Discussion questions for Connell (1961) paper
1. What is the question or main purpose addressed in this study?
2. What are the three alternate hypotheses being tested? Are they mutually
exclusive (in other words, could more than one be true)?
List two other possible hypotheses that were not tested in this study.
3. Briefly describe the experimental design used to test each of the three
hypotheses. If you were to repeat Connell’s 1954-1955 experiments today with
modern technology, what might you do differently?
4. What is the difference between interspecific competition and intraspecific
competition?
Did Connell test for interspecific competition, intraspecific competition, or both?
How did (or would) the experimental design to test these two types of competition
differ?
5. From Figure 1, do you think the distributions of Chthamalus and Balanus are
clumped, uniform, or random?
6. Figure 2 contains a lot of information, including enough data to test all three of
Connell’s hypotheses. To assess the effect of competition on the number of
Chthamalus, compare the data for unmodified and “Balanus removed” treatments at
each site. Do these data support the hypothesis that competition with Balanus
affects the abundance of Chthamalus? Why?
What comparisons can you make within figure 2 to assess the other two
hypotheses? Do the data support or refute those hypotheses? Why?
7. Now look at Figure 3, which shows the results of the transplant experiments. Do
these data support or refute Connell’s three hypotheses?
Why did he conduct the transplant experiments in addition to manipulating
densities? What did he learn from these experiments?
8. Connell’s paper is one of the most highly cited in marine ecology and is widely
regarded as a classic paper that ecology students should read. Why do you think this
paper is so important? What did you learn from the paper? What did you like about
it?
9. This paper focused on competition for space. What other types of competition can
you think of?