Geology notes for my.ccsd.net

Geologic time notes pg. 45 Notes must be cornell style: If you forgot questions in red on the left hand side of the page. Vertical line down page – must be there no exceptions. Answers in blue ink, black ink or pencil. Five sentence summary in Green ink: Summary must be labelled by first drawing a line under the last sentence of notes then writing the word summary in green with a colon after it then writing your summary.

Earth History: Geologic Time

1. What is Geologic Time? Geologic Time: It is very, very long. Earth is estimated to be around 4.6 billion years old based on the rock and fossil record. Geologic time is broken up into sections based on major changes in Earth .

2. What are the Divisions of Geologic Time? Largest Division: Eons Eons divided into Eras: PreCambrian, Paleozoic, Mesozoic, Cenozoic Ceno - recent Meso - middle Paleo - ancient Zoic - life Eras are divided into Periods

3. When was the PreCambrian 3. When was the PreCambrian? 543 million years ago to ~ 4 billion years ago (?) “Age of Bacteria” Oldest Era Longest era because we know so little about the earth that long ago Life: Very little life: only basic forms including bacteria, the oldest fossils ever found, seaweed, jellyfish, and worms Photosynthesis of the seaweed added oxygen to the early atmosphere, paving the way for land life.

4. What was the First Life? One celled plants (algae) entered the fossil record approximately 3 b.y. ago (Precambrian). Large colonies of this algae are called stromatolites.

5. What were Atmospheric Changes? Through photosynthesis, O2 was released into the atmosphere and ocean allowing animals to eventually evolve.

6.When was the Paleozoic 543 million years ago to 248 million years ago? “Age of the Fish” Explosion of life in the sea: trilobites, shellfish, Fish Life appears on land: Ferns, Amphibians Pangaea formed Largest mass extinction ever at the end of the Paleozoic. 90% of species became extinct.

7. When was the Carboniferous Time In Europe the Mississippian and Pennsylvanian periods are together called the Carboniferous period. Vast swamps and forests from that time created the huge coal beds found throughout eastern United States.

8. When was the Mesozoic 248 mya- 65mya “Age of the Reptiles” Life: Reptiles are the dominant life on land. Dinosaurs exist. Birds appear. Forests of trees appear Pangea broke apart during this peroid. Dinosaurs become extinct in a mass extinction at the end of the Mesozoic.

9. When did Reptiles Appear? Appeared in the Permian and quickly became the dominant life form. 9. When did Reptiles Appear? …until Dinosaurs took over. They ruled the planet throughout the Mesozoic era (the “Age of Dinosaurs”).

10. When did Birds first appear? Some of the dinosaurs are thought to have evolved into birds. Archaeopteryx is the oldest fossil bird found to date.

11. How did Dinosaur Extinction happen? 2. Meteorite impact causes multiple natural disasters 1. Volcanoes erupt and fill the atmosphere with CO2 and gasses that BLOCK the sun light preventing plant life…….

12. What is Evidence of a Meteorite? Layer of Iridium in rock layers

13. When was the Cenozoic 65 mya- present “Age of the Mammals” Life: Large mammals appear, Humans appear Ice Ages occur and ice sheets advance

14. When did the Mammals appear? Mammals first appeared in the Mesozoic as small rodents. After the dinosaurs were erased at the end of the Mesozoic, Mammals quickly evolved to become the dominant life form. The Cenozoic is the “Age of Mammals”.

Present We live in the Holocene epoch, of the Quaternary period, of the Cenozoic era.

Get out a sheet of loose leaf paper Open books to page 397 Do 3 column Vocabulary.