BOTANY 160         PLANT ECOLOGY                            FALL 1995

                          QUIZ I



CHOOSE 5 of 8 (5 points each; Total 25 points)


1. One of the premier scientific journals of ecology goes by the name 
Oikos. What is the literal  translation of this name and how does it 
relate to ecology?


     - Oikos is greek for home.
     - ecology is the study of the home.



2. What paradigm or perspective did the aquatic biologists of the late 
19th and early 20th  centuries contribute to the field of ecology?



     - the ecosystem concept, especially the concept of trophic levels 
       and energy flow.



3. Ecosystems are said to exhibit properties of cybernetic control. What 
is meant by this  statement? Give one example.


     - feed-back loops (checks and balances)
     - predator-prey, decomposition => energy storage and slow release of 
       nutrients.


4. Trophic dynamics start with the primary producers. What are primary 
producers and how do  you distinguish gross primary production from net 
primary production?



     - autotrophs or photosynthetic organisms or plants
     - GPP = NPP - Respiration



5. What information is conveyed by stating the trophic status of a lake?




     - nutrient levels and amount of primary production




6. Write out the chemical reactions of CO2 with H2O. Why are these reactions
important for aquatic plants?


     CO2 + H2O   H2CO3   H+ + HCO3 -   H+ + CO3 -  
     Plants need CO2 for photosynthesis; some can use HCO3 - 





7. Draw the vertical temperature profile of a temperate zone lake in summer 
and early spring. Of what importance is this to the phytoplankton community?



     - see overhead on reserve.
     - water stratified in summer which restricts mixing and resupply of 
       nutrients. In early spring water column is isothermic and therefore 
       abundant mixing and resupply of nutrients occurs.



8. Draw a typical seasonal  succession  graph of the major types of 
phytoplankton in a temperate zone lake. Pick one group and give one reason 
for it s dominance at that time of the year.


     - diatoms in early spring and fall, greens in late spring and mid-summer,
       blue-greens in late summer.
     - diatoms: lower temperature optima, abundant silica after the spring and 
       fall overturns.
     - greens: replace diatoms after silica depletion in the epilimnion, higher
       temperature optima.
     - blue-greens: highest temperature optima, nitrogen fixation, grazed by
       zooplankton less.
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