Alex McColgan

How on Earth could life emerge?

Well, there is little consensus on the precise way that life actually emerged on Earth, but let's explore the molecules that, without exception, build every single life form on Earth.

Perhaps life offers clues to its own origin.

The key basic building blocks life uses today in no particular order are fatty acids, amino acids, and nucleotides, and all three are believed to have been present on the early Earth, and have even been found on asteroids in our solar system.

The first are fatty acids, and despite having little chemical functionality, they create structure and have an extraordinary function built in.

These long chain molecules make up cell walls of all life on Earth and are believed to have made the first membranes of protocells.

Membranes are barriers and fundamental to create an individual unit.

After all, you can't have a house without walls or a country without borders.

That's not a political statement.

Remarkably, cell-like structures made from fatty acids form spontaneously in water.

As anyone who's failed to make simple mayonnaise will know all too well, oil and water don't like to mix.

These fatty acids, with a water-loving head and a water-hating tail,

will spontaneously arrange to minimize water's contact with the tail and maximize it with the head.

These simple pressures can create a bilayer membrane with a cavity for an early cell to call home.

This is called a liposome.

Unbelievably, these liposomes can also spontaneously divide and speed up chemical reactions by encapsulating and concentrating the molecules in a smaller space.

This is a perfect example of how unexpected life-like behaviours can emerge out of the laws of quantum mechanics.

But won't these crude divisions just go wrong and kill the cell more often than not in hot, salty water?

Well, yes, there's a good chance.

However, the environment isn't a simple system.