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05.14.03
Bio Class Predators Savage Wooly Worm Population |
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THE WOOLY WORM HUNT is an exciting "game" where the students are
the Predators, hunting the great (and desirable) wooly worm. The class is given 60 seconds to pick up as many colored wooly worms as possible from the 1400 worms scattered across the Prep's
front lawn. The 14 varieties vary with colors like white, neon pink, yellow, peach, teal, green and brown. Some varieties survive the onslaught of the dreaded "grey shirt"
while others are hunted to near extinction. To test the hypothesis that there is preference for particular colors and that the wooly worms are not picked up randomly we use Chi Square
analysis. This of course illustrates with greater than 99.5% certainty that earth tones are selected for and bright colors are selected against. The students are then asked to suppose
that these are live, reproducing organisms and to predict what upcoming generations of wooly worms would look like. A really fun and interesting way to teach about Natural Selection
Wooly Worm Lab • The Chi Square Test:
If the wool pieces are collected randomly, then the
number of each color collected should be nearly equal. Thus, a null hypothesis may be proposed that states that there will be no significant difference in the number of each color of yarn
collected. If this null hypothesis is not supported by the data, then selection of some colors over others must occur. You use the chi square test to test this null hypothesis by comparing the
number of each color of yarn expected to be collected against the number that is actually collected. The chi square value calculated from the formula is a measure of the variation from the
expected values. The closer the expected and observed values, the smaller the chi square value will be and the more likely that the data is the result of random choice. Once you get your chi
square value, you can use this number to estimate the probability that the null hypothesis is acceptable, i.e. that the wool was collected randomly without color preference. If the null
hypothesis is unacceptable then the selection of some colors over others must have occurred. To get the probability look on the chi square distribution chart in the row with the correct degrees
of freedom (# of colors - 1). Look for the nearest value and look at the top row for the probability. If the probability is to the left of the center vertical line then the null hypothesis is
acceptable . If to the right then the hypothesis is not acceptable and natural selection probably took place. Be sure to include a discussion of this in your paper. Questions:
The following questions are just some of the points you should consider in your paper. Do not reproduce these verbatim in your paper but rather incorporate them into the discussion.1. Was the
original null hypothesis acceptable? What is the probability for accepting or rejecting the null hypothesis?
2. Which colored worms were subjected to positive selection pressures and which
ones to negative selection pressures and why?
3. What factors contributed to these selection pressures besides the color of the worms?
4. As predacious birds, you collected many wooly
worms. What assumptions have been made concerning a birds ability to find and feed on the wooly worms?
5. What would happen to the population of wooly worms if they could reproduce? If the
predation of the wooly worms continued over time?
6. Include any other points you think are important Formula for chi square: Wooly Worm Lab chi square = [(observed - expected)
2] / expected
degrees of freedom (df) = number of colors - 1 |
04.03 • Easter Break Trip to Central America |
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With Bio teacher Michael Metelsky at the helm, a group of 14 Prep
students set sail, well actually headed off to the airport for 11 days in Belize in Central America during the Easter Break. Their Newark to Houston to Belize City flight began their journey, and
left them off to spend their first nights at DuPlooy's Lodge, in the Cayo District of San Ignacio. They later traveled to Guatemala and back to Hopkins City in southern Belize.Their activities
had them caving, canoeing, snorkeling and hiking. With the group's cameras wrapped up for protection from the water, there are, unfortunately, no photos of Mr. Metelsky's canoe flipping over at
the end of the run. Guides from the lodge pointed out the Mayan ruins and artifacts that abound in the area and a side trip to Guatemala for more Mayan ruins rounded out their itinerary.
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12.18.02 • Christmas Band Concert |
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The Winter Concert proved to be another huge hit and kicked off the Christmas
Season in fine fashion. 1-6 Pre-concert preparation, including a welcome back to Rob Esposito, currently living in Switzerland after three stellar years at the Prep. 7-17 The concert-
selections ran the gamut from "The Right Stuff" to "Lt Kije", from Gershwin to Mercury. Christmas music was featured after intermission, closing, of course, with "Rudolph."
• previous concerts
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11.28.02 • TURKEY TROT |
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The Thanksgiving morning Turkey Trot continues to grow in popularity; this year
another great crowd braved the frigid temps to join at the Kelly Athletic Complex for an early morning Mass, followed by the 5K Run through the woods, and then light refreshments. Alumni [some of
them still in shape!], friends and families spent a couple of hours together before heading off, sporting a Turkey Trot commemorative T-shirt, to football games and family feasts.
• To see last year's run. • download a large-sized group photo more suitablefor printing at home
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