Transcript Diversity
Diversity 2.7 billion years ago, microbes invented photosynthesis Water split to get H needed to turn CO2 into sugars, O2 left behind All the iron on the surface rusted Oxygen accumulated Organisms adapted to new world They could get bigger; more efficient metabolism Eukaryotes Bigger, more complicated cells than prokaryotes Multicellular organisms developed Four kingdoms of eukaryotes currently recognized. Fungi, the champion decomposers Familiar terms: what do they mean exactly? Molds: types of fungi that grow as long threads or filaments. When Yeasts: another way fungi can look; oval, unicellular in appearance. Some they reproduce, they look different. fungi can grow as yeasts or molds. Mushrooms: these are reproductive structures of certain types of fungi. How do Fungi grow? Fungi are heterotrophs They are the great decomposers, break down all kinds of polymers. Can destroy wood, rubber, paint, all types of things. They are never photosynthetic! Fungi grow into, through their food. They release enzymes that break things down They take up resulting small molecules They grow at the tips and penetrate. Fungi and plants Some fungi are parasites Many plant diseases are caused by fungi Fusarium, for example Many fungi grow along with plants Myco (fungi) rrhizae (roots) = mycorrhizae Fungi growing with plant roots help furnish the plant with minerals from the soil Plants leak nutrients to feed fungi Both prosper Fungi and humans As decomposers, important in ecosystem Industrial problems Some cause disease Athlete’s foot, yeast infections, histoplasmosis Serious infections with diseases like AIDS Source of important antibiotics Penicillium is a fungus Important in food and other industries Citric acid, soy sauce, cheeses, mushrooms How are they classified? Once again, it’s about sex. Three main types of fungi When two different mating types get together, they make sexual spores The type of structure the spores are found in determines the type of fungus Mushroom is a type of spore-bearing structure Fungi also reproduce asexually too They make lots of spores this way, but not involved in classification Sexual reproductive structures that Fungi make Protista: one kingdom, or 8? The Protists are unicellular eukaryotes For “pond scum” they show incredible diversity Protists were always lumped together by what they aren’t. New schemes suggest grouping them into 8 or more different KINGDOMS As different from each other as they are from plants and animals. Is there an easy way to learn about the Protists? Here’s one. Divide them into 3 groups: Plant-like Animal-like Fungus-like Plant-like Protists Contain chloroplasts Representatives Diatoms (right). Diatomaceous earth = fossilized diatoms: abrasives and slug repellants. Red, brown, yellow algae Seaweed, source of agar Dinoflagellates Neurotoxins and red tide http://www.bhikku.net/archives/03/img/diatoms.JPG www.enviroliteracy.org/ article.php/534.html Animal-like protists Capable of ingesting their food. Capable of moving around Amoebas Protozoa with flagella or cilia Disease-causing protists belong to this group Diarrhea, malaria, STD http://en.wikipedia.org/wiki/Slime_mold http://ar.geocities.com/seti_argentina/estamos_solos/ameba.jpg Fungus-like Water molds Motile by flagella (fungi aren’t.) Phytophora infestans, cause of Irish potato blight Slime molds “the blob”, one giant cell or groups of cells that crawl over the ground Digest everything in their path res2.agr.ca/lethbridge/ emia/SEMproj/phyinf_f.htm http://en.wikipedia.org/wiki/Slime_mold The Kingdom Plantae Plants are highly successful Photosynthetic, use sunlight energy and carbon dioxide Also need minerals to grow The world of Plants The most abundant and successful type of plant are flowering plants, the Angiosperms. There’s actually 9 other completely different types of plants. Mosses Ferns Cycads Conifers 6 others (most evergreens w/ needles) Examples: most primitive to most advanced Mosses Have no roots No seeds Ferns Produce spores, not seeds Gymnosperms Naked seeds, in cones Angiosperms Flowers and seeds Pictures cited http://www.mpm.edu/collect/fern-6.gif www.maxwaugh.com/ arb02/moss.html http://www.huntergardens.org.au/images/conifer1.jpg www.sbs.utexas.edu What have angiosperms got that makes them good? Specialized structures for pulling water out of dry ground: roots Specialized structures for exchanging gases with the atmosphere and collecting sunlight: leaves Structures for holding the leaves up where they can do these things: shoots Flowers Attract pollinators that spread male gametes (pollen, from anthers) to female gametes (inside ovaries) Provide a protective place for embryo (within seeds) to form. Seeds are within or attached to fruit. Fruit is a mechanism for dispersal of seed Some is eaten and excreted elsewhere Some sticks and is carried about Some blow, some float, many strategies