1. Geologic Timescale

2. Archaean Eon 4.6-2.5 billion years ago (bya) Earth’s origin
3.7 bya: First protobionts
3.5 bya: First Prokaryotes
2.5 bya: atmospheric Oxygen increases

3. Proterozoic Eon 2.5 bya to 542 mya 2.2 bya: first Eukaryotes
Prokaryotes with plastids, mitochondria, and DNA
600 mya: algae and soft bodied invertebrate animals
Snow ball Earth Hypothesis: Life can only exist where sunlight can reach deep ocean (where there was no ice), like vents and plate boundaries

4. Phanerozoic Eon Eras: All of life evolves to current state
Paleozoic: 542 mya to 251 mya
Mesozoic: 251 mya to 65 mya
Cenozoic: 65 mya to today
All of life evolves to current state
Two mass extinctions:
Permian
Cretaceous

5. Paleozoic Era Periods:
Cambrian: Cambrian explosion and diversity of species
Ordovician: Plants and Arthropods colonize land
Silurian: vascular plants diversify
Devonian: Bony Fish, tetrapods, insects
Carboniferous: GIANT FOREST OF VASCULAR, Reptiles
Permian: More reptiles, origin of modern insects, MASS EXTINCTION

6. Permian Mass Extinction
96% of marine species gone
Increased volcanic activity in modern day Siberia
More CO2 in atmosphere, warmed planet
Less difference in equator and poles, slowed ocean currents
No currents, less oxygen for marine life

7. Mesozoic Era
Periods:
Triassic: Cone bearing plants, dinosaurs diversify, and mammal like reptiles
Jurassic: Continued dominance of Cone bearing plants and dinosaurs
Cretaceous: Flowering plants emerge, Mass Extinction

8. Cretaceous Mass Extinction
50 % of marine life gone, most land plants and dinosaurs gone
Theory: asteroid or comet hit modern day Mexico and created a cloud of dust on Earth
This dust became a layer of clay with Iridium, which is an element not common on Earth
There was also an increase in volcanic activity in India

9. Cenozoic Era Periods: Paleogene: 65 - 23 mya Neogene: 23 mya – today
Diversity of mammals, birds and insects
Flowering plants become dominant
Origin of Primate groups
Neogene: 23 mya – today
Origin of genus Homo
Ice Ages
Modern Day