Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Source:google.com.pk
The Earth is a little over 4.5 billion years old, its oldest materials being 4.3 billion-year-old zircon crystals. Its earliest times were geologically violent, and it suffered constant bombardment from meteorites. When this ended, the Earth cooled and its surface solidified to a crust - the first solid rocks. There were no continents as yet, just a global ocean peppered with small islands. Erosion, sedimentation and volcanic activity - possibly assisted by more meteor impacts - eventually created small proto-continents which grew until they reached roughly their current size 2.5 billion years ago. The continents have since repeatedly collided and been torn apart, so maps of Earth in the distant past are quite different to today's.
The history of life on Earth began about 3.8 billion years ago, initially with single-celled prokaryotic cells, such as bacteria. Multicellular life evolved over a billion years later and it's only in the last 570 million years that the kind of life forms we are familiar with began to evolve, starting with arthropods, followed by fish 530 million years ago (Ma), land plants 475Ma and forests 385Ma. Mammals didn't evolve until 200Ma and our own species, Homo sapiens, only 200,000 years ago. So humans have been around for a mere 0.004% of the Earth's history.
The Earth is a little over 4.5 billion years old, its oldest materials being 4.3 billion-year-old zircon crystals. Its earliest times were geologically violent, and it suffered constant bombardment from meteorites. When this ended, the Earth cooled and its surface solidified to a crust - the first solid rocks. There were no continents as yet, just a global ocean peppered with small islands. Erosion, sedimentation and volcanic activity - possibly assisted by more meteor impacts - eventually created small proto-continents which grew until they reached roughly their current size 2.5 billion years ago. The continents have since repeatedly collided and been torn apart, so maps of Earth in the distant past are quite different to today's.
The history of life on Earth began about 3.8 billion years ago, initially with single-celled prokaryotic cells, such as bacteria. Multicellular life evolved over a billion years later and it's only in the last 570 million years that the kind of life forms we are familiar with began to evolve, starting with arthropods, followed by fish 530 million years ago (Ma), land plants 475Ma and forests 385Ma. Mammals didn't evolve until 200Ma and our own species, Homo sapiens, only 200,000 years ago. So humans have been around for a mere 0.004% of the Earth's history.
The Cretaceous ended with the most famous mass extinction in history - the one that killed the dinosaurs. Prior to that, it was a warm period with no ice caps at the poles. Much of what we now know as dry land - such as southern England and the midwest of the USA - was underwater, since sea levels reached their highest ever during this time. The Atlantic Ocean grew much wider as North and South America drew apart from Europe and Africa. The Indian Ocean was formed at this time, and the island that was India began its journey north towards Asia.
The classic dinosaur paintings are from the Cretaceous, in large part because this was when the famed Tyrannosaurus Rex lived. Note how in the background a volcano erupts, adding to the drama of the scene (it makes it look more "prehistoric"), but supported by the fact that enormous amounts of volcanism was occurring in the Sierra Nevada from the subduction zone that lay off the west coast of North America in the Mesozoic. However, such a scene would not be appropriate, for example, in Europe or the Middle East, where there were no Cretaceous subduction zones but plentiful Tyrannosaurus Rex and other dinosaurs. The late Cretaceous was one of the warmest climates the Earth has seen, which undoubtedly promoted growth of very large creatures (above).
However, at the end of the Cretaceous, 65 m.y., saw a catastrophic impact of an asteroid in the Yucatan Peninsula (eastern Mexico), which generated such dust in the atmosphere that sunlight was reduced, and the temperature plummeted. This caused almost all dinosaurs to become extinct (although some branches survived as birds). The colder climate of the Cenozoic was perfect for mammals, who thrived and came to dominate the Earth in the Cenozoic.
In the later part of the Cenozoic, in the Quaternary period, continental ice sheets covered many parts of the continents, including the Upper Midwest. The latest of these glacial stages, which ended about 10,000 years ago, is called the Wisconsin Glaciation because the evidence is so well preserved in our state
The classic dinosaur paintings are from the Cretaceous, in large part because this was when the famed Tyrannosaurus Rex lived. Note how in the background a volcano erupts, adding to the drama of the scene (it makes it look more "prehistoric"), but supported by the fact that enormous amounts of volcanism was occurring in the Sierra Nevada from the subduction zone that lay off the west coast of North America in the Mesozoic. However, such a scene would not be appropriate, for example, in Europe or the Middle East, where there were no Cretaceous subduction zones but plentiful Tyrannosaurus Rex and other dinosaurs. The late Cretaceous was one of the warmest climates the Earth has seen, which undoubtedly promoted growth of very large creatures (above).
However, at the end of the Cretaceous, 65 m.y., saw a catastrophic impact of an asteroid in the Yucatan Peninsula (eastern Mexico), which generated such dust in the atmosphere that sunlight was reduced, and the temperature plummeted. This caused almost all dinosaurs to become extinct (although some branches survived as birds). The colder climate of the Cenozoic was perfect for mammals, who thrived and came to dominate the Earth in the Cenozoic.
In the later part of the Cenozoic, in the Quaternary period, continental ice sheets covered many parts of the continents, including the Upper Midwest. The latest of these glacial stages, which ended about 10,000 years ago, is called the Wisconsin Glaciation because the evidence is so well preserved in our state
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
Islamic Quotes About Life Inspirational Islamic Quotes In Urdu About Love In English About Life Tumblr Wallpapers In Arabic Images On Marriage About Women
No comments:
Post a Comment