\section{Amino-Acid Soup to ``It's Alive!''}

\lettrine[lraise=0.1]{B}{ut} there are other striking examples of order emerging out of chaos. Consider perhaps the most momentous event in the evolution of Life on Earth --- the emergence of Life from Non-Life.

Roughly four billion years ago, Earth had no free oxygen, no ozone layer. Conditions were lethal to life as we know it.

Instead, there was an unstable soup of amino acids and simple organic molecules, made restless by hydrothermal vents, lightning, and ultraviolet radiation.

Then, after about 300 million years of simmering, a self-replicating molecule became enclosed in a lipid membrane. The inside\slash outside distinction was born. Something now had a stake in continuing. Chemistry crossed a threshold into biology.

The new order of complexity was LUCA --- Last Universal Common Ancestor. It possessed DNA, RNA, a genetic code, and much more. Not fumbling toward complexity but already sophisticated. Not a primitive proto-cell but already a remarkably complex organism.

No other chemical lineage survived. Hundreds of millions of years of chemical experimentation, and only one survivor --- the family of living organisms we know today, all descended from LUCA.

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Including us.