3-28 Protists and Fungi-1.pdf

Protists and Fungi Life is organized into three domains 1. Bacteria 2. Archaea 3. Eukarya (Plants, Animals, Fungi, and Protists) 4 Eukaryotes One domains: Eukarya Characteristics of Eukaryotes: Single or Multicellular organisms Have a membrane bound nucleus and other membrane-bound organelles “eu” =...

Protists and Fungi Life is organized into three domains 1. Bacteria 2. Archaea 3. Eukarya (Plants, Animals, Fungi, and Protists) 4 Eukaryotes One domains: Eukarya Characteristics of Eukaryotes: Single or Multicellular organisms Have a membrane bound nucleus and other membrane-bound organelles “eu” = true “karyote” = nucleus 5 Endosymbiotic Theory The idea that some eukaryotic organelles arose from symbiotic interactions between eukaryotic cells and engulfed prokaryotes. DNA sequencing reveals 24 Eukaryotic Kingdoms Plants DNA sequencing Animals Plant, Animal, Fungi Kingdoms confirmed Former Protist Kingdoms split into 21 new Kingdoms Fungi Animals, Plants, and Fungi are more closely related to Protists Kingdoms than to each other 9 The Supergroups of Eukarya 9 Supergroup SARs SARs: Stramenopiles, Alveolates, Rhizaria Included in the same Supergroup due to DNA similarities. These groups don’t share defining physical characteristics. Brown Algae 11 Ciliates Foraminiferan Supergroup Amoebozoans Amoeboid Characteristics: - Single cellular - Have pseudopods Cellular slime mold - Heterotrophic Include: - Cellular slime molds - Plasmodial slime modes - Amoeboids 16 Plasmoidal slime mold Supergroup Opisthokonts Single cellular or multicellular - Some have flagella or pseudopods - All heterotrophs Includes: - Choanoflagellates - Fungi - Animals Supergroup Excavates Characteristics: - Single cellular - Atypical or absent mitochondria - Have a feeding groove - Possess unique flagella - Heterotrophic of photoautotrophic Euglenids Diplomonads Kinetoblasts 15 Parabasalids Supergroup Archaeplastids Characteristics: - Photoautotrophs - Contain plastids (organelles descended from engulfed cyanobacteria such as chloroplasts) - Single cellular (individual and colony forming) or multicellular 10 Red Algae Charophytes Green Algae Archaeplastids Include Plants Features of Fungi Cell walls made of chitin Heterotrophic Multicellular or single celled Reproduce asexually or sexually Fungi: Heterotrophic Organisms Fungi absorb simple organic molecules directly through their cell walls. Fungi secrete digestive enzymes that break down complex organic molecules into simpler molecules that can be absorbed. Fungal Hyphae In fungi, the filamentous structure of hyphae provides a high surface area-to-volume ratio for absorption of organic molecules. Hyphae are characterized by rapid growth, and the network of hyphae form the mycelium in a fungus. Material Transport in Fungi: Turgor Pressure and Bulk Flow Molecules absorbed from the environment drive water into the fungal cell via osmosis. The fungal cell wall maintains the shape of the hypha and increases turgor pressure. Turgor pressure pushes the hypha into its surroundings in search of food. Fungal Asexual Reproduction: Sporangia Black bread mold is a fungus consisting of sporangia, within which spores are produced mitotically. The sporangium form allows for rapid spore dispersal, but because their spores are asexual, sporangia do not increase fungal genetic diversity. Fungal Sexual Reproduction: Fruiting Bodies Fruiting bodies are above-ground reproductive structures produced by many fungi. They are formed from densely packed hyphae. The increased elevation helps with dispersal of sexually produced spores. Fungal Life Cycles can be Sexual or Asexual Fungi have life cycles that include haploid and diploid stages. Nuclei in fungi are haploid, so their life cycles are similar to haploiddominant organisms. Cells (Hyphae) fuse before nuclei in many fungi Fungi have life cycles that include haploid and diploid stages. Nuclei in fungi are haploid, so their life cycles are similar to haploiddominant organisms. Fungi are most closely related to protists The protist Kingdom of Microsporidia is most closely related to fungi Fungi first arose in aquatic environments May have migrated onto land with early plants as symbiotes Fungal Phylogeny Chyrtids: Aquatic fungi, lack hyphae Zygomycetes: produce hyphae w/o septa, rare Glomeromycetes: form endomycorrhizea Basidiomycetes: Some mushrooms (toadstools and puffballs), plant pathogens Ascomycetes: Some mushroom, ectomycorrhiza, animal pathogens, brewers and bakers yeasts