1. Do Now: Begin reading the introduction to the algae on your museum visit handout.

2.  Algae are aerobic photoautotrophic eukaryotes.  They contain chloroplasts and mitochondria.  Almost all of them are aquatic.  Algae may be unicellular, colonial, or multicellular. Multicellular forms are not as complex as land plants.

3.  Algae are the main producers in aquatic ecosystems.  Without algae, there would be nothing for heterotrophs to eat!

5.  Algae are a diverse group of organisms, with diverse classification and evolutionary history.  A few of the more important types are explored here.

6.  Diatoms are best known for their beautiful silica shells.  They are unicellular, and are common in fresh and salt water.  Also, they produce oils!

7.  Dinoflagellates are very similar to diatoms, because they are unicellular and have a silica shell.  The major difference between the two is that dinoflagellates have flagella for movement  Some kill sea life.

8.  Brown algae are multicellular algae that contain pigments other than chlorophyll.  They are commonly known as kelp.

10.  Red algae are similar to brown algae, except that they have different pigments, giving them their characteristic red color.  Agar, and other polysaccharides come from these organisms

11.  Chlorophytes contain chlorophyll, have cellulose cell walls, and thus as a group are most similar to more familiar land plants

12. Algae and Protists Diversify

13.  Fossils.  These multicellular fossils are from a rock formation in Southern China, and are some of the best preserved early eukaryotes ever discovered.  The rock formation has been dated to 551-635 MYA.  The journal article presenting the fossil describes 7 different isotope dating techniques that confirm this range.

14.  Some species of algae are colonial in nature.  Colonial organisms are different from truly multicellular organisms because individual cells can survive in the environment if separated from the rest of the organism.

15.  Some algae may reproduce asexually or sexually, depending on environmental factors