Organically, biosphere is the most active
sphere of the earth in comparison to
the lithosphere, atmosphere and
hydrosphere. It is a shallow zone at the earth
surface, both on land and in water. All living
organisms together with the environment with
which they interact form the biosphere.
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A D V E R T I S E M E N T
Whether they belong to the plant or animal
kingdom, they all interact with each other. The
study of these interactions between life forms
and the environment is called ecology. All the
components which enter into interactions with
a group of organisms is called ecosystem.
The earth is full of diversities. There is
diversity in soils and minerals, diversity in
plants and animals, and diversity in cultures
and civilisations. Charaka, the father of
Ayurveda, who lived in the first century A.D.,
listed over 200 kinds of animals and about 340
kinds of plants in his book of Indian medicine
titled Charaka Samhita. Carolus Linnaeus, the
eighteenth century Swedish naturalist,
identified about 5,900 species of plants and
4,200 species of animals. Since then some 1.7
million species have been given scientific
names; of these, over a million are animal
species and the rest plant species. According
to an estimate, over 5 million species of living
organisms exist in the world today, and over
half of these are believed to be found in the
unexplored tropical rain forests of the world.
The rain forests constitute less than 8 per cent
of the total land area of the world but support
a very rich diversity of life.
CLASSIFICATION OF ORGANISMS
Scientists can identify many kinds of
organisms with scientific names because they
have been described and ordered by a system
of classification which has been internationally
accepted. The science of classification of
organisms is called taxonomy. Earlier, all
organisms used to be broadly grouped into two
categories � the plant kingdom and the
animal kingdom. Under each category there
used to be several species. Whittaker, in 1969,
divided different organisms into five
kingdoms, namely:
(i) Monera (single cell microscopic
organisms);
(ii) Protista (unicellular, primarily aquatic
organisms);
(iii) Plantae (multicellular photosynthetic
plants);
(iv) Fungi (multicellular decomposers) and;
(v) Animalia (multicellular animal consumers).
The above classification into five kingdoms
is made on the following criteria: complexity
of cell structure, complexity of organism�s
body, and mode of obtaining nutrition.
Bacteria belong to the monera kingdom. Its
cells are microscopic and do not contain a
nucleus. It prepares its own food by reducing
carbondioxide and using light energy or energy
derived from chemical reactions.
Protistan organisms are mostly unicellular.
Many are photosynthetic autotrophs and
chief producers in oceans and fresh water
environments. They are collectively called
phytoplankton, microscopic, floating photosynthetic
organisms.
Plantae includes all the coloured,
multicellular, photosynthetic plants which we
all see on land, on sea shores, in lakes and in
streams. Main groups are the sea weeds
consisting of algae, mosses, ferns, and seed
plants with or without flowers.
Fungi includes diverse kinds of multicellular
heterotrophic organisms. There are over
100,000 species of fungi. Some are unicellular
like yeasts, others complex like mushrooms. The
fungi are the major decomposers and their
activity is essential for the recycling of inorganic
resources in the biosphere.
Members of the animal kingdom are
multicellular. This includes sponges, snails,
insects, starfishes, amphibians, birds,
mammals etc. Under each kingdom, there are
several species.
Human beings belong to one of the species
of the animal kingdom. But because of their
unique characteristics, they are called Homo
sapiens (homo= man; sapiens = wise). At the
biological level, the human beings are not unique
for strength, ability, speed or endurance. They
have a poorer sense of hearing, smell and vision
than many other animals, but their brains are
large and highly developed, and they have skilled
hands. They can change themselves according
to environment and need and hence, more
powerful than other animals.
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AKHAND PRATAP SINGH
