the emergence of life - on a short list of the biggest unknowns in science

"Did life begin in small, warm pond at the edge of a primordial sea (Charles Darwin's speculation) or deep beneath that sea, around one of the burbling hydrothermal vents first seen in the 1970s?" (National Geographic, March 2006)

Biologist Harold Morowitz (George Mason University) and Eric Smith (Santa Fe Institute): "a central set of chemical reactions has been place since life's earliest moments about four billion years ago. these reactions involve just 11 small carbon molecules, such as citric and acetic acids, very ordinary stuff that would have been abundant on the young Earth... Those 11 molecules could have played a role in other chemical reactions that led to the development of such biomolecules as amino acids, lipids, sugars, and eventually some kind of genetic molecule such as RNA. In other words, metabolism came first - before cells, before replication, before life as we commonly think of it." (National Geographic, March 2006)

Kennzeichen des Lebens

Makromoleküle --> Ordnung (= Information) --> auslesbar, replizierbar, speicherbar, übersetzbar

nur wässrige Phase --> polare Grenze

Wasser, theoretisch NH3 auch möglich, aber nur unter 0°C --> extrem langsame Reaktionen

Kohlenstoff

andere Elemente (z.B. Silizium --> ebenfalls nur bei sehr geringen Temperaturen) können auch Makromoleküle bilden, sind aber um Potenzen unwahrscheinlicher, wegen den möglichen funktionellen Gruppen und den Polymerisationsbedingungen.