Protists are a diverse group of eukaryotic organisms that can be unicellular or multicellular, and include photosynthetic and heterotrophic species. They include algae, which are photosynthetic protists that can be single-celled or colonial, and diatoms and dinoflagellates, which are important marine algae with distinctive cell coverings or structures. Reproduction in algae can occur sexually through meiosis or asexually through cell division or fragmentation.

1. Kingdom Protista

2. 2
Protista
•Most are
unicellular
•Some are
multicellular
•Some are
autotrophic, while
others are
heterotrophic
•Aquatic
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3. • If you look at a drop of pond water under a
microscope, all the "little creatures" you see
swimming around are protists.

4. • All protists have a nucleus and are therefore
eukaryotic.
• Protists are either plant-like, animal-like or fungus-
like.

5. KEY CONCEPT
Algae are plantlike protists.

6. Plantlike protists can be single-celled or
multicellular.
• Photosynthetic plantlike protists are called
algae.
colony
daughter colony

7. STRUCTURE
• Thallus (haploid)
• Four types of algae
–Unicellular
–Colonial
–Filamentous
–multicellular

8. holdfast

9. Many plantlike protists can reproduce
both sexually and asexually.
• All algae can reproduce asexually.
– Multicellular algae can fragment.
– Chlamydomonas divides into zoospores.

10. • Some algae produce sexually.
– Some species alternate generations.
– Sexual reproduction can be triggered by environmental
stress.

12. • Diatoms are plantlike protists with glasslike shells.
– shells made of silica
– produce large amounts of oxygen

13. DIATOMS

14. • Dinoflagellates are mostly marine plantlike protists.
Dinoflagellates
– have two flagella
– may be bioluminescent
– have stiff protective plates
– can cause red tide

17. • Multicellular algae are classified by color.

20. A Volvox is a hollow boll composed of hundreds of
flagellated cells in a single layer.