PROTISTA

In General• Usually unicellular• Reproduction: Some

asexual, some sexual, some both

• Kingdom for life that doesn’t fit in animals, plant or fungi kingdom

• Mostly aquatic life• 3 main categories

• AKA: Protozoans• Basic Features:

– Aquatic, unicellular– Heterotrophic: pathogens, parasites,

predators

• Classified by how they move:1) Pseudopods : move w/

pseudopodia (false- feet)– Engulf by phagocytosis– Ex: Amoebas

2) Flagellates: move w/ flagella– Ex: Zooflagellates

3) Ciliates: move w/ cilia– Ex: Paramecia

Animal-Like Protista

Amoeba (Pseudopod)

Flagellate Moving

Ciliate Moving

Animal-Like Protista & Disease• Malaria– Caused by: Plasmodium• Vector: Mosquitoes

– Effects in humans: Fatigue, fever, vomiting, coma, death

• Sleeping sickness– Caused by: Trypanosoma• Vector: Tsetse flies

– Effects in humans: Coma & death

Plant-like Protista• AKA: Algae• Most unicellular; No leaves,

stems, roots• Perform photosynthesis with

chloroplasts• Classified by their type of cell wall1) Euglenoids: use flagella to swim– Animal & plant-like

2) Dinoflagellates– Most (~ 90%) plankton – Basis of aquatic food chains

3) Diatoms– Glasslike shells– Provide ~ ½ the O2 on earth

Red algae

Green algae

Brown algae

Euglena

Fungus-like Protista• Basic Features:– Decomposers: Absorb and

recycle nutrients– Live in moist environments

• 2 major groups:1) Slime Molds– large (~1 meter) single celled

mass of cytoplasm– Fungus-like (absorbs food)– Animal-like (can move)

2) Water molds: Can be parasitic– Ex: Potato blight: caused Irish

potato famine (1840’s)

Cool Slime Mold Video

Origins of Multicellularity

Protista live in 3 arrangements…• 1) Single-celled

– Live by themselves• 2) Colonial

– Group of independent acting cells– No specialized cells

• 3) Multicellular– Cells specialized to be specific

jobs

Importance: • Cells in colonies became efficient at

certain tasks. • Cells & their offspring became

specialized and dependent on each other.

= ANCESTORS OF MULTICELLULAR LIFE

Unicellular EuglenaThis is a colony of cells called Volvox

Multicellular Kelp

And lastly (if you couldn’t tell already)…Protists are difficult to classify

• Protista is one kingdom in the domain Eukarya. – Some protists are not closely related.– Molecular evidence supports reclassification.– Protista classification will likely change.

REview• 1) Name the three categories of protista.• 2) Which category of protista has members that are able to

move?• 3) Which category of protista has members that absorb

nutrients?• 4) Which category of protista has members that are

heterotrophs?• 5) Which category of protista has members that hunt?• 6) How does a pseudopod, flagella, and cilia differ?• 7) Name the 3 major categories of protozoa.• 8) Name the 3 major categories of algae.• 9) Name the 2 major categories of fungus-like protista.