We have been far too aggressive about extracting ocean wildlife, not appreciating that there are limits and even points of no return.

Globally sharks have been killed for their fins, for their cartilage, for their livers, for their meat. But mostly what has driven some species of sharks to near extinction - including the hammerhead shark - is the new luxury taste for shark fin soup.

Earth as an ecosystem stands out in the all of the universe. There's no place that we know about that can support life as we know it, not even our sister planet, Mars, where we might set up housekeeping someday, but at great effort and trouble we have to recreate the things we take for granted here.

It doesn't matter where on Earth you live, everyone is utterly dependent on the existence of that lovely, living saltwater soup. There's plenty of water in the universe without life, but nowhere is there life without water.

We are depleting this immense diversity and abundance of life, and it matters tremendously for the future of the planet.

The Arctic is an ocean. The southern pole is a continent surrounded by ocean. The North Pole is an ocean, or northern waters. It's an ocean surrounded by land, basically.

Why does evolution matter? There is so much about the evolution of life, the development of life on Earth that should rivet the attention of everyone to understand where we've come from and where we might be going. We need to understand the world around us if we are to succeed as a species on the planet.