1. Diversity in living
organisms
By group 1

2. The bewildering variety of life around us
has evolved on earth over millions of
years.
We do not have enough time to view each
and every fraction of these living
organisms alone.
Instead we look at them as a whole and
find similarities and dissimilarities among
the organisms which allows us to classify
them into different types.

3. Evolution of living organisms

4.  Attempts at classifying living things
into groups have been made since the
time immemorial.
 Greek thinker Aristotle classified
animals according to where they lived
i.e. land, water or air.
 This was then rejected by the people of
that time since it wasn’t an
appropriate way to classify animals by
the basis of their habitat.

5. What is meant by characteristics?
• When trying to classify a diverse group of
organisms, finding ways in which some of them are
similar enough to be thought of together is the
easiest.
• Characteristics mean a particular form or
function. Eg. Humans have 5 fingers in each hand.

6. Characteristics for hierarchical
classification -
Characteristic No.1
An eukaryotic cell has membrane bound organelles
including a nucleus which allows cellular process to be
carried out easily.
Organisms which do not have a clearly demonstrated
nucleus need not have their biochemical practices
always organized.
This would effect every aspect of the cell design.

7. Eukaryotic cell

8. Characteristic No. 2
• Cells that group together to form a single
organism use the principle of division of
labour.
• In such a cell type, all the cells wouldn’t be
identical .
• Groups of cells will carry out specialized
functions
• Eg. An amoeba and a worm.

9. Amoeba and a worm.

10. Characteristic No. 3
• Some organisms can produce their own food
like plants.
• The other cannot produce their own food and
depend on the environment they live in for food
like bear, lion, zebra.
• The organisms which can produce food are
more organised and complex than the one’s
who cant produce food on their own.

11. Plant and lion.

12. Characteristic No.4
•There are different ways in which
some animal’s body organs develop
faster or more complexly from the
other animals.
•There are also some special organs for
a particular function in some animals.
Eg, A cheetah’s leg’s muscular
contraction and relaxation speed.

13. A Cheetah

14. Classification and evolution
• All living things are categorized on the
basis of their body design and function.
• Once a certain body design comes into
existence it will shape the effects of all
other subsequent body designs.
• There is an important role of time in the
change of characteristics.

15. Human life stages

16. • The classification of life forms are closely
related to their evolution.
• Evolution means the accumulation of the
changes in body design which allow the
organism to survive better in its
surroundings.
• Charles Darwin described this idea of
evolution in his book -The origin of species

17. An camel’s eye – Charles Darwin –
His book The origin of species.

18. The hierarchy of classification
of groups
• Biologists Ernst Haeckel, RobertWhittaker and Carl
Woese have tried to classify all living organisms into
broad categories called kingdoms.
• The classification RobertWhittaker proposed has five
kingdoms namely
a) Monera
b) Protista
c) Fungi
d) Plantae
e) Animalia

19. Ernst Haeckel, Robert Whittaker
and Carl Woese

20. Monera
• These organisms do not have a defined nucleus
or organelles nor do any of them show multi-
cellular designs.
• Some have cell walls and some do not.
• Can be seen only through a microscope.
• Some synthesize their own food (autotrophic)
and some get it from the environment
(heterotrophic)
• Eg. Bacteria, cyanobacteria and mycoplasma.

21. Cyanobacteria and mycoplasma

22. Protista
• Includes many unicellular eukaryotic
organisms.
• Some use appendages like cilia or flagella for
moving around.
• Mode of nutrition can be autotrophic or
heterotrophic.
• Eg.Unicellular algae, diatoms and protozoans.

23. Unicellular Algae, Diatoms and
protozoans.