Youtor
One Billion Years of Earths Evolution in 45 Seconds
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=Atorchensy0
Important EvEnts In thE Earth’s hIstory • 4600 mya (million years ago) – Planet Earth formed. Dust left over from the • birth of the sun clumped together to form planet Earth. The other planets in our • solar system were also formed in this way at about the same time. • 4500 mya – Earth’s core and crust formed. Dense metals sank to the centre of the Earth and • formed the core, while the outside layer cooled and solidified to form the Earth’s crust. • 4400 mya – The Earth’s first oceans formed. Water vapour was released into the Earth’s • atmosphere by volcanism. It then cooled, fell back down as rain, and formed the Earth’s first oceans. • Some water may also have been brought to Earth by comets and asteroids. • 3850 mya – The first life appeared on Earth. It was very simple single-celled organisms. Exactly • how life first arose is a mystery. • 1500 mya – Oxygen began to accumulate in the Earth’s atmosphere. Oxygen is made by • cyanobacteria (blue-green algae) as a product of photosynthesis. For 2,200 million years this oxygen • was removed from the atmosphere as it reacted with iron, sank to the bottom of the sea and became • trapped in rock layers. 1,500 million years ago the free iron ran out and oxygen began to be released • into the atmosphere. • 700 mya – The first animals evolved. These were simple single-celled animals. • 530 mya – The first vertebrates (fish) evolved. • 400 mya – The first land plants evolved. Oxygen in the atmosphere reacted to form ozone, which • formed a layer. This served as a protective barrier to the harmful rays coming from space and which • allowed plants to colonise the land. • 350 mya – The first land vertebrates evolved. With plants present on the land to provide a food • source, animals rapidly followed. The first to venture onto the land were primitive amphibians, and • reptiles evolved soon afterwards. • 225 mya – The first dinosaurs evolved from lizards. • 65 mya – The dinosaurs went extinct. The dinosaurs, and many other species with them, were • wiped out by the after-effects of a meteorite impact, or perhaps several impacts. The impact(s) set off • chains of earthquakes, tsunamis and volcanic eruptions, which threw lots of dust and acid into the • atmosphere, creating an impact winter. The dust blocked out the sunlight so plants could no longer • photosynthesise, and food chains collapsed. After the extinction of the dinosaurs, • mammals evolved rapidly and filled the evolutionary niches they left behind. • 130,000 years ago (0.13 mya) – Modern humans evolved. Homo sapiens • evolved in Africa from earlier humans. They left Africa around 35,000 years ago and • spread around the globe. Human evolution is still pretty mysterious, due to gaps in the • fossil record. • Topics covered in this channel; • Science news, • astronomy updates, • news about latest inventions, • latest science related updates, • NASA's missions, • space related stuffs, • and many more. • Our official facebook page: • / scientificwonk
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