Kingdom ProtistaKingdom Protista

Chapter 19Chapter 19

What is a protist?What is a protist?

• Protists may be:Protists may be:– unicellularunicellular or or multicellularmulticellular..– microscopic to very large.microscopic to very large.– heterotrophicheterotrophic or or autotrophicautotrophic..– beneficial, parasitic, or innocuous.beneficial, parasitic, or innocuous.

• Are all Are all eukaryoteseukaryotes..• There are 3 major categories of There are 3 major categories of

protists:protists:– animal-likeanimal-like protists protists– plant-likeplant-like protists protists– fungus-likefungus-like protists protists

Protozoa: The animal-like Protozoa: The animal-like protistsprotists

• unicellularunicellular

• heterotrophicheterotrophic

• reproductionreproduction– usually asexuallyusually asexually– sometimes sexuallysometimes sexually

• 4 main groups4 main groups– amoebasamoebas– flagellatesflagellates– ciliatesciliates– sporozoanssporozoans

Phylum Phylum RhizopodaRhizopoda: The : The AmoebasAmoebas

• Are Are shapelessshapeless protistsprotists

• Move and feed Move and feed with the aid of with the aid of cytoplasm filled cytoplasm filled projections called projections called pseudopodiapseudopodia ((false footfalse foot))

• Live in mostly Live in mostly marine marine environments, but environments, but are also found in are also found in freshwater freshwater environmentsenvironments

Phylum Phylum ZoomastiginaZoomastigina: The : The FlagellatesFlagellates

• Protozoans with Protozoans with one or more one or more flagellaflagella

• Some are Some are parasitesparasites– ex. ex. Trypanosoma Trypanosoma

bruceibrucei (African (African sleeping sickness)sleeping sickness)

• Some are Some are beneficialbeneficial– ex. ex. TrichonymphaTrichonympha

spp. (termites)spp. (termites)

Phylum Phylum CiliophoraCiliophora: The : The CiliatesCiliates• Are covered with Are covered with

ciliacilia that aid in that aid in locomotionlocomotion

• Live in aquatic Live in aquatic environmentsenvironments

• ex. ex. ParameciumParamecium

Phylum Phylum SporozoaSporozoa: The : The SporozoansSporozoans

• Most produce Most produce sporesspores– spore is a spore is a

reproductive cellreproductive cell– forms without forms without

fertilizationfertilization

• All are All are internalinternal parasitesparasites

• Have complex life Have complex life cyclescycles

• Ex. Ex. PlasmodiumPlasmodium, , which causes which causes malariamalaria

Algae: The plant-like Algae: The plant-like protistsprotists

• Are Are photosynthetic photosynthetic autotrophsautotrophs

• Are unicellular or multi-Are unicellular or multi-cellularcellular

• Unicellular (also know as Unicellular (also know as phytoplankton)phytoplankton)– euglenaeuglena– diatomsdiatoms– dinoflagellatesdinoflagellates

• Multicellular: Multicellular: – red algaered algae– brown algaebrown algae– green algaegreen algae

Phylum Phylum EuglenophytaEuglenophyta: The : The EuglenoidsEuglenoids

• Are unicellularAre unicellular

• Are Are bothboth autotrophic autotrophic and heterotrophicand heterotrophic

• Have a Have a flagellaflagella

• Photosynthesize Photosynthesize when light is when light is favorablefavorable

• Ingest food when light is Ingest food when light is not favorablenot favorable

• Do Do NOTNOT have a cell wall, but have a flexible have a cell wall, but have a flexible

pelliclepellicle made of protein made of protein

Phylum Phylum BacillariophytaBacillariophyta: The : The DiatomsDiatoms

• Are unicellularAre unicellular

• Photosynthetic Photosynthetic autotrophsautotrophs

• Have shells Have shells composed of composed of silicasilica (SiO (SiO22))

• Aquatic Aquatic environmentsenvironments

Phylum Phylum DinoflagellataDinoflagellata: : DinoflagellatesDinoflagellates

• Have cell walls composed of Have cell walls composed of cellulosecellulose

• Have two Have two flagellaflagella located in grooves at right located in grooves at right angles to each otherangles to each other

• Mostly marineMostly marine

• Some live in Some live in symbioticsymbiotic

relationshipsrelationships– ex. coral ex. coral

• Some are Some are toxictoxic– ex. ex. Gonyaulux catanellaGonyaulux catanella

(red tide)(red tide)

The Multicellular Algae: 3 The Multicellular Algae: 3 PhylaPhyla

• RhodaphytaRhodaphyta: red algae: red algae– Live in deep watersLive in deep waters

• PhaeophytaPhaeophyta: brown : brown algaealgae– Include kelpInclude kelp– Have air bladders to Have air bladders to

floatfloat

• ChlorophytaChlorophyta: green : green algaealgae– Most diverse (>7000 Most diverse (>7000

spp.)spp.)– Ex. Ex. VolvoxVolvox & & SpirogyraSpirogyra

The Fungus-like ProtistsThe Fungus-like Protists

• Are all Are all heterotrophicheterotrophic decomposersdecomposers

• Two main groups Two main groups with 3 phylawith 3 phyla– The slime moldsThe slime molds

• MyxomycotaMyxomycota• AcrasiomycotaAcrasiomycota

– Water molds and Water molds and downy mildewsdowny mildews• OomycotaOomycota

Phylum MyxomycotaPhylum Myxomycota• Consist of the Consist of the

plasmodialplasmodial slime slime moldsmolds

• Plasmodium: Plasmodium: – mass of cytoplasm mass of cytoplasm

that contains many that contains many diploid nuclei but diploid nuclei but contain contain no cell walls no cell walls or membranesor membranes

– Move at ~2.5cm/hrMove at ~2.5cm/hr

• Can reach 1mCan reach 1m+ + in in diameter and diameter and contain thousands contain thousands of nucleiof nuclei

• Can reproduce Can reproduce asexually or asexually or sexually sexually

Phylum AcrasiomycotaPhylum Acrasiomycota

• Consist of the Consist of the cellularcellular slime moldsslime molds

• Spend part of their life Spend part of their life as a single amoeboid as a single amoeboid cellcell

• Forms a mass, like a Forms a mass, like a plasmodium, when plasmodium, when food is scarce but is food is scarce but is multicellular with multicellular with plasma membranesplasma membranes

• Cells are Cells are haploidhaploid for for their entire life cycle.their entire life cycle.

Phylum OomycotaPhylum Oomycota

• Water moldsWater molds– Appear white and Appear white and

fuzzyfuzzy– Produce Produce

flagellated flagellated reproductive cellsreproductive cells

• Downy mildewsDowny mildews– Have caused Have caused

major crop major crop destructiondestruction

– PhytophthoraPhytophthora infestansinfestans : : responsible for the responsible for the Irish potato famine Irish potato famine of the 1840’sof the 1840’s