1. “Animal-Like” Protists:
Protozoans

2. “Animal-like” Protists: Protozoans
Kingdom Protista
Four phyla of “animal-like” protists differentiated by locomotion
All heterotrophs

3. Phylum Zoomastigina - Flagellates
Move by flagella – long, whip-like structures
Absorb food through cell membranes
No shell
Some free-living, some parasites
Most reproduce asexually by binary fission = genetically identical. Some reproduce sexually as well – gametes formed by meiosis = new combination of genetic information.

4. Phylum Sarcodina - Sarcodines
Best known sarcodina is amoeba
Move and feed by use of pseudopods – temporary projections of cytoplasm
No body shape, the “blob”
Move by amoeboid movement – cytoplasm of the cell streams into the pseudopod, and the rest of the cell follows
Food vacuole temporarily stores food
Reproduce by binary fission

5. Amoeboid Movement

6. Amoeba Anatomy
Food vacuole
Nucleus
Contractile vacuole
Pseudopods

7. Other Sarcodinas
Heliozoans and radiolarians – these both produce shells of SiO2 (silica)
Foraminifers – produce shells of CaCO3 (calcium carbonate), used in dating rocks and chalk

8. Phylum Ciliophora – Ciliates
Cilia – short, hair-like projections used in feeding and/or locomotion
Found in fresh and saltwater
Most are free-living
Genus Paramecium one of the most studied protists

9. Anatomy of Typical ciliate
Pellicle – “skin”
Trichocysts – small, bottle-shaped structures used for defense and protection
Macronucleus – daily genetic material
Micronucleus – contains “reserve copy” of cell’s genes/reproduction genetic material
Gullet – indentation in one side of organism to trap food
Food vacuole – food storage and digestion
Anal pore – excretion
Contractile vacuoles – collect water and when full, contracts, pumping water out
Why is this necessary?

10. Paramecium Anatomy Trichocysts Oral groove Lysosomes Gullet Anal pore
Food vacuoles
Contractile vacuole
Micronucleus
Macronucleus
Cilia

11. Reproduction of Ciliates
Under most conditions, ciliates reproduce asexually by mitosis and binary fission – cell splits lengthwise, forming 2 genetically identical cells
When placed under stress, conjugation may occur
Conjugation allows for a crossover of genetic information, but in the end, the two cells are genetically the same – the two cells simply swapped half of each other’s genetic information. This does make new combinations of genes though = genetic diversity

12. Conjugation
Macronucleus
Micronucleus

13. Conjugation
Macronucleus
Micronucleus

14. Conjugation
Macronucleus
Micronucleus

15. Conjugation
Macronucleus
Micronucleus

16. Phylum Sporozoa - Sporozoans
Do not move, all are parasitic
Live in worms, insects, fish, birds, and humans
Very complex life cycles
Reproduce by means of spores (groups of cells which invade a new host)
Plasmodium killing red blood cells

17. The Life Cycle of Plasmodium
Mosquito bites human, injecting saliva that contains Plasmodium sporozoites
Plasmodium undergoes several stages of development in mosquito’s body
Plasmodium sporozoites
Sporozoites infect liver cells
Anopheles mosquito bites infected human and picks up Plasmodium cells
Liver
Infected liver cells burst, releasing Plasmodium cells that infect red blood cells
Infected red blood cells burst, releasing Plasmodium cells; some can infect other red blood cells, and others can infect mosquitoes
Plasmodium cells
Red blood cells

18. “Animal-like” Protists and Disease
Sporozoans – Plasmodium – malaria
Zoomastigina – Trypanosoma – African sleeping sickness
Sarcodina – Entamoeba – amebic dysentery

19. Ecology of “Animal-like” Protists – Helpful
Serve as food at the base of the food chain
Trichonympha – live inside termites and help break down cellulose in wood for termites to then digest