The Nature of Consciousness

Piero Scaruffi

(Copyright © 2013 Piero Scaruffi | Legal restrictions )
Inquire about purchasing the book | Table of Contents | Annotated Bibliography | Class on Nature of Mind

These are excerpts and elaborations from my book "The Nature of Consciousness"

Life And Heat

Whatever the mechanism that created it, the progenitor of all terrestrial life, four billion yeas ago, was able to tolerate the extreme heat conditions of the time (a few hundred degrees or even a thousand).  As a matter of fact, if we walk backwards up the phylogenetic tree (the tree of species), we find that genetically older organisms can survive at higher and higher temperatures.  Thermophiles (the microbes that live at temperatures of 70-80 degrees) are living relics of the beginnings of life on Earth.

Based on such a phylogenetic tree, the US biologist Carl Woese proposed a classification of living creatures in which thermophiles (or "archaea", first discovered in 1964 by the US biologist Thomas Brock) are different both from eukaryotes (in which DNA is held by a nucleus) and prokaryotes (in which DNA floats free in the cells of bacteria): in thermophiles, DNA floats free (like in prokaryotes) but resembles the DNA of eukaryotes.  Thermophiles can be found underground: some have been retrieved from 3 km beneath earth.  An archaea has about two million base pairs of DNA (a human cell has about three billion).

The Australian physicist Paul Davies retraced the history of life on Earth and concluded that it began inside the Earth, with microbes that lived several kilometers under the crust of the Earth. His reasoning was that the surface of the Earth and the oceans were just too unstable and dangerous for life to appear and survive. Furthermore, the record of genes seems to prove that the ancestor of all life forms lived underneath the Earth’s surface at very high temperatures.

Surprisingly, very little has been made so far of a discovery due to the French chemist Louis Pasteur in the 19th century: that living systems prefer molecules with a certain handedness (all proteins are made of L-aminoacids and genetic material is made of D-sugars). This molecular asymmetry is, actually, the only difference between the chemistry of living and of inanimate matter.

 


Back to the beginning of the chapter "The Evolution of Life: Of Designers and Design" | Back to the index of all chapters