Protista and Fungi - 2 kingdoms of Eukarya Protists Protists were first eukaryotes to evolve. All eukaryotes lacking distinct characters of 3 higher kingdoms are placed in kingdom Protista Most protists are unicellular others are simple multicellular without evolving higher organs or organ-systems. Mitosis, Meiosis and sexual reproduction arose for the first time in this kingdom. All the organelles of plants, fungi and animals arose in this kingdom. Body Forms in protisita Unicellular: formed of 1 cell – Chlamydomonas, Euglena, Vorticella Colonial: many unicellular organisms live together in a colony – Volvox Filamentous – Cells are placed end to end to form a row = filament - Spirogyra Body Coverings in Protista Plasma membrane = cell membrane – Amoeba Pellicle: protein strips present below cell membrane and supported by microtubules, strips may slide to form flexible covering (Euglena) Alveolate: alveoli are flattened sacs just below cell membrane – Ciliates-Paramecium, dinoflagellates, sporozoans-malarial parasite. Cell wall outside cell membrane in green, brown and red algae Main Groups of Protists Refer to table given separately Fungi These are multicellular, heterotrophic-absorptive eukaryotes. The fungus body is called Mycelium, formed of many thread like Hyphae (singular is hypha). Hypha can be septate with one nucleus per cell or aseptate = coenocytic with many nuclei. Chytridiomycota Chytridiomycota are oldest fungi; only group to possess flagellated spores, zoospores. They have both cellulose and chitin in their cell walls. These are predominantly aquatic. Example is Allomyces. Zygomycota Zygospore Fungi-Zygomycota are molds with non-septate hyphae. These reproduce asexually by spores. The gametes formed at the tips of special hyphae, fuse to form zygospore, a thick walled zygote. Under favorable conditions zygospore undergoes meiosis and forms spores which produce the mold again. Table 17.3. Common example is Rhizopus the black bread mold. Ascomycota Sac fungi - Ascomycota have septate hyphae. Most of them reproduce asexually by conidia. Conidia are formed in chains by budding. Two hyphae of + and – strains fuse. The resulting hyphae have 2 nuclei in each cell. Fusion takes place in a special structure called Asci (singular ascus) which are enclosed in a fruiting body called Ascocarp. Common examples are Yeasts, Morels and Truffles. Basidiomycota Club Fungi- Basidiomycota has special bodies called basidia. Fusion of nuclei take place in it and 4 sexual spores are formed externally from each basidium. Spores germinate to form monokaryotic mycelium. The tips of + and – strains of hyphae fuse to form dikaryotic hyphae which form the fruiting body called basidiocarp. Basidiocarp bears gills on its under surface. Gills have basidia. Table 17.3 Common examples are Mushrooms, puff-balls. .