This is a text version of the notes presented in class.

Feel free to email the instructor (alisonjs@kent.edu) with any
comments about the format and ease of use of these online notes.

Today we will be...
1) Finishing up plate tectonics
2) Having a review for Exam I
 

Finishing up Plate Tectonics-We will wrap up the whole section on the ocean floor and plate tectonics today.  Briefly, there are two points to cover:

 1.  hydrothermal vent communities-These are communities living in the hot water vents that occur along the mid-ocean ridge system.  These are complex communities with the following characteristics:

        a.     The base of the food chain is chemosynthesis, not photosynthesis.  That means that bacteria are busy splitting the hydrogen from sulfides in hydrogen sulfide molecules to obtain their energy to make carbon compounds.  There is no need for sunlight in this process, as compared to the  more common process of photosynthesis.
        b. The sizes of organisms is unusually large.  Clams about a foot long, tube worms from 10-14 feet long, for example.
        c. Adapted to very hot water (many vents expel superheated water of 350 C (650 F).
        d. Although any single vent community may have a relatively short lifespan of less than 20 years, the fossil record indicates that these kinds of communities have been in existence for most of geologic history, just part of the mid-ocean ridge systems.

2.  Hot Spots-Geologically active areas in the middle of tectonic plates, not on the plate boundaries.  We conclude our section on the ocean floor & plate tectonics with a look at hot spots.
        a. Plumes of magma rising from the core/mantle boundary pierce the lithospheric plates in some places, forming a volcano.
        b. The lithospheric plate, however, keeps on moving, and so another volcano forms, and this keeps on until a line of volcanic islands may develop.  On continents, this can be seen as a volcanically active area not on a plate boundary.
        c. The youngest volcanic island will be the biggest, since it is most active, and the islands will be older as one moves progressively away from the present, active one.  It is an interesting way to trace the motion of a plate.

        d. Examples of this phenomenon include the Hawaiian Islands and the Emperor Seamount Chain, and on land, the area we know as Yellowstone National Park!
 

3.  Now for the Review for Exam I

How the Review Works-I will go over some general information about the exam, and then open the rest of the period (probably about 50 minutes) up to questions.  Bring your questions, and figure that if you have one, probably 20 other people have the same question, but may be too shy to ask.  It is always hard to ask questions in large classes, but I know everyone will get used to it, and get a lot out of the review.  See you there!

Exam 1 on Thursday, February 12th
Covering Lectures 1-7 (introduction through today’s lecture)
Style:  Multiple Choice & Matching UNLESS YOU ARRIVE LATE:  THEN...ITS GOING TO BE ESSAY STYLE
Number of Questions:  Between 45 and 50
 Approximately 95% from lecture material
 Approximately 5% from readings not covered in lecture

How much does this count?  Each of your best 2 exam scores (best 2 of 3) will count towards 30% of your final grade.
You will need to turn in both your scantron answer sheet AND your test to get credit on the exam.
BRING A PENCIL AND AN ERASER!