How did life originate?

Answer 1

The study of the origin of life from non-life through natural means is called abiogenesis. Many people reject a natural origin of life due to religious beliefs.

In general, abiogenesis says that, once conditions on Earth were just right, the building blocks of life were able to form. Energy from different sources catalyzed the synthesis of organic molecules from inorganic molecules. Over billions of years, organic molecules such as amino acids, lipids, and nucleic acids formed, creating an organic "soup" in the oceans. These began to assemble to create primitive biological systems. They were the predecessors of cells and could form some simple life functions.

Eventually self-replicating molecules such as RNA and DNA originated, although the details of this process are currently unknown. The earliest life forms were single prokaryotic cells that were able to replicate themselves and pass on their genetic information. Eventually, eukaryotic cells arose. They probably evolved from the mutual relationships between prokaryotic cells (look up the endosymbiotic theory). This would explain why eukaryotic organelles such as mitochondria and chloroplasts have their own DNA.

Once the first true life forms arose, they were able to diversify relatively quickly into a variety of multicellular organisms (compared to the billions of years it took to assemble a simple living cell).

The basic ideas about the origin of life have been established, but most of the details currently remain unknown and are subject to speculation, considering life originated billions of years ago and almost no fossil evidence remains from that time. It has been proven through laboratory experiments (Such as the Miller-Urey experiment) that the building blocks of life can arise naturally. While we are very far from producing true life from scratch, scientists are working hard trying to replicate what could have been the process that occurred over 3 billion years ago in the Earth's oceans.