Grade 11 Zoology

 Protists

Protists are unicellular organisms that have a nucleus.

Kingdom: Protista

General characters

1. All the Protista are unicellular microscopic, Eukaryotic Organisms

2. The kingdom includes plant-like, animal-like, or fungi like organisms

3. They have protoplasmic or acellular level f body organization.

4. They may be free-living, parasitic, saprophytic, or symbiotic

5. They are holozoic or holophytic or saprozoic

6. Their reproduction takes place by sexual and asexual method

7. They can move with their locomotory organ-like pseudopodia, cilia, and flagella

• Categories

I. Animal-like Protists (Protozoa)

II. Plant-like Protists (Algae)

III. Fungus-like Protists (Moulds)

I. Animal-like Protists

1. Protozoan means “First Animal”.

2. Cells contain a nucleus. Cells lack a cell wall.

3. They are heterotrophs.

4. Most can move on their own.

5. Digestion occurs within the food vacuole

6. Excretion occurs by the general body

7. Surface or opening called cytopyge.

8. Contractile vacuole Perform the task of osmoregulation

Groups of Animal-like Protists

1. Sarcodines

2. Ciliates

3. Flagellates

4. Sporozoans

Sarcodina or Rhizopoda



• (Eg. Amoeba,Radiolaria, E. coli)

• locomotion by Pseudopodia (Extensions of the cell

• membrane and cytoplasm) used to capture food.

• Nutrition Holozoic – free-living or parasitic

• Pellicle absent

• Asexual reproduction occurs either by binary fission

• or multiple fission

Ciliata

• (Eg, Paramecium, Vorticella)

• Cilia as locomotory organs (Tiny hair-like projections used for movement, to gather food and as feelers)

• Nutrition holozoic

• Many free-living, some are parasitic

• Pellicle present to provide definite shape

• Have contractile vacuole

• Nuclear dimorphism (macro and micro

• nucleus) is seen.

3. Flagellata /Mastigophora

(Zooflagellates)

• Have flagella for locomotion and food capture

• Body covered with pellicle which provides shape

• They are uninucleate organisms

• Nutrition is heterotrophic

• Parasitic or free living

• They reproduce only asexually

• Eg. Zooflagellates, Trypanosoma,

• Leishmania, Giardia

Sporozoans

• (Plasmodium, Babesia, Isopora)

• Body covered with pellicle which provides shape

• Locomotory organ absent

• All Sporozans or parasites.

• They feed on cells and body fluids.

• Form from Spores (tiny reproductive cells).

• Pass from one host to another.