Chapter 18: Protists
Virus
Monera
Protista
Taxonomic thinking
Animals
Plants
Fungi
Protists
Monera
Phylogenetic Thinking
EUKARYA
Protists
Prokaryotes vs Eukaryotes
Prokaryotes
• Kingdoms: 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 flagella
BACK
Eukaryotes
• Cells have nuclei and
membrane-bound organelles
What are Protists?
What are Protists?
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Greek word meaning “first”
First kingdom of eukaryotes
Unicellular
Nuclei
Organelles
Reproduce by mitosis
Multiple chromosomes
Protists 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
All protists live in water, or moist soil, or moist
interiors of other organisms
Surface waters
teem with
microscopic
protists
In some nearshore areas,
gigantic protists
form underwater
forests
Protists are
particularly
abundant in
tidal habitats
Classification
• 115,000
species
• Major debate
regarding how
they should be
classified
• “animal-like” =
zooplankton or
protozoans
• “plant-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 locomotion
• 1) Sarcodines
– Blob-like asymmetrical
– Assume infinite variety of shapes
– Ex. Amoebae
• 2) Flagellates
– Ex. Euglena
• 3) Ciliates
– Ex. Paramecium
• 4) Sporozoans
– Have no organs for locomotion in adult form
– Many are parasitic
Figure 27.1
PROTISTS
Kinetoplastids
Diplomonads
Slime molds
Brown algae
Parabasalids
Amoebae
BACTERIA
ARCHAEA
Dinoflagellates
Ciliates
Euglenids
Oomycetes
Diatoms
Apicomplexa
Red algae
Fungi
Green algae
Land plants
Animals
We will observe the following four:
• Ciliates
– 1) Paramecium caudatum
– 2) Stentor coeruleus
• Sarcodines
– 3) Amoeba proteus
• Flagellates
– 4) Euglena gracili
Paramecium
• Live in FRESH water
• Osmosis causes water to move
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into the paramecium
Contractile vacuole collects the
extra water so that the paramecium
doesn’t lyse
Covered in cilia used for
locomotion and for directing food
into the oral cavity
Most are free-living (not parasites)
Amoeba
• Sizeable amount of
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cytoplasm
Cytoplasmic streaming
pushes on the cell
membrane resembling
arms
A clear nucleus
False foot: pseudopods to
move and capture prey
Feeding: endocytosis:
surround food; creates a
food vacuole.
Ameoba reproduce by
binary fission
Euglena
• Plant-like
• Long flagellum
•
excellent
swimmers
A red-spot
(photoreceptor)
helps euglena
detect sunlight so
it’s chloroplasts
can make glucose
using
photosynthesis
Stentor coeruleus (S.coeruleus)
• trumpet-shaped or
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cylindrical; highly
contractile
contractile vacuole
anterior-left; fresh
water