Era, Period, Epoch Monroe
Objectives ~ Geologic Column ~ the ordered arrangement of rock in layers, based on age Time Periods Eras ~ the longest. Periods ~ the middle Epochs ~ the shortest
Precambrian Era 1st Really long. Really, really long. Really loooooooonnnnnnnggggggggg 2nd Not many fossils. Mostly simple life forms, and marine and not land life forms. 3rd Lots of trilobites.
Palezoic Era 1st Means “ancient life” in Greek 2nd Lots of fossils, land and marine life, and more complex. 3 Age of fishes 4 Ends with a really huge mass extinction.
Mesozoinc Era 1st Means “middle life” 2nd More complex life, like reptiles and birds. Dinosaurs rule the roost. Lots of them. 3rd Dinosaurs actually turned into birds. Really, I am not kidding you. Angiosperm (flowering plants) Age of Reptiles 6 First Mammals 7hEnds with a really huge mass extinction.
Cenozoic Era 1st Means “recent life” 2nd Rise of the mammals. Lots of things like Mastadons. 3rd We win !!!!!!
Periods are not as long, and they cut the eras into manageable pieces. Epochs cut the periods into smaller pieces. Our Holocene epoch is only 11,000 years old. Does the future hold an epoch that is “post homosapien”?
Mass Extinctions • There have been 5 MASSIVE extinctions. • 1. 443 million years ago ~ end of Ordovian period. • 2. 374 million years ago ~ end of Denovian period. • 3. 251 million years ago ~ end of Permian. The great dying. Death of 90% of ocean dwelling species, and 70% of land animals, even insects. • 4. 201 million years ago ~ end of Triassic period. • 5. 65 million years ago ~ end of Mesozoic (and dinosaurs). • Biologists believe that plants changed quickly, and that animals could not adapt.
Astonomers believe that most (all) of them were caused by asteroids. They believe that the first kill (Ordovian) was a result of a nearby exploding star, but that the others were falling rocks. Geologist have never “called Uncle” in the debate.