Sub-Kingdom Protozoa

General Characteristics Single-celled or unicellular organisms; some live in colonies; Size = microscopic (3 to 1,000 microns). No germ layers, tissues, or organs; However, specialized intracellular "organelles" are present Over 64, 000 species have been described; about 50, 000 are free-living

Locomotion by pseudopodia, flagella, or cilia. Symmetry = all types (bilateral, radial, spherical, or asymmetrical) Free living, commensal, parasitic, or mutualistic Mostly naked, but few have simple protective exoskeletons (tests), E.g. Arcella and Difflugia

Nutrition = autotrophic (holophytic), saprozoic, saprophytic, or holozoic. Reproduction: asexual = longitudinal and transverse binary fission, budding, multiple fission (sporogony, schizogony) Sexual = syngamy, autogamy, conjugation

List of Phyla Phylum Sarcodina Phylum Mastigophora Amoeba-like organisms (e.g. Amoeba, Entamoeba, Arcella) Phylum Mastigophora Phytomatigophorans (e.g. Euglena, Chlamydomonas) Zoomastigophorans (e.g. Trypanosoma, Giardia, Trichonomas, Trichonympha) Phylum Chlorophyta (e.g. Volvox) Phylum Ciliophora (e.g. Paramecium, Balantidium,) Phylum Apicomplexa (e.g. Plasmodium, Eimeria, Toxoplasma, Isospora)

Phylum Sarcodina Organisms move by pseudopodia, flagella, or a combination Single nucleus, or monomorphic nuclei Genera Amoeba - without a test, naked (free-living) Arcella - with a calcareous test (free-living) Entamoeba - without a test (parasitic)

Figure 11.10

Amoeba Pseudopod Food Vacuole Contractile Vacuole Nucleus Phagocytosis Hyaline Cap

Amoeba hunting food

Arcella Test Nucleus Pseudopod Arcella

Phylum Mastigophora Organisms move by one or two flagella Single nucleus, or monomorphic nuclei Some are capable of photosynthesis; chloroplasts usually present Others are either mutuals or parasites Common symmetry is bilateral

Subphylum Euglenoidea Plant like organisms; photosynthesis Solitary Symmetry is usually bilateral Presence of stigma for light detection

Euglena

Euglena Chloroplasts Contractile Vacuole Flagellum not visible Stigma

Kinetoplastida Organisms are only heterotrophic No chloroplasts present all parasitic Red Blood Cells Organism Trypanosoma smear – cause of sleeping sickness

Trypanasoma sp. Trypanosoma Red Blood Cells

Leishmania sp Giardia sp

Phylum Chlorophyta Flagellated single or colonial organisms All members are autotrophic, chloroplasts with chlorophyll Genetically different from Euglenozoa

Volvox life cycle

Zygote Egg Mother Colony Volvox

Phylum Apicomplexa organisms do not have locomotor structures; all species are parasitic asexual reproduction involves multiple fission (schizogony, sporogony) Plasmodium smear – cause of Malaria

Final Host Plasmodium – agent For malaria Vector

Ring stage merozoite trophozoite Red blood cell Trophozooite

Ring stage in red blood cell Ring stage – Early Trophozoite

Merozoites in the Schizont Schizont with merozoites in red blood cell Red blood cell Merozoites in the Schizont

Female Male Gametocytes

Phylum Ciliophora: The Ciliates Organisms move by cilia Usually two sizes of nuclei ; Macronucleus and micronucleus Reproduction usually by transverse binary fission Sexual reproduction by conjugation

Paramecium

Binary Fission – Asexual Reproduction

Conjugation – sexual reproduction

Vorticella

Stentor

Protozoa: Ecological Importance Unicellular level of organization Highly specialized organelles for various physiological processes Prominent members of the aquatic food chain, especially detritivores and Symbiosis is highly developed among members i.e. Commensals, parasites, mutuals, and detritivores with multicellular organisms