“Animal-Like” Protists:

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. Contractile vacuole Pseudopods Nucleus Food vacuole Amoeba Anatomy

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

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