TABLE 3: Quadrat Counts Data Area A TAJUS Area B Quadrat # of Weeds Quadrat # of Weeds 1 38 1 0 2 20 2 12 3 3 8 4 7 4 51 Mean # 20.75 Mean # 19.25 Conclusions (Questions): For full credit, these questions should be answered thoroughly, in complete sentences, in legible handwriting. 1. Identify two reasons why ecologists would want to use a scientific technique of determining ecosystem populations as opposed to doing an actual count of all the animals in an area. 2. In using the capture-mark-recapture technique, why is it important to take an average of several recaptures rather than doing just a single recapture? 3. For the simple mark-recapture in Part 1, how did your initial guess of the population size compare to the actual population number determined by a direct count? 4. For the simple mark-recapture in Part I, how did your calculated population estimate (N) compare to the actual population number determined by a direct count? 5. For the repeated mark-recapture in Part II, how did your initial guess of the population size compare to the actual population number determined by a direct count? 6. For the repeated mark-recapture in Part II, how did your calculated population estimate (N) compare to the actual population number determined by a direct count? 7. Did the simple mark-recapture or the repeated mark-recapture provide the most accurate estimate of population size (N), 8. What do you have to assume to be true in order to believe your estimates of population size? What might happen in a real population of animals that would affect your results? (Give at least two assumptions) 9. List three additional populations for which the Mark-Recapture technique would work well. 10. List three populations for which the Mark-Recapture technique would not work well. (R No 11. Using the quadrat technique you calculated a series of population samples from two different locations. Is the mean number of acorns the same for both locations? Do you think the difference is simply the result of chance? Give reasons for your answer. 12. What would be the advantage of increasing the number of quadrats sampled? What would be the disadvantage or cost of increasing this number? 13. How should you arrange quadrats to get the best possible estimates of population size/density? 14. List three additional populations for which the quadrat technique would work well. 15. List three populations for which this technique would not work well. 16. Complete the table using the information from your quadrat counts. Mean density Site A Variance Variance/Mean Site B 17. Why did you think the organisms were living in this pattern? Distribution Pattern