the protists chapter 22. the protists 2outlineprotist biology protist evolution protist diversity...
TRANSCRIPT
2The ProtistsThe Protists
OutlineOutline
Protist BiologyProtist Biology
Protist EvolutionProtist Evolution
Protist DiversityProtist Diversity
Green AlgaeGreen Algae
Red AlgaeRed Algae
Brown AlgaeBrown Algae
DiatomsDiatoms
DinoflagellatesDinoflagellates
Protist Diversity, Protist Diversity, cont.cont.
EuglenoidsEuglenoids
ZooflagellatesZooflagellates
PseudopodsPseudopods
CiliatesCiliates
SporozoansSporozoans
Slime MoldsSlime Molds
Water MoldsWater Molds
3The ProtistsThe Protists
General Biology of the ProtistsGeneral Biology of the Protists
Classified into the Domain Eukarya & Classified into the Domain Eukarya & the Kingdom Protistathe Kingdom Protista
Morphology:Morphology:Most unicellularMost unicellularMany with amazingly high level of Many with amazingly high level of strucrural and functional complexitystrucrural and functional complexity
Life cycles:Life cycles:Asexual reproduction commonAsexual reproduction commonSexual reproduction may occur when Sexual reproduction may occur when conditions deteriorateconditions deteriorate
Some life cycles simple, many Some life cycles simple, many extremely complexextremely complex
5The ProtistsThe Protists
Ecology of ProtistsEcology of ProtistsProtists are of enormous eco-logical Protists are of enormous eco-logical importanceimportance
Photoautotrophic forms:Photoautotrophic forms: Produce oxygenProduce oxygen Function as producers in both freshwater and Function as producers in both freshwater and saltwater ecosystemssaltwater ecosystems
Major component of planktonMajor component of plankton Organisms that are suspended in the waterOrganisms that are suspended in the water Serve as food for heterotrophic protists and Serve as food for heterotrophic protists and animalsanimals
Many protists are symbiontsMany protists are symbionts Ranges from strict parasitism to mutualismRanges from strict parasitism to mutualism Coral reefs greatly aided by symbiotic Coral reefs greatly aided by symbiotic photoautotrophic protists in tissues of coralsphotoautotrophic protists in tissues of corals
6The ProtistsThe Protists
Evolution of ProtistsEvolution of ProtistsComplexity and diversity of protists Complexity and diversity of protists makes them difficult to classifymakes them difficult to classify
Many classification schemes proposedMany classification schemes proposed
None has broad supportNone has broad support
Cannot be classified as plants, animals, or Cannot be classified as plants, animals, or fungifungi
Could be split into as many as a dozen Could be split into as many as a dozen kingdomskingdoms
The scheme chosen for this discussion is The scheme chosen for this discussion is based on modes of nutritionbased on modes of nutrition
8The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:Green Algae – The ChlorophytaGreen Algae – The Chlorophyta
Phylum ChlorophytaPhylum ChlorophytaApproximately 7,500 speciesApproximately 7,500 speciesInhabit a variety of environments including oceans, Inhabit a variety of environments including oceans, freshwater, snowbanks, tree bark, and turtles freshwater, snowbanks, tree bark, and turtles backsbacks
Many are symbionts with fungi, plants, or animalsMany are symbionts with fungi, plants, or animalsMorphology variedMorphology varied
Majority unicellular, but many are filamentous or Majority unicellular, but many are filamentous or colonialcolonial
Some are multicellular and resemble leaves of Some are multicellular and resemble leaves of lettuce lettuce
Plants thought to be derived from Chlorophyta Plants thought to be derived from Chlorophyta because both groups:because both groups: Have a cell wall that contains celluloseHave a cell wall that contains cellulose Possess chlorophylls a and b, andPossess chlorophylls a and b, and Store excess food as starchStore excess food as starch
9The ProtistsThe ProtistsGreen Algae:Green Algae:ChlamydomonasChlamydomonas
A minute (<25 A minute (<25 μμ m), actively moving flagellatem), actively moving flagellate
Inhabits still, freshwater poolsInhabits still, freshwater pools
Fossil ancestors date back over a billion yearsFossil ancestors date back over a billion years
Anatomy:Anatomy: Definite cell wallDefinite cell wall Single, large, cup-shaped chloroplastSingle, large, cup-shaped chloroplast Chloroplast with a pyrenoid where starch is Chloroplast with a pyrenoid where starch is synthesizedsynthesized
