Chapter 18: ProtistsChapter 18: Protists

VirusVirus

MoneraMonera

ProtistaProtista

Taxonomic thinking

Animals

Plants

Fungi

Protists

Monera

EUKARYA

BA

CTE

RIA

AR

CH

AE

A

Protists

Pla

nts

Fung

i

Ani

mal

s

Phylogenetic Thinking

ProkaryotesProkaryotes vs vs EukaryotesEukaryotes

ProkaryotesProkaryotes• Kingdoms: Monera (bacteria)Kingdoms: Monera (bacteria)

• cell membrane and cell wall. cell membrane and cell wall.

• Prokaryotic cells lack nucleus and Prokaryotic cells lack nucleus and membrane bound "organelles,“membrane bound "organelles,“

• Some have flagella for locomotion Some have flagella for locomotion or hair like pili for adhesion. or hair like pili for adhesion.

• Cells: multiple shapes: cocci Cells: multiple shapes: cocci (round), baccilli (rods), and spirilla (round), baccilli (rods), and spirilla (helical cells).(helical cells).

Note: prokaryotes will not have microtubules in Note: prokaryotes will not have microtubules in

flagellaflagellaBACK

EukaryotesEukaryotes

• Cells have nuclei and Cells have nuclei and membrane-bound membrane-bound organellesorganelles

What are Protists?What are Protists?

What are Protists?What are Protists?• Greek word meaning “first”Greek word meaning “first”

• First kingdom of eukaryotesFirst kingdom of eukaryotes

• UnicellularUnicellular

• NucleiNuclei

• OrganellesOrganelles

• Reproduce by mitosisReproduce by mitosis

• Multiple chromosomesMultiple chromosomes

• Protists often have a very Protists often have a very complicated internal structure: a complicated internal structure: a single cell must do all the single cell must do all the functions that we have many functions that we have many different cell types to do. different cell types to do.

Increasing in diversity

Surface watersteem with microscopic protists

In some near-shore areas, gigantic protists form underwater forests

Protists areparticularlyabundant intidal habitats

All protists live in water, or moist soil, or All protists live in water, or moist soil, or moist interiors of other organismsmoist interiors of other organisms

ClassificationClassification• 115,000 115,000

speciesspecies

• Major debate Major debate regarding how regarding how they should they should be classifiedbe classified

• ““animal-like” animal-like” = zooplankton = zooplankton or protozoansor protozoans

• ““plant-like” = plant-like” = phytoplanktonphytoplankton

Increasing diversityIncreasing diversity

• Protists share characteristics with more then Protists share characteristics with more then one multicellular kingdomone multicellular kingdom

- plant-like - plant-like

-fungus-like-fungus-like

-animal-like forms-animal-like forms

Animal-likeAnimal-like Protists Protists

Plants-like ProtistsPlants-like Protists

Fungus-like ProtistsFungus-like Protists (slime molds) (slime molds)

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

Protists are divided into groups largely Protists are divided into groups largely based on locomotionbased on locomotion

• 1) Sarcodines1) Sarcodines– Blob-like asymmetricalBlob-like asymmetrical– Assume infinite variety of shapesAssume infinite variety of shapes– Ex. AmoebaeEx. Amoebae

• 2) Flagellates2) Flagellates– Ex. EuglenaEx. Euglena

• 3) Ciliates3) Ciliates– Ex. ParameciumEx. Paramecium

• 4) Sporozoans4) Sporozoans– Have no organs for locomotion in adult formHave no organs for locomotion in adult form– Many are parasiticMany are parasitic

BACTERIA

ARCHAEA

Parabasalids

Diplomonads

Kinetoplastids

Euglenids

Amoebae

Slime molds

Ciliates

Apicomplexa

Dinoflagellates

Oomycetes

Diatoms

Brown algae

Red algae

Green algae

Land plants

Fungi

Animals

PROTISTS

Figure 27.1

We will observe the following four:We will observe the following four:

• CiliatesCiliates

– 1) Paramecium caudatum1) Paramecium caudatum

– 2) Stentor coeruleus2) Stentor coeruleus

• SarcodinesSarcodines

– 3) Amoeba proteus3) Amoeba proteus

• FlagellatesFlagellates

– 4) Euglena gracili4) Euglena gracili

ParameciumParamecium• Live in FRESH waterLive in FRESH water

• Osmosis causes water to move Osmosis causes water to move into the parameciuminto the paramecium

• Contractile vacuole collects the Contractile vacuole collects the extra water so that the extra water so that the paramecium doesn’t lyseparamecium doesn’t lyse

• Covered in cilia used for Covered in cilia used for locomotion and for directing food locomotion and for directing food into the oral cavityinto the oral cavity

• Most are free-living (not parasites)Most are free-living (not parasites)

AmoebaAmoeba• Sizeable amount of Sizeable amount of

cytoplasmcytoplasm• Cytoplasmic Cytoplasmic

streaming pushes on streaming pushes on the cell membrane the cell membrane resembling armsresembling arms

• A clear nucleusA clear nucleus• False foot: False foot:

pseudopods to move pseudopods to move and capture preyand capture prey

• Feeding: endocytosis: Feeding: endocytosis: surround food; creates surround food; creates a food vacuole. a food vacuole.

• Ameoba reproduce by Ameoba reproduce by binary fissionbinary fission

EuglenaEuglena

• Plant-likePlant-like

• Long flagellum Long flagellum excellent excellent swimmers swimmers

• A red-spot A red-spot (photoreceptor) (photoreceptor) helps euglena helps euglena detect sunlight detect sunlight so it’s so it’s chloroplasts can chloroplasts can make glucose make glucose using using photosynthesisphotosynthesis

Stentor coeruleus (S.coeruleus)Stentor coeruleus (S.coeruleus)• trumpet-shapedtrumpet-shaped

or cylindrical; or cylindrical; highly highly contractilecontractile

• contractile vacuole contractile vacuole anterior-left; fresh anterior-left; fresh water water