Chapter 21Learning Goals #1-7 Protists & Fungi

1.What are Protists? Protists are eukaryotes Difficult to classify because of diversity They can be unicellular, multicellular, and colonial Some Protists share similarities with animals, plants, and fungi and others do not Collection of organisms that belong to different clades

6 Major Groups: Excavates-Euglena Chromalveolates-Brown algae & Diatoms Cercozoa, Foraminiferans, and Radiolarians Rhodophyta- Red Algae Amoebazoa- Slime molds & Amoebas Choanozoa

The "dilemma" Current classification puts Protists into 6 different clades Plants, fungi, and animals fit within these clades Proposed each clade. of Protists should be a separate kingdom

2. How are Protists related to other eukaryotes? Eukaryotes arose from Archea Protists were the 1st eukaryotes Plants, animals, and fungi arose from the ancestors of multicellular Protists

3. How do Protists move? Protists move by changing their cell shape,others use specialized organelles, and others don't move at all depending on wind or water

Types of Movement amoeboid movement with pseudopods- cytoplasmic projections; ex: Amoebas cilia- made of microtubules, are short and there are many of them per cell; called ciliates; ex: paramecium flagella- also made of microtubules, are long and there's usually one or two per cell, some spin and others wave; called flagellates passive (nonmotile)-Protists that depend on wind, water, or other organisms via spores- reproductive cells

Diseases caused by spores of Protists Plasmodium- spores carried by mosquitoes causing malaria Cryptosporidium- spores in contaminated water causing intestinal disease

4. How do Protists reproduce? Some reproduce asexually by mitosis, ex: amoebas Some life cycles include asexual and sexual processes, Ex: paramecium and other ciliates Reproduce by mitosis OR they undergo conjugation- sexual process where genetic material is exchanged with another individual, then they divide by mitosis(see pg.608)

alternation of generations- life cycle which includes a diploid and haploid phase, ex: water molds (see pg.609)

5. Ecological Imtance of Photosynthetic Protists Photosynthetic Protists- phytoplankton, red & brown algae, Euglenas, & dinoflagellates. As autotrophs, they are at the base of the food chain Play major roles in ecology: phytoplankton feed sea life & perform half of Earth's photosynthesis, support coral reefs, provide shelter, and recycle wastes (pg. 611)

6. How Heterotrophic Protists Eat... As heterotrophs, they obtain food from other organisms by engulfing and digesting OR absorbing nutrients Amoebas capture & engulf food forming a food vacuole, endocytosis Ciliates sweep food into gullet that becomes food vacuoles Lysosomes digest food vacuoles Both release waste by exocytoss

#6 Cont'd... Slime molds are decomposes that thrive on dead organic matter; play important role in recycling nutrients; plasmodium - aggregate of cells that feed and move! Water molds absorb nutrients from dead, decaying matter. through cell walls & membranes

7. Symbiotic Relationships (pg. 615) Mutualistic Symbiosis-both organisms benefit, ex: Trichonympha & termites (pg. 614) Parasitic relationship- Protists benefits and the host is harmed, produce several diseases world wide, ex: Giardia & Cryptosporidium cause intestinal disease, Trypanosoma causes African Sleeping sickness