Many with a bright red eyespot, or stigma on Many with a bright red eyespot, or stigma on chloroplastchloroplast
Two long, whip-like flagellaTwo long, whip-like flagella Project from the anterior endProject from the anterior end
Operate with a breaststroke motionOperate with a breaststroke motion
11The ProtistsThe ProtistsGreen Algae:Green Algae:ChlamydomonasChlamydomonas
Most often reproduces asexuallyMost often reproduces asexually As many as 16 daughter cells within parent cellAs many as 16 daughter cells within parent cell
Escape by digesting the parent cellEscape by digesting the parent cell
Occasionally reproduces sexually Occasionally reproduces sexually Gametes fuse to form a zygoteGametes fuse to form a zygote
Becomes a heavy-walled, resistant zygosporeBecomes a heavy-walled, resistant zygospore
Goes into a period of dormancyGoes into a period of dormancy
Upon germination produces four zoospores by Upon germination produces four zoospores by meiosismeiosis ““Spore” - a reproductive cell that develops into a Spore” - a reproductive cell that develops into a new organism without fusing with another cellnew organism without fusing with another cell
““Zoospore” - flagellated spores, typical of aquatic Zoospore” - flagellated spores, typical of aquatic speciesspecies
13The ProtistsThe ProtistsGreen Algae:Green Algae:SpirogyraSpirogyra
Filamentous green algaeFilamentous green algae
Found in green masses on the surfaces of Found in green masses on the surfaces of ponds and streamsponds and streams
Has ribbon-like, spiraled chloroplastsHas ribbon-like, spiraled chloroplasts
Sexual reproduction by conjugation:Sexual reproduction by conjugation: A temporary union during which the cells A temporary union during which the cells exchange genetic materialexchange genetic material
Two filaments line up parallel to each otherTwo filaments line up parallel to each other Cell contents of one filament move into the Cell contents of one filament move into the cells of the other filamentcells of the other filament
Forms diploid zygospores Forms diploid zygospores In spring, undergo meiosis to produce new In spring, undergo meiosis to produce new haploid filamentshaploid filaments
15The ProtistsThe ProtistsGreen Algae:Green Algae:Multicellular FormsMulticellular Forms
UlvaUlvaMulticellular green algaMulticellular green alga
Commonly called sea lettuceCommonly called sea lettuce
Thallus (body) is two cells thickThallus (body) is two cells thick
Can be as much as a meter longCan be as much as a meter long
Sexual cycle involves alternation of Sexual cycle involves alternation of generations generations
Similar to higher plants, exceptSimilar to higher plants, except
Both generations look exactly alike, andBoth generations look exactly alike, and
The gametes all look the sameThe gametes all look the same
17The ProtistsThe ProtistsGreen Algae:Green Algae:Colonial FormsColonial Forms
VolvoxVolvoxA colony is a loose association of independent A colony is a loose association of independent cellscells
A Volvox colony:A Volvox colony: A hollow sphereA hollow sphere Thousands of cells arranged in a single layer Thousands of cells arranged in a single layer surrounding a watery interiorsurrounding a watery interior
Each cell of colony resembles a Chlamydomonas Each cell of colony resembles a Chlamydomonas cellcell
Flagella beat in a coordinated fashionFlagella beat in a coordinated fashion Some cells are specialized for reproductionSome cells are specialized for reproduction Each can divide asexually to form a new daughter Each can divide asexually to form a new daughter colony within the parental colonycolony within the parental colony
Leaves parental colony by releasing an enzyme Leaves parental colony by releasing an enzyme that dissolves away a portion of the parental that dissolves away a portion of the parental colonycolony
19The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:Red Algae – The RhodophytaRed Algae – The Rhodophyta
MulticellularMulticellular
About 5,000 speciesAbout 5,000 species
Live mostly in warmer seawater, some as Live mostly in warmer seawater, some as deep as 200 mdeep as 200 m
Economic ImportanceEconomic Importance Agar - capsules; dental impressions; Agar - capsules; dental impressions; cosmetics; culture medium; electrophoresis; cosmetics; culture medium; electrophoresis; food prep.food prep.
