KINGDOM PROTISTA

“The Junk Drawer” of Classification

• Classified based on what they are NOT – they are NOT fungi, plants, or animals, but they are eukaryotes (in fact, they were probably the FIRST of the Eukarya)

• Most are unicellular & microscopic• Groups (phyla) are based on physical characteristics (such as motility) and nutritional characteristics (heterotroph/autotroph)

• First to reproduce sexually; first multicellular organisms

• Live where ever there is moisture• Historically, divided into algae (plant-like) and protozoa (animal-like)

Kinds of ProtistsUse the following slides to complete the table in your notes. Look for:

* Distinguishing Characteristics* Mode of Nutrition* Typical Example (sketch it)

RhizopodsEx) Amoeba

• Flexible surface, no cell wall, pseudopodia• Heterotrophs – engulf prey with pseudopodia;

endocytosis/phagocytosis

nucleus

pseudopodia

Amoeba engulfing a paramecium with pseudopodia – An example of phagocytosis (a form of heterotrophy)

JUST FYI – not in your notes!Heliozoans and Radiolarans

* Related to amoebas – pseudopodia & phagocytosisNote the long, slender pseudopodia coming from the heliozoan on the leftHeliozoans are freshwater; radiolarans are marineBoth form the ooze on the floor of these bodies of water with the shells left from their dead bodies

FYI – Not in your notesForaminiferans – another organism related to the amoebas; note the long pseudopodia coming out of the shell of calcium carbonate

- compose sedimentary rock - both heterotrophic and photosynthetic

(depending on the species)

Euglenoids/flagellatesExample – Euglena

• Called flagellates because of their mode of motility• Have an eyespot for phototaxis• Have a contractile vacuole for water balance

• Autotrophic/photosynthetic (look at the chloroplasts!) AND heterotrophic

FYI – Not in your notesTrypanosoma – genus of the protist that causes African sleeping sickness in humans (host) following the bite of the tsetse fly (vector)Closely related to the euglenoids because they have similar body coverings.

FYI – Not in your notesGiardia – genus of another flagellated protist that causes disease in humans

Ciliophora - ciliatesExample - Paramecium

All members of this group have cilia. Note there are even cilia lining the oral groove*Have a contractile vacuole*Have micro and macro nuclei*Heterotrophic – food enters through oral groove, food vacuole forms, lysosomes help digest food

LOOK! Waste leaving cell via exocytosis

FYI – Not in your notesAnother look at Ciliophorans:

Stentor and Paramecium

DinoflagellatesPlanktonic, photosynthetic protists – called phytoplankton (phyto = plant) AND heterotrophic species as wellResponsible for red tide (named for the photosynthetic pigment they contain); “blooms” of these organisms cause massive kills due to the toxins they produceHeterotrophic species use the toxins to stun prey (like fish) and then feed on its body fluidsSome are bioluminescent Also related to the euglenoids (note the presence of the flagella)

DiatomsAnother group of protists (actually related to water

molds and golden & brown algaes)Shells made of silica house the photosynthetic organism inside

The shells are in two parts, fitting together like a shoe box or Petri dish

The AlgaeAlgae – collective term referring to all of the photosynthetic, plant-like protists; alga – singular; algal – adjective• Multicellular• Photosynthetic – the algae along with other photosynthetic

protists are the largest group of producers on Earth, producing 1/3 of the oxygen

• Have a variety of pigments, on which the name of each group is based (remember, -phyta means “plant”)

• Golden algae – Chrysophyta; related to diatoms• Brown algae – Phaeophyta; “seaweed”; also closely related to

the diatoms; kelp• Red algae – Rhodophyta; includes some “seaweeds” but not.

Form a separate group from the golden & browns algaes and the green algae; some species are heterotrophic

• Green algae – Chlorophyta; “seaweeds”; have chlorophyll similar to plants; gave rise to the plant kingdom

Golden algae - microscopic Brown algae - macroscopic; this is a

kelp forest, supplying habitat and food for an entire ecosystem

25 nm

60 m

Red algae Green algae

multinucleate green algae; these are NOT leaves

Volvox (microscopic)

Water MoldOomycota – heterotrophic protist commonly found in very wet environments growing on dead or decaying organisms, such as on the fish below; called “mycota” because they look like fungi (but they’re NOT)

- late blight, a water mold, was responsible for the Irish potato famine

Slime MoldsProtists that aggregate in times of stress to form spore-producing bodies• Heterotrophic• Look like fungi but are NOT (do not have chitin in cell

walls)• 2 types: cellular and plasmodial (you don’t have to

know which is which )

SporozoansProtists that are:• Nonmotile *Unicellular• Parasitic *Spore-forming• Disease-causing *Heterotrophic

Diseases caused include:• Malaria (host – vertebrates;

vector - mosquito)• Toxoplasmosis (host – humans

& cats)• cattle tick fever (host – cattle,

mice, humans, deer, dogs)• Cryptosporidiosis (host –

cattle humans, birds, deer, dogs, cats)

Malaria sporozoans of genus Plasmodium

Protist VocabularyThis list may not be complete for YOU. If you don’t know these words (or any others in this unit), look them up or ASK!

Colony Nonmotile/motile/sessileAggregation Conjugation Multicellular Alternation of generationsComplex multicellularityHeterotroph/autotrophPseudopodia PhotosyntheticFlagella GameteCilia SporePlanktonic/plankton HostSilica VectorSpore Parasitic/saprophytic Phototaxis Contractile vacuole

RhizopodaAmoeba, related organisms

Flexible, no cell wall, pseudopodia, related – shells

Heterotrophs – phagocytosis

p. 464

EuglenophytaEuglena and related flagellates

FlagellaEye spots

Autotrophic – photosynthetic & heterotrophic

p. 467

CiliophoraParamecium and related ciliates

CiliaContractile vacuoleOral groove

Heterotrophic p. 469

Dinoflagellates PlanktonicFlagellatedToxic – red tide

Heterotrophic & autotrophic/photosynthetic

p. 467

BacillariophytaDiatoms

Shells of silicaShoe box like shellPlanktonic

Photosynthetic p. 466

Algae (golden, brown, red & green)

Many multicellular Photosynthetic p. 461, 465

“-mycota” groups; water molds & slime molds

Fungus-likeSome aggregate in times of stress; spores

Heterotrophic p. 470

SporozoansComplex life cycle - Apicomplexa

nonmotile, unicellular, parasitic, spore-forming, disease-causing

Heterotrophic p. 471 & p. 473