study-guide-3 - GLY1101 Study Guide Nr 3...

GLY1101: Study Guide Nr. 3
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Phanerozoic Eonothem:
This Eonothem is often referred to as the time of "Visible Life". Organisms with skeletons or hard shells appeared
by the first time in the geological record. The Phanerozoic Eonothem spans from 543 mya through today. The
Phanerozoic is divided into three Erathems, from older to younger: Paleozoic, Mesozoic, and Cenozoic.
The Mesozoic Erathem: 248 to 65 mya
The Mesozoic is divided into three time systems: the Triassic (245 ‐ 208 Million Years Ago), the Jurassic (208 ‐ 146
Million Years Ago), and the Cretaceous (146 ‐ 65 Million Years Ago).
Mesozoic means "middle life ", and is the time during which the world fauna changed drastically from that which
had been seen in the Paleozoic. Dinosaurs, which are perhaps the most popular organisms of the Mesozoic,
evolved in the Triassic, but were not very diverse until the Jurassic. Except for birds, dinosaurs became extinct at
the end of the Cretaceous. Some of the last dinosaurs to have lived are found in the late Cretaceous deposits
of Montana in the United States.
The Mesozoic was also a time of great change in the terrestrial vegetation . The Lower Mesozoic was dominated
by ferns, cycads, ginkgophytes, bennettitaleans, and other unusual plants. Modern gymnosperms, such as conifers,
first appeared in their current recognizable forms in the early Triassic. By the middle part of the Cretaceous
System, the earliest angiosperms had appeared and began to diversify, largely taking over from the other plant
groups.
The breakup of Pangaea can be divided into four stages: a. The first stage involved the separation of North
America from Africa during the Late Triassic, followed by the separation of North America from South America. b.
The second stag e involved the separation of Antarctica, India, and Australia from South America and Africa during
the Jurassic. During this stage, India broke away from the still ‐ united Antarctica and Australia landmass. c. During
the third stage , South America separated from Africa, while Europe and Africa began converging. d. In the last
stage , Greenland separated from North America and Europe.
The Lower Mesozoic = Triassic + Jurassic Sytems
The Lower Mesozoic is an informal division of the Mesozoic Erathem which includes the lower two systems: the
Triassic and the Jurassic. See Chronostratigraphic Chart
Paleogeography: Triassic <http://www.scotese.com/newpage8.htm >
Jurassic <http://www.scotese.com/jurassic.htm >
Cretaceous <http://www.scotese.com/cretaceo.htm >
Summary of Lower Mesozoic Events: Important facts in the history of Mesozoic life
The Mesozoic is divided into three time systems: the Triassic (245 ‐ 208 Million Years Ago), the Jurassic (208 ‐
146 Million Years Ago), and the Cretaceous (146 ‐ 65 Million Years Ago).
Mesozoic means "middle life", and is the time during which the world fauna changed drastically from that
which had been seen in the Paleozoic. Dinosaurs, which are perhaps the most popular organisms of the Mesozoic,
evolved in the Triassic, but were not very diverse until the Jurassic. Except for birds, dinosaurs became extinct at