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big bang
According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the Universe to cool and resulted in its present continuously expanding state. According to the most recent measurements and observations, the Big Bang occurred approximately 13.75 billion years ago, which is thus considered the age of the Universe.
http://www.youtube.com/watch?v=cD8-2S952Zw -
Birth of Earth
According to the recognized scientific evidence the earth was once a huge ball of burning gas, just as the sun is now. But the planet Earth and the others have cooled down quite a bit over the millions of years that our universe has been in existence.The spinning slowed, the temperature cooled and eventually the Earth was not a source of light, as the sun is today.
http://www.thegeminigeek.com/how-was-the-earth-formed/
http://www.youtube.com/watch?v=hwVU0-2Qnso -
Precambrian Time
The Earth forms, continental shields appear; fossils are rare; and stromatolites and are the most common organisms. Makes up 88% of earth’s history and we know very little of what happened that time. Nearly half of the valuable mineral deposits in the world occur in the rocks of this time and they include: nickel, iron, gold, and copper. Imprints of marine worms, jellyfish, and single celled organisms have been discovered in rocks from this time. Also there was volcanic activity, Mt. building. -
Cambrian Period
Shelled marine invertebrates appear like the most common one trilobite and brachiopods. Other invertebrates include worms, jellyfish, snails, and sponges. However no evidence of land-dwelling plants or animals has been discovered in Cambrian rocks. Also first vertebrates appear. -
Ordovician Period
Ordovician Period populations of trilobites began to shrink. Clam like brachiopods and cephalopod mollusks became dominate invertebrate life forms. Large number of corals and primitive fish appeared. Vertebrates appeared, the most common vertebrates were fish, but the fish didn’t have jaws or teeth and were covered with thick boney plates. Also there was no plant life but atmosphere reaches modern O2- rich state. -
Silurian Period
The beginning of this period was 444 Ma. Vertebrate and invertebrate marine life continued to thrive, relatives of modern sea stars and corals became more common. Scorpion-like sea creatures called eurypterids and their fossils have been discovered in New York. Near the end of the Silurian Period the earliest land plants an animal such as scorpions, evolved on land. -
Devonian Period
The beginning of this period was 416 Ma. The Devonian Period is called the Age of Fishes because fossils of many bony fishes were discovered in rocks. One type is of fish is the lung fish who could breath air and another is the rhipidistians who had strong fins that allowed them to crawl on land for little bit of time. The first amphibians the genus Ichthyostega. Land plants, such as giant horsetails, ferns, and seed-bearing plants developed. -
Carboniferous Period
The beginning of this period was 354 Ma.Climate was warm and humidity was high over most of the world. Forest and swamps covered lots of the land. Amphibians and the fish continue to flourish. Crinoids were common in the oceans and insects such as giant cockroaches and dragonflies were common on land. -
Mississippian Period
The beginning of this period was 359 Ma. Amphibians flourish; brachiopods are common in oceans; and forest and swamps cover most of land. Climate hot & humid but glaciated at the poles and oxygen level 40% above today- abundant wildfires. Plants develop bark, but bacteria not yet able to break it down. Dense layers of dead wood form coal beds. Sea life dominated by sharks, corals, bryozoa, brachiopods, ammonoids, crinoids and foraminifera. -
Pennsylvanian period
The beginning of this period was 318 Ma. At the end of this period vertebrates that were adapted to life on land appeared. Early reptiles resembled large lizards. Giant cockroaches and dragonflies are common; coal deposits form; and reptiles appear. -
Permain Period
The Permian Period marks the end of the Paleozoic Era. The beginning of this period was 229 Ma. A mass extinction of a large number of the Paleozoic life forms occurred at the end. The continents had joined to form the supercontinent Pangaea. The collision of the tectonic plates created the Appalachian Mt. areas of dessert and dry savanna climates developed. Many species of marine invertebrates became extinct. But reptiles and amphibians survived the environmental changes and dominated. -
Triassic Period
The first period of the Mesozoic Era, it began 251 million years ago. Climates were predominately warm and dry and the Earth’s crust was relatively quiescent. At the end of the Triassic, however, plate tectonic activity picked up, and a period of continental rifting began. Dinosaurs appeared this period, who roamed through lush forest of cone-bearing trees and cycads. Reptiles called ichthyosaurs lived in the oceans and new forms of marine invertebrates also evolved. The first mammals, rodents -
Jurassic Period http://www.nytimes.com/2011/08/02/science/02fossil.html?_r=0
The beginning of the Jurassic Period was 200 Ma. Dinosaurs became the dominant life-form and fossil records indicate that to major groups of dinosaurs evolved. One group is called saurischians also known as lizard-hipped dinosaurs, included herbivores and carnivores. The other group was the ornithischians known as bird-hipped dinosaurs, were herbivores. Also there were flying reptiles called pterosaurs like modern bats, pterosaurs. And fossils were found of the earliest birds occurred. -
Cretaceous Period
This period had a warm climate. These oceans and seas were populated with now extinct marine reptiles, while dinosaurs continued to dominate on land. New groups of mammals and birds, as well as flowering plants appear. The period ended with a large mass extinction. No dinosaur fossils have been found in rocks that formed after this period. The extinction was caused by environmental changes that were the result of the movement of continents and increased volcanic activity or the impact hypothesi -
paleocene 7:00 A.M.
The beginning of this epoch was 65.5 Ma. During the Paleocene Epoch many new mammals such as small rodents evolved. The first primates also evolved. The early part of the period experienced cooler temperatures and a more arid climate than existed before the asteroid. But in the latter part of the epoch, the temperatures warmed significantly, resulting in the absence of glaciated poles and the presence of verdant, tropical forests. -
eocene 9:00 A.M.
The beginning of this epoch was 55.8 Ma. Other mammals evolved like the ancestor of the horse evolve during the Eocene Epoch. Fossil records show that the first whales, flying squirrels, and bats appeared. Small reptiles continued to flourish. Worldwide temperatures dropped about 4C at the end. -
oligocene 12:00 P.M.
The beginning of this epoch was 33.9 Ma. The Indian subcontinent began to collide with the Eurasian continent which caused uplifting of the Himalayas. The climate became cooler and dryer. Many early animals became extinct but large animals like deer, pigs, camels, cats, horses, and dogs; also marine invertebrates such as claims and snails flourished. -
miocene 1:00 P.M.
The beginning of this epoch was 23.0 Ma. The modern Antarctic icecap began to form. The largest known land mammals existed during the Miocene Epoch. Miocene rocks also contain fossils of horses, camels, deer, rhinoceroses, pigs, raccoons, wolves, foxes, and the earliest saber-toothed cats. The earliest human ancestors date back to this epoch. -
pliocene 8:00 P.M.
The beginning of this epoch was 5.3 Ma. During these predators such as bear, dog, and cat families evolved into modern forms. First modern horses also appeared. Climate changes occurred toward the end of the epoch, and the continental ice sheets began to spread which caused sea level to fall. The Bering land bridge appeared between Eurasia and North America. Species migrated between the land bridges. -
pleistocene 11:30 P.M.
The beginning of this epoch was 1.8 Ma. In Eurasia and North America ice sheets advanced and retreated several times. Some animals could stand this weather because they had thick fur like that covered the wholly mammoth. And the ones who don’t like colder weather migrated to warmer regions to survive, but some didn’t and became extinct like the giant ground sloths. Fossils of the earliest modern humans were discovered in the Pleistocene sediments. -
holocene 11:59 P.M.
The beginning of this epoch was 11,500 and includes the present. Coast lines took their present shapes. The North America Great Lakes formed. Humans developed agriculture and began to make their own tools.
