title: The  Earth's Biosphere: Evolution, Dynamics, and Change
author:  Vaclav Smil 
description: Smil, in a presentation marked by balance and clarity, synthesizes the field of science dealing with the biosphere. It is an interdisciplinary one, combining organic chemistry, geology, solar physics, microbiology, zoology, and more. Whatever characteristics the biosphere displays on a global scale depend on living matter's fundamental chemistry, so Smil diagrams the structural backbone of cells--molecules such as cellulose or DNA. Moving next through types of metabolism, such as the ATP cycle, Smil explains the resultant chemical products and how they become fixed or cycled through the ground, water, or atmosphere. Addressing concerns about human influences on the biosphere, Smil describes them, but he is a scientist to the core (at the University of Manitoba) and is hesitant to proclaim doom as the certain outcome. That scientific humility only enhances Smil's work. A superior, comprehensive survey. <i>Gilbert Taylor</i><br /><i>Copyright  American Library Association. All rights reserved</i>
zlib_text: Part I
  Problems of Biosphere Evolution
  and Origin of Life
  
  On Important Stages of Geosphere
  and Biosphere Evolution
  N. L. Dobretsov, N. A. Kolchanov, and V. V. Suslov
  Abstract The necessary conditions for the existence of protein–nucleic acid life
  are the presence of liquid water, some protection against high-amplitude tem-
  perature jumps and cosmic factors (these may be the atmosphere and or a thick
  layer of water or same rocks) and the accessibility of biogenes, which are
  macroelements and microelements. Two geosphere-related canalizing vectors
  of biosphere evolution can be discerned. One is associated with an irreversible
  cooling and oxygenation of the planet and the associated complex pattern of
  interplaying endogenous cycles, which affect climates as well as the amount and
  composition of the biogenes in the ‘‘liquid water zone.’’ Change of the convec-
  tion mode in the mantle between 3 and 2 Byr ago had the most important
  implications for the biosphere: the formation of plate tecto