OBJECTIVE: Create the geologic timeline. 54 January 2012 5 OBJECTIVE: Create the geologic timeline. INTRO When did Humans first evolve? When did dinosaurs roam? When did dinosaurs become extinct? When did life first appear? When did the Earth form?

Geologic Timeline

Geologic Timeline Geologic time scale How is it divided? The standard method used to divide the Earth’s long natural history into manageable parts Major increase or decrease (extinction) of life helps scientists divide Earth’s geologic history

Geologic Timeline Eon Era Largest division of geologic time 4 eons: Hadean Archean Proterozoic Phanerozoic Smaller subdivisions of an eon

Geologic Timeline Period Smaller subdivision’s of an eon.

Geologic Timeline Hadean Eon 4.57 – 3.8 BYA No life Earth’s crust cools and solidifies Moon forms Came from Greek word for “Hades” which mean’s “Underworld” Earth had no liquid water and was covered with many active volcanoes.

Geologic Timeline Archeon Eon 3.8 – 2.5 BYA First life is bacteria that forms in the ocean 3.5BYA Atmosphere mostly methane and ammonia Continents beginning to form Greek word for “earlier life”

Geologic Timeline Proterozoic Eon 2.5 BYA – 543 MYA First multi-cell life appears Sponges First complex life is algae appears 1.4BYA Oxygen begins to fill atmosphere Greek for “Origin”

Geologic Timeline Phanerozoic Eon 543MYA – Present Divided into 3 Era’s Paleozoic Era Mesozoic Era Cenozoic Era Most recent eon that is we are in right now

Geologic Timeline Paleozoic Era 540 – 251 MYA Divided into 6 period’s Fish first appear in oceans. Greek word for “Ancient Life” First animals evolve in ocean and then land

Geologic Timeline Plants are first life on land and begin to create first forests and an oxygen-rich atmosphere First animals appear on land: insects, amphibians, and reptiles Amphibians dominate the land Period ends with largest mass extinction ever 95% marine life die 50% of all animals die

Geologic Timeline Mesozoic Era 251 – 65 MYA “Age of Dinosaurs” Divided into 3 periods: Triassic Period Jurassic Period Cretaceous Period Mammals, dinosaurs, and crocodiles appear Dinosaur’s dominate the land Period ends with extinction of dinosaurs

Geologic Timeline Cenozoic Era 65 MYA – Present Greek word for “ New Life” “Age of Mammals” Divided into 2 periods Paleogene Period Neogene Period (we are in this one now) Rise of mammals Neogene period begins with the first humans appearing 23,000 years ago By the end of the period, modern humans appear and develop civilization

OBJECTIVE: Create the geologic timeline. 54 January 2012 5 OBJECTIVE: Create the geologic timeline. OUTRO List 3 things you never knew about Earth’s geologic history before making this timeline?