Overview of Earth´s History and Periods Essay

A person’s identity is a mask on their lives; underneath that mask lies the unadulterated version of a human’s existence-- all people go through similar tragedies, deal with the same emotions, and are in a constant pursuit of happiness and success. As The New York Times puts it, the novel The Good Earth by Pearl S. Buck is “a comment upon the meaning and tragedy of life as it is lived in any age in any quarter of the globe." Set in the early twentieth century in rural China, this story follows the life of the poor farmer Wang Lung and his family. During Wang Lung's search for prosperity, several mishaps blocks his way to what he wants most. The struggles Wang Lung face, the ups and downs in his tumultuous life, and ultimately, Wang Lung’s

The science that is connected with planet earth encompasses geosciences or earth science among others. Containing old histories, this is considered as a part of planetary science while it possesses holistic and reductionist approaches in the science of the planet Earth. This discipline can cope with lithosphere, atmosphere, biosphere or hydrosphere. Quantitative understanding has been developed by the scientists to understand the ground systems with the tools by mathematics, physics, chronology, biology, chemistry alike that help to know how the universe is evolved.

Shifting from the end of the Permian period 250 million years ago into the next era, the Triassic period occurred between 250 and 199 million years ago and was know for further diversifying life on land. After the Permian period, the Triassic period was largely successful in adapting and evolving, as the world was going through many changes. The land mass known as Pangea began its separation, which would be completed in the Jurassic period. The climate was relatively more severe during this time, with hotter summers and colder winters, but because of the warmer atmosphere, there were no polar ice caps at this time. Towards the center of Pangea, it was mostly a dry desert climate. As for life on earth, most of the marine life had been wiped

The Cambrian Period marks the beginning of the Paleozoic Era. This period gets its name from a place in Wales where the first examples of this type of ancient life was found. The period lasted for nearly 53 million years, from about 543 million years ago until 490 million years ago. The Cambrian Period marks an important point in the history of life on earth; it is the time when most of the major groups of animals first appear in the fossil record. This event is sometimes called the "Cambrian Explosion", because of the relatively short time over which this diversity of forms appears. It was once thought that the Cambrian rocks contained the

The beginning of the Jurassic brought a new climate. The weather changed from arid, dry, and seasonal to humid, hot, and stable. The weather allowed for lush jungles to flourish, and with the lush jungles, the dinosaurs. The weather change was due to the supercontinent Pangea breaking apart. Two new smaller supercontinents were formed, Gondwana and Laurasia. The supercontinents now had more area that was touching the ocean. This meant the water from the ocean made the supercontinents more humid than before. The dinosaurs thrived in this climate. New species are being discovered to this day from the Jurassic Period due to the immense diversity amongst them.

<b>Introduction</b><br>Think of a world which existed 290 million years ago. As you look out over the terane in front of you, you think that you are on an alien planet. You see volcanoes spewing ash and lava. Beside them is the ocean which is swarming with many different species of echinoderms, bryozoans and brachiopods. As you look down onto the sea floor you are amazed at the countless number of starfish and urchins. Some animals leave you can't even describe and you have no idea even what phylum they belong to. This is a world at its height in diversity of oceanic species. Millions of wonderous species existed at this time in the ocean and most of them will never appear again in earth's history. In the geologic time scale, a million

what made life today last up until this generation. Before this period, the Earth provided shelter

“The early Earth was probably partially or largely molten” (The Solar Nebula. N.d). Over time the earth cooled and the crust was formed. “Much continental crust, the most silica rich and least dense kind, has been produced by 2.5 billion years” (The Solar Nebula. N.d). Over a period of time and a series of volcanic eruptions water vapor was thrown into the atmosphere and eventually condensed to form the oceans. From a spinning cloud of dust the evolutionary process began and the Earth that is inhabited today came into existence according to the nebular hypothesis.

The Permian mass extinction, that struck about 250 million years ago, caused a mass extinction of reef and shallow water communities. Groups that lived on the seafloor and filtered organic material from the water for nourishment suffered the greatest extinction. Those include corals, shelled in-vertebrates, and a variety of sea lilies. Others marine groups includes trilobites, zooplankton and snails. Even though these species died in the water, living organisms on land were not much better off. Terrestrial vertebrates and insects both experienced a big loss in each of their groups. Also suffering a big loss was the insect family due to the lack of plant life and food. Seventy Eight percent of reptiles became extinct and sixty seven percent of the amphibian family became extinct during this time period.

Some 480 million years ago, way before the dinosaurs, the Ordovician period, was the period when plants were finally able to inhabit land. It lasted for 42 million years. Sea levels were very high during this time, which allowed the already present sea creatures to grow to even larger proportions.

Early Earth is predicted to have been a very hostile environment. Due to high levels of tectonic activity, there were thought to have been many volcanic eruptions. These eruptions mixed with high temperatures caused an out-gassing of volatile molecules and initiated gases such as methane, ammonia, hydrogen, nitrogen, and carbon dioxide to exist. However, even after the introduction of these gases, oxygen was still not present. The absence of oxygen meant that the earth had no ozone layer, and was therefore exposed to large amounts of UV radiation. Early Earth was under very dangerous conditions and was unstable.

The oxygen revolution: During the Proterozoic, biotic system were being established, which gave rise to biomass of the prokaryotic organisms like the “benthic and planktonic photosynthesizing organisms” Due to the vast developing diversity of environment, organisms could well adapt to these various environments, which increased the input of oxygen on Earth. Hence, in order for the oxygen to be accumulated in the atmosphere, Iron and Sulfur like oxygen-sinks had to be depleted.

India, a large subcontinent that is separated from other lands because of landmasses, like the Himalayas. Northwest is penetrable, but incoming people have to go through the Hindu Kush Mtns. and the Thar Desert.

The carboniferous period lasted from about 359.2 to 299 million years ago, during the Paleozoic era. The name “carboniferous” came from the large amounts of carbon-bearing coal that was formed during the period. Several major biological, geological, and climatic events occurred at this time. The amniote egg allowed further exploitation for certain tetrapods. It enabled ancestors of birds, mammals, and reptiles to lay their eggs on land without fear of being dehydrated. The carboniferous period was divided into two major subdivisions, the Mississippian and the Pennsylvanian. The Mississippian was the early half and the Pennsylvanian being the last half.

Jurassic is a period of time with Dinosaurs, rodents and birds. There were also island seas consisting of sharks, sea monsters and blood-red planktons. The existing plants in that period were cycads, ferns and conifers. The Mesozoic era was about 245 million years ago to 65 years ago, so it almost lasted about 180 years in total. The Mesozoic era is divided into three periods of Triassic, Jurassic and Cretaceous. Mesozoic era means middle animals and it is the era, which the word’s fauna has changed from what is in the Paleozoic era and the most famous organisms of this era are dinosaurs. In the Mesozoic era, the extinction of more than 90 percent of species in the earth was observed and the reason behind it was mostly volcanic eruptions and climate changes. On the other hand, this era had massive changes that represented ecological niches and rise to new creatures such as rodent-size mammals and first dinosaurs. In Triassic, which was the first period of Mesozoic, the mammals and first dinosaurs existed. Later than that, the second period was Jurassic, which giant shaped dinosaurs and other kinds of dinosaurs were developed. Besides that the first flowering plants and primitive birds, with long teeth appeared in that era as well.