The document discusses the characteristics and life cycle of protozoans, particularly focusing on the paramecium, a unicellular organism that utilizes cilia for movement and feeding. It details their reproduction methods, including asexual binary fission and sexual conjugation, as well as their ecological roles in various environments and their potential to cause diseases in host organisms. Paramecia are significant in ecosystems, feeding on bacteria and smaller protists while also having adaptations for survival and waste management.

1. SAMSUDEEN. S

2. • Sometimes called the “Junk drawer”
• Contains animal-like, plant-like and
fungus-like organisms
• Plankton (zoo-/phyto-/myco)

3.  Unicellular
 Eukaryotic
 Basically Ingestive Heterotrophs
 Lack cell walls but have definite
shapes
 Most are motile
 Basically reproduce by asexual
reproduction
 Aerobic but some can live in
anaerobic conditions (ones living in
digestive tracts)

4. 1. Macronucleus – controls metabolism
2. Micronucleus - involved in conjugation
3. Contractile vacuoles – maintains structure
4. Homeostasis – auto regulate
5. Ingestion structures
6. Anal pore – excretion of wastes
7. Trichocysts – defense mechanism

5.  Majority of free-living
 Marine, terrestrial & freshwater.
 Some are parasites on algae to
vertebrates
 Make up the zooplankton in marine
ecosystems. Feed on phytoplankton
 Abundant in soil or on plants &
animals
 Some live in guts of termites, roaches
& ruminants (cows)

6. Paramecium
Stenor
Paramecium with trichocysts
Vorticella
Didinium

7.  Paramecium is a
small unicellular
organism.
 It is plentiful in
freshwater
ponds.

9.  Ciliata (Ciliophora)
- Have cilia.
- Similar in structure to flagella but
shorter and all over surface of organisms
- Cilia usually arranged in rows &
connected to each other
- Cilia near oral cavity involved food
gathering.
- Transverse fission & sexual
reproduction by conjugation
i.e) – Paramecium.

10.  Ciliata (Ciliophora)
- Have cilia.
- Similar in structure to flagella but shorter
and all over surface of organisms
- Cilia usually arranged in rows & connected
to each other
- Cilia near oral cavity involved getting food.
- Transverse fission, & sexual reproduction
by conjugation
i.e) – Paramecium, Didinium.

11. Animal-Like Protists

12.  Flagellates are the ancestors of
ameoboid protozoan
 Phytoflagellated (photosynthesizing)
 Zooflagellated (particle feeding and
parasitic)

13. macronucleus
micronucleus
oral groove
gullet
contractile
vacuole
food
vacuole
cilia
pellicle
anal pore
cytoplasm:
ectoplasm
endoplasm

14. • The outer surface of the cell is
covered with many hundreds of
tiny hair-like structures called
cilia.
• These act like microscopic oars to
push through the water, enabling
the organism to swim.
• If Paramecium comes across an
obstacle, it stops, reverses the
beating of the cilia, swims
backwards, turns through an angle
and moves forward again on a
slightly different course.
• It moves so quickly that we have
to add a thickening agent or
quieting solution to the slide to
slow it down to study it.

15.  Paramecium has a permanent feeding
mechanism, consisting of an oral
groove and a funnel-shaped gullet into
which food is drawn by the combined
action of cilia which cover the body and
other cilia lining the oral groove and
the gullet.
 As it moves through the water it rotates
on its axis and small particles of debris
and food are collected and swept into
the gullet.
 They feed on small organisms such as
bacteria, yeasts, algae and even other
smaller protozoa.

16. • Food waste left in a food
vacuole is excreted
through the anal pore
(the vacuole and pore
fuse.
• Other wastes left over
from cellular activity
(metabolic waste) simply
diffuse through the
pellicle.
• Excess water and some
metabolic wastes are
excreted through the
contractile vacuole.

18. Asexual Reproduction in Protozoa

19. Conjugation in Paramecium

20. • In favourable conditions
the cell divides in two by a
process called binary
fission (asexual
reproduction).
• This forms two new cells,
each of which rapidly
grows any new structures
required and increases in
size.
• This whole process may
take place two or three
times a day if conditions
were right.

21.  This is a more
complicated method
called conjugation
(sexual reproduction).
 It involves two cells
coming together to
exchange nuclear
material.
 The two cells then
separate and continue to
reproduce by simple
division.
 It is similar in some ways
to sexual reproduction in
more complex animals.

22. Paramecium
conjugating
Transverse Binary
fission

23.  Adaptations:
 Cilia to help feed and escape
 Contractile vacuoles
 Trichocysts

24. • Movement: by cilia in circular motion,
move ~ 60 mm/hr
• Metabolism:
-food pulled into oral groove by cilia
-food vacuole forms at gullet
-lysosome aids with digestion
• Feed mostly on bacteria, smaller
protozoans and algae.

25.  Excretion:
-Contractile vacuole removes excess
H20.
-C02 across pellicle by diffusion
-anal pore removes waste.
 Reproduction: Asexual - cell division
Sexual – conjugation
(exchange of micronucleus DNA)

26.  Cause disease in host organisms
Malaria – Plasmodium via mosquito
Toxoplasmosis – Toxoplasma
African Sleeping Sickness – Trypanosoma
via tsetse fly
Chagas – Toxoplasma
Vaginitis – Trichomonas
Giardiasis – Giardia
150 million people/year in world contract
Malaria & 1.5 mill/year die of it.

27. “One scientist calculated that if all the
progeny of a single Paramecium
survived, assuming a division rate of
once a day, then after 113 days, the
mass of paramecia would equal the
volume of the Earth! “