Carrageen - an emulsifying agent used in Carrageen - an emulsifying agent used in chocolate, low-fat foods, & cosmeticschocolate, low-fat foods, & cosmetics
The reddish-black wrappings around sushi The reddish-black wrappings around sushi rolls consist of processed Porphyra bladesrolls consist of processed Porphyra blades
21The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:Brown Algae – The PhaeophytaBrown Algae – The Phaeophyta
About 1,500 species About 1,500 species Most live in colder ocean waters along rocky Most live in colder ocean waters along rocky coastscoasts
No unicellular or colonial brown formsNo unicellular or colonial brown formsMorphology:Morphology:
Some small forms with simple filamentsSome small forms with simple filaments Others large multicellular forms that may Others large multicellular forms that may exceed 200 m in lengthexceed 200 m in length
Pigments:Pigments: Chlorophylls a and c Chlorophylls a and c Fucoxanthin (a type of carotinoid pigment) Fucoxanthin (a type of carotinoid pigment) gives them their colorgives them their color
Excess food stored as a carbohydrate called Excess food stored as a carbohydrate called laminarinlaminarin
23The ProtistsThe Protists
The PhaeophytaThe PhaeophytaMulticellular forms of green, red, and Multicellular forms of green, red, and brown algae are called seaweedsbrown algae are called seaweedsLaminariaLaminaria (a kelp), and (a kelp), and FucusFucus, , (rockweed), are common intertidal (rockweed), are common intertidal seaweedsseaweeds
NereocystisNereocystis and and MacrocystisMacrocystis often form often form forest-like thickets in deeper watersforest-like thickets in deeper waters
SargassumSargassum forms floating masses where forms floating masses where other organisms find shelterother organisms find shelter
Harvested for food and fertilizerHarvested for food and fertilizer
MacrocystisMacrocystis is source of algin, a is source of algin, a thickener for foodsthickener for foods
24The ProtistsThe Protists
The PhaeophytaThe PhaeophytaLaminariaLaminaria shows tissue differentiation shows tissue differentiation
Transport organic nutrients in a tissue Transport organic nutrients in a tissue resembling phloem resembling phloem
Life cycleLife cycle
Most brown algae have alternation of Most brown algae have alternation of generationsgenerations
In some species of In some species of FucusFucus
Meiosis produces gametes instead of Meiosis produces gametes instead of sporesspores
The adult is always diploid, as in animalsThe adult is always diploid, as in animals
25The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:Yellow-green Algae – The Yellow-green Algae – The ChrysophytaChrysophyta
Diatoms (formerly Bacillariophyta) are the Diatoms (formerly Bacillariophyta) are the most numerous unicellular algae in the most numerous unicellular algae in the oceansoceans
Significant portion of phytoplanktonSignificant portion of phytoplanktonCell wallCell wall
Two valves, with the larger valve acting as a Two valves, with the larger valve acting as a lid (like a mint tin)lid (like a mint tin)
Contains silicaContains silica
Diatomaceous earth used asDiatomaceous earth used as Filtering agentsFiltering agents Sound-proofing materialsSound-proofing materials Polishing abrasivesPolishing abrasives
26The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:Dinoflagellates – The PyrrophytaDinoflagellates – The Pyrrophyta
About 4,000 species of unicellular aquatic and marine About 4,000 species of unicellular aquatic and marine organismsorganisms
Morphology:Morphology: Cell is usually bounded by protective cellulose plates Cell is usually bounded by protective cellulose plates impregnated with silicates impregnated with silicates
