160
J. HESLOP-HARRISON
which he accommodated within the discipline of genecology. The essential unity of these early researches lay in their concentration upon the
species as “a genetically complex community, the distribution and the
composition of which is largely determined by ecological factors and the
genotypical constitution of the individuals . . .” (Turesson, 1923). Their
aims, in brief, were to lay bare the patterns of infraspecific” ecological
adaptation, and elucidate the mechanisms whereby this adaptation was
achieved.
The separate identity of genecology depends upon the preservation of
this combination of aims; like all synthetic disciplines, it breaks up into
its components when purposes different from or more specific than those
constituting the original frame of reference are introduced. Thus genecology merges into taxonomy when the primary aim is to systematize for
classificatory purposes patterns of infraspecific variation ; into genetics,
when the mechanisms of variation and selection form the main targets
of study; and into plant physiology when it is the physical responses of
the organism to the environment which are of interest.
There seems still to be a need to preserve the identity of genecology in
the original Turessonian sense, since for the understanding of an important phase of micro-evolution the synthesis is indispensable, in the
same way that a synthesis - on a broader canvas - was essential in the
development of the argument of “The Origin of Species”. It is the purpose of this article to assess the present position of genecology and to
attempt to distinguish a few of the general principles that appear to have
emerged since the pioneer days. In doing this, facts and concepts have
been drawn not only from researches which have been expressly oriented
towards genecology, but also from related fields, where they contribute
to the genecological synthesis in the broad sense.
B. S O M E BASIC PROPOSITIONS
The basic propositions of Turessonian genecology may be summarized
as follows: (1) Wide-ranging plant species show spatial variation in
morphological and physiological characteristics ; (2) much of this infraspecific variation can be correlated with habitat differences; (3) to the
extent that ecologically-correlated variation is not simply due to plastic
response to environment, it is attributable to the action of natural selection in moulding locally adapted populations from the pool of genetical
variation available to the species as a whole. Turesson’s own work, as
exemplified particularly in the papers of 1922, 1925 and 1930, was devoted in large part to the substantiation of propositions (1) and (2), and
to showing that ecologically-correlated inter-population variation was
Linnaeaa species (See the discussion pages 165 to 167).
* “Infraspecific variation” in this article means variation below the level of the average
J. HESLOP-HARRISON
which he accommodated within the discipline of genecology. The essential unity of these early researches lay in their concentration upon the
species as “a genetically complex community, the distribution and the
composition of which is largely determined by ecological factors and the
genotypical constitution of the individuals . . .” (Turesson, 1923). Their
aims, in brief, were to lay bare the patterns of infraspecific” ecological
adaptation, and elucidate the mechanisms whereby this adaptation was
achieved.
The separate identity of genecology depends upon the preservation of
this combination of aims; like all synthetic disciplines, it breaks up into
its components when purposes different from or more specific than those
constituting the original frame of reference are introduced. Thus genecology merges into taxonomy when the primary aim is to systematize for
classificatory purposes patterns of infraspecific variation ; into genetics,
when the mechanisms of variation and selection form the main targets
of study; and into plant physiology when it is the physical responses of
the organism to the environment which are of interest.
There seems still to be a need to preserve the identity of genecology in
the original Turessonian sense, since for the understanding of an important phase of micro-evolution the synthesis is indispensable, in the
same way that a synthesis - on a broader canvas - was essential in the
development of the argument of “The Origin of Species”. It is the purpose of this article to assess the present position of genecology and to
attempt to distinguish a few of the general principles that appear to have
emerged since the pioneer days. In doing this, facts and concepts have
been drawn not only from researches which have been expressly oriented
towards genecology, but also from related fields, where they contribute
to the genecological synthesis in the broad sense.
B. S O M E BASIC PROPOSITIONS
The basic propositions of Turessonian genecology may be summarized
as follows: (1) Wide-ranging plant species show spatial variation in
morphological and physiological characteristics ; (2) much of this infraspecific variation can be correlated with habitat differences; (3) to the
extent that ecologically-correlated variation is not simply due to plastic
response to environment, it is attributable to the action of natural selection in moulding locally adapted populations from the pool of genetical
variation available to the species as a whole. Turesson’s own work, as
exemplified particularly in the papers of 1922, 1925 and 1930, was devoted in large part to the substantiation of propositions (1) and (2), and
to showing that ecologically-correlated inter-population variation was
Linnaeaa species (See the discussion pages 165 to 167).
* “Infraspecific variation” in this article means variation below the level of the average