Section 1:  The biosphere or volume in which organism actually live （生物圈：生命真实栖居之所）

The part of the planet in which organisms live is usually called the biosphere. Regarded from a cosmic point of view it is a rather peculiar region, though we may suspect that a very large class of biosphere exists on other planets throughout our galaxy and beyond. 

地球上栖居生命体的区域，名为生物圈。宇宙视角看，这片区域确实殊常，毕竟银河系及其他星系存在生命空间的想法，尚未实证。

The biosphere, its nature and structure 

The emperical extent of the biosphere as a natural region, that is to say as unextended by advanced human technology, reaches from very high on the highest mountains to the greatest depths of the ocean of probably more correctly a little way into the deepest ocean sediments. On land the biosphere penetrates to various depths in caverns and apparently also in very minute cracks and channels in which water may percolate and in which bacteria and animals may be found. 

高山山尖、深海及其沉积区、地表水渗可达的缝隙，皆有生命的身影。

It is convenient to distinguish an active eubiosphere in which the physiological functions of organisms are possible, surrounded by a parabiosphere in general too hot, too cold, or too dry to permit any active metabolism but in which spores or other resting stages may exist. Most of the Antarctic and Greenland ice sheets, some local deserts, and the uppermost parts of the troposphere, in which spores but no other organism occure, belong to this inactive part. The tops of the highest mountains may also belong here, though there is record of the barheaded goose Anser indicus flying over the top of Mount Everest, and so at an altitude of about 9,000 m. and at an atmospheric pressure of about one-third that at sea level. 

eubiosphere：合成词，eu-表示‘善、优’，中心生物圈；

parabiosphere：合成词，‘近、类’，类生物圈；

类生物圈中，仅能供特殊阶段的生命存活其间，比如孢子。类生物圈的例子：格陵兰冰盖、某些沙漠、对流层顶等。9,000 m的高空被记录斑头雁（Anser indicus）的身影。

Within the eubiosphere two conditions are ordinarily met. The temperature is always near enough to that at which water is a liquid, so that within active organisms aqueous solutions can be present in a liquid state. There is also always, at some time of the year, either a radiation flux from the sun, which can be trapped by photosynthetic organisms, or a supply of photosynthetic products, which can be made avaiable by the force of gravity or through transport by wind and water in regions that are inhabitable but lack autotrophic plants. 

生命的两大环境基础：液态水、能量。

The two conditions of a liquid and an energy source are presumably fundamental. It is almost impossible to imagine anything like an organism developing as a pattern in a gaseous mixture, and though an adult completely solid-state organism might be thought of, it is difficult to conceive how it could develop. It is also important to not that although organisms can live in the free liquid phase of lakes and oceans, most species prefer an environment of interfaces; this may well have been a primitive preference. 

小时候游离如气，长大却又型固，无法想象的生命形态。

Some energy source and sink are clearly needed if organisms are to function. Whenever the liquid water requirement can be met it is likely that the planet would be at the right distance from its sun star for the latter to be the obvious source of energy. The internal heat of a planet, mostly of radioactive origin, in theory would provide an alternative to incoming radiation though we have little precedent as to how an organism could use it. In considering some of the evidence of former extraterrestrial life the possibility of such endogenous energy stored as an unstable mixture of inorganic minerals has perhaps to be considered. Within the region of the eubiosphere we may distinguish between an autobiosphere in which the external energy source is trapped and converted into the chemical energy of organic compounds, today exclusively by the photosynthetic activity of chlorophyll-bearing plants, and two regions together forming the allobiosphere in which animals, heterotrophic plants, and bacteria can live, but into which organic food material must be transported, ordinarily by gravity or by wind. 

autobiosphere：合成词，auto-表示‘自养’；

allobiosphere：合成词，allo-表示‘异养’。

地热资源生命体利用很少，太阳辐射能是主要能量源。