Typically with two flagellaTypically with two flagella One in a longitudinal groove with its distal end freeOne in a longitudinal groove with its distal end free The other lies in a transverse groove that encircles the The other lies in a transverse groove that encircles the
organismorganism
Symbiotic dinoflagellates in corals called zooxanthellaeSymbiotic dinoflagellates in corals called zooxanthellae Dinoflagellates provide their host with organic nutrientsDinoflagellates provide their host with organic nutrients Corals provide wastes that fertilize the algaeCorals provide wastes that fertilize the algae Some lack chloroplasts and are parasiticSome lack chloroplasts and are parasitic
Gymnodinium brevisGymnodinium brevis may cause “red tide” may cause “red tide” Produce a powerful neurotoxin that has caused massive fish Produce a powerful neurotoxin that has caused massive fish kills kills
Consume shellfish during outbreak can cause respiratory Consume shellfish during outbreak can cause respiratory paralysisparalysis
29The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:The Euglenoids – Phylum The Euglenoids – Phylum EuglenophytaEuglenophyta
Small freshwater unicellular organismsSmall freshwater unicellular organisms
Difficult to classifyDifficult to classify
Have two flagella and an eyespot (shades a Have two flagella and an eyespot (shades a photoreceptor)photoreceptor) One flagellum much longer than the otherOne flagellum much longer than the other Projects out of an anterior, vase-shaped Projects out of an anterior, vase-shaped invaginationinvagination
Called a tinsel flagellum because of hair-like Called a tinsel flagellum because of hair-like projectionsprojections
Cell bounded by flexible pellicleCell bounded by flexible pellicle
Chloroplasts:Chloroplasts: Surrounded by three rather than two membranesSurrounded by three rather than two membranes With a pyrenoid which produces an unusual type With a pyrenoid which produces an unusual type of carbohydrate called paramylonof carbohydrate called paramylon
31The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:Zooflagellates – Phylum Zooflagellates – Phylum ZoomastigophoraZoomastigophora
Colorless heterotrophsColorless heterotrophsMost symbiotic and many parasiticMost symbiotic and many parasiticWell known for causing various diseases in Well known for causing various diseases in
humanshumans TrypanosomaTrypanosoma
African sleeping sickness - Tsetse flyAfrican sleeping sickness - Tsetse fly Chagas disease – Kissing bugChagas disease – Kissing bug
Giardia lambliaGiardia lamblia Most common flagellate in human digestive tractMost common flagellate in human digestive tract Causes severe diarrhea Causes severe diarrhea Cysts are transmitted in contaminated waterCysts are transmitted in contaminated water Beavers are important reservoir hostsBeavers are important reservoir hosts
Trichomonas vaginalisTrichomonas vaginalis Sexually transmitted protist,Sexually transmitted protist, Infects urogenital organs; a common cause of Infects urogenital organs; a common cause of
vaginitisvaginitis
34The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:Protists with PseudopodsProtists with Pseudopods
Pseudopods form when cytoplasm streams Pseudopods form when cytoplasm streams forward in a particular directionforward in a particular direction
Amoeboids (phylum Rhizopoda) are protists Amoeboids (phylum Rhizopoda) are protists that move and ingest their food with that move and ingest their food with pseudopodspseudopods Phagocytize foodPhagocytize food
Entamoeba histolyticaEntamoeba histolytica - a parasite of the human - a parasite of the human colon; colon;
Causes amoebic dysenteryCauses amoebic dysentery
Can be fatalCan be fatal
