Slide 2:
The Earth is believed to have formed around 4 billion years ago. Gases and space rock and dust formed a dense ball that came together to form a core.
Later, as it continued to be bombarded by asteroids the planet was larger and covered by volcanoes and molten lava fields and poisonous gases.
Millions of years later as the Earth began to cool and become more stable, these gases combined to form water creating the oceans.
Soon after, simple microscopic forms of life would appear called bacteria. Formation of the Earth
Slide 3:
From evidence gathered by the Apollo missions to the moon, scientists believe a large asteroid struck the Earth causing debris to rise up into space forming the moon.
Soon an atmosphere of oxygen would replace the methane gas and carbon dioxide that was present.
Billions of years later the first supercontinent would form called Pangaea.
The continents of Earth reston plates that are in constantmotion. Because of this, thecontinents have drifted apartto form our modern daycontinents. This is called continental drift. Early Earth
Slide 4:
The largest span of time in the Geologic Time Scale is called Precambrian time. It starts at the formation of the Earth….4.6 billion years ago and runs to 544 million years ago.
The Time Scale is then broken up into 3 major blocks of time called Eras. Geologic Time Paleozoic EraMeans – Ancient Life
544 – 245 Million Years Ago
Commonly called “The Age of Trilobites”
Organisms were well adapted for sea life with exoskeletons
that were soft. Mesozoic EraMeans – Middle Animals
245 – 66 Million Years Ago
Commonly called
“The Age of Reptiles”
Organisms were large and welladapted to life on land. Dinosaurs Cenozoic Era
Means – New Life
66 Million Years Ago to Present
Commonly Called
“The Age of Mammals”
Marked the demise ofreptiles and the rise of mammals including man.
Organisms were covered withhair, fur, and feathers.
Slide 5:
Each Era is further divided into Periods. Geologic Time Paleozoic Era
Cambrian Period
Ordovician Period
Silurian Period
Devonian Period
Carboniferous Period
Permian Period Mesozoic Era
Triassic Period
Jurassic Period
Cretaceous Period Cenozoic Era
Tertiary Period
Quaternary Period