kingdom protista chapter 19. general characteristics of protists: all eukaryotes that cannot be...

Kingdom ProtistaChapter 19

General Characteristics of Protists:

• ALL Eukaryotes that cannot be classified as a plant, animal, or fungus.

• They have a nucleus and membrane bound organelles;

• some are autotrophic, some are heterotrophic;

• some are multicellular, most are unicellular.

They are classified by the way they OBTAIN

NUTRITION.

Three kinds of protists• Animal-like (consume food)• Plant-like (make their own food)• Fungus-like (decomposer)

19.2 Animal-like Protists TEKS 11C, 12A

KEY CONCEPT Animal-like protists are single-celled heterotrophs that can move.

Animal-like Protists• Called Protozoans- meaning “first

animals”• Examples:

– Zooflagellates– Sarcodines– Ciliates– Sporozoans

Protozoans• these are “Animal-like” protists that

consume their food (heterotrophs)• Unicellular• characterized by modes of

locomotion (how they move)– Cilia– Flagella– Pseudopod

Zooflagellates• Characteristics: move by flagella (one or

two)• Reproduction: mostly asexual by mitosis,

some sexual reproduction- produce gametes that fuse

• Role/Function:– Mostly free swimming– Some are parasites– Trypanosoma causes African Sleeping

Sickness, Giardia causes diarrhea– Termites have a zooflagellate living inside

them that helps them digest wood

Trichomonas

nucleus

flagella

Zooflagellates

Sarcodines• Characteristics: move by pseudopods-

extensions of cytoplasm• Reproduction: asexually by mitosis• Role/Function:

– free-swimming in aquatic environments– Amebic dysentery (diarrhea)

Ameba proteus

PseudopodPseudopod

NucleusNucleus

Ciliates• Characteristics:

– use cilia for movement and feeding– Have a macronucleus (active nucleus)

and micronucleus (reserve copy)• Reproduction: asexually by mitosis, can

exchange material through conjugation (Figure 20-6 in book)

• Role/Function: free-living

Paramecium

Ciliates

Macronucleus

Micronucleus

Cilia

Sporozoans• Characteristics: Do not move on their

own• Reproduction: complex reproduction with

two phases- a sexual phase and asexual phase inside two different organisms!

• Role/Function: – Parasitic– Malaria is caused by the

sporozoan Plasmodium

Nucleus

Sporozoans

19.3 Plantlike Protists TEKS 8B, 8C, 11C

KEY CONCEPT Algae are plantlike protists.

Plant-like (Algae)• Unicellular

– Euglenophyta– Chrysophyta– Bacilliarophyta

(Diatoms)– Pyrrophyta

(Dinoflagellates)

• Multicellular– Rhodophyta– Phaeophyta– Chlorophyta

Unicellular Algae• (describe their ecology/uses):

– autotrophic, capture sunlight with chlorophyll and other accessory pigments to make food

– base of many aquatic food chains•Example: phytoplankton- floating

photosynthetic organisms

Euglenophyta• Characteristics: two flagella, no cell wall• Reproduction: asexually by mitosis• Role/Function:

– free-swimming– can absorb material for food- recycling

sewage– can lead to algal blooms choking

waters of nutrients

19.3 Plantlike Protists TEKS 8B, 8C, 11C

• Euglenoids are a large group of plantlike protists.

pellicle

nucleus

chloroplast

eye spot

contractilevacuole

flagellum

– mostly photosynthetic – some heterotrophic – single-celled – one or two flagella

Euglenophyta

Flagellum Nucleus

Chloroplast

Chrysophyta

• Characteristics: – cell walls sometimes of pectin– Gold-colored chloroplasts

• Reproduction: asexually and sexually• Role/Function: free-floating

• Known as “golden algae”

Diatoms• Characteristics: secrete thin cell walls of

silica (main component of glass)• Reproduction: asexually and sexually• Role/Function:

– Free-floating, or – live in soil

19.3 Plantlike Protists TEKS 8B, 8C, 11C

• Diatoms are plantlike protists with glasslike shells. – shells made of silica – produce large amounts of oxygen

Pyrrophyta-Dinoflagellates• Characteristics: have two flagella and

thick cell wall• Reproduction: asexually by mitosis• Role/Function: responsible for red tides

(algal bloom of dinoflagellates that secrete toxins that can cause illness paralysis, and death in fishand humans)

19.3 Plantlike Protists TEKS 8B, 8C, 11C

• Dinoflagellates are mostly marine plantlike protists.

Dinoflagellates

– have two flagella – may be bioluminescent – have stiff protective plates – can cause red tide

DinoflagellatesNucleus

Flagella

19.3 Plantlike Protists TEKS 8B, 8C, 11C

• Multicellular algae are classified by their pigments.

– Green algae contain chlorophyll a and b. – Brown algae contain chlorophyll c. – Red algae contain chlorophyll a and phycoerythrin.

Multicellular Algae• (describe their ecology/uses)-

– Autotrophic– Multicellular– some have specialized tissue– seaweeds and kelp– used in foods such as sushi, ice cream,

salad dressing, candy, etc.

Red Algae (Rhodophyta)

• Characteristics: contain pigments- Chlorophyll a and Phycobilins (red)

• Reproduction: sexually• Role/Function:

– Deeper sea, great at harvesting light

– Help form coral reefs– Some used in foods and to make

agar

Brown algae (Phaeophyta)• Characteristics: contain pigments

Chlorophyll a and c and Fucoxanthin (brown)

• Reproduction: sexually by mitosis and meiosis

• Role/Function: – Form large habitats in aquatic

ecosystems– Used some in food

Green algae (Chlorophyta)

• Characteristics: – unicellular, colonial, or multicellular– chlorophyll a and b

• Reproduction: sexually by mitosis and meiosis like true plants

• Role/Function: some form symbiotic relationships with other organisms

Spirogyra- multicellular

Volvox- colonial

Ulva- multicellula

r

19.3 Plantlike Protists TEKS 8B, 8C, 11C

• Some algae produce sexually. – Some species alternate generations.– Sexual reproduction can be triggered by environmental stress.

Kaikoura, New Zealand

19.4 Funguslike Protists TEKS 8B, 8C, 11C

KEY CONCEPT Funguslike protists decompose organic matter.

Fungus-like• Slime Molds• Water Molds

19.4 Funguslike Protists TEKS 8B, 8C, 11C

Slime molds and water molds are funguslike protists.• Slime molds have both funguslike and animallike traits.

– decomposers, like fungi – can move, like animals

Fungus-like• (describe their ecology/uses):

– heterotrophic using external digestion to break down dead and decaying organic matter

Slime Molds• Characteristics:

– cellular or acellular (masses with several nuclei)

– Unicellular but can gather and act multicellular

• Reproduction: sexually• Role/Function: Forest floor or

composting- recycle organic matter

19.4 Funguslike Protists TEKS 8B, 8C, 11C

• Slime molds can be plasmodial or cellular.

– Plasmodial slime molds are giant cells with many nuclei.– Cellular slime molds contain independent cells.

Water Mold

• Characteristics: – also called oomycetes (O-O-my-sets)– Produce filaments called hyphae

• Reproduction: sexually and asexually• Role/Function:

– dead decaying matter in aquatic environments

– some are plant parasites– attack tomatoes and potatoes

19.4 Funguslike Protists TEKS 8B, 8C, 11C

• Water molds are freshwater, funguslike protists.– one type of water mold caused Great Potato Famine

of Ireland in the 1800’s – made of branching strands of cells – can be parasites of plants or fish