Foraminiferans (phylum Foraminifera) and Foraminiferans (phylum Foraminifera) and radiolarians (phlyum Actinopoda)radiolarians (phlyum Actinopoda) Both have a skeleton (test) of either calcite or Both have a skeleton (test) of either calcite or silicasilica
36The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:The Ciliates – Phylum CiliophoraThe Ciliates – Phylum Ciliophora
Ciliates (phylum Ciliophora) are among Ciliates (phylum Ciliophora) are among the most complex of the protozoansthe most complex of the protozoansHundreds of cilia beat in coordinated Hundreds of cilia beat in coordinated rhythmrhythm
Most are holozoic, swallowing food Most are holozoic, swallowing food wholewhole
Divide by transverse binary fission Divide by transverse binary fission during asexual reproductionduring asexual reproduction
Two nuclei of differing typesTwo nuclei of differing types
Micronucleus – HeredityMicronucleus – Heredity
Macronucleus – MetabolismMacronucleus – Metabolism
38The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:The Sporozoans – Phylum The Sporozoans – Phylum ApicomplexaApicomplexa
Nonmotile obligate parasitesNonmotile obligate parasites
Most serious parasitic disease of Most serious parasitic disease of human is malariahuman is malariaPlasmodium Plasmodium sppspp
Kills 3,000,000 people each yearKills 3,000,000 people each year
Transmitted by mosquitoTransmitted by mosquito
ToxoplasmaToxoplasma
Humans get from catsHumans get from cats
Causes birth defects and mental Causes birth defects and mental retardation when pregnant mom exposedretardation when pregnant mom exposed
40The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:Slime MoldsSlime Molds
Plasmodial Slime Molds - Phylum Plasmodial Slime Molds - Phylum MyxomycotaMyxomycotaBody in the form of a plasmodiumBody in the form of a plasmodium
Diploid, multinucleated, cytoplasmic massDiploid, multinucleated, cytoplasmic mass
Enveloped by a slimy sheathEnveloped by a slimy sheath
Eventually produces sporangium which in Eventually produces sporangium which in turn produces sporesturn produces spores
Cellular Slime Mold - Phylum AcrasiomycotaCellular Slime Mold - Phylum AcrasiomycotaBody in the form of individual amoeboid cellsBody in the form of individual amoeboid cells
Later aggregate into pseudoplasmodium Later aggregate into pseudoplasmodium which then forms sporangium & sporeswhich then forms sporangium & spores
42The ProtistsThe ProtistsDiversity of Protists:Diversity of Protists:Water Molds - Phylum OomycotaWater Molds - Phylum Oomycota
Most live in the waterMost live in the water
Phylum name refers to the enlarged tips Phylum name refers to the enlarged tips (called oogonia) where eggs are produced(called oogonia) where eggs are produced
Body filamentous, appearing like true Body filamentous, appearing like true FungiFungiCell walls largely of cellulose rather than Cell walls largely of cellulose rather than chitinchitin
The organism is diploid (not haploid as in The organism is diploid (not haploid as in the fungi) the fungi)
Phytophthora infestansPhytophthora infestans caused the 1840’s caused the 1840’s potato famine in Irelandpotato famine in Ireland
SaprolegniaSaprolegnia is often seen as a white, is often seen as a white, cotton-like coating on dead aquarium fishcotton-like coating on dead aquarium fish
44The ProtistsThe Protists
ReviewReview
Protist BiologyProtist Biology
Protist EvolutionProtist Evolution
Protist DiversityProtist Diversity
Green AlgaeGreen Algae
Red AlgaeRed Algae
Brown AlgaeBrown Algae
DiatomsDiatoms
DinoflagellatesDinoflagellates
Protist Diversity, Protist Diversity, cont.cont.
EuglenoidsEuglenoids
ZooflagellatesZooflagellates
PseudopodsPseudopods
CiliatesCiliates
SporozoansSporozoans
Slime MoldsSlime Molds
Water MoldsWater Molds