|how many eras is the time scale divided into? ||4|
|waht are the four eras in order ||precambrian, peleozoic mesozoic and cenozoic|
|Precambrian Era- ||Is the oldest era and lasted the longest amount of time (approx. 4 billion years). Organisms were bacteria, sea pens (fans) and jellyfish.
|Paleozoic Era (age of fishes ||Is made up of the Cambrian, Ordovician, Silurian, Devonian (age of amphibians), Carboniferous (age of forests), and Permian (extinction of trilobites).|
|Mesozoic ||Is made up of Triassic, Jurassic, and the Cretaceous Periods. The Mesozoic Era is the age of Dinosaurs.
|when did dinosaurs become extinct ||`65 millions years ago|
|how many theories about dinosaur extinction are ther ||3|
|A large astroid hit Earth resulting in an Ice Age. The astroid hit the Yucatan Peninsula. ||...|
|A large Super Volcano (Mount Tambour erupted causing an Ice Age. ||......|
|India runs into Asia, causing the ice caps to melt, which indirectly caused an Ice Age. ||...............|
|cenozoic ||Is made up of the Tertiary and Quaternary Periods. The Cenozoic Era is the age of mammals.