Chapter 20: Protists Biology- Kirby

20-1: The Kingdom Protista Protist- any organism that is not a plant, animal, fungus, or prokaryote. Protists are eukaryotes, and most are unicellular. The first eukaryotic organisms on Earth were protists (1.5 billion years ago).

20-1: The Kingdom Protista 3 types of protists: Animallike- heterotrophs Plantlike- autotrophs Funguslike- external digestion such as decomposers or parasites.

20-2: Animallike Protists: Protozoans There are 4 types of protozoans classified by their movement: Zooflagellates Sarcodines Ciliates Sporozoans

20-2: Animallike Protists: Protozoans Zooflagellates- move through aquatic environments with flagella. They can have more than 1 flagella. Able to absorb food through cell membrane. Most reproduce asexually by mitosis and cytokinesis. Some reproduce sexually by meiosis and the formation of gametes.

20-2: Animallike Protists: Protozoans Sarcodines- use pseudopods for feeding and movement. Pseupod- “false foot” Example: Amoeba- capture and digest food by forming a food vacuole with its cytoplasm. They reproduce by mitosis and cytokinesis.

20-2: Animallike Protists: Protozoans Ciliates- use cilia for feeding and movement. Cilia- short hairlike projections similar to flagella. Cilia move together, or beat, and move the organism very quickly. Example: Paramecium- have a macronucleus and a micronucleus. Cilia sweep food into the gullet.

20-2: Animallike Protists: Protozoans Continued: Waste exit through an anal pore in the membrane. A cavity called contractile vacuole holds and expels water. Usually reproduce asexually by mitosis and cytokinesis. Under stress, paramecium undergo conjugation.

20-2: Animallike Protists: Protozoans Sporozoans- do not move on their own; parasitic. Attaches itself to a host and lives inside it. Some animallike protists cause diseases like malaria and African sleeping sickness. Others are beneficial to organisms.

20-2: Animallike Protists: Protozoans Zooflagellates Sarcodines Ciliates Sporozoans

20-3: Plantlike Protists-Unicellular Algae Plantlike protists are called algae. They contain chlorophyll which makes them appear green. Some scientists think algae are more closely related to plants; but we consider them to be protists.

20-3: Plantlike Protists-Unicellular Algae Accessory pigments- absorb light at different wavelengths than chlorophyll- give algae a range of color. There are 4 phyla of unicellular algae: Euglenophytes Chrysophytes Diatoms Dinoflagellates

20-3: Plantlike Protists-Unicellular Algae Euglenophytes: Plantlike protists that have 2 flagella and no cell wall. Have an eyespot which allows the organism to find sunlight. Can also live as heterotrophs by absorbing nutrients.

20-3: Plantlike Protists-Unicellular Algae Chrysophytes: Means “golden plants” because they have gold-colored chloroplasts. Diatoms: Produce thin cell walls made of silicon which make the walls look like glass.

20-3: Plantlike Protists-Unicellular Algae Dinoflagellates: Half are autotrophs, half are heterotrophs. Many are luminescent and give off light when agitated by sudden movement in water.

20-4: Plantlike Protists-Red, Brown, & Green Algae There are 3 phyla of multicellular algae: Red algae Brown algae Green algae

20-4: Plantlike Protists-Red, Brown, & Green Algae Red algae: Able to live deep in the water. Have chlorophyll a and reddish accessory pigments called phycobilins. Important to the formation of coral reefs.

20-4: Plantlike Protists-Red, Brown, & Green Algae Brown algae: Contain chlorophyll a and c, and a brown accessory pigment called fucoxanthin. Largest and most complex of the algae. Live in cool, shallow waters.

20-4: Plantlike Protists-Red, Brown, & Green Algae Contain chlorophyll a and b, and cellulose in cell walls. Live in fresh and salt water. Unicellular green algae- 2 flagella & single chloroplast. Colonial green algae- cells are stacked. Multicellular green algae- has specialized cells & lives on rocky coasts.

20-4: Plantlike Protists-Red, Brown, & Green Algae Green algae Reproduction: Life cycle includes both a diploid and haploid generation.

20-5: Funguslike Protists Funguslike protists are heterotrophs that absorb nutrients from dead/decaying matter. Slime molds- funguslike protists that recycle organic material. Cellular slime molds- individual cells remain separated during life cycle. Acellular slime molds- cells fuse to form large cells with many nuclei called plasmodia.

20-5: Funguslike Protists Water molds- thrive on dead/decaying matter in water & some are plant parasites on land. Produce thin filaments called hyphae which aid in reproduction. Slime and water molds are very beneficial because they help decompose matter, but some can cause plant diseases.