Eons, Eras, Periods, Epochs

Monroe

Objectives ~

Geologic Column ~ the ordered arrangement of rock in layers, based on age

Time frame/segmentEons ~ the very, very longestEras ~ the almost longest.Periods ~ the middleEpochs ~ the shortest

Precambrian Era1st Really long. Really, really long. Really

Precambrian Era1st Really long. Really, really long. Really loooooooonnnnnnnggggggggg2nd Not many fossils. Mostly simple life forms, and marine and not land life forms.

Precambrian Era1st Really long. Really, really long. Really loooooooonnnnnnnggggggggg2nd Not many fossils. Mostly simple life forms, and marine and not land life forms.3rd Lots of trilobites at the end.4th Stromatilites were around to change “bad gasses” in to oxygen and nitrogen atmosphere. Ours.

Palezoic Era1st Means “ancient life” in Greek

Palezoic Era1st Means “ancient life” in Greek2nd Lots of fossils, land and marine life, and more complex.

Palezoic Era1st Means “ancient life” in Greek2nd Lots of fossils, land and marine life, and more complex.3Age of fishes4Ozone (3 oxygen atoms per molecule) is needed to protect life on land from the Sun’s UV rays. In oceans, water does that job.

Palezoic Era1st Means “ancient life” in Greek2nd Lots of fossils, land and marine life, and more complex.3 Age of fishes4 Ends with a really huge mass extinction.

Mesozoic Era1st Means “middle life”

Mesozoic Era1st Means “middle life”2nd More complex life, like reptiles and birds. Dinosaurs rule the roost. Lots of them.

Mesozoic Era1st 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.

Mesozoic Era1st 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.4 Angiosperm (flowering plants)

Mesozoic Era1st 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.4 Angiosperm (flowering plants)5 Age of Reptiles

Mesozoic Era1st 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.4 Angiosperm (flowering plants)5 Age of Reptiles6 First Mammals

Mesozoic Era1st 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.4 Angiosperm (flowering plants)5 Age of Reptiles6 First Mammals7h Ends with a really huge mass extinction.

Cenozoic Era1st Means “recent life”

Cenozoic Era1st Means “recent life”2nd Rise of the mammals. Lots of things likeMastadons.

Cenozoic Era1st Means “recent life”2nd Rise of the mammals. Lots of things likeMastadons. 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 homo sapien”?

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.