I think a lot of people learn about evolution and only have general knowledge about how it happens on the micro scale. People know that evolution is the gradual change of an organism as they respond to their ever changing environments. When learning about Darwin’s finches we are told that the birds “needed” to change their beak shape to adapt the the type of food available on each island. Although this is true, I don’t believe it adequately communicates what actually goes on within the species’ gene pool. I think to understand this theory, you must need to go back to the beginning about the origin of life.
This experiment, the Stanley Miller experiment, demonstrates of complex molecules could have been formed in the harsh early environment of earth 3.8 billion years ago. The apparatus used is meant to simulate the same environment of earth back then. The air in the set up is methane, ammonium, and hydrogen gas which is primarily what the atmosphere back then was composed of. The Earth was still very hot then, so the water is heated to a boil. Not only was it very hot then, it was also covered in constant lightening storms which is simulated by the electrode sparks.Now with the weather, temperature, and atmospheric contents all replicated in this system, we can see how these molecules might have behaved in that environment. Water is evaporated and mixes with the methane, ammonium, and hydrogen gas. In the next flask, an electric current is sent through the contents and this causes chemical bonds to break and reform. The reformed contents are collected and identified. Several organic compounds we see in our own bodies were detected such as amino acids. Amino acids are the building blocks of our DNA. This proves that the formation of organic molecules was possible during this time. But how does one amino acid forming out of nowhere lead to DNA and cells and life? There’s a huge gap in time most text books don’t explicitly mention. This was in no means a fast process. The world then was a very random and chaotic place. The likely hood of this amino acid forming out of a lightning strike and a few odd molecules is very VERY unlikely. Let me reiterate. These atoms and small molecules have no idea who they are going to bump into next. If an oxygen molecule happens to be next to a hydrogen molecule, a collision might form water or it might not. Again, I will use the word random to explain how these things happened. As much as we’d like to credit the beginning of life on Earth to aliens, that’s just no how it went down. So you have an earth sized pot of boiling water seasoned with atoms from the whole periodic table. And molecules are randomly and spontaneously forming and breaking bonds. If you were to put the likelihood of an amino acid forming in this pot you might get some crazy huge number of like 1/36×10^600 or some huge number. But remember, Rome wasn’t built in a day. It took 3.8 billion years to form the first primitive cell so when you literally have all the time in the world you can make these odds work in your favor.
The origin of life is defined as the moment when a simple single strand of amino acids, RNA, met with this bubble made out of these balloon looking molecules that act as a barrier. If this meeting didn’t happen there may not have been life on Earth. This was the formation of the first protocell, a strand of RNA enclosed in a sphere of fatty acids. This may not seem to exciting but the strand of RNA being protected from the chaotic world outside that membrane is what allowed evolution to occur. Ill finally explain how evolution works next.