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