February 21, 2012

Today, we turned in our Hydra/Planaria lab (and also reviewed the answers to the questions), and we got back pages 15-18 and 11-14, and the Lab #44.

We also completed pages 7-10 in our note packet, all about the protist kingdom--extra info can be found in Chapter 15, pages 311-316 in our textbook. To sum up all the information, with key points as written in our packet:

• Protists are the first eukaryotes to evolve from prokaryote (bacteria) ancestors; they are much more complex than prokaryotes.
• How did eukaryote cells, as well as their membrane-enclosed organelles, evolve?
• 2 theories of these processes:

1. All organelles (except mitochondria and chloroplasts) evolved from inward folds of the plasma membrane of a prokaryotic cell.
2. Endosymbiosis: Largely developed by Lynn Margulis of the University of Massachusetts:

• "Chloroplasts and Mitochondria evolved from small prokaryotes that established residence in other, larger host prokaryotes."
• Mitochondria evolved 1st

• Protists vary in structure and function more than any other group or organism
• MOST are unicellular, but some are colonial or multicellular.
• The four major categories are:

1. Protozoans: They ingest food and thrive in all types of aquatic environments, including wet soil and the watery environment inside animals (parasites).
2. Slime Molds: Resemble fungi in appearance and lifestyle, but are NOT closely related at all... Role=decomposers
3. Unicellular Algae: Photosynthetic protists (have chloroplasts)--they support food chains in freshwater and marine ecosystems.
4. Seaweeds: Large, multicellular marine algae--used for a variety of human foods (for anything from sushi wraps to ice cream!)

Next, we filled out unit packet page 33, "Examining a Phylogenetic Tree", as a class. Lastly, we did a lab on page 35 in our unit packets, in which we classified real organisms (around the classroom--from centipedes to scorpions) based on their appearances into the correct phylum.

The homework for tonight is:

• To finish the "General Classification of Invertebrates" lab (pages 35-38)
• Prep for labs on pages 45-54
• The "Nature" assignment (due 3/2)
• And to read CH 17 if you haven't already!!!
• (It also might be a good idea to read up on pill bugs, just to get a little background knowledge for an upcoming lab)

Next Scribe: Austin