Diversity 2.7 billion years ago, microbes invented photosynthesis  Water split to get H needed to turn CO 2 into sugars, O 2 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 they reproduce, they look different. Yeasts: another way fungi can look; oval, unicellular in appearance.  Some 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 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

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

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 (most evergreens w/ needles)  6 others

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 arb02/moss.html

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