A Street Cat Named Bob is the autobiography of James Bowen's life on the street, and the story of the friend he find's in a cat he names Bob. I must admit Bob never stops amazing me in this book, he is so intelligent and loyal! I'd love to meet him myself and I can see why everyone who encounters Bob loves him, too.
The Silurian atmosphere shows a decline from carbon dioxide values of 1200 ppm in the Upper Ordovician. Budyko and others (1987) (see Fig. 8) indicated atmospheric oxygen declines from about 65 percent of PAL (Present Atmospheric Level) to about 35 percent of PAL in the Late Silurian.
However, the atmosphere was not always like this. In fact, the atmosphere we know is the third of series of atmospheres that have surrounded our planet. The first atmosphere on Earth, the primary atmosphere, appeared soon after the planet was formed, about 4.5 billion years ago.This atmosphere would have consisted of gases captured from the Sun-hydrogen, helium, ammonia, methane and water vapor-and resembled the atmospheres of the gas giants.n fact, the atmosphere we know is the third of series of atmospheres that have surrounded our planet. The first atmosphere on Earth, the primary atmosphere, appeared soon after the planet was formed, about 4.5 billion years ago.