Today, students learned all about life cycles, food webs, and populations. We began by discussing discussing food webs and life cycles and then transitioned into discussing populations. We watched an awesome video, where the students discovered that the world population increased from 1 billion to 7 billion people in just over 200 years. Students correctly identified China (1.3 billion) and India (1.2 billion) as the most populous countries in the world. We also mentioned how Russia and Canada, though very large countries, do not have a lot of people because of living conditions!
Students learned about two major concepts in population ecology – carrying capacity and the Tragedy of the Commons. Carrying capacity is the maximum number of individuals that an area can support without exhausting or depleting the available resources.
We explored the Tragedy of the Commons in a game where students grouped together in villages that survived by fishing. Inevitably, villagers who caught the too many fish each year ended up not leaving enough fish in the pond to reproduce to provide food for the next year. Villagers starved and villages collapsed until some students realized that if they fished enough to survive, but not enough to deplete the fish resource, the game could continue indefinitely – or as we say in ecology – sustainably – for many generations.
During recess some of the students played a game of Oh deer!, where we recreated a deer population based on the resources available: water, food, and shelter. We graphed our results and realized that populations are dynamic: they fluctuate over time.
We watched a great video about population that you can review here. http://www.npr.org/2011/10/31/141816460/visualizing-how-a-population-grows-to-7-billion
Watch this short video to find out more about Tragedy of the Commons. https://www.youtube.com/watch?v=KZDjPnzoge0