Kingdom- Protista (protists)

Common Characteristics of all protists:

-cell type-eukaryote-unicellular and multicellular-microscopic-live in moist environment

Protists are grouped into categories based on the way they feed

1. protozoans-animal-like protists

-feed by ingestion

-all are unicellular

2. algae- plant-like protists

-make own food by photosynthesis (autotroph)

-unicellular and multicellular

3. slime molds and mildew- feed by decomposition

Major Roles of Protists

1. Algae (plant-like protist) is the base of the aquatic food chain

2. Slime molds decompose and recycle nutrients

3. Causes many diseases (ex. Malaria)

Protozoans (animal-like protists)

Includes 4 main groups:

1. Amoebas – have no definate shape-have extensions of the

cytoplasm called pseudopodia (used to move and feed)

-most live in saltwater and must constantly take in

water to dilute the salt and pump excess out in vacuoles

-most reproduce asexually (1 parent produces an offspring identical to parent)

2. flagellates- have flagella-move by whipping the tail-are beneficial and harmful

3.ciliates- have cila (short hair-like extensions)-live in aquatic areas (ex. Paramecium)

4. sporozoans-produce spores-spores-reproductive cell that forms without

fertilization and produces new offsprings

-live inside a host such as the intestines or blood (these are the ones that cause disease like malaria)

-all are parasites

Algae (plant-like protists)-unicellular and multicellular

phytoplankton (unicellular)

-a major producer of nutrients and oxygen in the aquatic ecosystem

-base of the aquatic food chain

multicellular plant protists are much like a plant but lack roots, stems, leaves

6 algae phyla:1. euglenoids-unicellular, aquatic

-feed like an animal and plant

2. diatoms-golden algae –unicellular-have shells that have the pigment carotenoid

that gives it a gold color-store food as oil-organisms that eat these have a oily taste-as these die, their shells sink to the bottom and are mined and used as abrasives such as in toothpaste

3. dinoflagellates-several produce toxins and some are lethal

-red tide –due to numerous dynoflagellates with reddish color (40-60 million/liter of water)

-cannot harvest shellfish during red tide because their tissue may have the toxins in it

4. Red algae- marine seaweed-body area of these is called the thallus-have a pigment called phycobilins-green,

blue, violet color

5. brown algae (kelp)-live on rocky coast of ocean floor-the chlorophyll in it is yellow brown calledfucaxanthin-many have air bladders that help it to float-food habitat for marine organisms

6. green algae-has the major pigment chlorophyll-can reproduce by fragmentation (breaks off and each piece can grow a new organism)

Fungi-like protists

-includes slime molds, water molds and downy mildews

-the decompose like fungi but do not have all the characteristics of fungi

3 phyla of fungus-like protist:

• 1. slime molds

• 2. water molds

• 3. downy mildew

Slime molds:

• Exist in many colors

• Live in cool, moist, shady areas

• Grow on organic matter like rotting leaves and stumps

• Reproduce similar to fungi (release spores)

Water molds:

• Liver in water or moist places

• Most feed on dead organic matter

• Appear as fuzzy growths on decaying matter

Downy mildew:

• Causes many plant diseases because they are plant parasites