III. Plant-like Protists : Unicellular Algae Algae – plant-like protists that perform photosynthesis. A. Characteristics of Algae 1. Algae contain chlorophyll in their chloroplasts to produce their chloroplasts to produce food & O 2 through photosynthesis. food & O 2 through photosynthesis. Photosynthesis – the process by which autotrophs convert sunlight into a usable form of energy. 2. Have no specialized tissues/organs. 3. Are classified based on differences in structure & type of pigments that they structure & type of pigments that they contain. contain. 4. Can be unicellular or multicellular.

7 major groups of plant-like protists : 1. Euglenophytes 2. Chrysophytes 3. Diatoms 4. Dinoflagellates 5. Red algae 6. Brown algae 7. Green algae

Unicellular algae include : 1. Euglenophytes (Euglenophyta) plant-like protists that have 2 flagella plant-like protists that have 2 flagella but no cell wall Ex, Euglena. but no cell wall Ex, Euglena. -Have characteristics of both plants & animals. Plant-like characteristics include : -Photosynthetic pigments Animal-like characteristics include : -No cell wall & move with flagella

Characteristics of Euglena : 1. Are single-celled. 2. Have 2 flagella : A. Large one for movement. A. Large one for movement. B. Small one that is inactive. B. Small one that is inactive. 3. Have a large central nucleus. 4. Are primarily photosynthetic but may also be heterotrophic.

Chrysophytes 2. Chrysophytes (Chrysophyta) – the diverse group of plant-like protists that have gold-colored chloroplasts. -Chrysophyta means “golden plants”. Chrysophyta includes : a. Yellow-green algae b. Golden-brown algae -Cell walls sometimes contain pectin instead of cellulose. -Store food in the form of oil. -Reproduce asexually & sexually.

Diatoms 3. Diatoms (Bacillariophyta) – protists that produce thin, delicate cell walls rich in silicon. They look glass-like. -Are among the most abundant & beautiful organisms on Earth. -Cell walls fit together like a Petri dish. -Remains of diatoms form diatomaceous earth, which is used in : toothpaste, filters, insulation, & polish.

Dinoflagellates 4. Dinoflagellates (Pyrrophyta) - type of algae with 2 flagella that spin the of algae with 2 flagella that spin the cell in a corkscrew fashion. cell in a corkscrew fashion. -The name Pyrrophyta means “fire plants”, after some dinoflagellates that are luminescent when disturbed. -Have an armor-like cell wall with plates made of cellulose & silicon. -Can be autotrophic or heterotrophic. -Are a major source of food for aquatic animals. Phytoplankton – population of small, photosynthetic organisms found near the surface of the ocean. 70% of our oxygen comes from them. -Cause red tide – Release of toxins that poison shellfish.