Species

202 Species

In the forefront of his denitions, Lotsy has the Mendelian genetics then being

rst investigated in detail. He thinks that classication by the genetic constitution

forms a kind of Lockean “real essence,” which is the point of the race example.

If our groupings match nature’s real essence (i.e., genetic constitution), then they

are natural groups. Otherwise they are not, and given the typological nature of his

denition, ordinary species (i.e., what came to be called “biological species”) were

not natural entities. The remainder of his argument relies on Mendelian assortment

forming novel varieties, as we would call them, or “allogamous forms” as he calls

them, from mutations.^65

Göte Turesson on Ecospecies and Agamospecies

The Swedish botanist Göte Turesson undertook a series of experiments in the
1920s and early 1930s,^66 in which he transplanted the “ground stock” of widely
distributed Swedish plants into various different habitats—dunes, seacliffs,
woodlands, high altitudes and so on,^67 and discovered that differing forms arose
as a response to climate. He made a number of inuential distinctions on taxa
which later formed the basis for ecological species concepts. He proposed ecospe-
cies “to cover the Linnean species or genotype compounds as they are realized in
nature” and related coenospecies (the Linnaean taxon) to ecospecies in a diagram
( Fig u r e 6.1).^68
Coenospecies are “the total sum of possible combinations in a genotype com-
pound,” and include one or more ecospecies, which include one or more eco-
types, the forms that develop in different ecosystems or habitat types. These
comprise all the “reaction-types” of ecotypes that are elicited by extreme habi-
tats, called ecophenes. In a similar inclusive hierarchy, he listed a genetical array
of concepts—genospecies (the genetical construction of ecospecies), genotypes
(Johannsen’s 1909 term) and the “reaction-types” of genotypes, genophenes. This
dual hierarchy between the ecological and genealogical was repeated later by
Eldredge and Salthe.^69 Turesson’s “reaction-types” are in modern terms the reac-
tion norms of genes, although the idea of a reaction norm for an ecotype appears
to have been abandoned.
In one paper, he gave succinct denitions of the major terms:
a) Ecospecies: An amphimict-population the constituents of which in nature
produce vital and fertile descendants with each other giving rise to less vital
or more or less sterile descendants in nature, however, when crossed with
constituents of any other population. ...
b) Agamospecies: An apomict-population the constituents of which, for mor-
phological, cytological or other reasons, are to be considered as having a
common origin. ...

(^65) Lotsy 1916, 159.
(^66) Turesson 1922a, 1922b, 1925, 1927, 1929, 1930.
(^67) Turrill 1940, 52.
(^68) Turesson 1922a, 344.
(^69) See Salthe 1985, Eldredge 1989.