BOTANY 160       

MID-SEMESTER EXAM KEY                                           FALL 1993

I. Definitions: (Choose 5; 4pts each)

    Ombrotrophic bog
    Compensation point
    Reynolds number
    Littoral zone
    Collective properties 


II Short Answer:

  1. Describe and contrast the two types of ecosystem stability discussed 
     in class:


  2. Illustrate and label the temperature- and oxygen-depth profiles that 
     would be observed during the four seasons in a termperate-zone 
     eutrophic lake. (_No_credit_will_be_given_for_a_written_explanation_)


  3. What is meant by the River Continuum Concept 



  4. Describe and contrast the energy flow patterns in  a typical lake and 
     stream located in the Northeastern Deciduous Biome (Labelled diagrams 
     comparable to those in your text are acceptable)



III Essay:



1. Recall that several weeks ago two scientists (an auecologist and a 
   synecolgist) were arguing about how to aquire a scientific ungderstanding 
   of the Shelburne Pond - Muddy Brook ecosystem. While paddling down Muddy 
   Brook they noticed an area of abundant sunshine where the rocks on the 
   stream bottom were a mosaic of living colors representing green, 
   blue-green and and brown diatom algae. They noted that the diatoms were 
   mostly on the tops of the rocks, the blue-greens on the sides and the 
   greens on the down-stream surfaces. the autecologist decided to apply 
   strong inference in attempting to understand why this pattern exists.


     a) Drawing on your knowledge from lecture and your readings list the 
        steps one follows in applying the strong inference method.


     b) Think of some multiple hypotheses to explain the observed pattern. 
        List them and briefly describe an experiment to test them.