PROTISTSPROTISTS

ProtistsProtists

• ProtistsProtists: Unicellular : Unicellular eukaryoticeukaryotic organisms. organisms.• Over 115,000 speciesOver 115,000 species• Eukaryotic cells - contain membrane-bound Eukaryotic cells - contain membrane-bound

organelles (particularly mitichondria & organelles (particularly mitichondria & chloroplasts)chloroplasts)

• Protists & eukaryotes probably evolved from a Protists & eukaryotes probably evolved from a large eukaryotic cell ingesting a photosynthetic large eukaryotic cell ingesting a photosynthetic and oxygen metabolizing bacteriaand oxygen metabolizing bacteria– Known as Known as endosymbiotic theoryendosymbiotic theory

• Two major classes of protistsTwo major classes of protists– Animal-like protistsAnimal-like protists– Plant-like protistsPlant-like protists

Animal-like ProtistsAnimal-like Protists

• Phylum Phylum CiliophoraCiliophora (Cilia bearing (Cilia bearing protists)protists)

– Aka "Aka "ciliatesciliates""– Have Have ciliacilia (short hairlike structures) on their plasma (short hairlike structures) on their plasma

membranesmembranes– Cilia rapidly beat and provide propulsion for the Cilia rapidly beat and provide propulsion for the

protist.protist.– Over 7000 species in this phylum.Over 7000 species in this phylum.– Example is Example is parameciumparamecium. .

ParameciumParamecium•Large organisms ~305 Large organisms ~305 micrometers longmicrometers long•Important features:Important features:•Have 2 nucleiHave 2 nuclei

•MacronucleusMacronucleus (large) (large)•MicronucleusMicronucleus (smaller)(smaller)

•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 •Move by coordinated Move by coordinated movement of hair-like movement of hair-like ciliacilia..

More ParameciumMore Paramecium

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

mosquitomosquito..

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) – Movement is by extending pseudopod, then the Movement is by extending pseudopod, then the

remainder of cytoplasm flows into extension. remainder of cytoplasm flows into extension. – Feeding is done by extending 2 pseudopods Feeding is done by extending 2 pseudopods

around object and engulfing object, forming a around object and engulfing object, forming a food vacuole food vacuole

• Examples are Examples are amoebasamoebas (amebas) (amebas)

AmoebasAmoebas

More amoebasMore amoebas

Plant-like ProtistsPlant-like Protists

• 5 phyla of plant-like protists5 phyla of plant-like protists• Are usually Are usually photosyntheticphotosynthetic, and also , and also

heterotrophicheterotrophic..• All are unicellular, most are motileAll are unicellular, most are motile• Example: Phylum Example: Phylum EuglenophytaEuglenophyta

Phylum EuglenophytaPhylum Euglenophyta

• Example is euglena.• Has a flagellum, is

motile• Is both heterotrophic

& autotrophic• Contains chloroplasts

& is photosynthetic.• Can become

heterotrophic in low-light conditions

EuglenaEuglena

DinoflagellatesDinoflagellates • Have 2 flagella for motility Have 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 elaborate silicon (glass) shells to protect Form elaborate silicon (glass) shells to protect

themselvesthemselves• Shell is porous to allow materials in/out of the cell.Shell is porous to allow materials in/out of the cell.

Multicellular / Other AlgaeMulticellular / Other Algae

• Are not generally true multicellular Are not generally true multicellular organisms, but rather "colonies"organisms, but rather "colonies"

• Show beginnings of specialized Show beginnings of specialized functions / tissuesfunctions / tissues

• 3 types 3 types – Green algaeGreen algae– Red AlgaeRed Algae– Brown algaeBrown algae

Green algae (Chlorophyta)Green algae (Chlorophyta)

Green algae Green algae (Chlorophyta)(Chlorophyta)•Contain chlorophyl a Contain chlorophyl a & b& b•Most frequently found Most frequently found in fresh waterin fresh water•Often colonialOften colonial

Volvox: a green colonial algaeVolvox: a green colonial algae

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

– Found in salt/brackish waterFound in salt/brackish water– Have additional pigments which give them a reddish color.Have additional pigments which give them a reddish color.– In uncontrolled blooms, these organisms can cause serious In uncontrolled blooms, these organisms can cause serious

ecological damageecological damage

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')

– Most primitive Most primitive plant like plant like organism to organism to show show alternation alternation of of generationsgenerations..

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

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