BY Ms SUMAN LATA
TGT BIOLOGY , KV MIRC
DEFINITION
 CLASSIFICATION-
Biological classification, or scientific
classification in biology, is a method of scientific taxonomy
used to group and categorize organisms hierarchically according
to their observed similarities/ differences and relationships. The
Rank-based systems use a fixed number of levels in the
hierarchy, such as kingdom, family, genus or species etc.
 Also known as Taxonomy
 TAXONOMY is the science of naming, describing and classifying
organisms and includes all plants, animals and microorganisms
of the world. Using morphological, behavioural, genetic and
biochemical observations, taxonomists identify, describe and
arrange species into classifications
NEED FOR CLASSIFICATION
 Classification is important because it allows scientists
to identify, group, and properly name organisms via a
standardized system (Linnaeus Taxonomy); based on
similarities found in the organisms DNA/RNA
(genetics), Adaptations (Evolution), and Embryonic
development (Embryology) to other known organisms
to better study and understand the new organism as a
whole.
 Several other branch of studies are also benefitted like
Ecology, Forestry, Biogeography etc
DIFFERENT APPROACH FOR
CLASSIFICATION
CLASSIFICATION (with example)
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HEIRARCHY OF CLASSIFICATION GROUPS
 The groups in the classification are known as taxa (singular: taxon).
 Each taxon has a specific level of similarities and differences.
Kingdom is the first category of taxon. A group of division forms kingdom. It is the
largest group pf living organism. Differences are higher and similarities are very less in
Kingdom
Species: It is a group of organism that shows maximum similarities and capable of
interbreeding. They are capable to give rise to fertile offspring.
Genes: A group of species form genus that are having common ancestor.
Family: A group of genera forms family that possesses certain common characters.
Order: A group pf family who inter-related with each other forms order.
Class and Division (Phylum): A group of orders forms class and group of class forms
division.
CELLS : DIFFERENTIATION
Recall that there are two basic types of
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cells: eukaryotes and
prokaryotes.
EUKARYOTES are more complex in structure, with nuclei and
membrane-bound organelles. Some characteristics of eukaryotes
are:
Large (100 - 1000 μm)
DNA in nucleus, bounded by membrane
Genome consists of several chromosomes. Most forms are
multicellular Aerobic
PROKARYOTES refer to the smallest and simplest type of cells,
without a true nucleus and no membrane-bound organelles.
Bacteria fall under this category. Some characteristics:
Small (1-10 μm)
DNA circular, unbounded
Genome consists of single chromosome.
Most forms are singular Anaerobic
HISTORICAL PERSPECTIVE :
LEGENDARY TAXONOMISTS