Ch. 20 Protists

Ch. 20 Outline

20-1: The Kingdom Protista What is a Protist Classification of Protists

20-2: Animal-like Protists: Protozoans Zooflagellates Sarcodines Ciliates Animal-like Protists and Disease Ecology of Animal-like Protists

Ch. 20 Outline

20-3: Plant-like Protists: Unicellular Algae Chlorophyll and Accessory Pigments Euglenophytes Chrysophytes Diatoms Dinoflagellates Ecology of Unicellular Algae

Ch. 20 Outline

20-4: Plant-like Protists: Multicellular Algae Red Algae Brown Algae Green Algae Human Uses of Algae

20-5: Fungus-like Protists Ecology of Fungus-like protists

What is a Protist?

Protist: Any eukaryotic organism that is not a plant, animal, or fungus.

Kingdom Protista is the most diverse kingdom. They can be unicellular or multicellular

Classification of Protists

One way to classify protists is by how they obtain nutrition: Heterotrophs – animal like Autotrophs – plant like Decomposers/Parasites – fungus like

Phyla Tree

Zooflagellates

Animal-like protists that swim using a flagella are classified in the Phylum zoomastigma and are often referred to as zooflagellates. Flagella: Long, whiplike projection that enable

movement.

Sarcodines

Sarcodines are animal-like protists that use pseudopods for feeding and movement

Ex. Amoebas Amoebas capture food by surrounding it, then

taking it in and forming a food vacuole. Food Vacuole: small cavity in the cytoplasm

that temporarily stores food.

Amoeba

Pseudopods

Ciliates

Members of the phylum Ciliophora, known as ciliates, use cilia for feeding and movement. Cilia beat like oars

Ex. Paramecium Anatomy of a Paramecium Macronucleus: “Working Library” of a genetic

information Micronucleus: contains a “reserve copy” of all the cell’s

genes Gullet: Indentation on one side of the organisms (food

enters here) Anal Pore: Region where waste is emptied Contractile vacuole: Expels excess water

Paramecium

Sporozoans

Members of the Phylum Sporozoa do not move one their own and are parasitic.

Animal-like Protists and Disease

Protists can causes some diseases. Example: Malaria

Caused by the sporozoans Plasmodium, which is carried by the Anopheles mosquito

Plasmodium infects liver cells and RBC’s where it reproduces causing those cells to burst

Malaria

Ecology of Animal-like Protists

Recycle nutrients in the environment Serve as food for larger animals Live symbiotically with other organisms

Ex. Trichonympha live in the guts of termites and enable them to digest wood (by the enzyme cellulase)

Chlorophyll and Accessory Pigments

Many protists contain the green pigment, chlorophyll and carry out photosynthesis. One the ways plant-like protists are categorized is by the type of photosynthetic pigment they contain.

Accessory pigments: absorb light at different wavelengths than chlorophyll Review: The energy from sunlight is used by

photoautotrophs to make sugars for food

Euglenophytes

These protists have two flagella but no cell wall.

Ex. Euglena Eyespot: Reddish pigment near the gullet

Senses light

Euglena can also be heterotrophic

Euglena

Gullet

Chloroplast

NucleusEyespotFlagella

Carbohydrate storage bodies

Pellicle

Contractile vacuole

Chrysophytes

These protists have gold-colored chloroplasts

Ex. Yellow-green and golden-brown algae

Diatoms

Diatoms produce thin, delicate cell walls rich in Silicon (Si) – the main component in glass.

Used in pesticides – Like Shrapnel!

Dinoflagellates

Many of these are lumniscent. About half are photosynthetic and half are

heterotrophs. They have two flagella also.

Dinoflagellates

Ecology of Unicellular Algae

Plant-like protists serve as the base of a food chain in many aquatic ecosystems

Phytoplankton: population of small, photosynthetic organisms found nears the surface of the ocean. Protists make up much of phytoplankton

Agal Blooms

When waste is high the number of plant-like protists increases greatly (since they use the organic matter for food). This is called a bloom

A “red tide” is a bloom of dinoflagellates. They give off a toxin that harms both humans and fish.

Red Algae

Red Algae are able to live at great depths due to their efficiency in harvesting light energy. Red Algae contain chlorophyll a and reddish accessory pigments called phycobilins.

Brown Algae

Brown Algae contains chlorophyll a and c, as well as a brown accessory pigment called fucoxanthin.

Green Algae

Green Algae share many characteristics with plants, including their photosynthetic pigments and cell wall composition.

Pigments: a and b

Human Uses of Algae

Photosynthesis oxygen in atmosphere Chemicals in algae used in medicines Food source Chemicals used to make plastics, waxes,

paints and more!

Fungus-like Protists

Like fungi, funguslife protists obtain their food by digesting outside their bodies (heterotrophs), but they do not have cell walls of chitin like fungi.

Two types of mold: Slime Molds Water Molds

Water Mold

Slime Mold

MEIOSIS

FERTILIZATION

ZygoteGerminating spore

Spores

Young sporangium Mature

plasmodium

Feeding plasmodium

Haploid (N) Diploid (2N)

Mature sporangium

Ecology of Fungus-like Protists

Important recyclers of organic material Decomposers of dead things!

Some cause plant diseases Potato Blight in Ireland caused by water mold Lead to Irish immigration to America