Chapter 18: ProtistsVirusMoneraProtista

Taxonomic thinkingAnimalsPlantsFungiProtistsMonera

EUKARYABACTERIAARCHAEAProtistsPlantsFungiAnimalsPhylogenetic Thinking

Prokaryotes vs Eukaryotes

ProkaryotesKingdoms: Monera (bacteria)cell membrane and cell wall. Prokaryotic cells lack nucleus and membrane bound "organelles,Some have flagella for locomotion or hair like pili for adhesion. Cells: multiple shapes: cocci (round), baccilli (rods), and spirilla (helical cells). Note: prokaryotes will not have microtubules in flagellaBACK

EukaryotesCells have nuclei and membrane-bound organelles

What are Protists?

What are Protists?Greek word meaning firstFirst kingdom of eukaryotesUnicellularNucleiOrganellesReproduce by mitosisMultiple chromosomesProtists often have a very complicated internal structure: a single cell must do all the functions that we have many different cell types to do.

Increasing in diversity

Surface waters teem with microscopic protistsIn some near-shore areas, gigantic protists form underwater forestsProtists are particularly abundant in tidal habitatsAll protists live in water, or moist soil, or moist interiors of other organisms

Classification115,000 speciesMajor debate regarding how they should be classifiedanimal-like = zooplankton or protozoansplant-like = phytoplankton

Increasing diversity

Protists share characteristics with more then one multicellular kingdom- plant-like -fungus-like-animal-like forms

Animal-like Protists

Plants-like Protists

Fungus-like Protists (slime molds)

Protists exhibit wide variation in morphology, size, and nutritional strategies

Protists are divided into groups largely based on locomotion1) SarcodinesBlob-like asymmetricalAssume infinite variety of shapesEx. Amoebae2) FlagellatesEx. Euglena3) CiliatesEx. Paramecium4) SporozoansHave no organs for locomotion in adult formMany are parasitic

BACTERIAARCHAEAParabasalidsDiplomonadsKinetoplastidsEuglenidsAmoebaeSlime moldsCiliatesApicomplexaDinoflagellatesOomycetesDiatomsBrown algaeRed algaeGreen algaeLand plantsFungiAnimalsPROTISTSFigure 27.1

We will observe the following four:Ciliates1) Paramecium caudatum2) Stentor coeruleusSarcodines3) Amoeba proteusFlagellates4) Euglena gracili

ParameciumLive in FRESH waterOsmosis causes water to move into the parameciumContractile vacuole collects the extra water so that the paramecium doesnt lyseCovered in cilia used for locomotion and for directing food into the oral cavityMost are free-living (not parasites)

AmoebaSizeable amount of cytoplasmCytoplasmic streaming pushes on the cell membrane resembling armsA clear nucleusFalse foot: pseudopods to move and capture preyFeeding: endocytosis: surround food; creates a food vacuole. Ameoba reproduce by binary fission

EuglenaPlant-likeLong flagellum excellent swimmers A red-spot (photoreceptor) helps euglena detect sunlight so its chloroplasts can make glucose using photosynthesis

Stentor coeruleus (S.coeruleus)trumpet-shaped or cylindrical; highly contractilecontractile vacuole anterior-left; fresh water

Box 27.1 Figure 1a

Caption:(a) In taxonomic thinking, organisms are grouped according to morphological similarity.

Box 27.1 Figure 1b

Caption:(b) In phylogenetic thinking, groups are named if they represent distinct lineages on the tree of life.

Figure: 27.2

Caption:Protists are abundant in a wide variety of aquatic habitats. In marine environments, they are found in the open ocean as well as in near-shore and intertidal habitats.

Figure: 27.1

Caption:The lineages indicated by the bold line are considered protists.Exercise: Draw an arrow to the node on this tree that represents the common ancestor of all living eukaryotes.