6. INTRODUCTION
◈ It is 3rd largest phylum.
◈ One called body performed all the biological activities
like multicellular animals. So they are termed as
“Acellular” organism, proposed by Dobell.
◈ Protozoans were first studied by Leeuwenhoek.
◈ The name Protozoa was coined by Goldfuss.
◈ Study of protozoon’s is known as Protozoology.
8. OTHER FEATURES
◈ They are world wide, Cosmopolitan mostly
◈ Microscopic, Aquatic, terrestrial, free living (Amoeba)
or parasitic (Plasmodium). Solitary or colonial
(Proteropongia). Causes serious diseases or pathogenic
◈ Protozoas are small microscopic, Eukaryotic
Unicellular, Colourless, Spherical, Oval, Bell shaped,
Spindle shaped slipper like having irregular symmetry.
9. OTHER FEATURES
◈ Body level of organisation of Protozons is Protoplasmic level.
◈ Consists of uninucleate or multinucleate protoplasm mostly
naked or some have body bounded by delicate membrane or a
firm pellicle, Lorica or shell.
◈ In few groups of protozoa CaCO3 & Silica shell’s Exoskeleton
is found e.g Radiolarian group & Foraminiferan group.
◈ Number of nuclei vary from one to many. Few show nuclear
dimorphism e.g. Paramoecium. Body performs all necessary
biological activity so in them subcellular - Physiological
division of Labour is found.
19. RESPIRATION AND EXCRETION
◈ Respiration and Excretion take place by exchange of
gases through body surface. Some excretion may
occur through contractile vacuole.
◈ Nitrogenous waste is Ammonia.
◈ Some fresh water protozoans get rid of excess water
through contractile vacuole known as Osmoregulation.
Amoeba has one and Paramoecium has two vacuoles.
22. Asexual
◈ Binary fission (Ameoba)
◈ Transverse fission
(Paramoecium)
◈ Longitudinal fission
(Trypansoma, Euglena)
◈ Multiple fission
(Plasmodium)
◈ Budding
REPRODUCTION
Sexual
◈ Syngamy (Plasmodium)
◈ Conjugation
(Paramoecium)
Some also form cyst which help during
unfavourable condition for reproduction of
organism. They do not have natural -
death because in unicellular animals there
is no division of somatoplasm & germplasm
so these are considered as immortal.
23.
24.
25. Thanks!
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