How did lifeless chemistry begin to edge toward biology? This episode starts with Stanley Miller’s famous attempt to recreate the chemistry of the early Earth, showing that simple gases, water and energy could generate some of life’s basic organic building blocks. But making molecules is not the same as making life. The deeper problem is how random chemistry could become organized without requiring one fantastically improbable stroke of luck. The answer may have been a long sequence of small chemical successes, each preserved and built upon rather than everything appearing at once.

We then follow a possible route: self-sustaining cycles of reactions driven by continual energy, sped up by catalysts, and eventually able to make more of their own components. Once slightly different versions of these chemical networks could arise and some worked better than others, something resembling evolution could begin - even before genes and cells existed. Autocatalysis, in which parts of a chemical network help make more of that same network, provides a tantalizing bridge between ordinary chemistry and the first primitive systems capable of reproducing and evolving.

Molecules Made Me Do It is written and presented by Jeremy Smith.

A popular-science podcast about the beautiful and devious molecules behind life, the mind, sex and the cures of the future. No scientific background required.

Music written and performed by Jeremy Smith.

Follow or subscribe to Molecules Made Me Do It wherever you get your podcasts.

The first episode of Molecules Made Me Do It begins, naturally enough, with sex — or more precisely, “aquasex.” An ancient Mesopotamian creation story imagined life beginning with the fertile mingling of fresh and salt waters, personified by the gods Apsu and Tiamat. Surprisingly, this provides a useful jumping-off point for asking what modern science thinks life actually is. We explore definitions from Jacques Monod and NASA, meet Darwinian evolution, and ask what distinguishes a living chemical system from things such as flames and crystals that display some lifelike properties. PODCAST 1 PODCAST 1

We then travel back to the violent young Earth and its hypothetical primordial soup. Why wouldn't a mixture of the right chemicals simply turn into life if we waited long enough? The answer leads us into thermodynamics, entropy and the Second Law — and the loophole that allows life to create local order without breaking any laws of physics. The missing ingredient is a sustained supply of usable energy, perhaps from sunlight, electrical discharges or hydrothermal vents. Finally we return to Apsu and Tiamat and discover an amusing parallel: mixture plus generative energy producing something entirely new — what modern science would call an emergent phenomenon. PODCAST 1 PODCAST 1PODCAST 1

Molecules Made Me Do It is written and presented by Jeremy Smith.

A popular-science podcast about the beautiful and devious molecules behind life, the mind, sex and the cures of the future. No scientific background required.

Music written and performed by Jeremy Smith.

Follow or subscribe to Molecules Made Me Do It wherever you get your podcasts.