Anthony Van Leuwenhoek invented a powerful microscope in 1674 that could magnify objects 300 times, allowing him to discover bacteria and other microorganisms. He observed bacteria, protozoa, algae, fungi, and other microbes under his microscope. Microscopes are necessary to see most microorganisms because they are too small to be viewed with the naked eye. Microbes come in different shapes, sizes, and configurations and include bacteria, viruses, algae, fungi, protozoa, and micro arthropods. Bacteria are single-celled prokaryotes that can live in diverse environments and reproduce through binary fission.

1. Story of Micro Organisms

2. Anthony Van Leuwenhoek invented in
1674 a single lens powerful microscope
which could magnify the 300 times

3. The First Microscopes

4. His keen observation of different things
under his microscope helped him to
discover small moving organisms, which
he named “Animalcules”. Later these
were named as Bacteria.

5. Along with the animalcules, he also
observed many other micro organisms
under his microscope which got their
respective names later on.

6. We can see several organisms in our
surroundings but we can not see many of
them with our unaided eyes.
Micro organisms can be seen only with the
help of a microscope

7. Groups of Micro Organisms
Bacteria Viruses Algae
Fungi Protozoa Micro
arthropods

8. Bacteria
Bacteria are prokaryotes and microscopic
organisms . The entire organism consists of a
single cell with a simple internal structure.
Bacterial DNA floats free, in a twisted thread-
like mass called the nucleoid

9. Bacteria
Bacteria thrive in diverse environments. They
can live within soil, in the ocean and inside the
human gut. Sometimes they lend a helping
hand, by curdling milk into yogurt, or helping
with our digestion. At other times they are
destructive, causing diseases like pneumonia
and MRSA

10. Bacteria types by shape
Round bacteria are referred to as cocci
(singular: coccus); cylindrical, capsule-shaped
bacteria as bacilli (singular: bacillus); and
spiral bacteria are aptly called spirilla
(singular: spirillum).

11. Bacteria types by configuration
Cocci can also associate with one
another in different configurations:
combinations of two or diplococcus; a
linear chain or streptococcus; and a
cluster or staphylococcus.

12. The shapes and configurations of bacteria are
often reflected in their names. For example,
the milk-curdling Lactobacillus acidophilus
are bacilli, and pneumonia-causing
Streptococcus pneumoniae are a chain of
cocci.

13. Bacteria reproduction
Most bacteria multiply by a process called binary
fission. A single bacterial cell, the "parent," makes a
copy of its DNA and grows large in size by doubling its
cellular content. The doubled contents are pushed out
to either end of the cell. Then a small fissure emerges
at the centre of the parent, eventually splitting it into
two identical "daughter" cells.

14. Bacteria reproduction
Some bacterial species such as cyanobacteria
reproduce via budding. During budding, the daughter
cell grows as an offshoot of the parent. It starts off as
a small nub, grows until it is the same size as its
parent, and splits off.

15. Thiomargarita namibiensis
Rare, exotic microorganism
In 1997 Heide N Schulz discovered a biggest
bacterium Thiomargarita namibiensis found
in coastal waters of Namibia (0.75 mm) which
can be seen with unaided eye.

16. Fungi

17. • Fungi can be single celled or very complex
multicellular organisms. They are found in
just about any habitat but most live on the
land, mainly in soil or on plant material
rather than in sea or fresh water.

18. • A group called the decomposers grow in the
soil or on dead plant matter where they
play an important role in the cycling of
carbon and other elements.

19. • Some are parasites of plants causing
diseases such as mildews, rusts, scabs or
canker. In humans these include skin
diseases such as athletes’ foot, ringworm
and thrush.

20. • Eukaryotic and heterotrophic
• Chitin made cell wall
• Filamentous hyphae
• No true tissue

21. Algae
Algae can exist as single cells, an
example of which is Chlamydomonas, or
joined together in chains like Spirogyra
or made up of many cells (colonial), for
instance Volvox.

22. Algae
Most algae live in fresh or sea water
where they can either be free-floating
(planktonic) or attached to the bottom.
Some algae can grow on rocks, soil or
vegetation as long as there is enough
moisture.

23. Algae
A few algae form very close partnerships
with fungi to form lichens.
All algae contain a pigment called
chlorophyll and they make their own food
by photosynthesis. The chlorophyll is
contained in the chloroplasts and gives
many algae their green appearance.

24. Algae
However some algae appear brown,
yellow or red because in addition to
chlorophylls they have other accessory
pigments that camouflage the green
colour.

25. Algae
Diatoms a type of algae, are found
floating in the phytoplankton of the
seas.

26. Algae
Diatoms a type of algae, are found
floating in the phytoplankton of the
seas.

27. Protozoa
Protozoa are single celled organisms. They
come in many different shapes and sizes
ranging from an Amoeba which can change its
shape to Paramecium with its fixed shape and
complex structure. They live in a wide variety
of moist habitats including fresh water,
marine environments and the soil .

28. Protozoa
Some are parasitic, which means they live in
other plants and animals including humans,
where they cause disease. Plasmodium, for
example, causes malaria. They are motile and
can move by. Some are sedimentary, for
example, vorticella.

29. Micro Arthropods
Soil Micro arthropods support ecosystem
productivity and soil C accrual

30. Viruses
Since viruses are so small (tinier than bacteria) they may be considered microbes. However, since they
are not "alive" outside of a host organism, it is debatable whether they are really organisms at all.

31. Viruses
Viruses are an interesting type of micro organisms. They
behave like non living things when they are outside a
living cell. But behave like living organisms why they are
inside host living cells and reproduce. They can only be
seen through very powerful electron microscope. Diseases
like Polio, Swine flu, Conjunctivitis, Smallpox, chickenpox
and AIDS are caused by Viruses.

32. Viruses size compared
Viruses