D Kingdom Protista Part 3

Fungus-like Protists • Slime Mold o Found on moist, decaying matter o Motile: move by pseudopodia o Stationary reproductive stage that produce fungus-like spores • Water Mold o Filamentous branches of cells o Found in water or soil o Some parasitic Phylum Myxomycota • Plasmodial slime mold • Mass of cytoplasm called a plasmodium • Can vary in size (several meters) • Multinucleated: diploid nucleus • No cell wall to separate nucleus • Moves by cytoplasmic streaming • Consumes dead organic material by phagocytosis • Poor living environments cause it to reproduce o Forms stalks with fruiting body containing haploid spores that are formed as the nucleus undergoes meiosis o Spores are resistant to harsh environments o Spores crack open to reveal haploid nucleuses which fuse with other haploid nuclei to form a diploid nucleus o Nucleus undergoes mitosis to form many nuclei & cells that results in a multinucleated plasmodium Phylum Dictyostecida • Cellular slime mold • Move with pseudopodia • Exists as haploid cells • Creep along the ground or water, ingesting small organisms • Exist as independent cells • When conditions are harsh they reproduce o Secrete chemicals that attract other cellular slime molds o Pseudoplasmodium: thousands of them meeting together o Colony of cells move together as one yet each cell remains independent o Colony forms floating bodies that contains spores which open under good conditions o Each haploid spore becomes an individual cell

Phylum Oomycota • Water mold • Parasitic (infect fish) • Asexual reproduction o Produce spores with flagella o Germinate into threadlike cells o Becomes another water mold • Sexual reproduction o Develop eggs & sperm o Fertilization tubes grow between molds o Produces diploid zygote which grows into new filaments Phylum Chytridiomycota • Water mold • “aquatic protists” • Have gametes & zoospores with flagella • Unicellular • Parasitic • Have some fungal characteristics o Same method of eating o Same cell walls o Filaments o Similar enzymes • Considered the evolutionary link between fungus & protists