\nAnd now I want to share with you one of the most interesting short videos I've seen in a while. It's about the idea of trophic cascades:<\/i> how a small change to an ecosystem can lead to tremendous consequences. In this case, the change was the reintroduction of wolves to Yellowstone in the 1990's, after a 70-year absence.<\/p>\n
The direct effects of the wolves were small: the wolves eat a few deer, but apart from that mostly keep to themselves. But the indirect effects were huge.<\/p>\n
It started because the deer, who had been running roughshod over the entire park, quickly figured out that places like valleys were not good places<\/i> to be a deer when there are wolves about. This led to trees being able to grow in those areas for the first time in decades.<\/p>\n
The effects of that are complex and profound, and I encourage you to watch the video, because I can't possibly summarize it better than it does. Everything from the animals to the plants to the very physical geography of the rivers was changed. <\/p>\n
The key lesson of this is that ecosystems are connected. You can't make a single change to one and expect it not to have consequences, including very far-reaching ones of a sort you couldn't ever have predicted. This is a general property of all large, strongly-interacting systems, including societies, and it's worth keeping in mind whenever things change.<\/p><\/blockquote>\n