We have all this Paleolithic art that suggests that our ancestors really venerated animals and that they depended on wild animals to survive - as opposed to domesticated animals that we depend on. Would it radically change things if we had more rhinos in our midst? I kind of suspect it would.

If in your lifetime you watch a species go extinct, or plummet almost to the point of extinction, that is a sign that something really serious is going on.

There's this idea of shifting baselines. It was coined by a guy named Jeremy Jackson. It's the idea that every generation takes what it sees, and says, "Okay, well, that's the norm."

Some of these species that are now no longer with us were killed off by a fungal disease that was moved around the planet by people.

In a poll commissioned by Time and CNN, two-thirds of American parents said they think that their children are spoiled.

No matter what Donald Trump says, it's clear that global warming is rapidly changing conditions on our planet.

You're an animal that needs to move across the landscape, you can't anymore, and that's another way we're just changing the surface of the Earth in very dramatic ways.