ProtistansProtistans
The unicellular eukaryotic organisms
Outline of TodayOutline of Today’’s lectures lecture
� Compare Prokaryotes & Eukaryotes
� Protista• Key concepts• Characteristics• Classification
• Fungus-like protistans• Plant-like protistans• Animal-like protistans
• Three major groups
� Four Eukaryotic Kingdoms
Compare Prokaryotes & EukaryotesCompare Prokaryotes & Eukaryotes
Key Concepts:Key Concepts:
�The kingdom Protista includes single-
celled eukaryotic cells
�Fungus - like Protistans include some
parasitic organisms that are decomposers
�Animal - like Protistans include
nonphotosynthetic flagellated protozoans
Key Concepts:Key Concepts:
�Many plant - like protistans are
photosynthetic flagellates and are
important members of phytoplankton
�Some protistans are multicelled forms
that include the red, brown, and green
algae
Systematists do not use
the term “protist” as a
formal group name, but a
term of convenience
ProtistansProtistans
Characteristics:Characteristics:
�First eukaryotes – about 2 billion
years ago
�Unicellular, true nucleus, organelles
�Autotrophic or heterotrophic
FungusFungus--like like ProtistansProtistans
� Resemble fungi
� Water molds (Live in water
&wet soil): causing molds-
downy mildew (grapes)
late blight (rotting of potato
and tomato) – 1845-1860
� Slime molds - Slime molds
are decomposers that inhabit
the forest floor
The Animal The Animal -- Like ProtistansLike Protistans� Protozoans – first animals
�Amoeboid protozoans - free-living predators/parasite
Entamoeba histolytica - amoebic dysentery
�Cilitated protozoans
Paramecium - free living predators (bacteria/algae/others)
�Animal-like Flagellates (free-living predators/parasite)
Trichomonas vaginalis - infection of urinary and
reproductive tracts
Trypanosoma brucei - African sleeping sickness
Giardia lamblia – diarrhea
�Apicomplexans -parasitic protistans: Life cycle complex
(Involve 2 hosts or more)
Plasmodium – four species cause Malaria
Body Plan of a Ciliated Body Plan of a Ciliated Protozoan, Protozoan, ParameciumParamecium
Scanning electron
micrograph
AnimalAnimal--Like FlagellatesLike Flagellates
Giardia
lamblia
Trypanosoma
brucei
Trichomonas
vaginalis
Life Cycle of Life Cycle of Plasmodium Plasmodium -- MalariaMalaria
A Sampling of the A Sampling of the Single Single -- Celled AlgaeCelled Algae
�Algae
� Euglenoids
�Euglena
�Chrysophytes
�Diatoms
�Golden algae
�Yellow-green algae
Plant-like protistans:Phytoplankton (floating plants)- autotrophic (produce 70% O2)
Euglena Euglena –– an animal or a plant?an animal or a plant?
AlgaeAlgae
� Red
�Rhodophyta
�Tropical seas
�Agar - from extracts
�Baked goods
�Cosmetics
�Jellies
�Culture gels
�Drug capsules
AlgaeAlgae
� Brown
� Phaephophyta
�Sargassum
�Macrocystis
�Kelp
�Underwater
forests
�Commercial harvest
� Extracts used in foods
AlgaeAlgae
�Green Algae
�Chlorophyta
�Photosynthetic
�Volvox
�Acetabularia
�Ulva (sea lettuce)
�Chlamydomonas
�Spirogyra
� Sexual and asexual reproduction
Four Eukaryotic KingdomsFour Eukaryotic Kingdoms
In ConclusionIn Conclusion
�Protistans are eukaryotes
�Many are heterotrophs which include the
water molds, slime molds, and protozoans
�The fungus-like protists are decomposers
or parasites
�Animal-like protozoans are internal
parasites or live freely in aquatic habitats
In ConclusionIn Conclusion
�Sporozoans have complex life cycles
involving multiple hosts
�Single-celled and multiple-celled algae are
photoautotrophs
�The red, brown and green algae are
multicelled photosynthesizers
�The protistans are the simplest of the
eukaryotes
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