BILD 3 Lecture Notes - Lecture 15: Brown Algae, Green Algae, Red Algae
13 Jun 2018
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BILD 3 Lecture 15
5/7/2018
• Bacteria and Eukarya are each considered monophyletic
• Bacteria
o Examples: proteobacteria, gram-positive, cyanobacteria, spirochetes
o Cyanobacteria are photoautotrophs
• Prokaryotes= bacteria and archaea
• Archaea examples
o Extremophiles are common
▪ Halophiles live in highly saline environments
▪ Thermophiles in live in extremely hot environments
▪ Methanogenic live in anoxic environments
• Largest clades of Eukaryotic species are land plants, fungi, and animals
o Everything else= protists (not fungi, animals, or land plants)
▪ Refers to the simplest Eukaryotes
▪ Exist in unicellular and multicellular forms
▪ Unicellular protists:
• Giardia: an intestinal parasite that persists in water as dormant
cysts.
• Trypanosomes: causes sleeping sickness in humans
• Dinoflagellates: blooms cause red tides, some are bioluminescent
• Diatoms: major component of plankton in lakes and oceans, are
considered algae, fossilized algae make up diatomaceous Earth
▪ Algae
• Is unicellular and multicellular
• Are photoautotrophic
• Exhibit complex life cycles
• Are polyphyletic (characteristics are independently derived
multiple times)→red, brown, and green have converged
characteristics. Green algae are most closely related to land plants
• Brown algae: only marine, grouped with diatoms and
dinoflagellates; contain algin→used as a thickening agent in foods
• Red algae: mostly marine, exhibit alteration of generations; nori is
a red algae
• Green algae: many exhibit alternation of generations; have
chloroplasts; are photosynthetic; some are terrestrial
o Plants
▪ Transformed the surface of the Earth: 500 MYA small plants colonized the
land, 370 MYA the first forests appeared
▪ Explosion of plants during the Silurian period
▪ They provide oxygen and food, as well as alter and stabilize the soil
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