I. The Kingdom Protista

A. What is a Protist?

1. Any eukaryote that is not an animal, plant, or fungus

a. Eukaryote – any unicellular or multicellular organism that has a nucleus and other organelles within its cell or cells

2. Most unicellular, some multicellular.

II. Protists were the first eukaryotic organisms to evolve on Earth

A. Lynn Margulis- hypothesized first eukaryotic cell formed by a close relationship among several prokaryotes

B. Many scientists agree that animals and plants evolved from protists.

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III. Classification of Protists

A. Classified by how they obtain food. Include: Animal-like, Plant-like, and Fungus-like protists

IV. Protozoans- animal-like protists (Consumers) obtain food from environment (they eat).

• Ex: Paramecium and Amoeba

Section 20-2

Figure 20-5 A Ciliate

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Lysosomes - digestion

Trichosysts - protection

Oral groove -mouth

Gullet - stomach

Anal Pore – waste removal

Cilia -movement

Food Vacuoles – Store food

Macronucleus – Daily functions

Contractile Vacuole – water removal

Micronucleus –Back up memory

Food vacuole

Nucleus

Contractile vacuole

Section 20-2

An Amoeba

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Pseudopods

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B. Importance of Protozoa (Animal-like protists)1. Cause many human diseases like African

sleeping sickness and amoebic dysentery (diarrhea)

Blood culture of Trypanosoma – causes African

Sleeping Sickness

Image contributed by Pr. J. Le Bras, Hôpital Bichat

Fever, chills, neurological problems, coma, death

V. Slime molds and Water molds- fungus-like protists are consumers that obtain food by external digestion (this is weird). Act like fungus, but cell structure is like protists, no chitin in cell walls

A. Importance of Fungus-Like Protists

- Slime molds- important decomposers in forests and swamps

- Water molds – decomposers in water, parasites on land.

1. Water mold Phytophthora infestans caused the Great Potato Famine in Ireland in 1845.

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VI. Algae- plant-like protists (producers) use sunlight to make food through the process of photosynthesis.

• Ex: Unicellular Algae and Multicellular Algae

Gullet

Chloroplast

NucleusEyespot-Detects light

Flagella-movement

Section 20-3

Euglena

Carbohydrate storage bodies

Pellicle - protection

Contractile vacuole –water removal

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B. Importance of Algae (plant-like protists)

1. Unicellular Algae – all contain some type of chlorophyll, most contain accessory pigments used for photosynthesis.

• Form the base of food chains in oceans as phytoplankton

• Carry out the majority of earth’s photosynthesis – produce most of Earth’s oxygen

2. Algal blooms- huge masses of algae quickly deplete nutrients in water; algal cells quickly die in great numbers; their decay depletes the supply of oxygen in water; kills fish and invertebrates

A. Red tides- blooms of algae that produce a potentially dangerous toxin- shellfish can become full of the toxin- if eaten can cause serious illness, paralysis, even death

Algal Blooms

Red Tides

C. Importance of Multi-cellular Algae1. Food source for many sea animals.2. Home or refuge for many sea animals

(kelp forests and Sargasso sea).3. Produce much of earth’s oxygen.

B. Human uses

1. Source of vitamin C and Iron.

B. Human uses

1. Source of vitamin C and Iron.

2. Wrap for sushi.

B. Human uses1. Source of vitamin C and Iron.2. Wrap for sushi.3. Additive for ice cream, pudding, candy

bars.4. Chemicals from Algae used in plastics,

waxes, deodorants, paints and lubricants.5. Some chemicals extracted from algae

used to treat ulcers, high blood pressure, etc.

Section 20-1

are classified as

and include

usewhich which

Protists

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s

called called

animalike plantlike Funguslike

protozoa algaeSlim moldsWater molds

Take in food from environment

Produce food by photosynthesis External digestion

Decomposers parasites

called

: bioweb.uwlax.edu

White Cliffs of Dover

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