Protista

Do Now:What domain does the

kingdom Protista fall into?

Protists• Extremely diverse group of organisms• Any Eukaryotic organism that is NOT a plant, fungi or animal• Some are Autotrophs (Algae)• Some are Heterotrophs (Protozoans feed on bacteria or other

protists)• Some are both Heterotrophs and Autotrophs (depending on the

available of light and nutrients)• Most are Unicellular• Simplest of the Eukaryotic cells• They are the FIRST Eukaryotic cells• Often very elaborate (analogous to an entire plant, animal, or

fungi)• Classification of Protists is a work in progross, this is a very

diverse group!

Classification of Protists

• The two main ways we classify Protists…– How they obtain energy (plant-like, animal-like,

decomposers)– How they move (cilia, flagella, pseudopods)– Genetic studies (DNA) show that the way the

organisms are currently grouped may change!– http://www.youtube.com/watch?v=-zsdYOgTbOk

Animal-like Protists

• All Heterotrophs• Not animals because they are unicellular (all

animals are multi-cellular)• 4 Phyla

– Zooflagellates– Sarcodines– Ciliates– Sporozoans

Zooflagellates

• Phylum: Zoomastigina• Animal-like protists that swim using a flagella• Flagella are long and whip-like and allow a cell to

move. • Most reproduce asexually: Mitosis and

Cytokinesis• Some sexual reproduction: Meiosis and Gametes.• Many live in lakes and streams• Absorb food through their cell membranes• free-living, symbiotic, commensal, or parasitic in

humans and other animals and in certain plants• Some form colonies of cells

Leishmania donovani(parasite in vertebrates)

http://www.cdc.gov/eid/content/13/3/476.htm

Trichomona vaginalis(anaerobic parasite)

Sarcodineshttp://www.youtube.com/watch?v=W6rnhiMxtKU&feature=related

•Move via pseudopods, which are temporary cytoplasmic extensions. This is called amoeboid movement.•Foraminiferans: secrete silicate shells, and live in warm marine waters. Pseudopods extend through small pores in the silica test. Pseudopoda are much skinnier than amoebas.

Forams Amoeba

Ciliates• Use cilia for feeding and movement• Cilia: short, hair-like structures.• Paramecium is an example• Macronucleus: controls the daily activities of the cell. Working

copy of genetic material.• Micronucleus: used in reproduction (usually have more than

one) and has reserve copy of genetic material (DNA).• Oral Grove: It is sort of like a mouth. The cilia sweep food into

the oral groove, then it moves into the gullet.• Gullet: the gullet is an indentation in the cell where food

molecules collect and are then moved into food vacuoles. (Lysosomes have the enzymes to actually digest the food molecules)

• Food vacuole: stores food molecules• Anal pore: waste materials are released into the environment.

Food vacuole fuses with anal pore.• Contractile Vacuole: stores water and pumps water out of the

cell once its full.• Pellicle: a thin layer made of protein supporting the cell

membrane.• http://www.youtube.com/watch?v=l9ymaSzcsdY

Sporozoans

• Do not move on their own• Are all parasitic• Reproduction: Sporoziote

– Attach to host cell– Penetrate host cell– Live within host cell as a

parasite• Reproduction can be

complex and involve more than one host.

Plasmodium falciparum

Plant-Like Protists (commonly called Algae)

• Four Phyla– Euglenophytes– Chrysophytes– Diatoms– Dinoflagellates

• Unicellular Algae• Red, Green, and Brown Algae (Seaweeds)• Contain Chlorophyll (green pigment)• Perform Photosynthesis• Used to be considered plants

Seaweeds• Green algae share characteristics with plants like

having cellulose in their cell walls and chlorophyll a and b for photosynthesis. Can be unicellular, colonial (Volvox), or multicellular (Ulva lactuca or sea lettuce)

• Brown algae are all multicellular, include the giant kelp forests of the coast of CA, contain chlorophyll a and c pigments, plus an accessory pigment fucoxanthin. Usually found in cool, shallow coastal waters.

• Red algae contain chlorophyll a and reddish pigment called phycobilins (good at absorbing blue light). They can live at great depths compared to other seaweeds, because they are efficient at capturing light. Range from arctic waters to the tropics. Most are multicellular.

Euglenophytes• Named after the genus Euglena• Common in lakes and ponds• Plant-like, but no cell wall (they have a pellicle)• Share characteristics with zooflagellates• They have a reddish pigment near the gullet called an eyespot• They can use their two flagella to move towards light• Photosynthesize (make their own food using light.• Asexual reproduction: Binary Fission

Chrysophytes

• Pectin in the cell wall (not cellulose like plants)

• Chloroplasts have a golden color• Store food as oil instead of starch• Unicellular• Solitary or thread-like colonies• Motile cells have flagella• Used to be grouped with multi-cellular

brown algae• Diverse group of organisms• Mostly found in fresh water

Diatoms

• Single celled photosynthetic algae• Common in plankton• Two hard coverings of silica that

fit together like the lid and bottom of a shoe box

• The silica SiO2 is almost identical to opal

• The can reproduce asexually by mitosis or sexually by meiosis (gametes)

Dinoflagellates• Unicellular aglae• Some are photosynthetic• Some are parasitic on fish or

other protists• Some Bioluminescence

(produce their own light, same way fireflies make light)

• Red Tide!, they produce a neurotoxin that affect fish and can accumulate in shellfish (making the shellfish toxic to people). The algae population explodes, called a bloom.

Fungus-Like Protists

• Slime Molds• Water Molds• NOT fungus because they lack Chitin in their

cell walls.

Slime Molds

•Slime molds are fungus-like•They do not have chitin, like true fungi•They feed on dead or decaying matter•They have a complex reproductive cycle•http://www.youtube.com/watch?v=bkVhLJLG7ug&NR=1•The amoebiod cell can move•Two haploid cells will combine to form a zygote (diploid cell)•Plasmodium is a multi-nucleic mass used for reproduction•The fruiting body (sporangium) contains spores •The spore germinates and a haploid amoebiod cell emerges•The cycle will then repeat

Water Molds

• There are more than 500 species in the Oomycota

• Filamentous• Eat by absorbing food

through the water or surrounding soil

• They were once considered fungi, but their cell walls have cellulose and glycan and not chitin like true fungi

Classification

• Protists used to be included in Animal, Plant or Fungi Kingdoms.

• They were kicked out and grouped as protists because they were lacking something indicative or important to that kingdom.