1. Plant-like Protists Biology 112

2. Characteristics of Plant-like Protists  Commonly referred to as algae  All undergo photosynthesis  Many contain the green pigment chlorophyll  Others contain accessory pigments that absorb additional wavelengths of light  Many are able to move freely  They are both unicellular and multicellular  May reproduce asexually and/or sexually

3. Unicellular Algae - Euglenophytes  Closely related to the flagellates  They contain flagella but no cell wall  Contain chloroplasts  An eyespot is present to detect sunlight and power photosynthesis  They also live as heterotrophs when light is not available  Their cell membrane is called a pellicle

4. Euglenophytes

5. Unicellular Algae- Chrysophytes  Yellow-green and golden-brown algae  Have a yellow appearance due to their gold-coloured chloroplasts  Most are solitary but some colonize

6. Unicellular Algae – Diatoms  Their cell walls are composed of silicon – the main component of glass

7. Unicellular Algae - Dinoflagellates  Half are photosynthetic, other half are heterotrophs  Many are luminescent, contain flagella

8. The Ecology of Unicellular Algae  They are the basis of many food chains  Make up a large component of phytoplankton – small photosynthetic organisms found near the surface of the ocean  A large problem may be an overpopulation of algae in areas where sewage is discharged – algal blooms  Rob the water of oxygen

9. Multicellular Algae – Red Algae  Very good at harvesting light energy  In addition to chlorophyll, also contain phycobilins (reddish pigments)  Help in the formation of coral reefs  Diverse habitats

10. Multicellular Algae – Brown Algae  Contain chlorophyll and the brown pigment, fucoxanthan  Largest and most complex of all algae  Most are marine  Ex. Giant kelp, rockweed

11. Unicellular/Multicellular Algae – Green Algae  Very closely related to plants  Contain the same chlorophyll and cell wall composition  Many exist as single cells but some live in colonies, others are multicellular

12. Practical Uses of Algae  Brown algae is the home to many species  Produce much of the Earth’s oxygen through photosynthesis  Rich in vitamin C and iron  Found in many medicines  Heavily used in the food industry  Manufactured into plastics, thickeners, artificial materials, deodorants, etc.