A key component of any comprehensive theory of evolutionary history is the explanation of the origin of life.
The question of how life originated has been the central topic in modern biology.
As the theory of evolution explains, the chemical mechanisms by which a vast variety of complex molecules arose from simpler ones was a process involving a great number of interacting molecules and their interactions with each other, among other things.
How did life begin? The theory of evolution states that life came from simple, ancestral molecules called ‘prebiotic’ molecules. These precursors of more complex, living substances were able to take on the characteristics of living forms. This is important because if these precursors of life were of the right kind, such as organic molecules, they should contain the same kinds of chemistry and have the right characteristics for being the building blocks for life as they are today. But life’s origin was a bit different than this because prebiotic molecules can vary widely in many different ways. For instance, one kind of prebiotic molecule might not be able to combine with another kind of prebiotic molecule very well, which means that prebiotic molecules that came into contact with each other would have different properties. Such ‘arbitrary’ differences in the chemical structure of prebiotic molecules would not create life’s building blocks, however.
To explain the origin of life, we must come up with a theory that accounts for this different quality of prebiotic molecules
(some are better than others for being able to combine), as well as the differences in some prebiotic molecules (such as their electrical charge)
that would lead to the production of life, and the differences between prebiotic molecules from the same kind of prebiotic molecule.
This process of chemical evolution is called natural selection.
This is the subject of modern molecular evolution science.
Modern scientists study prebiotic molecules based on different types of chemical analysis,
such as chemical reactivity and particle size analysis and analysis of the chemical structure.
They also use computational methods to explain how these particles changed and eventually, how new properties of the prebiotic molecules led to life.
Modern life (or “life”) consists of very simple cells. If all the molecules that compose life were identical, such as simple sugars, then life’s origin would be easy. The basic components of life — amino acids, carbon-based sugars, and so on — would have existed since the Big Bang. A single gene, and so forth, could be duplicated and mutated, producing many different living species — including us.
That’s because molecules (and life) are composed of atoms and subatomic particles.
This is why you cannot have a life without the right atoms and their subatomic particles.