Earth is where humans dwell. the surface of the planet is 73% water and 27% land, including numurous islands.
earth itself is 4.5 Billion years old, during most of this time, however, life did not exist
Hadrian era, 4.5-3.5 Billion years ago
the hadrian era is earth's true formation. during which the earth was in essence a volcanic wasteland, with huge amounts of heat being generated by a then radioactive core and surface. as earth cooled, heavier elements sank to the core and lighter elements stayed on top.
Archeon, 3.5-3.2 billion years ago
earth developed a primative atnosphere of carbon dioxide and earth was essentally a water world, however, the continents began to form about halfway through this era. eventully, a single continent existed, and primitive plants and bacteria evolved. However, the continent blocked major ocean currents, resulting in the earth being completely frozen for some time. eventally, the continent broke up and volcanic activity thawed the earth. life survived, and subsequently changed the composition of the atnosphere, allowing life to evolve further.
Cambrian era, 3.2 Billion years ago -645 million years ago
this time peoriod marked the rapid evolution in marine and aquatic organisims. primitive creatures made their way onto the land, but intentense volcanic activity in what is today siberia caused a mass extinction of all land based creatures.
Permian era, 645-365 million years ago
the evolution of land-based creatures continued, resulting in primitiv e dinosaurs evolving, however, the Permian Mass exinction, which wiped out 95% of all life on earth, almost destroyed our evolution. as deaserts expanded, many sought to escape underground. those that did survived and all other lifeforms were destroyed.
carnifierous era,365-65 million years ago
commonly called the 'age of reptiles' this marked exponientian advances in the evolution of both animals and plants, however, after amjor meter strike,almost all life on earth was destroyed. this also set the stage for our own evolution.
procene Eprach,65 million years ago-present
this era is the Age of Man. after the ice age, when many large herbivores and other predatory animals went extinct, our civilization began to develop, begainning with the agricultral revolution, at about 5,000B.C. eventally, the first village grew into towms, and then into cities. the firast cities grew in the indius river valley,and slowly spread into the river valleys of the tigris and Eupraiteses rivers, where writting was developed. meanwhile, similar advances were taking place in africa and eroupe, but asia alwayas maintained technical superiority.