Ch 9, Sec 3 Protists

1. Protists - eurkaryotes not classified as animals, plants, or fungi - diversity - some are unicellular, some are multicellular - live in moist surrounds - most reproduce asexually, some sexually Ch 9, Sec 3 Protists

2. Protists divided into 3 categories based on shared characteristics with other kingdom organisms 1. Animal-like protists 2. plantlike protists 3. funguslikeprotists Animal-like protists (Protozoans) - heterotrophs, most able to move from place to place to obtain food - unicellular

3. 4 groups of Protozoans, based on how they move & live: - Protozoans w/Pseudopods (temp. bulge of cell) - amoeba belong to group called sarcodines ex of pseudopods - Pseudopods form when cytoplasm flows towards one location and rest of organism follows - how sarcodines move & trap food - amoeba have contractile vacuoles to expel extra water from cell to keep from exploding; live in water or soil, feed on bacteria & smaller protists

4. - Protozoans with cilia (ciliates) - Cilia - hairlike projections from cells that move with a wavelike motion - Ciliates - use cilia to move & obtain food - ex: paramecium (live mostly in fresh water, feed on bacteria & smaller protists) - complex: 2 contractile vacuoles, > 1 nucleus (lg controls everyday tasks, sm handles reproduction) - usually reproduce asexually by binary fission, sometimes by conjugation

5. - Protozoans with Flagella - protists that use long, whiplike flagella to move - some of these live inside bodies of other organisms - ex: type of flagellate that lives in the intestines of termites: digesting wood, producing sugars for themselves & termites Symbiosis - a close relationship in which at least one of the species benefits

6. Mutualism - relationship where both partners benefit from living together Sometimes a protozoan harms its host - ex: Giardia (human parasite) - found on soil, food, or water contaminated with infected human or animal feces - causes diarrhea, condition also known as hiker’s disease - protected by outer shell, able to survive outside body for long periods, tolerant to chlorine

7. Protozoans that are Parasites (4th type of protozoans) • Characterized more by the way they live than how they move • Feed on cells and body fluids of their hosts • Some have flagella, some depend on host for transportation, one makes its own layer of slime to slide • Many of these types have more than one host (ex: Plasmodium; causes malaria [disease of blood]. Two hosts are humans and a species of mosquitoes from tropic areas. Healthy mosquito bites a malaria infected person, mosquito now infected, passes on disease when bites healthy person)

8. Plantlike Protists - Algae - plantlike protists - autotrophs, very diverse - play significant role in environment (food source for water organisms, create much of Earth’s oxygen) *Vary greatly in cell organization, structure, and function. Some algae unicellular, others have differentiated tissues & organs. Others are groups of unicellular organisms that live together in colonies.

9. - algae can vary in color, depending on its pigment - Types of algae - Diatoms (type algae) - unicellular protists with glasslike cell walls - some float near surface of lakes or oceans, others attach to objects in shallow water - food source for heterotrophs - move by sliming - when die, cell walls collect on bottom of oceans & lakes, forming layer of diatomaceous earth (used for cleaning & insecticide)

10. - Dinoflagellates (type algae) - unicellular algae surrounded by stiff plates (suit of armor) - different pigment colors, many glow in dark - have two flagella, twirl through water - Euglenoids (type algae) - green, unicellular algae found in fresh water - when sunlight available, act as autotrophs, when sunlight not available, act as heterotrophs & obtain food from environment - uses “eyespot”, which is sensitive to light, to find direction of light source

11. - Red algae - multicellular seaweeds - has been found more than 260 meters below ocean’s surface - red pigment absorbs small amt of light through deep ocean water - used in ice cream & hair conditioner - Asian cultures eat fresh, dried, toasted - Green algae - mostly unicellular, some multicellular - lives in either fresh or salt water - a few live on land in rocks, tree bark crevices, or moist soil - contain chlorophyll & share similarities with plants - some scientists believe belong in plant kingdom

12. - Brown algae - seaweeds - also contain green, yellow, & orange pigments - multicelluar - most complex structure of all algae Funguslike Protists - “sort of like” organisms (sort of like animals, sort of like plants) - Spore - tiny cell able to grow into a new organism

13. -*Like fungi, funguslike protists are heterotrophs, have cells walls, and use spores to reproduce - 3 types of funguslike protists - slime molds - water molds - downy mildews - Slime Molds - colorful, live on forest floors & moist shady places - ooze along surface of decaying materials, feeding on bacteria & other microorganisms

14. - some so small need microscope to view - begin life cycle as tiny amoeba-like cell, then use pseudopods to feed & creep around - grow bigger to form giant, jellylike mass -when conditions become too harsh, develops spores, which develop into new generation of slime molds - Water Molds & Downy Mildews - most live in water or moist places - grow as tiny threads, look like fuzz - attack fish, plants, & food crops (potatoes, corn, grapes) - destroyed the Irish potato crops in 1845 & 1846, caused a famine and > than million people from Ireland died