BOTANY Higher Secondary Second Year - Textbooks Online

Methods in the study of biosystematics
Three important methods are as follows.
i) It involves thorough sampling analysis of the taxonomic species
under study. Its population, cultivation, geographical range, cytology,
anatomy, palynology, phytochemistry, chromosomal number and behaviour
are keenly observed and studied for finding any genetic differences that
may arise among different populations.
ii) It includes determination of ability of different populations to
interbreed among one another to form a variant species with its vigor and
fertility. This will reveal the presence or absence of breeding barriers
between taxa at various levels.
iii) It involves the study of similarity of chromosomes in the hybrids
during meiosis.
Ecotype is the basic unit in biosystematics, adapted to a
particular environment but capable of producing fertile hybrids
with other ecotypes. Ecotype is regarded as equivalent to
subspecies of classical taxonomy.
Ecospecies is a group of plants comprising one or more
ecotypes within the cenospecies, whose members are able to
interchange their genes. Ecospecies is regarded as equivalent to
species of classical taxonomy.
Cenospecies is a group of plants representing one or more
ecospecies of common evolutionary origin. It is regarded as
equivalent to subgenus of classical taxonomy. Cenospecies of
the same comparium are separated by genetic barriers and all
hybrids between them are sterile.
Comparium is composed of one or more cenospecies that
are not able to intercross. Complete genetic barriers exist between
different comparia.
The informations obtained from the above mentioned studies were
compared with the data obtained through comparative morphology and
geographical distributions resulted in the recognition and identification of
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