Page 33 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

Aren't you now convinced that an organism is a combination of
different organ systems?
An organism can survive only when these organ systems work in a
coordinated way.

As organ systems become complex, the
structure of the body also becomes
complex. The structure of higher order
animals including human beings is
complex, as it is formed by a
combination of various organ systems.
Do all organisms have an organ system?
However unicellular organisms also exist on Community
the earth?

Discuss.
Cell is the basic unit of life.
Parts of the cell are formed of various
Population
substances.

You might have learnt that all substances are
basically formed of atoms.
Observe the illustration which shows the levels
of organisation from atom to Organism
community. Prepare a note
and record it in your
science diary.
Atom
Organ
system
Molecule

Organ
Cell organelle Tissue
Cell
Illustration 2.4
A complex living body is formed by the continuous division and
differentiation of cells. In organisms that belong to higher levels of
organization, different types of tissues act complementarily to perform
several complex physiological activities. Efficiency of the organisms
increases with the variety of its tissues. Hope you have understood
the importance of functioning together. Isn't it relevant in our social
life too?

32 Basic Science VIII