16 lines
1.2 KiB
TeX
16 lines
1.2 KiB
TeX
\section{Amino-Acid Soup to ``It's Alive!''}
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\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.
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Roughly four billion years ago, Earth had no free oxygen, no ozone layer. Conditions were lethal to life as we know it.
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Instead, there was an unstable soup of amino acids and simple organic molecules, made restless by hydrothermal vents, lightning, and ultraviolet radiation.
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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.
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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.
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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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\nopagebreak
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Including us. |