10
MARCEL FLORKIN AND HOWARD S. MASON
on the other hand, applied to life, has been to extend this understanding
to the molecular level. From this extension has come two basic concepts
which comprise the physicochemical foundations of comparative biochemistry.
The first of these concepts, formulated by Theodor Schwann, is
that life is consistent with the fundamental properties of matter and
energy, and is a consequence of them. From this point of view, the
modern history of which commenced with Descartes and Hobbes about
350 years ago, it is matter and energy interacting at subatomic, atomic,
and molecular levels which give rise to the dynamics from which the
more highly organized aspects of biological unity and diversity are derived. These interactions also give rise to the dynamics of the universe.
"The properties of matter and the course of cosmic evolution are now
seen to be intimately related to the structure of the living being and to
its activities" (4). Hence, the working hypothesis which, although
rarely made explicit, underlies the activity of contemporary biochemistry, is that "the framework of a single classification," the fundamental
properties of matter and energy, suffice to describe all the phenomena
of life. The testing of this hypothesis is the most significant activity of
comparative biochemistry, comparative in the sense that it studies the
physicochemical consistencies between life and the universe in which it
occurs.
The second comparative concept arising from the physicochemical
study of life has been clearly stated by Baldwin: "We arrive from several different lines of approach at essentially the same conclusion; there
exists a common, fundamental chemical ground plan of composition and
metabolism to which all animals and very probably other living organisms also, conform, and that superposed on these foundations, there
are numerous secondary, specific, and adaptational variations, some of
addition and others of omission" (2). The expression "numerous variations" is perhaps an understatement because there exist at least two
million species of plants and animals, among which the ultimate differences are almost certainly chemical (that is, in nucleic acid structure,
although nucleic acids are common to all forms of life), added to
which there are the secondary species, specific and adaptional variations, and biochemical variations (such as in human blood groups)
which occur among individuals of a species. Nevertheless, as this
Treatise will show, a common chemical ground plan (biochemical
unity) is apparent in the midst of this diversity. That this is the case
was foreshadowed in the development of nineteenth and twentieth century chemistry by the isolation of metabolites and the determination of
their structures, by the discovery of enzymes, their proteinaceous struc-
MARCEL FLORKIN AND HOWARD S. MASON
on the other hand, applied to life, has been to extend this understanding
to the molecular level. From this extension has come two basic concepts
which comprise the physicochemical foundations of comparative biochemistry.
The first of these concepts, formulated by Theodor Schwann, is
that life is consistent with the fundamental properties of matter and
energy, and is a consequence of them. From this point of view, the
modern history of which commenced with Descartes and Hobbes about
350 years ago, it is matter and energy interacting at subatomic, atomic,
and molecular levels which give rise to the dynamics from which the
more highly organized aspects of biological unity and diversity are derived. These interactions also give rise to the dynamics of the universe.
"The properties of matter and the course of cosmic evolution are now
seen to be intimately related to the structure of the living being and to
its activities" (4). Hence, the working hypothesis which, although
rarely made explicit, underlies the activity of contemporary biochemistry, is that "the framework of a single classification," the fundamental
properties of matter and energy, suffice to describe all the phenomena
of life. The testing of this hypothesis is the most significant activity of
comparative biochemistry, comparative in the sense that it studies the
physicochemical consistencies between life and the universe in which it
occurs.
The second comparative concept arising from the physicochemical
study of life has been clearly stated by Baldwin: "We arrive from several different lines of approach at essentially the same conclusion; there
exists a common, fundamental chemical ground plan of composition and
metabolism to which all animals and very probably other living organisms also, conform, and that superposed on these foundations, there
are numerous secondary, specific, and adaptational variations, some of
addition and others of omission" (2). The expression "numerous variations" is perhaps an understatement because there exist at least two
million species of plants and animals, among which the ultimate differences are almost certainly chemical (that is, in nucleic acid structure,
although nucleic acids are common to all forms of life), added to
which there are the secondary species, specific and adaptional variations, and biochemical variations (such as in human blood groups)
which occur among individuals of a species. Nevertheless, as this
Treatise will show, a common chemical ground plan (biochemical
unity) is apparent in the midst of this diversity. That this is the case
was foreshadowed in the development of nineteenth and twentieth century chemistry by the isolation of metabolites and the determination of
their structures, by the discovery of enzymes, their proteinaceous struc-