ProtistsDomain EukaryaKingdom Protista
Microscopic Critters Abound!
Characteristics of Kingdom Protista
• Heterogeneous assemblage of unicellular, colonial and multicellular Eukaryotes that do not have the distinctive characters of plants, animals or fungi• Contains a number of organisms previously classified as plants, animals or fungi. • Classification based on movement and pigment (our text)• Cells typically 1 μm to 50 μm, up to 60 meters (seaweed)
Importance• Important components of food chains. E.g. kelp beds are among the most
productive ecosystems on earth• Unicellular aquatic Protista (plankton) form an important component of the food chain. The photosynthetic ones are called phytoplankton and the heterotrophic ones are called zooplankton (which also includes many animal larvae or tiny crustaceans)
Motility Motility – the ability to move spontaneously and independently
Some are motile, some are NOT motile Some move using:
cilia flagella streaming (amoeba use “arms"
called a pseudopod)
Domain Eucarya
Kingdom ProtistaPhylum Sarcodina
Phylum Sarcodina• Unicellular• Move by pseudopodia• Some surrounded by a calcium
"shell" • Amoeba has no definite shape• Shape is constantly changing• Food is surrounded by pseudopods
and stored in a food vacuole
Amoeba proteus
Sarcodina Reproduction
• Asexual–only known method!
Phylum Ciliaphora
• Unicellular• Nuclear dimorphism : two
functionally distinct kinds of nucleii• Micronucleus is specialized for
sexual exchange • Macronucleus is specialized for
transcription
•Move by cilia in a spiral path
Paramecium Anatomy
Paramecium Reproduction• Asexual – binary fission
• Sexual - conjugation Under certain conditions, such as overcrowding or
environmental stress, Paramecium turns from strictly asexual reproduction to sexual reproduction. Sexual reproduction involves the exchange of genetic material between two individuals of different 'mating strains'. Involves meiosis.
Reproductive Cycle
And now for a pleasant review of
mitosis and meiosis!
Phylum Zoomastigina
• Move by flagellum or flagella• Other zooflagellates may live inside
as parasites• Some diseases caused by flagellates
are transmitted by insects• Can become infected by
contaminated water• Some live in the digestive tracts of
termites and assist in the digestion of cellulose.
The Flagellates
Pathogenic examples of Zooflagellates
• Giardia lamblia – “Hiker’s disease”
• Trypanosoma cruzi
• Transmitted by insects-Reduviid insect
• Causes Chagas’ disease
http://www.cdc.gov/ncidod/dpd/parasites/chagasdisease/factsht_chagas_disease.htm
Mainly in Latin America:18 million are infected each year; 50,000 die yearly.Affects major organs:HeartLiverG.I. tractBrain
• Vector - <L. vehere to carry• Metacyclic – infective stage• Trypomastigotes flagelatted form
of parasite that lives in the blood.• Amastigotes or mastigotes -
Unflagelatted form that lives in cells
Phylum Sporozoa
• Unicellular• All Parasitic!• Responsible for malaria• Move by gliding motion in some
stages
Plasmodium
Plasmodium Lifecycle
Domain EucaryaThe Algae
Kingdom Protista
All algae provide food for microorganisms which larger animals and fish can eat
Surface and hair algae provide food for fish directly All algae absorb excess pond nutrients like ammonia,
nitrate, and phosphate Suspended algae provides some shade to pond
animals and plants in the spring All algae provide oxygen during the day (but use it at
night) Hair algae provides a soft spawning site for fish.
Benefits of Algae
Phylum Euglenaphyta 800 to 1000 species Photosynthetic when light available Heterotrophic when light unavailable Resemble protozoans due to flagella Freshwater and brackish water
inhabitants
Algae Classification
Euglenaphyta
Euglena
Euglena Reproduction
Binary Fission
Euglena rubra
E. sanguinea This is due to
the pigment called astaxanthin
7,000 species Most freshwater, but some terrestrial; a
few marine Contain chlorophylls a, b, and
carotenoids Unicellular, colonial, and multicellular
Phylum Chlorophyta
Spirogyra
Hair algae
Phylum Chrysophyta
850 species Store food as oils Most unicellular, some colonial Cell walls made of cellulose
Chrysophyta Vaucheria
Phylum Bacillariophyta
Supply more oxygen than all other organisms
1150 species
Store food as oil
Silica walls contain silica used for filters, insulate boilers, abrasive factor in toothpaste
Bacillariophyta Diatoms
Phylum Phaeophyta
All multicellular Almost all marine Brown algae Contain chlorophyll a, c, and fucozanthin Provides algin – thickener in cheap ice
cream Stem-like structure has air bladders that
allow it to float near surface of water
Phaeophyta
Fucus
Phylum Rhodophyta
Mostly marine Multicellular Color derived from phycobilins Less than 30 cm long Important in building reefs from calcium
deposition Products: agar, gelatin shells of drug
capsules
Rhodophyta
Gelidium pulchrum
Phylum Dinoflagellata
Unicellular Possess two flagella Cell walls composed of cellulose Mostly marine Some bioluminescent Responsible for red tides!
Dinoflagellates
Ceratium sp. Protoperidinium sp.
RED TIDE!
Disadvantages of Algae
Suspended algae reduces clarity so that animals and plants cannot be seen in the pond
All algae reduce oxygen levels at night All algae may cause pH fluctuations All algae may cause the death of submerged
plants, water lilies, etc. due to either reduced light levels or strangulation in the case of hair algae
Hair algae can clog filters, pumps, etc Finally, many people find algae ugly
EutrophicationCan occur naturally or induced