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Devonian Period – 408 mya
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First adapt radiation after Ordovician Period was the Silurian period, This happened about 443.7 - 416 years ago and after the first extinction. (N/A,N/A) This was the beginning of fresh water fish, plants and animals left the water to be on land. This began the terrestrial form of life with plant being assigned to the cooksonia genus and the vascular systems of complex plants. this period was subdivided into four epochs which had stages. (Fischer,Liu, Yip, and Yu, 1998) The next period was the Devonian around 408 - 360 million years ago and the Carboniferous Period, about 359.2 - 299 million years ago and after the second extinction. this was divided in to two subsystems the Pennsylvanian and the Mississippian which were subdivided to stages. (Waggoner, 1996) This was a time of the first appearance of amphibians, bony fish, sharks and the diversity of terrestrial life. Also came the beginning of reptiles, the diversity of amphibians, conifers and the first coal beds. (Klappenbach,N/A,) Next was extinction which is the largest extinction in history. (Alexander, Chang, Tsai, and Wu, 1998) This was the time of diversification of insects and reptiles, with the expansion of conifers. (Klappenbach,N/A,) Triassic comes after the forth extinction about 248 - 246 million years ago and was divided into seven epochs.( Asaravala, Lam, Litty, Phillips and Wu, 1998) This brings the first dinosaurs the diversity of bony fish, reptiles, many insects and conifers. (Klappenbach,N/A,) The Jurassic period brought dinosaurs roaming the earth, the first of birds and mammals, more insect, conifers and the diversity of bony fish. the earth had a tropical climat... ... middle of paper ... ...ic Retrieved at http://paleobiology.si.edu/geotime/main/jurassic1.html E.O. Wilson, 1984, Biophilia Retrieved at http://books.google.com/books?id=BapY4GLfMOAC&pg=PA121&lpg=PA121&dq=%E2%80%9CThe+one+process+now+going+on+that+will+take+millions+of+years+to+correct+is+the+loss+of+genetic+and+species+diversity+by+the+destruction+of+natural+habitats.++This+is+the+folly+our+descendants+are+least+likely+to+forgive+us.%E2%80%9D&source=bl&ots=cIwt3ieMYJ&sig=3YKnnPORVYwhurvHMaBAXocPP2I&hl=en&sa=X&ei=YLjlUsa_JunlyQG9qoGoCw&ved=0CD0Q6AEwAg#v=onepage&q=%E2%80%9CThe%20one%20process%20now%20going%20on%20that%20will%20take%20millions%20of%20years%20to%20correct%20is%20the%20loss%20of%20genetic%20and%20species%20diversity%20by%20the%20destruction%20of%20natural%20habitats.%20%20This%20is%20the%20folly%20our%20descendants%20are%20least%20likely%20to%20forgive%20us.%E2%80%9D&f=false
In this paper Martin is arguing that late quaternary or near time extinctions where caused by human activity or as he calls it “overkill”. Martin recognizes that there have been many forces that have triggered extinctions in the planet on the past but disagrees with the idea that near time extinctions where caused by some commonly believed causes like climate change, disease or nutrient shortage. He argues that the arrival of humans to different continents, islands and the subsequent excessive hunting, the introduction of diseases and other competitors and predators was the cause of extinction of a great number of species “As our species spread to various continents we wiped out their large
Around 144 million years ago, began the emergence of the Ornithischian dinosaurs during the cretaceous period and diversified into North America and Asia.
Paleolithic is often referred to as the Old Stone Age. "Paleo" means old and "lithic" means stone. The Neolithic time period is often referred to as the New Stone Age. "Neo" means new and "lithic" also means stone. The Paleolithic culture or way of life began about 2.5 to 2 million years ago. The Paleolithic Period ended at different times in different parts of the world, generally around 12,000 years ago in Europe and the Middle East. When the Paleolithic period ended, the Neolithic period took over and began 12,000 years ago somewhere in the Middle East, and later in other parts of the world. It is characterized by the beginning of farming, the domestication of animals, the development of crafts such as pottery and weaving, and the making of polished stone tools. Life changed dramatically between Paleolithic and Neolithic times.
paper will analyze the quaternary period, specifically the “Holocene epoch from 8000 B.C. to Present; the last 10,000
In conclusion, The Mesolithic Period is part of the upper Paleolithic. It was followed by the pre-pottery Neolithic era and represented a new phase of culture, characterized by the beginning of settled life.
The biggest mass extinction of the past 600 million years (My), the end-Permian event (251 My ago), witnessed the loss of as much as 95% of all species on Earth. Key questions for biologists concern what combination of environmental changes could possibly have had such a devastating effect, the scale and pattern of species loss, and the nature of the recovery. New studies on dating the event, contemporary volcanic activity, and the anatomy of the environmental crisis have changed our perspectives dramatically in the past five years. Evidence on causation is equivocal, with support for either an asteroid impact or mass volcanism, but the latter seems most probable.
