327 - 11th Botany Textbook Volume 1

Division is the next level of classification
that consists of number of classes.
Example: Magnoliophyta.
Kingdom is the highest level or rank
of the classification. Example: Plantae
Rank Ending Example
Kingdom - Plantae
Phylum = Division -phyta Magnoliophyta
Subphylum = Sub division -phytina Magnoliophytina
Class -opsida Asteropsida
Sub class -idea Asteridea
Order -ales Asterales
Suborder -ineae Asterineae
Family -aceae Asteraceae
Sub family -oideae Asteroideae
Tribe -eae Heliantheae
Genus - Helianthus
Sub genus - Helianthus subg. Helianthus
Series - Helianthus ser. Helianthus
Species - Helianthus annuus
5.3 Concept of species-Morphological,
Biological and Phylogenetic
Species is the fundamental unit of taxonomic
classification. Greek philosopher Plato
proposed concept of “eidos” or species and
believed that all objects are shadows of the
“eidos”. According to Stebbins (1977) species
is the basic unit of evolutionary process.
Species is a group of individual organisms
which have the following characters.
1. A population of organisms which
closely resemble each other more than
the other population.
2. They descend from a common
ancestor.
3. In sexually reproducing organisms,
they interbreed freely in nature,
producing fertile offspring.
4. In asexually reproducing organisms,
they are identified by their
morphological resemblance.
5. In case of fossil organisms, they are
identified by the morphological and
anatomical resemblance.
Species concepts can be classified into
two general groups. Concept emphasizing
process of evolution that maintains the
species as a unit and that can result in
evolutionary divergence and speciation.
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