Life from the Ancient Soup: The Miller and Urey Experiment
Alright, so we know how eukaryotes came to be, but how did life arise in the first place? In the early 1950s, an experiment performed by a couple of guys at the University of Chicago gave us a pretty good idea.
Early in Earth’s history, the conditions of the planet were relatively hostile. Temperatures were high, lots of energy was running riot (such as lightning, volcanoes, and UV radiation), and the atmosphere was reducing rather than oxidising, meaning that it was devoid of gaseous oxygen, but had plenty of methane, hydrogen, carbon dioxide, water vapour and nitrogen.
Miller and Urey decided to simulate these early Earth conditions in the lab to see if they could produce some form of life. Basically, their aim was to find out whether these abiotic (lifeless) conditions were conducive to the rise of living organisms.
To do this, they sealed ammonia, methane, hydrogen and water into a closed, sterile system. Then they heated it to form water vapour, and passed electrical sparks through it to simulate lightning.
After a week or two of brewing time, they analysed their mixture and found that up to 15% of the carbon in their system had formed into organic molecules—most noticeably, amino acids. Amino acids are the building blocks of proteins, which are one of the three most important macromolecules of life.
By themselves, amino acids are relatively small and simple, but together they join to build structures far bigger and grander than individual molecules: life.
So, Miller and Urey found that it’s a cinch to synthesise at least the building blocks of life out of some messy soup.
Further resources: Animation
Hello darkness my old friend…