If I’m not mistaken, prokaryotes were the earliest life forms, but what factors played into effect of making them? Did a specific chemical reaction change inorganic matter to life or was it brought to Earth from extra terrestrial objects?
In: Biology
Organic matter just means that the matter is carbon based and such matter has always been present on earth. The real mysterious element of life on earth is about its amino acids. Amino acids can also form spontaneously through known reactions but the naturally occurring amino acids on Earth are what’s known as “D-Amino Acids” but all life on earth is based on “L-Amino Acids”. Because of this there is ever increasing support for the theory that life on earth arose thanks to impact from comets and asteroids containing those types of amino acids. A specific meteor that struck Earth on September 28, 1969, over Murchison, Victoria, Australia contained tons of L-Amino Acids and water as well, creating a big push for the acceptance of this theory.
There are a lot of different theories about how life first developed. Prokaryotes, though, are latecomers, compared to the strange things that scientists have dreamt up to explain how we began billions of years ago. There’s the RNA World Hypothesis, the Clay Hypothesis, and others. What all of these theories try to explain is how the chemicals necessary for life as we know it could become sufficiently concentrated that they could do life-y things without the need for extraneous additions like proteins and cell membranes. Once life is able to get a toehold, it can start augmenting itself through the process of evolution which eventually produces the prokaryotes and their descendants.
A lot of people, me included, don’t really like the Panspermia Hypothesis, that life came from somewhere else in space, because it doesn’t really explain how it came to be. It just adds an extra unnecessary step to the sequence. We still have to figure out, in that case, how life arose in that other part of space.
Life likly originate from alrealy exising organic matter and inorganim matter just like out composition today.
Organic just mean containing carbon in carbon-hydrogen or carbon-carbon bound. It can be create in non biological processes. Saturns moon Titan have lakes of organic compound, metand and ethane to be exact.
Complex organic compounds like the amioacid our DNA is made of have bee found in molecular clouds. It is from molecular clouds that stars and planes system are formed. So organic matter have existed in our solar system before planets was formed and on earth before life emerged.
The idea that life was brought to earth is not a satisfying solution. It just kicks the bucket down to asking where that life came from.
If I knew the answer to your question, I would be quite famous, it is one of a few really difficult problems in science. The first life just has to be an accurately self replicating molecule, such as RNA. It more than likely happened in the bottom of the sea by volcanic areas, allowing high temperature and lots of elements to gather.
This is called [Abiogenesis](https://en.m.wikipedia.org/wiki/Abiogenesis) and there is not an exact answer. The idea that life came from extraterrestrial origins is called [Panspermia](https://en.m.wikipedia.org/wiki/Panspermia) but it is not a substitute for abiogenesis as that still had to happen at some point.
The general process likely involved the formation by chance of simple self replicating molecules. As long as there was some error/variation in their replication then natural selection could act on them and lead slowly to the life we see today.
The most popular hypothesis for this is called [RNA world](https://en.m.wikipedia.org/wiki/RNA_world). RNA molecules can form spontaneously, we have detected RNA on asteroids which did not come from life, it was formed chemically by chance (we know this because it is [racemic](https://en.m.wikipedia.org/wiki/Racemic_mixture), or relatively racemic while life is entirely enantiospecific – i.e. we know its from chemical reactions not from aliens or contamination on earth). So we know RNA can form without life, we also know it can both store information (like DNA) and catalyze chemical reactions for self replication (like proteins). From there DNA eventually replaced RNA for information storage as it is more stable and protein replaced RNA for catalyzing reactions because it is more effective. However, RNA based enzymes are used by all life to make protein in the first place (ribosomes) and RNA is still the code directly read for cell functions, not DNA, which is strong evidence that life passed through an RNA world at some point.
The challenge is all direct evidence of early life on earth was destroyed by later life. So we have no way to confirm how abiogenesis occurred.
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