‘The Protists’

Characteristics of Protists• Animal-like• Plant-like = algae/phytoplankton -

Responsible for most of O2 released into atmosphere. Oxygen is a metabolic waste that is recycled for cellular respiration.

• Parasites

• Decomposers

Characteristics of Protists

• All are eukaryotic (has a nucleus) with membrane-bound organelles

• What is this cell? How can you tell?

Prokaryote!---NO Nucleus

Where did Protists come from?Endosymbiotic Theory : Lynn Margulis

The eukaryotes evolved from the symbiosis of several cells

Mitochondria and chloroplasts may be descended from small aerobic and photosynthetic prokaryotes

The prokaryotes began to live inside larger cells

Endosymbiotic Theory

Animal-like Protists = “Protozoans”Classified by how they move

Phylum Sarcodina• Moves by pseudopods-

temporary projections of cytoplasm (false feet)

• Reproduce by binary fission

Ex: Amoeba & Entamoeba ‘the

revenge’

ProtozoansPhylum Zooflagellates

(Zoomastigina)• Have flagella - whip-like

structures that aid movement

• Ex: Trichonympha - lives in gut of a termite, digests wood

Ex. Trypanosomas - African sleeping sickness from bite of Tsetse fly

• Ex. Giardia - causes humans to become sick when drinking water with cyst

Protozoans

Phylum Ciliaphora - ciliates

• Cilia - short, hair-like projections used for movement

• Most free living

• Ex: Paramecium

Protozoans

Phylum Sporozoans - parasitic protists

• Nonmotile - do not move

• Ex: Plasmodium - causes malaria, carried by Anopheles mosquito

Plant-like Protists = “Algae”Unicellular & Autotrophic

Phylum Pyrrophyta - Dinoflagellates

• Luminescent - give off blue light

• Causes ‘red tides’ = produces a nerve toxin that kills fish

• Gonyaulax - in shellfish & produces toxins that paralyze and kill humans and fish

(Look At Article!)

Unicellular Algae

Phylum Euglenophyta - flagellates with chloroplast

• Has 2 flagella and 1 eyespot

• Ex: Euglena - both autotrophic & heterotrophic

Unicellular Algae (Fill-In On Notes)Phylum Bacillariophyta - Diatoms• Has glass-like cell walls made of silica

• Forms diatamaceous soil used to filter and as an abrasive (toothpaste). Shaped like 2 sides of a pillbox/culture dish

Unicellular Algae -

Phylum Chrysophyta: yellow-green and golden-brown algae

(Fill-In On Notes)

Multicellular Algae

Phylum Chlorophyta - Green Algae

Ex: Volvox are colonial

Similar to plants. Both have….• cell walls• photosynthetic pigments• multicellarity

Fill in on notes

Multicellular AlgaePhylum Rhodophyta -

Red AlgaeUsed to make agar

Phylum Phaeophyta - Brown Algae

Ex: Kelp and Sargassum

Unusual Protists – “Decomposers”

Slime molds

Water molds• Grow in water or damp places on land

• Ex: mildews, white rusts,

water molds &

Saprolegnia (ick on fish)

• Ex. Phytopthora infestans (Potato blight) -threatened crops in Ireland “The Great Potato Famine”

Unusual Protists - Decomposers