Kingdom ProtistaA very large and diverse group - comprising at least 16 phlya

A paraphyletic group - it does not contain all of the descendantsof the common ancestor of this group - some descendants aremulticellular - the fungi, plants, and animals

Many of the protists groups did not give rise to multicellularorganisms - at least 13 phyla have have remained single celled

Current classification is changing and likely to change greatly inthe near future.

Sixteen Phyla comprise the Kingdom Protistaclassically grouped into 5 informal groups based on mobility andnutrition - differs from evolutionary estimates of relatedness

Protistan DiversityThe Cell Surface

Amoebas lack a cell wallAlgae and slime molds encased in strong cell wallsDiatoms and Foraminiferans have shells of silica, calcium, debris

Locomotor OrganellesMany move by flagellar motions, or ciliary action, pseudopodialmovement - many are immobile

NutritionPhototrophs and Heterotrophs (phagotrophs (ingesters) and

saprobes)Reproduction

Asexual reproduction by mitosis, fission, budding, sporesSex by gametic meiosis, zygotic meiosis, or sporic meiosis

The Sarcodines - all can have pseudopodiaPhylum Rhizopoda - the amoebasPhylum Actinopoda - actinopods, heliozoansPhylum Foraminifera - forams

Phylum Rhizopoda - the amoebasHeterotrophicFresh and salt water, abundant in soil, some parasitize animalsReproduction by simple mitotic fissionNo cell walls, flagella, sexual reproductionLocomotion via pseudopodiaPseudopodia also used for prey capture

Parasitic species may form resistant cystsEntamoeba histolytica : Causes amoebic dysenteryCysts resist digestion by hostCarriers exhibit no symptoms but can spread cystsSpread through fecal contamination in food or water

may be dispersed by flies

Phylum Actinopodia - Actinopods -silica (glass) skeletons covering most of cellwith many thin needlelike pseudopods thatproject through pores

Phylum Foraminifera - ForamsHeterotrophic, marine organismsPossess pore-studded shells called tests tests: organic matter reinforced with inorganic

usually multichambered, often spiral shapedmaterial: often calcium carbonate, can use sand grains,

echinoderm plates, sponge spiculesPodia extrude through pores in test - used for swimming,

gathering material for test, feeding

White Cliffs ofDover - chalkformed fromdeposited forams

Algae and other photosynthetic protists

Phylum Chlorophyta - green algae

Phylum Rhodophyta - red algae

Phylum Pheophyta - brown algae

Phylum Chrysophyta - golden algaeand diatoms

Phylum Pyrrophyta - dinoflagellates

Phylum Euglenophyta - euglenoids

Phylum Chlorophyta: Green AlgaeAncestors of all plants were multicellular green algaegreen algae and plants use chlorophylls a and b, carotenoidsfound in aquatic and semiterrestrial habitatsUnicellular and multicellular forms

Chlamydomonas is atypical unicellular form

biflagellatedlight sensitive eye-spotzygotic meiosis withzygospore resting stage

Some green algae are motile andcolonial like VolvoxSpecialized reproductive cells give riseto new colonies within the parentcolonyHas zygotic meiosis and zygosporesform within a parent colony.

Some green algae arefilamentous - like Spirogyra

named for its spiral chloroplasts

Sex is through conjugationof cells from + and - strains

Some green algae, like Ulva, formmulticellular sheets and have sporicmeiosis

Except for their ploidy,the gametophytes andsporophytes are verysimilar

Economic importanceSome make sulfated polysaccharides like agar and carrageenanAgar used as laboratory medium, a base for cosmetics, used inbaked goods and as a temporary preservative for meat and fishCarrageenan used in paints, cosmetics and ice cream

Phylum Rhodophyta - Red AlgaeMost common coastal seaweeds - mostly multicellular, common inwarm watersChloroplasts have Chlorophyll a and phycobilins, like cyanobacteria

Absorb green, violet and blue lightGrow at greater depths than other algaehave sporic meiosisCompletely lack flagellaBody composed of interwoven filamentsAn ancient group of eukaryotes

Phylum Phaeophyta - Brown AlgaeMostly multicellular and marineConspicuous seaweeds, include kelps and SargassumUse chlorophylls a and c (like diatoms)Photosynthetically productive - fast growingProvide food for many animalsSome kelps grow up to 100 meters in lengthHave sporic meiosis

sporophyte: large, conspicuous kelp-like formgametophyte: small, filamentous formseparate male and female gametophytes

Use chlorophylls a and c, and carotenoidsfossilize well - thick sediments of fossil

diatoms are called “diatomaceous earth”Some move by secretions from shellAsexual reproduction separates shell halves

each half produces new shell within oldone - become smaller with each divisionHave gametic meiosis - cells are diploid

and produce sperm or eggs by meiosis

Phylum Chrysophyta - Diatoms and Golden AlgaeDiatoms are photosynthetic, unicellular organismsDouble shells of silica - Resemble box with lid

Golden Algae - use yellow and brown carotenoid pigments, andxanthophyll accessory pigments

Unicellular, two flagella, often colonial, common in freshwaterForm resistant cysts when ponds dry out in summer

Reproduce primarily asexually by longitudinal cell division withnuclear mitosis - like fungi