Mother earth has gone through a lot of changes throughout its four and a half billion-year existence. Earth has seen many different climates and many different species. Because of these changes geologists have broken earths history into different time periods. One such time period was the Pennsylvanian time period. The Pennsylvanian time period is a subdivision of the Carboniferous period. The Pennsylvanian period saw the introduction of many different species that are still present today along with a very different climate and different geographical features than are present today.
The Precambrian Era is when the Earth formed. Earth was barley a spec of dust in outer space and as time went by it gathered ice, rock and more dust particles. It eventually formed into a big rock flying around in space. The Earth was extremely hot and so when it rained the rain would evaporate in mid air or immediately after it hit the ground. But even though it evaporated these great rains cooled the Earth eventually building up water in lower areas creating oceans. The Earths atmosphere was water vapor, carbon dioxide, nitrogen and gases. After awhile oxygen level grew in the atmosphere. The earliest life forms were single celled organisms that lived in the oceans. These organisms used light energy to produce food called photosynthesis. These were called Prokaryotes and Eukaryotes. The evolution of multi celled organisms were Dramatic in change.
Dinosaurs held their own, according to studies, for at least 150 million years. After becoming extinct and finding fossilized remains dinosaurs have become a way in which we not only measure the changes that have occurred as the planet evolved, but also how we express ourselves today.
The Permian Period occurred around 298 million years ago. It stretched from the Carboniferous Era to the Triassic. Sir Roderick Murchison in the early 1800’s noticed a differentiation among the overlay of the rock formation in the Ural Mountains in Russia. These rocks differed from the older Carboniferous rocks in Britain, and seemed younger than the Triassic rocks of Europe. Murchison named this differentiation after the prehistoric kingdom of Perm, thus the Permian Period.
According to scientists, one of the most extraordinary bursts of evolution ever known was the Cambrian Explosion. For most of the nearly 4 billion years that life has existed on Earth, evolution produced little beyond bacteria, plankton, and multi-celled algae. Then, about between 570 and 530 million years ago, another burst of diversification occurred. This stunning period is termed the "Cambrian explosion," taking the name of the geological age in which the earlier part occurred. A recent study revealed that life evolved during the Cambrian Period at a rate about five times faster than today. But it was certainly not as rapid as an explosion; the changes seems to have taken around 30 million years, and some stages took 5 to 10 million years. The Cambrian explosion was a period of time where life evolved into numerous multifaceted organisms that developed into the vertebrates and human life as we know today.
Before humans ever roamed the Earth, many unique and strange life forms roamed the Earth such as dinosaurs and gymnosperms. They learned how to adapt to the changing and an unstable atmosphere of the Earth before it became what it is today. At the same time, the plants were also quite a discovery in the fossil record. The plants grew immensely and were quite plentiful for the herbivorous that roamed the Earth. However, there was one particular group of plants that eventually took over as the leading plant in the Cretaceous, which were angiosperms. Theses angiosperms are unique plants that later evolved along with sauropods and other creatures in the Cretaceous period. These plants were also known as flowering plants that were considered as
The most significant event of the Cretaceous era came at its end. Nearly 65 million years ago, the second most severe mass extinction in earth’s history occurred. This resulted in the loss of around 80% of species living at the time. Though nowhere near as severe as the end-Permian mass extinction, the end-Cretaceous extinction is the most well known mass extinction event. This is due to the violent event that caused it the extinction, as well as the chapter of earth’s history that it closed: the Dinosaurs. The Cretaceous Event ( often shortened to K-T event) Of the animals that were killed off were the flying reptiles (pterosaurs) and the last few mosasaurs and plesiosaurs, both early marine reptiles. Many mollusks and species of microscopic plankton were killed. Terrestrial plants suffered mass extinction as well. Almost 60% of terrestrial plants were lost. This led to high extinction rates among insect populations, especially insects that were highly specialized to feed on just a few types of plants had it the worst. It took approximately 9 million years for the global insect populations to recover from the Cretaceous extinction. Immediately after the extinction, the earth saw an explosion of short term species who respond well to fire, or other external disturbance. Evidence of the catastrophe comes from a thin rock layer deposited worldwide just after the impact. It is dominated by fossil plants whose descendants recover quickly after fires of other disturbances, such as Fire Weed in Alaska. The causes of the Cretaceous extinction are still being debated by paleontologists. Scientists agree that the main cause of the extinction was a...
seems like it happened so sudden, as geologic time goes, that almost all the dinosaurs
The Cretaceous period occurred between 144 and 65 million years ago. The K-T Extinction is an event that happened at the end of this period 65 million years ago. By the beginning of the Tertiary period eighty-five percent of all species disappeared, making it the second largest mass extinction event in geological history (“The End-Cretaceous (K-T) Extinction”, accessed 2000).