Life
For most of the Late Ordovician, life continued to flourish, but at and near the end of the period there were mass-extinction events that seriously affected planktonic forms like conodonts, graptolites, and some groups of trilobites (Agnostida and Ptychopariida, which completely died out, and the Asaphida, which were much reduced). Brachiopods, bryozoans and echinoderms were also heavily affected, and the endocerid cephalopods died out completely, except for possible rare Silurian forms. The Ordovician–Silurian Extinction Events may have been caused by an ice age that occurred at the end of the Ordovician period as the end of the Late Ordovician was one of the coldest times in the last 600 million years of earth history.
Read more about this topic: Ordovician
Famous quotes containing the word life:
“Taking food alone tends to make one hard and coarse. Those accustomed to it must lead a Spartan life if they are not to go downhill. Hermits have observed, if for only this reason, a frugal diet. For it is only in company that eating is done justice; food must be divided and distributed if it is to be well received.”
—Walter Benjamin (1892–1940)
“The child thinks of growing old as an almost obscene calamity, which for some mysterious reason will never happen to itself. All who have passed the age of thirty are joyless grotesques, endlessly fussing about things of no importance and staying alive without, so far as the child can see, having anything to live for. Only child life is real life.”
—George Orwell (1903–1950)
“Sunday morning may be cheery enough, with its extra cup of coffee and litter of Sunday newspapers, but there is always hanging over it the ominous threat of 3 P.M., when the sun gets around to the back windows and life stops dead in its tracks.”
—Robert Benchley (1889–1945)