Phylum Pyrrhophyta - DinoflagellatesUnicellular, photosynthetic, mostly marine, some bioluminescentDistinctive flagella and coat

two flagella beat in groovescoat composed of cellulose plates

Most use chlorophyll a & c and carotenoidsSome are symbiotic with animals

sea anemones, mollusks and coralsin corals - called “zooxanthellae”,

required for formation of coral reefsSome forms cause “red tide”

large blooms result in red colored waterrelease toxins that kill fish and shellfishconsumption of poisoned fish can kill

Phylum Euglenophyta - EuglenoidsMostly fresh water organismsGroup has characteristics of plants and animalsSome specimens are photosynthetic

use chlorophylls a and b, and carotenoidsOthers lack chloroplasts and are heterotrophicSome can transform from autotrophs to

heterotrophs and back, depending on presence of light and food

Reproduction via nuclear mitosis and cell division

No sexual reproduction known

have two flagella - both with bases in reservoir -one is very small

Contractile vacuoles collectand pump out excess water at reservoir

have light sensitive stigmaparamylon granules are

for food storage

Euglena is typicalThin flexible pellicle lies within cell membrane - composed of

interlocking strips of protein

Heterotrophs with flagella or cilia -Phylum Sarcomastigophora - ZoomastigotesUnicellular, heterotrophic, highly variable in formPossess one to thousands of flagellaSome free-living, some parasiticSome reproduce asexually onlyOne group alternates between amoeboid and

flagellated stagesSome trypanosomes are human pathogens

cause sleeping sickness, East Coast fever, Chagas' diseasemany spread by insects, such as tsetse flies

Some inhabit guts of wood-eating insectshave enzymes capable of digesting cellulose

Choanoflagellates are similar to feeding cells of sponges and are likely ancestors of all animals

Hiker's Diarrhea:Caused by Giardia lamblia, found world-wideOccurs in water, infects wild and domesticated animals, and

humansLives in small intestine of hostSpreads as cysts in feces, can survive for months in cool waterMay appear in city water suppliesResistant to treatment with chlorine and iodine, requires boilingwater to kill

Phylum Ciliophora - The CiliatesUnicellular, heterotrophic, with many cilia

Coordinated beating provides motilityOuter pellicle is tough but flexibleTwo types of nuclei

micronuclei - diploid - reserved for sexmacronuclei - polyploid - for normal

cellular metabolismSpecialized vacuoles ingest food and contractile

vacuoles regulate water balanceFood enters through gullet (cytostome) and

passes into vacuoles where it is digested

Asexual reproduction by transverse fission

Sexual reproduction by conjugationTwo different mating types

exchange haploid micronucleiMacronucleus in each individual

disintegratesMultiple rounds of chromosomal

replications in micronuclei reconstitutes macronucleus

Phylum Apicomplexa - SporozoansNonmotile, spore-forming animal parasitesHave an “apical complex” at one end of cell - with fibrils,

microtubules, and vacuoles - used to enter host cells

Have complex life cycles with sexual and asexual phases

Exhibit alternation of haploid anddiploid generations

Fusion of gametes produces a thick-walled cyst, the oocyst

Meiotic divisions in oocyst produce infective haploid spores, sporozoites

Plasmodium causes malaria

Gametocytesbecomegametes ingut ofmosquito

syngamyforms zygoteand oocyst

meiosis inoocyst formssporozoites

Malariaestimated that 500 million infected, 200 million humans die

each year, most infected children die

symptoms include chills, fever, sweating, enlarged spleen, confusion, thirst - repeating every 48 to 72 hours

Victims die of anemia, kidney failure, brain damage

Effects can be reduced with drugs

Focus is on eradication of malaria through elimination of mosquito carriers

Vaccines against malaria may be available in near future

Slime Molds

Phylum Acrasiomycota - CellularSlime Molds

Phylum Myxomycota -PlasmodialSlime Molds

Phylum Oomycota - water molds,rusts, mildew

Phylum Acrasiomycota - Cellular Slime MoldsOnce thought to be related to fungi

most closely related to amoebasCommon in fresh water, damp soil, rotting vegetation

Usually found as free living amoebas

Sometimes cells aggregateinto motile slug

Slug transforms into sorocarp,

within sorocarp some amoebas fuse sexuallyforming diploid macrocysts

meiosis occurs in macrocysts - spores released form new amoebas

Phylum Myxomycota -Plasmodial Slime MoldsConsist of streaming multinucleate plasmodium

feeding phase may be yellow, orange or other colorCytoplasm exhibits conspicuous streamingEngulf and digest bacteria, yeast, bits of organic matterforms sporangium under adverse conditions

Phylum Oomycota - water molds, rusts, mildewLive in freshwater or soil, many are plant or animal parasitesCell walls are composed of cellulose or similar polymersBody consists of filamentous hyphaeHyphae are diploid (unlike fungi) and produce gametes by meiosisExhibit normal mitosis (unlike fungi)have unique life cycle

Diploid spores produced asexually in sporangiumSex: female gametangium called oogonium with one to eight eggs

male gametangium called antheridium with many spermFusion produces zygote that becomes thick-walled oosporeoospore germinates and forms new hypha