Protists Domain Eukarya Kingdom Protista Microscopic Critters Abound!

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