5 famous theories about how life evolved on earth

How life on earth evolves has always been a hot topic. Scientists have different views on evolution, and there is currently no consensus on this issue. Five famous theories about the origin of life on Earth are listed here:

1. Pan-speech theory

Perhaps life on Earth did not fully evolve, but was brought here from space. This theory is called panspermia. For example, rocks from Mars are often destroyed by cosmic effects, and many Martian meteorites appear on the earth, which controversially indicates that microorganisms have been brought here. Therefore, it can be said that we were originally Martians. Other scientists believe that life on comets may come from other star systems. However, even if this hypothesis is true, the question: how life started on earth will only transfer to how life started in space or elsewhere.

2. Special creation theory

The special creation theory states that a certain supernatural force called the Creator or God creates living things on our plants, so it is based on the divine creation of life. This theory claims that all living things on our plants are formed suddenly, and they have no evolutionary history. God created all living things in their present form, and there is no relationship between them. In addition, life is immutable, so these creatures have not undergone any evolutionary process since they were formed.

3. Biogenesis theory

The spontaneous generation theory asserts that life on earth spontaneously originated from decaying or inanimate matter about 3.5 billion years ago. The theory is that butterflies are produced from cheese, maggots are produced from rotten meat, frogs are produced from mud in ponds, and insects are produced spontaneously from dewdrops. But this theory was experimentally rejected by scientist Francisco Redi in 1668.

4. Biogenesis theory

The theory of biological origin states that living organisms can only be produced by pre-existing life. In 1668, Francisco Redi's experiments established the idea of biogenesis or non-spontaneous generation. Later, many other famous scientists, such as L. Spallanzani and Louis Pasture, provided supporting experiments to prove the theory of biogenesis. But this theory has a limitation. It cannot answer the origin of life on Earth.

5. Biochemical evolution theory:

According to the theory of biochemical evolution, life may be started by a series of simple chemical reactions that lead to the formation of complex biochemical structures or biomolecules. This theory was supported by A.I. Oparin and J.B.S. Haldane in 1923 and 1928, respectively. They believe that the gases in the primitive atmosphere have undergone simple chemical reactions to produce simple organic chemicals, which combine to form complex molecules. Afterwards, these complex molecules were separated from the surrounding environment, and some important characteristics of the organism were obtained. They begin to absorb nutrients, reproduce, grow, and so on.

All these theories are related to evolution, but none of them can explain the complete phenomenon.