Since the first production of tools at the beginning of human presence on Earth, human evolution is
linked to the invention of new tools, usually combined with new environmental adaptations.
The symbiosis of man with tools and environments represents one of the main factors in human
evolutionary processes. It is evident how this coupling is based on the biophysics of our bodies and the
development of the social memory system called culture.
Chemical reactions (abiotic reactions) are “classical” chemical reactions that
are not mediated by bacteria. They may include reaction processes such as
precipitation, hydrolysis, complexation, elimination, substitution etc. that
transform chemicals to other chemicals and potentially alter their phase/state
(solid, liquid, gas, dissolved).
Precipitation is the removal of ions from solution by the formation of insoluble
compounds, i.e. a solid-phase precipitate.
Hydrolysis is a process of chemical reaction by the addition of water.
Chemical precipitation and complexation are primarily important for the inorganic species.
The formation of coordination complexes is typical behaviour of transition metals, which
provide the cation or central atom. Ligands include common inorganic anions such as Cl
as well as organic molecules such as amino acids. Such
complexation may facilitate the transport of metals.
Biodegradation is a reaction process mediated by microbial activity (a biotic reaction).
The biotic world is doubtlessly the best known example
of what Nobelist Murray Gell-Mann has termed
‘‘complex adaptive systems’’—a name given to those
systems possessing the innate capacity to learn and
evolve by utilizing acquired information. Those familiar
with living systems cannot but marvel at each cell’s ability
to grow, to sense, to communicate, to cooperate, to move,
to proliferate, to die and, even then, to yield opportunity
to succeeding cells.
This book is for anyone interested in the consequences of disturbance.
What happens after the lava cools, or when the muddy floodwaters recede
or an old road is abandoned? Primary succession is the process
of ecosystem development on barren surfaces where severe disturbances
have removed most vestiges of biological activity. It includes the development
of complex systems from simple biotic and abiotic (non-biological)
components. Primary succession starts when plants, animals and microbes
colonize new surfaces. The process is influenced by local conditions, context
and site history.
Reactions and transformations of chemicals. Many chemicals undergo reaction or
transformation in the subsurface environment. In contrast to retardation contaminants may be
removed, rather than simply slowed down. Reactions of harmful chemicals to yield benign
products prior to arrival at a receptor are the ideal, e.g. many toxic hydrocarbons have
potential to biodegrade to simple organic acids (of low health concern and themselves
potentially degradable), carbon dioxide (bicarbonate) and water. Transformation often causes
a deactivation (lowering) of toxicity.