Post on 14-Dec-2015
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