Summer SAVY, Session 5 Day 4, Wildlife Ecology (5th-6th)
I hope your child showed you the deer-repellent device that they made. Some reported that they tried it with their dog and noticed a response. However, one reported that their dog ate it. Yep, some dogs will eat just anything. Today we discussed repelling deer and what kind of data would be collected. Yesterday we talked about the idea of a control group and what it would be in this study, a bush without the repellent. I gave them faux data, asked them to calculate averages for the control and experimental groups, and then created a graph. They quickly realized that a bar chart would be most appropriate. Again, we worked on how to properly create a graph. We then returned to population growth and compared logistic growth with exponential growth. I didn’t have them calculate the growth of a population using the logistic model, but we talked about limiting factors and discussed the S-shaped curve that the logistic model generates. We discussed the idea of the carrying capacity and I asked if populations reach this level and stay there. They thought that population size might fluctuate at which point we talked about the well-known lynx/hare data set. Our next activity took us outside for a test of the quadrat sampling method. I had this scheduled all along for Thursday and it was fortuitous that it was overcast and not too hot. We sampled a population of sweet and low packets in a field using meter square quadrats. I stressed the importance of randomization, so we used a random number generator to determine where they would place the quadrat. Not surprisingly two of the quadrats had no packets but the others had anywhere from 2 to 7. Our calculated average was 2.75 at which point they had to figure out the estimate of population size. The area sampled was 10 x 10 meters, and they correctly calculated an estimated population size of 275. The actual number was 200 so off but not off by a crazy amount.
After lunch, we read a document from the mayor of our fictional town requesting that a survey be created to determine how the community feels about deer. We talked about the nature of a survey including sample size and expected return rate. We didn’t create a survey but did create a list of possible questions. None of them knew what was meant by demographic questions so we talked about that and why it is important to gather such information. We then read a document that suggested hunting as a solution to the problem. They listed the pros and cons of using hunting to control deer. This led to an aside lesson on when to use “less” vs. “fewer”. Our last task was to introduce the nature of their final project. Tomorrow they will create a poster that introduces the topic, includes their research, and proposes a solution. They were told that they are welcome to do additional research at home tonight and some asked about printing out images at home. Since we can’t print on campus, I said this would be fine. Encourage your child to spend a little time tonight thinking about the problem and potential solutions. They may find solutions that we have not discussed. Regarding repellents, ask about the example of elephants and bees. It’s a fascinating story.