The Big Idea: Humans have transformed the Earth and now we are experiencing accelerating rates of species extinction.

Until the 18th century, scientists were unaware that species came and went, over the past billion years.

Big Five Mass Extinctions

1. End Ordovician, 444 million years ago, sudden cooling
2. Late Devonian, 375 million years ago
3. End Permian, 251 million years ago, sudden warming
4. End Triassic, 200 million years ago
5. End Cretaceous, 66 million years ago, asteroid

We’re currently in the Anthropocene. The book mentions many species affected by human encroachment, pollution, and climate change: golden frog, coral, cloud forest trees, rhinos, elephants, mastodons, great auk, ammonites, American chestnut, Neanderthals, Homo floresiensis, Denisovans, and lowland gorillas.

Ocean acidification is caused by excess CO2, absorbed by the oceans and lowering ocean pH levels.

Humans are also upsetting existing ecosystems by introducing invasive species, such as a European fungus that causes white nose syndrome that is killing off bats in North America.