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Chapter 20: Section 5

Chapter 20: Section 5. Funguslike Protists By: Alice, Darwin, Tate, and Kiara. Overview of the Section. Funguslike protists grow in damp, nutrient-rich environments and absorb food through their cell membranes, much like fungi.

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Chapter 20: Section 5

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  1. Chapter 20:Section 5 FunguslikeProtists By: Alice, Darwin, Tate, and Kiara

  2. Overview of the Section • Funguslikeprotistsgrow in damp, nutrient-rich environments and absorb food through their cell membranes, much like fungi. • Their cellular structures more closely resembles that of protists, though. • Like fungi, the funguslikeprotists are heterotrophs that absorb nutrients from dead or decaying organic matter. • They have centrioles, though, and lack the chitin cell walls of true fungi.

  3. Slime Molds • They are found in places that are damp and rich in organic matter, ex: the floor of a forest, a compost pile, etc. • Slime molds are funguslikeprotiststhat play key roles in recycling organic material. • Their appearances vary. • Two broad groups of slime molds are recognized: -Cellular slime molds -Acellular slime molds

  4. Examples of Slime Molds The yellow substance is the slime mold. Red raspberry slime mold.

  5. Cellular Slime Molds • Belong to the phylum Acrasiomycota • During much of their life cycle, they are unicellular organisms that look and behave like animallikeprotists. • When they aggregate, or collect into an unorganized whole, they behave like multicellular organisms. • They spend most of their lives as free-living cells, easily confused with soil amoebas.

  6. Cellular Slime Molds:Reproduction • Slime molds can reproduce sexually and asexually. • The sexual method is much like meiosis. • The asexual method is described below: • When they begin to run out of food, cellular slime molds reproduce to make sporesthat can survive with the limited resources. • They first send out chemical signals that attractothers of their species. • Thousands of cells aggregate into a large sluglike colony that begins to function like a single organism, within a few days. • The colony migrates a little, then halts and produces a fruiting body, or a slender reproductive structure that produces spores. • These spores will eventually scatter, and give rise to a single amoeba-like cell, that will start the cycle all over again.

  7. Visual of the cellular slime mold’s reproductive methods

  8. Acellular Slime Molds • Belong to the phylum Myxomycota. • Like cellular slime molds, they begin their life cycles as amoeba-like cells. • When they aggregate, their cells fuse to produce structures with many nuclei, or plasmodia. • A plasmodium can grow several meters long. • The plasmodium is a multinucleate (containing several nuclei) contained in a single cell membrane.

  9. Acellular Slime Molds:Reproduction • Acellular slime molds reproduce sexually: • Small fruiting bodies, or sporangia,spring up from the plasmodium. • The sporangia produce haploid spores by meiosis. • The spores scatter to the ground, where they germinate into amoeba-like or flagellated cells • These cells fused in a sexual union to produce diploid zygotes, which repeat the cycle.

  10. Visual of Asexual Slime Mold’s Reproduction

  11. What are water molds? • Have you ever seen white fuzz growing on top of a dead fish in the water? If you have, then you have witnessed water mold in action! • Water molds are also known as oomycetes. • They are members of the phylum Oomycota. • Oomycetes thrive on dead or decaying organic matter in water and some are plant parasites on land. • They are not true fungi, though, because they produce thin filaments called hyphae. • These hyphae do not have walls between their cells, and are multinucleate as a result. • Water molds’ cell walls are composed of cellulose and they produce motile spores. • These are two traits that real fungi do not have.

  12. Water Mold Visual

  13. Water Molds:Sexual Reproduction • Sexual reproduction in water mold takes place in specialized structures, created by the hyphae. • The antheridiumproduces male nuclei. • The oogoniumproduces female nuclei. • Fertilization occurs within the oogonium. • Spores are formed, as a result, and they develop into new organisms.

  14. Water Molds:Asexual Reproduction • In asexual reproduction, portions of the hyphae develop into spore cases, or zoosporangia. • Each zoosporangium creates flagellated spores that swim away to look for food. • When they find food, the spores develop into hyphae, which in turn grow into new organisms.

  15. Visual of Water Molds’ Asexual Reproduction

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