Unit 3 –Notes #1 Animal-Like Protists (PROTOZOANS)
Protista Introduction :
- Unicellular most are solitary but some are colonial
- Extremely diverse 115,000 different species, some heterotrophic, some
autotrophic.
- Any unicellular organism that is Eukaryotic is thrown into Kingdom
Protista.
- 1.5 - 2 billion years old.
Two theories from an evolutionist’s point of view:
a) Evolved from prokaryotes.
b) Evolved from symbiotically associated prokaryotes. “Endosymbiont
Hypothesis”
FUNGUS LIKE
2 Phyla
2 Phyla
3
A) Animal-Like Phyla (Protozoans)
- Classified into 4 smaller groups based on movement:
1) Ciliates  Move by cilia
2) Flagellates  Move by flagella
3) Amoeboid Extend cytoplasmic bodies in one direction
4) Sporozoans  No movement
1. Phylum - CILIOPHORA (Ciliates)
- Contain cilia (short hair-like
appendages) for movement.
- Free living
- Filter feeders or hunters
- Example: Paramecium
Functions of Parts:
- Pellicle: made up of cell membrane
and associated underlying structures.
- Trichocysts: spiny projections used for defense.
- Macronucleus and Micronucleus: genetic information
- Gullet/Oral Groove: brings food from the outside to the inside: (mouth)
- Food Vacuoles: Membrane enclosed vacuole, which contains food.
- Anal Pore: Where wastes are emptied
- Contractile Vacuole: Star-shaped, Removes excess water to prevent
bursting of cell.
- Cilia: Moves the protists as well as brings food to the gullet.
- Lysosome: Contain enzymes that help digest food particles. Fuse with the
food vacuole.
- Most of the time they will reproduce asexually by Binary Fission, but under
harsh conditions they will sexually reproduce by Conjugation.
2. Phylum - ZOOMASTIGINA (Flagellates)
- Also known as Phylum “Mastigophora”
- Use flagella
- Absorb food through their cell membrane.
- Reproduce by binary fission or by meiotically producing haploid gametes.
- Some are parasitic.
- Examples : Giardia (Gastro-intestinal trouble) and Trichomonas (Venereal
Disease)
Giardia:
3. Phylum – SPOROZOA (spore producing)
- Do not move (non-motile).
- Reproduce by spores
- Most are parasitic and cause disease in other organisms.
- Example : Plasmodium vivax, carried by Anopholes Mosquito. Forms spores
in mosquito, then passed into humans. Parasite then infects human blood and
liver cells causing them to lyse and release toxins. “Malaria”.
4. Phylum – SARCODINA (Sarcode-Jelly)
- Pseudopods for movement and feeding
-Most common family : Amoebae
- Engulf food with pseudopods : Phagocytosis
- NO cell wall, flagella or cilia, possess contractile vacuole to pump out excess
water.
- Reproduce asexually
binary fission.
- Other groups include
Radiolarans,
Foraminifers and
Heliozoans.
- Foraminifers secrete
shells of calcium
carbonate (CaCO3
chalk), form thick deposits at bottom of ocean.
LIVING WITH ANIMAL-LIKE PROTISTS
a. Harmful Relationships:
i) Plasmodium vivax  Malaria
ii) Members of Genus Trypanosoma of Zoomastigina cause a number of
diseases:
Ex #1. African Sleeping Disease : Tsetse fly carries parasite. Infection leads
to chills, fever, and rash. Parasite attacks nervous system leading to
unconsciousness and even death.
Ex. #2 Chagas Disease : Parasite Trypanasoma cruzi attacks muscle cells
including those of the heart causing heart (cardiac) failure.
iii) Sarcodinans - Some “entamoeba” cause amoebic dysentery results in
severe bleeding and bloody diarrhea.
b) Helpful Relationships.
i) Zoomastiginan – Trychonympha found in the gut of both the termite and the
wood roach. Have the enzymes that allow for the digestion of cellulose.
Animals by themselves do not have the correct enzyme to digest cellulose.
Recycle dead wood into nutrient cycle.
ii) Many zooplankton (any microscopic floating animal) play a crucial role in
aquatic food webs.