Name ______Period ______Date ______
Identifying Components of the Scientific Method- Guppies Galore!
Directions: After reading “The Beak of the Finch” reading #1 (pg. 88-94) go back through the reading and identify the components of the scientific method that John A. Endler used in his classic evolution experiment using guppies in northeastern South America. Fill in those components in the outline provided below.
1. What was the question Endler was trying to answer? (write this as a question):
2. What was Endler’s hypothesis?
3. What background information did Endler need to know about guppies and their environment (including predators) in order to design an experiment using guppies? List 5 pieces of specific information Endler (and now you!) learned about guppies while observing them in nature.
1.
2.
3.
4.
5.
4a. In any experiment, the set up is critical to testing the hypothesis. The following information pertains to the Princeton greenhouse experiment.
To create a heterogeneous stock of guppies for his 10 pond experiment:
Where did Endler get the guppies?
Where did he put each stock of guppies?
How many pairs did he take from each of the above to put in to 2 large tanks/ponds?
What were the guppies doing in these tanks? How long did they stay here?
What did he do next with these guppies?
How many fish ultimately went into each of his 10 ponds?
How were the ponds different? How were the ponds the same?
- -
-
-
4b. Describe the initial phenotypic mixture of the original guppy population for each pond in this experimental set up.
5. In order to find patterns and analyze their experimental results, the data must first be organized into data tables. Using a ruler, draw a data table Endler could have used to organize his results. Be sure to give your data table a title! (ex: Data Table 1: An Earthworm’s Heart Rate as it Relates to Soil Temperature) Hint: Think about what information can be measured quantitatively and also tests the hypothesis.
**STOPPING POINT #1! (to be continued)**
6. The information in data tables is often displayed in a graph. You will be constructing two bar graphs using some of the actual data Endler collected from his 10 pond experiment. Be sure to draw the graphs big enough and be sure to complete the graph by labeling both the x and y-axes and by giving the graph a title!
a) Relative length of spots for each color vs. predation intensity
b) Relative height of spots for each color vs. predation intensity
7. After you have completed both graphs, analyze them. What conclusions can you draw? What did the experimental results tell Endler (and now you!)? List 4 of these below.
1.
2.
3.
4.
8. Read a second excerpt from “The Beak of the Finch” (pg. 94-95 up to stopping point #2). Now that you have read the conclusions Endler himself drew from his data, what were those conclusions? (Don’t worry if they’re different from what you wrote!)
1.
2.
3.
4.
**STOPPING POINT #2! (to be continued)**