Kingdom Protista

Biology 11

S.Dosman

Evolution of Protists

• Fossils show that protists began appearing about 1.5 billion years ago, more recent than bacteria.

• Their evolution involved the development of a membrane bound nucleus and the development of organelles such as ribosomes, lysosomes and mitochondria.

• These are the first eukaryotic cells.

Basic Characterisitcs

All organisms within kingdom Protista share the following basic characteristics:

• Mostly microscopic and unicellular with some colonial or multicellular

• All eukaryotic (belong to Domain Eukarya)• Can be heterotrophic or autotrophic• Mostly aquatic, although some live in soil or inside a

host.• A protist is any eukaryotic organism that is not a plant,

animal or fungus.

Organization within Protista

Kingdom Protista is divided into three dinctinct groups. While they are not phyla, these divisions are widely accepted.

• Animal-like protists

• Plant-like protists

• Fungus-like protists

Animal-like Protists

• These organisms are often referred to as protozoans.

• They live primarily in aquatic habitats, although some can be found in the soil and the digestive tracts of animals.

• Some protozoans are parasitic. • All are unicellular except for one.• All are heterotrophs that ingest their

food and perform intracellular digestion.

Animal-like Protists

They are divided into phyla based on their method of locomotion.

• Zooflagellates: use flagella for motion

• Sarcodines: use cytoplasmic extensions (pseudopods) for motion

• Ciliates: use cilia for motion

• Sporozoans: do not move

Zooflagellates

Paramecium

Vorticella

Sarcodines

Amoeba

Heliozoan

Ciliates

Paramecium

Tetrahymena

Sporozoans

• This photo shows the sporozoan known as a plasmodium.

• This species causes malaria and is transferred to a human host via mosquito bites.

Plant-like Protists

• Organisms in this group contain chloroplasts and are photoautotrophic.

• Includes all algae except for the blue –greens.• May be unicellular, multicellular or colonial. • The multicellular marine algae, the seaweeds, are

similar to marine plants and may be moved to the plant kingdom.

• Almost all are aquatic or they live in very damp terrestrial environments.

The Phylums

• Rhodophyta – red algae• Phaeophyta – brown algae• Chlorophyta – green algae• Pyrrophyta – dinoflagellates• Chrysophyta – golden-brown algae and diatoms• Euglenophyta – euglena

Algae Bloom- The Red TideAlgae, algae, everywhere….in your ice cream, in your toothpaste?…

Brownie mix Cheese (yellow

and orange) Chocolate milk

Coffee creamer Cottage cheese Egg substitute

Evaporated milk Frozen foods and

desserts Frozen yogurt

Ice cream Infant formula

Margarine Mayonnaise

Multiple vitamins Pet food Pudding

(cooked) Relishes

Salad dressing Sauces and

gravies Sour cream Toothpaste

Whipped topping Whipping cream

Yogurt

Fungi-like Protists

• Organisms in this group are unique in that they have both unicellular and multicellular stages.

• They are heterotrophic and perform extracellular digestion.

• They are decomposers and referred to as slime molds.

• The plasmodium is a well known slime mold.

Dog vomit slime mold