained much less oxygen than it does now, and the mushrooms produced during volcanic eruptions were about 200 degrees Celsius warmer than they are today. This condition is very conducive to the synthesis of organic polymers and amino acids from a variety of substances in the mushroom cloud.

These substances fall to the ground, and after years of interaction, they can synthesize RNA molecules that have the ability to replicate themselves, making the emergence of primitive cells possible.

Hundreds of millions of years ago, due to the increase in temperature, the increase in oxygen content, and volcanic activity increased the nutrients in the ocean, and many strange creatures in the ancient ocean suddenly emerged, which is what is called the "Cambrian explosion of life" in geology. All kinds of life suddenly exploded, and the earth soon became lively.

The explosion of life lasted between 10 million and 20 million years and contained more than 200 species, the vast majority of which were invertebrates. One of the most representative creatures is the trilobite, a group of strange insects armed with sturdy thorns, similar in shape to three longitudinal leaves, it has "eyes" similar to crabs, bees and dragonflies, trilobites rely on the hard shell of the body to defend against foreign enemies, for a time all over the world. Since the most populous animals in the ocean at that time were trilobites, the Cambrian period is also known as the "age of trilobites".

The Cambrian period is the beginning of modern life, the beginning of the emergence and development of modern life on the earth, marking a new chapter in the history of the evolution of life on the earth.

This is the result of the landalization of the natural performance hall. The earth has a stable cosmic environment suitable for the existence of life, water, atmosphere, and evolution, and in the process of evolutionary collapse, proteins are formed first, and then simple life-like organisms with cellless structures are formed, and then single-celled organisms are formed. The constant evolution is that the earth is now rich in life forms, and it will continue to develop.

However, many of the current human activities seriously threaten biodiversity.

I thought that countless particles of matter interact with each other, and there are various modes of interaction. (Lao Tzu said that one life is two, two is three, and three is everything.) )

And among them, there must be a pattern, the orderly movement of material particles, and this mode of motion can appear in cycles! (This is the most essential nature of the bridge we call "life.") Because this pattern of material movement can be spontaneously reproduced, it can be developed, complicated, and even developed in different directions on this basis.

So it evolved to the present, and a rich and colorful biological world has been formed.

PS: It's not uncommon for loops of movement patterns to appear, and there are similar situations in various fields. )

But why are only living creatures? That's because the mode of action of other particles of matter cannot reproduce their own motion, so although it happens countless times in nature, it is not accumulated at all, and it will always remain in its original state.

In fact, the movement mode of matter particles that developed into living beings was not much different from other material particle motion modes in the beginning. It's just that it has the characteristics of retaining itself and improving itself, so that its movement mode can continue to be complex and enriched, and after an extremely long time, it finally shows a different state from the middle of the shed.

In this sense, life is about inheritance and development. Broadly speaking, everything that can be inherited and developed is life. And life on our planet is only the only type of manifestation we see.

In the vast universe, there may be many life forms that are fundamentally different from ours based on chemistry.

As for many of the current conclusions, they are hindsight, just stating some facts, and the explanation of the matter itself has no meaning.