XI
CH-1 Living World
Planet earth is made up of abiotic and biotic components.The biotic components are obviously the living beings present around us. The question is why do we call them living and how do they differ from non-living The organisms live in various habitats like forests, mountains, deserts, oceans, freshwater bodies, hot springs, polar regions & almost every place of the earth.
Basic principles of life :
i)
Metabolism:
These molecules undergo
various chemical reactions to perform their specific functions which are called
metabolism.
Metabolism
is breaking of molecules (catabolism) and making of new molecules (anabolism).
An organism performs metabolism in order to obtain energy and various chemical
molecules essential for survival.
ii)Birth =is organisms show tendency of growth and
development. This growth is a well-orchestrated process. You might have
observed sand mounds, boulders grow, etc. This growth is not from within and
hence these are not living beings.
(iii) Growth and development: All living organisms can undergo the process of
growth and development that results in an increase in the mass and number of
cells.
Organisms
tend to grow and develop in a well-orchestrated process from birth onwards.
(iv)
Ageing:
It
is the process during which molecules, organs and systems begin to lose their
effective working and become old.
(v)
Reproduction: The ability to produce
young ones is the process of reproduction which is observed only in the case of
living organisms.
In the case of fungi,
reproduction occurs through asexual spores, while in the case of hydra budding
occurs and in planaria regeneration occurs which are all the asexual methods of
reproduction.
(vi)
Death: As
the body loses its capacity to perform metabolism, an organism dies.
(vii)
Responsiveness: Living
organisms respond to thermal, chemical or biological changes in their
surroundings
viii)Consciousness -Any living being responds to thermal,
chemical or biological changes in the surrounding. This is unique property of
living beings.
There is immense diversity in living organisms. .
Since time immemorial, variety of organisms are living together on earth.
In order to understand the interrelations between living and non-living
as well as between two living beings or groups, systematic study of these is
essential.
Intensive laboratory and field studies in order to identify and classify
the organisms form strong basis for meaningful use of the collected data. .
If we need to study this diversity, certain aids called taxonomical aids
can be used. .
These includes herbaria, botanical gardens, museums, biodiversity parks,
etc.
A herbarium is a
collection of preserved plant specimens that are dried and labelled.
The plant species that are collected are first dried, pressed, mounted, and then labelled on the herbarium sheets.
The steps involved in
the herbarium technique are as follows:
1-Collecting various
specimens from different areas.
2-Drying the particular
specimen by placing them in between the various folds of newspapers or by iron
drying them.
3-By dipping the specimens in mercuric
chloride poisoning is done.
4-Certain specimen parts
that are difficult to attach to the sheet, like stems, are stitched so that
they stick to their position on the sheet.
5-To keep them for a
longer time, preserves must be sprayed.
6-The labeling for
identification of all the specimens must be done at the left side of the bottom
corner. The name, date of collection, area of collection, habit, etc must be
written.
7-Lastly, these
herbarium sheets are deposed under the herbarium covers where the rest of the
herbarium sheets are covered and packed.
8-These herbarium sheets are stored in the
cupboards named under their category. Biodiversity.:
Biodiversity
is the degree of variation of life forms in an ecosystem.
Conservation
involves attempting to slow down, stop or even reverse the loss in the natural
habitat of an organism.
Museums –
Museums
are places where collections of preserved plant and animal specimens are kept.
The
different types of specimens found in a museum include;
(a)Plant
and animal specimens preserved in formalin (10% to 40% formaldehyde) in
transparent ja
(b) Larger
animals like birds and mammals, usually stuffed and preserved.
(c)
Certain specimens in dried forms are also kept in a museum. (d) Systematic.
They are animal parks
within enclosures that display to the public and replicate their natural
habitats for behavioral patterns which benefit the animals and visitors.
Special climatic
conditions are created for the animals and the walkthrough exhibits are there
for visitors for non-aggressive species. Visitors are how to avoid eating
Zoological
park (zoo) is a place where wild animals are kept in captivity.
The
different tools used for maintaining biodiversity records are as follows:
•Flora: It
is the plant life occurring in a particular area at a particular time.
•Monograph:
It describes any one selected biological group.
•Manual:
It provides information and keys about identification of species found in a
particular area. foods that animals
might snatch or to keep their paths away.
The zoological park of
Kruger in South Africa is the largest zoo in the world.
The Zoo of Kolkata in India is the largest zoo
Biodiversity
parks= Biodiversity
park is an ecological assemblage of species that form self-sustaining
communities on degraded/ barren landscape, e.g. UttamraoPatilBiodiversity Park,
Gureghar, Mahabaleshwar.
Key =
Key is a
taxonomical aid used in the classification of plants and animals.
•Keys are
based on contrasting characters. One of the contrasting characters gets
accepted and the other gets rejected.
Botanical
gardens-:
Botanical
gardens are places where plants of different varieties collected from different
parts of the world are grown in vivo in a scientific and systematic manner,
They are those gardens
that are responsible for the cultivation and preservation of a wide range of
plants.
These plants are
reserved along with their botanical names that are tagged as a label.
It is a collection of
many species of plants such as succulent plants, garden herbs, and many more
exotic plants.
Visitors include
educational displays, art exhibitions, and open-air theatre musical
performances with tours and other entertainments.
They are under the
control of the universities or the scientific research organizations that
relate both herbaria and the research programs together in the botanical
sciences.
There are more than 600
botanical gardens present all around the world.
The ancient Botanical
Garden in the world is the Hanging Gardens of Babylon and comes under the
Wonders of the world.
The Royal botanical
garden at Kew in England is the largest Botanical Garden in the world and is
known as the botanical capital of the world. It was discovered by Bentham and
Hooker.
In India Indian
Botanical Garden at Kolkata is the largest botanical garden while Tropical
Botanical Garden at Thiruvananthapuram in Kerala is the largest tropical
botanical garden in Asia.
collections of shells, skeletons of animals and insect boxes are also found in
museums.