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We are using Apologia’s Elementary Zoology Book 3 for science this year.  It is the study of land animals.  We just finished chapter 4 and completed an interesting demonstration of the relationship between populations of predator and prey, specifically the cougar vs deer population.

The experiment called for marking off a 2 ft X 2 ft square on the floor.  In that square, begin by placing 3 “deer” (2 X 2 inch paper- we printed a picture of a deer on ours).  Then, a cougar (a 6 X 3 in cardboard) was tossed into the square. The cougar has to “eat” 3 deer to survive to the next generation.  If the cougar survives, then the next generation toss 2 cougars. If the cougar doesn’t survive, use 1 cougar for the next generation.  (The assumption being that another cougar will move into the territory) For each deer that doesn’t get eaten, add 1 additional deer to the next generation.

For our experiment, we had several generations where our cougar failed to eat any deer.  That made the deer population increase dramatically.  The instructions only said to make 20 deer.  We wound up needing over 90 deer at one point in our experiment.

In this picture, there are 3 “cougars” that have been tossed. We haven’t picked up the deer that have been eaten yet.

We graphed our results in Excel. I was impressed at how well the graph demonstrates the predator/prey population relationship. First, the population of the prey begins to increase, this allows the predator population to increase. As the predator population increases, more prey will get eaten. Eventually, the predator population will fall too because there is not enough prey.

My son also did several notebook pages on the computer about the experiment.

This one is sort of a procedure page. I honestly just give him free reign most of the time and see what he comes up with. It turns out better that way! We are really loving Elementary Apologia.

### 5 Responses to “Cougar vs Deer Population Experiment”

1. We've used Botany and Flying Creatures and are using Astronomy and General Science (for the 7th grader) this year. I've really enjoyed using the Apologia elementary books by Jeannie Fulbright, but I've been wondering about the others and how many more we'll purchase. It's nice to see your experiences, because it gives me some food for thought. I may only purchase two more, because I only really NEED enough to do a different study each year grades 1 through 5, with my younger ones. So, I'll have to choose! Ack, so many books, limited budget!

2. That should be grades 1 through 6, so I can pick one more title, I suppose!

I have half my mind on watching the toddler play with books right now, trying to make sure he's not destroying anything!

3. It looks and sounds like you all had a wonderful experiment. I like being able to see what different families are doing for school.

I bet your children learned a lot with this experiment.

Blessings,

Penny

4. I have been thinking of getting this for next year's studies. I love the idea of getting the lapbook to go with it.

5. I've resisted using a formal science in elementary school all along, letting our FIAR studies cover science. Then we moved to TOG and it doesn't really include science, so I've been relying on nature study (loosely) and them reading enjoyable books about nature and such. That experiment looks really cool, though.

April E.