The question of Life's origin is an old and complex one, which has plagued mankind for his whole existence. Numerous creation myths have sprung up throughout the ages in many different societies. Even today's scientific models are extensions on these themes. However it is the rivalry and complex interconnection between science and religion in this field that has fuelled many discoveries. Ultimately, these questions and their answers, regardless of form, have been pursued due to the need to understand and the inquisitive nature of our species.
Scientific theories on the origins of life have ranged from spontaneous generation, aliens, soap bubbles (lipids) from meteorites and dirty ice from comets, to the classic primordial soup being struck by lightning and bombarded by ultra voliot radiation from sunshine. In recent years the chemical environments found deep underground and those in mid-ocean ridges have been brought into play.
However, simply looking for the origin of life would lead round in circles. For a start, what is meant when we say that something is alive? The meanings and definitions in this scientific field have been shifting and changing for at least the last three centuries, and it therefore seems logical to instead start by looking at the STUFF of life - i.e. the molecules and elements which build up the highly organised assemblages we call organisms.
This brings us into the realm of chemistry as well as biology, ranging from organic/biogenic chemistry to universal elemental abundance with a large helping of cosmochemistry. Questions that arise include:
Other important questions include:
The debate over life's origin has raged for centuries but life's chemistry presents a slightly different problem. For a long time, most complex hydrocarbons were thought to be only capable of being syntheisised by organisms such as proteins and DNA. Indeed, for a long time even the constituent amino acids where thought to be biogenically produced. However, over the last 100 years or so, this no longer appears to be true thanks to the abiogenic syntheses of many of the more complex sugars and even the discovery of methane and amino acids inside meteorites. These discoveries have shifted the scientific community's perception slightly to a position of the preverbial chicken and egg scenario. Did life arise divising the synthesis of complex hydrocarbons through their self replicating techniques which may or may not themselves predate the life, or did the complex hydrocarbons discover self replication and then proceed to organise themselves into steadily more and more complex structures until life as we know it arose?
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