The Evolutionary Theory of
represents the most important challenge to the modern theory
the queen of problems... the main question is —why
V. Geodakyan’s theory can
be summarized in one sentence:
Males are the experimental animals of the Nature.
It appears that sex is more likely a way of asynchronous
rather than a way of reproduction as it was considered
V. Geodakyan (1991)
Answers the main question—What two sexes are
Substitutes Darwin’s theory of sexual selection.
Explains and predicts differences between sexes (sexual
Applies to plants, animals and humans.
Applies to all levels of organization: cell, organ,
population, social and psychological.
Reproduction, Reproduction analysis
Dioecism involves two fundamental phenomena: mating and sex
differentiation. Genetics considers only the results of
mating but not differentiation; therefore the phenomena
related to the differentiation itself
cannot be explained.
theory suggested considers sex differentiation as a useful
for population form of informational contact with the
environment, as evolutionary specialization by two main
information currents: genetic (from preceding generations)
which realizes stabilizing, conservative trends of
evolution, and ecological (about changes in environment)
which carries out operative trends of evolution.
case of sexual differentiation, the sequence of arrival of
the controlling information from the environment to the
subsystems is as follows:
→ male sex
In panmictic and polygamous
populations where each male can fertilize many females the
number of mothers always exceeds that of fathers. Therefore
hereditary information obtained by the offspring from their
mothers is more representative, better reflects genetic
distribution in population/preceding generation. Information
obtained from fathers is more selective; it reveals the
genotypes suitable for the environmental conditions.
Broader reaction norm of
females makes them more flexible, adaptive in Ontogeny
so they can move within the ecological niche from
discomfort and elimination to the comfort
narrows their phenotypic variation thus
better preserving their
genetic one. The narrow reaction norm of
males preserving wide phenotypic variation subjects them
to greater elimination. It means that males are the first to
be affected by evolutionary transformations.
death rate and damageability of males is a general
biological phenomenon. It is favorable to a population form
of information contact with environment, a payment for the
new (ecological) information. The higher male death rate and
more intensive sexual selection among males combined with
their potential opportunity to impregnate many females (the
wide liaison channel cross-section with posterity), lead to
that the hereditary information on distribution of genotypes
in a population, transferred to the following generation by
a female sex, is more representative (better reflects
distribution in previous generation), and the information
transferred by a male is more selective (better reflects the
genotypic distribution (variation) of the female
individuals participating in a reproduction, is wider, than
male's. Hence, in Phylogeny, contrary to Ontogeny,
male sex is more plastic (changeable), therefore the
evolutionary transformations of a population reflect males
first. The new view on appearance of sexual dimorphism as a
consequence not only sexual selection (as Darwin thought),
but natural and artificial selection as well.
Hence males can be considered
as evolutionary “vanguard” of population, and sexual
dimorphism for a character - as a “compass” indicating the
evolution of this character (“phylogenetic rule of sexual
dimorphism”). Therefore the characters which more often
appear and are more pronounced in females ought to be of the
“atavistic” nature, and those more often manifested in males
- of the “futuristic” one (search). Maximal sexual
dimorphism must be observed by evolutionary young (new)
Consequently, when different
forms are mated in reciprocal hybrids paternal breed must
dominate over the maternal one by divergently acquired new
characters (“paternal effect”), closer relationship of males
with heterosis must be also observed. The “paternal effect”
predicted by the theory is really observed for many
economically valuable (breeding) characters.
The theory connects three
main characteristics of dioecious population: sex ratio,
variation and sexual dimorphism, with the ecological
conditions and evolutionary plasticity of the species. These
characteristics decrease under stable environmental
conditions thus reducing the plasticity; under varying
conditions - they increase raising the plasticity.
The new theory enables to
reveal some earlier unknown regularities related to sex, to
explain many known phenomena from a single standpoint and to
predict new ones.
New view on the evolutionary role of
leads to a proper
understanding of all sex-associated derivatives:
sex variation (SV), sexual dimorphism (SD),
(SC), sex hormones (SH), psychological differences
associated with sex, and all other sex-related phenomena.
The sex ratio, variation and sexual
dimorphism—are regulated variables closely related to
environmental conditions, contrary to traditional view
of them as constants specific to a species. In stable
conditions (the optimum environment) they should decrease
thus reducing the evolutionary plasticity of the species and
in changeable conditions (the extreme environment)—grow,
raising the plasticity. The mechanism of
stress serves as a
transmitter of the ecological information and a regulator of
evolutionary plasticity at animals. The
quantity of pollen
getting on a pistillate flower serves the same purpose at
is the “distance” between sexes during evolution of any
character. It’s the genetic information which due to sex
specialization at the population level has already come into
the male subsystem, but not to the female one.
This interpretation allows answering many
Darwin's theory of sexual selection failed to explain.
serve the purpose of separating male and female subsystems.
New genes first appear in the Y-chromosome and stay in the
male subsystem for a long time. Only after many generations
they are transferred via X-chromosome into female subsystem.
New generalized concept of estrogens as compounds that widen
the norm of reaction, move the female subsystem away from
the environment, and slow down evolution. Contrary,
androgens narrow the reaction norm, bring male subsystem
closer to the environment, and speed up the evolution.
Sexual dimorphism on many diseases can be explained.
anomalies: Female congenital
anomalies are considered as a consequence of excessive
conservatism, as a return to a near past (in ontogenetic and
phylogenetic sense). They are of the "atavistic"
nature. Male congenital
anomalies are the attempts of the evolution to try new
things and can be viewed as "futuristic" ones (search).
Sexual Dimorphism in different ethnoses can be explained.
Effects related to
differentiation of sexes
More about the Evolutionary
Theory of Sex:
ili devoska (A boy or a girl. Sex ratio—value regulated by
Nature?) (Geodakyan V.). Nauka
i Zhizn (Science and Life)., 1965, № 1, p. 55–58.
Rol' polov v peredace i preobrazovanii
geneticeskoj informacii (Role of sexes in the transmission
and transformation of genetic information).
Geodakjan V.A. (1965) Probl, Peredaci Inform. 1: 105-112.
Why Two Sexes? Geodakyan V. Nauka i Zhizn (Science
and Life). 1966, N 3, с. 99–105.
Translated from Russian by B. Lubachevsky
Most complete scientific version:
The Evolutionary Theory of Sex. Geodakyan V. A. “Priroda
(Nature)” 1991, N 8, p. 60–69.
Geodakyan V. A. In: Evolution and morphogenesis.
(Mlikovsky J., Novak V. J. A., eds.), Academia, Praha, 1985,
Most recent publication:
Мужчина и женщина. Эволюционно-биологическое
(Man and woman. Evolutionary-biological purpose)
Геодакян В. А. Межд. Конф.: Женщина и свобода. Пути
выбора в мире традиций и перемен. Москва, 1–4 июня 1994,