Download presentation
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
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.