GEOLOGIC TIME SCALE Chapter 30 DIVISION OF GEOLOGIC

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GEOLOGIC TIME SCALE Chapter 30

GEOLOGIC TIME SCALE Chapter 30

DIVISION OF GEOLOGIC TIME Geologic Time Scale: a summary of major events in Earth’s

DIVISION OF GEOLOGIC TIME Geologic Time Scale: a summary of major events in Earth’s that are preserved in the rock record. Divided into four sub-categories. Eons Eras Periods Epochs

DIVISION OF GEOLOGIC TIME Eon: longest segment of geologic time. Archean (4 bya) –

DIVISION OF GEOLOGIC TIME Eon: longest segment of geologic time. Archean (4 bya) – Oldest/formation of Earth’s crust. Proterozoic(2. 5 bya)oldest fossils of simple ocean life. Phanerozoic(543 mya) – signs of visible life.

DIVISION OF GEOLOGIC TIME Phanerozoic Eon is subdivided into three ERAS: Paleozoic (543 mya)

DIVISION OF GEOLOGIC TIME Phanerozoic Eon is subdivided into three ERAS: Paleozoic (543 mya) – fossils of ocean and land plants and animals (age of invertebrates). Mesozoic (248 mya) – Dinosaurs(age of reptiles) Cenozoic (~65 mya) – Last ice age and the (age of mammals) appearance of humans in the fossil record. Eras are divided into periods and periods into epochs.

CHANGES THROUGH GEOLOGIC TIME The Earth has undergone many changes through history. Addition of

CHANGES THROUGH GEOLOGIC TIME The Earth has undergone many changes through history. Addition of O 2 from mostly Co 2, SO, intro of life, mountain/ocean formation…

EVOLUTION What is evolution? It is the process of change that introduces new life

EVOLUTION What is evolution? It is the process of change that introduces new life forms. The mechanism in which this happened is called natural selection. This concept was introduced by Charles Darwin, a naturalist.

EVOLUTION. What is natural selection? It’s the process by which organisms best suited to

EVOLUTION. What is natural selection? It’s the process by which organisms best suited to their environmental conditions are most likely to survive and reproduce.

KETTLEWELL’S RESEARCH

KETTLEWELL’S RESEARCH