We are surrounded by different kinds of living and non-living things. Human beings, plants and animals are examples of living things. Living things show some distinct characteristics that make them different from non-living things.
Living things are made up of cells.
Living thing respire.
Living things show movement and locomotion.
Living things need food to grow.
Living things show growth.
Living things show response to stimuli.
Living things reproduce.
Living things undergo a permanent change as they mature.
Living things exhibit a definite pattern in their life
cycles.
A distinct life in nature is the individual organism. In an
organism, a group of components are arranged systematically and form a system
for a particular purpose which is called organization. Each kind of living
organism whether simple (single-celled) or complex (multi-cellular), possesses
a certain level of organization that enables the organism to perform different
life activities. An organization is represented by an aggregation of smaller
units into a big unit referred to as a level.
Levels of Organization
The entire living world can be seen not just within the cell
but it moving at the organism level and finally to the entire population of
living organisms present on the earth.
In nature, one can recognize the following three levels of
organization.
The lower level of the organization
Individual level of organization
Higher level of organization
Lower Level of organization
Cellular Level
All living things are made up of cells. A cell is the lowest
level of organization. It forms the basic structural and functional unit to
perform all the vital functions of the body, e.g. blood cells, nerve cells and
bone cells.
In unicellular organisms like amoeba, euglena and paramecium,
all the vital activities such as nutrition, movement, respiration and
reproduction are carried out by the cell itself.
In multi-cellular organisms like dogs, fish and human beings,
the body is made up of millions of cells. The different cells carry out
different functions in an organized and coordinated manner.
A group of similar cells that perform a specific function
from the tissue. For example, a group of muscle cells form the muscular
tissue.
Organ Level
In multi-cellular organisms, different types of tissues that
perform a similar function are grouped together and form an organ of the body.
The stomach, kidney, brain and liver are examples of some of the organs of
animals. In plants, roots, stems, leaves and flowers are examples of plant
organs.
Organ System Level
Different organs which perform a similar function are grouped
together to form an organ system. For example, the mouth, oesophagus, stomach,
intestines, liver and pancreas are the organs grouped together and form the
digestive system of human beings.
Organism Level
The different organ systems work together in a coordinated
manner and form the organism level of an organization. An organism is a whole living being in
which different life processes occur in a coordinated manner.
Individual Level of Organization
An individual organism is a separate real biological unit
comprising different organ systems in a coordinated manner and forms the
individual level of organization. This level is also termed as the organismic
level. The individual may be a plant or an animal, irrespective of its kind,
structure and habitat.
Higher Level of
Organisation
An individual organism cannot live in isolation in nature.
For the survival and perpetuation of its race, an individual often associates
with other living organisms of its kind.
Each kind of organism is referred to as a species (a species
is a group of similar individuals that live together and interbreed to produce
young ones). Our environment comprises millions of species.
For example, rabbits represent one species while cows
represent another. Similarly, wheat, sunflower, and neem are examples of
plant species.
The higher level of organization is also called ecological organization. It includes the following order:
Population
All the similar individuals of a given locality, which form a
single sexually interbreeding group, constitute the next higher level of
organization, called population, e.g. human beings represent the human
population. Similarly, other animals such as dogs, cats and plants such as
mango and banyan constitute the other population.
Community
Different groups of populations belonging to different species
combine to form the next higher level of organization, called community, e.g.
different species of microorganisms, plants and animals inhabiting a pond form
a community.
Ecosystem
The communities found in any geographical region, such as
ponds, lakes, rivers, oceans, forests, deserts, mountains and other habitats,
have to interact with the physical environment of the place. Both the abiotic
and biotic factors of an area together constitute the next higher level of
organization, called an ecosystem.
Biosphere
The sum of the ecosystem of all geographical regions present on
the earth forms the next level of organization called the biosphere. The biosphere is the biggest ecological organization and in fact, is a huge
ecosystem that includes both living and non-living components. In other words, the biosphere can be considered as the highest level of living organization which
is a part of the universe and supports life.