Earth's History and Evolution
Mass Extinction (K-T Extinction)
At the end of the Mesozoic Era, dinosaurs and 70% of all life vanished, possibly due to an asteroid collision
Carbon Dioxide
Volcanic activity added carbon dioxide to the early atmosphere
Water Cycle
Water vapor condensed and precipitated on the Earth's surface
Amphibians
Amphibians followed plants and arthropods in colonizing dry land
Mass Extinction (Holocene Extinction)
Another mass extinction occurred with the close of the last ice age, possibly due to climate change and species competition
Photosynthesis
Archeobacteria used CO2 for photosynthesis and released molecular oxygen into the atmosphere
Water Vapor
Clouds of water vapor combined with carbon dioxide in the early atmosphere
Methane, Ammonia, Hydrogen, Water Vapor
Compounds in the atmosphere precipitated into the ocean and were the basis for the building blocks of life
Volcanic Activity
Continued volcanic activity shaped the surface of the Earth
Dinosaurs
Dinosaurs ruled the Earth during the Mesozoic Era
Carboniferous Period
During the Carboniferous period, much of the Earth's land was in tropical locations and photosynthesis was at an all-time high
Formation of Earth
Earth formed from heated, coalescing dust and gases
Early Atmosphere
Earth's early atmosphere started as mostly hydrogen and helium
Glaciers
Glaciers have advanced and retreated numerous times over the last 60 million years
Ozone Production
Molecular oxygen combined with atomic oxygen to produce ozone, a natural UV screen
Fossil Fuels
Incompletely decomposed vegetation from the Carboniferous period formed modern fossil fuel reserves
Colonization of Dry Land
Living organisms could exploit the exposed rocks on dry land
Mammal-Like Reptiles
Mammal-like reptiles appeared during the Paleozoic Era
Multi-Cellular Life
Multi-cellular life forms arose 1.5 billion years ago
Plants and Arthropods
Plants and arthropods were the first organisms to colonize dry land
Miller & Urey Experiment
Stanley Miller and Harold Urey recreated conditions of the primitive Earth and produced organic molecules
Cambrian Explosion
The Burgess Shale reveals a burst of new life forms during the Cambrian period
Cenozoic Era
The Cenozoic Era is known as the 'Age of Mammals'
Oceans
The Earth cooled as the oceans filled from precipitating water vapor
Mesozoic Era
The Mesozoic Era was characterized by deserts and the dominance of dinosaurs
Birds
The extinction of dinosaurs gave way to the rise of birds
Single-Celled Organisms
The first single-celled organisms evolved in the water and were protected from UV rays
Mass Extinction
The greatest mass extinction occurred at the end of the Paleozoic Era, causing the disappearance of 90% of all life forms
Hyperoxic Atmosphere
The hyperoxic atmosphere during the Carboniferous period may have contributed to the enormous growth of insects
Ozone Layer
The ozone layer protects life on Earth and has been damaged by human use of CFCs
Solar Radiation
The thin atmosphere allowed solar radiation to reach the Earth's surface
