PROTISTSPROTISTS

Domains

Classification Review

• Domain• Kingdom• Phylum• Class• Order• Family• Genus• Species

ProtistsProtists

• ProtistsProtists: : • Unicellular Unicellular eukaryoticeukaryotic organisms – very diverse organisms – very diverse

• Over 115,000 speciesOver 115,000 species

• Eukaryotic cells - contain membrane-bound organelles Eukaryotic cells - contain membrane-bound organelles (particularly mitichondria & chloroplasts)(particularly mitichondria & chloroplasts)

• Three major classes of protists (old system but still Three major classes of protists (old system but still used)used)– Animal-like protistsAnimal-like protists– Plant-like protistsPlant-like protists– Fungus-like protistsFungus-like protists

First Eukaryotes

• 1.5 billion years ago

Animal-like ProtistsAnimal-like Protists

• Ciliates (Cilia bearing protists)Ciliates (Cilia bearing protists)

– Have Have ciliacilia (short hairlike structures) on (short hairlike structures) on their plasma membranestheir plasma membranes

ParameciumParamecium•Important features:Important features:•Have 2 nucleiHave 2 nuclei

•MacronucleusMacronucleus•MicronucleusMicronucleus

•Feed by forcing H2O into Feed by forcing H2O into GulletGullet forming forming foodfood vacuolesvacuoles

•Excrete wastes through Excrete wastes through anal poreanal pore

•Excrete excess water Excrete excess water through use of through use of contractile contractile vacuolesvacuoles

More ciliatesMore ciliates

Phylum SporozoaPhylum Sporozoa

• Usually parasitic in natureUsually parasitic in nature

• Example is Example is PlasmodiaPlasmodia which causes which causes malariamalaria..– One of the most deadly diseases to manOne of the most deadly diseases to man– Malaria is transmitted by the Malaria is transmitted by the AnophelesAnopheles mosquito mosquito..

Lifecycle of Lifecycle of PlasmodiaPlasmodia

Phylum SarcodinaPhylum SarcodinaProtists with false feetProtists with false feet

• Use extensions of cytoplasm to move and Use extensions of cytoplasm to move and feed. feed.

• Extensions are called Extensions are called pseudopodspseudopods (false (false feet) feet)

AmoebasAmoebas

More amoebasMore amoebas

Plant-like ProtistsPlant-like Protists

• Are usually Are usually photosyntheticphotosynthetic, and also , and also heterotrophicheterotrophic..

• Most are unicellular, most are motileMost are unicellular, most are motile

• Example is euglena.

• Has a flagellum, is motile

• Is both heterotrophic & autotrophic

EuglenaEuglena

DinoflagellatesDinoflagellates • Have 2 flagella for motilityHave 2 flagella for motility• • Often have a cellulose covering Often have a cellulose covering

DiatomsDiatoms• Most abundant form of marine algae.Most abundant form of marine algae.

• Form silicon (glass) shells to protect themselvesForm silicon (glass) shells to protect themselves

Red Algae (Rhodophyta)Red Algae (Rhodophyta) • Red Algae (Rhodophyta)Red Algae (Rhodophyta)

• Red TideRed Tide

Red algeal bloomRed algeal bloom

Brown Algae (Rhodophyta)Brown Algae (Rhodophyta)

• Brown Algae Brown Algae (Rhodophyta)(Rhodophyta)

– Most Plant-Most Plant-like of all like of all algae.algae.

– Include kelpsInclude kelps

– Can grow to Can grow to huge sizes huge sizes (100')(100')

– ..

Giant Kelp ForestGiant Kelp Forest

Fungus like Protists:Fungus like Protists:

• Fungus like Protists:Fungus like Protists:– Act as decomposersAct as decomposers– Often have a slimy appearance/texture, Often have a slimy appearance/texture,

hence their name.hence their name.– 3 types: 3 types:

• Plasmodial slime moldsPlasmodial slime molds• Cellular slime moldsCellular slime molds• Water moldsWater molds

Plasmodial Slime MoldsPlasmodial Slime Molds• Plasmodial Slime MoldsPlasmodial Slime Molds

– Can grow very large, however, is still a single cell (with many nuclei)Can grow very large, however, is still a single cell (with many nuclei)

– Feeding stage is called a plasmodium.Feeding stage is called a plasmodium.

– Forms fruiting bodies under stress.Forms fruiting bodies under stress.

More slime molds

Cellular Slime Molds: Cellular Slime Molds:

Cellular Slime Molds: Cellular Slime Molds: •Exists a majority Exists a majority of its life cycle as of its life cycle as an amoebaan amoeba

•In  times of stress In  times of stress these amoebas these amoebas unite to form a unite to form a PseudoplasmodiumPseudoplasmodium, which crawls to , which crawls to another location another location (slug form), and (slug form), and forms a fruiting forms a fruiting bodybody

Water moldsWater molds:

• Water molds:Water molds:– Completely Completely

aquaticaquatic– Often Often

decomposersdecomposers– Sometimes Sometimes

parasiticparasitic

Water mold attacking a fish Water mold attacking a fish