Our website is the source for the latest security and strategic research from the militarys link to the academic community. The Strategic Studies Institute is the. History of Earth Wikipedia. This article is about scientific evidence concerning the history of Earth. For religious accounts, see Creation myth. For the history of modern humans, see History of the world. The history of Earth concerns the development of planet. Earth from its formation to the present day. Nearly all branches of natural science have contributed to the understanding of the main events of Earths past. The age of the Earth is approximately one third of the age of the universe. Unlike Canada and Australia, the Union of South Africa was a unitary state, rather than a federation, with each colonys parliaments being abolished and replaced with. SubSaharan Africa has a wide variety of climate zones or biomes. South Africa and the Democratic Republic of the Congo in particular are considered Megadiverse countries. An immense amount of geological change has occurred in that timespan, accompanied by the emergence of life and its subsequent evolution. Earth formed around 4. Volcanic outgassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen and so would not have supported known forms of life. Much of the Earth was molten because of frequent collisions with other bodies which led to extreme volcanism. A giant impact collision with a planet sized body named Theia while Earth was in its earliest stage, also known as Early Earth, is thought to have been responsible for forming the Moon. Over time, the Earth cooled, causing the formation of a solid crust, and allowing liquid water to exist on the surface. The geological time scale GTS depicts the larger spans of time, from the beginning of the Earth to the present, and it chronicles some definitive events of Earth history. The Hadean eon represents time before the reliable fossil record of life beginning on Earth it began with the formation of the planet and ended at 4. The Archean and Proterozoic eons follow they produced the abiogenesis of life on Earth and then the evolution of early life. The succeeding eon is the Phanerozoic, which is represented by its three component eras the Palaeozoic the Mesozoic, which spanned the rise, reign, and climactic extinction of the non avian dinosaurs and the Cenozoic, which presented the subsequent development of dominant mammals on Earth. Hominins, the earliest direct ancestors of the human clade, rose sometime during the latter part of the Miocene epoch the precise time marking the first hominins is broadly debated over a current range of 1. The succeeding Quaternary period is the time of recognizable humans, i. S/photo.goodreads.com/books/1312009368i/235016._UY475_SS475_.jpg' alt='Robert Ross A Concise History Of South Africa Pdf' title='Robert Ross A Concise History Of South Africa Pdf' />Homo, but that periods two million year plus term of the recent times is too small to be visible at the scale of the GTS graphic. Notes re the graphic Ga means billion years Ma, million years. The earliest undisputed evidence of life on Earth dates at least from 3. Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean. Eon. There are microbial matfossils such as stromatolites found in 3. Western Australia. Other early physical evidence of a biogenic substance is graphite in 3. Greenland1. 3 as well as remains of biotic life found in 4. Western Australia. According to one of the researchers, If life arose relatively quickly on Earth then it could be common in the universe. Photosynthetic organisms appeared between 3. Life remained mostly small and microscopic until about 5. What Type Of Plastic Are Airsoft Pellets Made Of more. Cambrian Explosion about 5. This event drove a rapid diversification of life forms on Earth that produced most of the major phyla known today, and it marked the end of the Proterozoic Eon and the beginning of the Cambrian Period of the Paleozoic Era. More than 9. 9 percent of all species, amounting to over five billion species,1. Earth are estimated to be extinct. Estimates on the number of Earths current species range from 1. Scientists recently reported that 1 trillion species are estimated to be on Earth currently with only one thousandth of one percent described. The Earths crust has constantly changed since its formation. Likewise, life has constantly changed since its first appearance. Species continue to evolve, taking on new forms, splitting into daughter species or going extinct in the process of adapting or dying in response to ever changing physical environments. The process of plate tectonics continues to shape the Earths continents and oceans and the life they harbor. Human activity is now a dominant force affecting global change, adversely affecting the biosphere, the Earths surface, hydrosphere, and atmosphere, with the loss of wild lands, over exploitation of the oceans, production of greenhouse gases, degradation of the ozone layer, and general degradation of soil, air, and water quality. Eons. In geochronology, time is generally measured in mya megayears or million years ago, each unit representing the period of approximately 1,0. The history of Earth is divided into four great eons, starting 4,5. Each eon saw the most significant changes in Earths composition, climate and life. Each eon is subsequently divided into eras, which in turn are divided into periods, which are further divided into epochs. Eon. Time myaDescription. Hadean. 4,5. 404,0. The Earth is formed out of debris around the solar protoplanetary disk. There is no life. Temperatures are extremely hot, with frequent volcanic activity and hellish environments. The atmosphere is nebular. Possible early oceans or bodies of liquid water. The moon is formed around this time, probably due to a protoplanets collision into Earth. Archean. 4,0. 002,5. Prokaryote life, the first form of life, emerges at the very beginning of this eon, in a process known as abiogenesis. The continents of Ur, Vaalbara and Kenorland may have been formed around this time. The atmosphere is composed of volcanic and greenhouse gases. Proterozoic. 2,5. Eukaryotes, a more complex form of life, emerge, including some forms of multicellular organisms. Download Auto Parts Stores Database Marketing here. Bacteria begin producing oxygen, shaping the third and current of Earths atmospheres. Plants, later animals and possibly earlier forms of fungi form around this time. The early and late phases of this eon may have undergone Snowball Earth periods, in which all of the planet suffered below zero temperatures. The early continents of Columbia, Rodinia and Pannotia may have formed around this time, in that order. Phanerozoic. 54. 1present. Complex life, including vertebrates, begin to dominate the Earths ocean in a process known as the Cambrian explosion. Pangaea forms and later dissolves into Laurasia and Gondwana. Gradually, life expands to land and all familiar forms of plants, animals and fungi begin appearing, including annelids, insects and reptiles. Several mass extinctions occur, among which birds, the descendants of dinosaurs, and more recently mammals emerge. Modern animalsincluding humansevolve at the most recent phases of this eon. Geologic time scale. The history of the Earth can be organized chronologically according to the geologic time scale, which is split into intervals based on stratigraphic analysis. The following four timelines show the geologic time scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. Therefore, the second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in the third timeline, and the most recent period is expanded in the fourth timeline. Millions of Years. Solar System formation. The standard model for the formation of the Solar System including the Earth is the solar nebula hypothesis. In this model, the Solar System formed from a large, rotating cloud of interstellar dust and gas called the solar nebula.