Читать книгу Oceans For Dummies - Joseph Kraynak - Страница 63

The Paleocene epoch (from 60 to 55 million years ago) was pretty much devoid of large animals, as small creatures were rapidly evolving to fill empty niches, and the planet warmed so much that rainforests sprouted even at the poles. Here are some of the highlights:

 Waimanu (a flightless water bird) claimed fame as the earliest penguin, while birds experienced a high degree of speciation (the evolutionary process by which populations evolve to become distinct species).

 Mammals also diverged into the modern groups of monotremes (mammals that lay eggs), marsupials (mammals that carry their babies in pouches), and eutherians (mammals with placentas; for example: humans).

 Early ungulate-like mammals appear (ungulate means hooved).

 Creodonts (carnivorous mammals) appear, generally belonging to one of the following two groups: galecyon (similar to dogs) and oxyaena (more like cats).

 Plesiadapiforms (primate-like mammals that took advantage of a heavily forested Earth) make their appearance.

 Most amphibians, freshwater crocodiles, and turtles survived the K-Pg Extinction event, but marine life took a long time to recover. The exception were small pelagic fish, which recovered quickly.

 Ancestors of the megalodons (the huge sharks we introduced you to in Chapter 2) appeared, and ray-finned fish took over the oceans.

The Paleocene epoch ended with the Paleocene-Eocene thermal maximum about 55 million years ago, marked by a massive release of carbon into the atmosphere over the course of 20,000 to 50,000 years, which raised the average temperature on land 5 to 8 degrees Celsius (9 to 14.4 degrees Fahrenheit). Any way you measure it, that’s huge in terms of global warming, and the warming lasted about 200,000 years. The huge carbon surplus also caused ocean acidification, which killed a lot of marine species. (Acidification currently threatens ocean life, as explained in Chapter 21).