How long for Nature to take over the earth?

Answer 1

Earth was formed about 4.54 billion years ago. We simply do not know when life actually began.

Officially the oldest fossils we have found date back to 3.5 billion years. These were single celled microbes. However many scientist have argued that these were already quite sophisticated. They argue that earlier life forms must have existed. They are believed to have evolved from prokaryotes which are simple celled microbes that do not have a cell nucleus.

Multi-celled animals were thought to have emerged about 600 million years ago. These Ediacarans were initially soft bodied and have been found in many locations though out the world.

During the Cambrian Period(542 - 288Ma) Earth saw a huge increase in diversity in life, known as the Cambrian Explosion. Except simple animals such as bacteria, fungi, algae and lichens all this life had been confined to the oceans, seas and lakes. It was during the Cambrian that the first evidence for animals venturing on the land appeared. Possible Tracks from arthropods (the phylum of life that includes centipede's, insects, scorpions and Spiders) have been found from this date.

Land plants seemed to have evolved about 470 million years ago during the Ordovician Period.

Land vertebrates such as amphibians did not evolve until the Devonian Period(416 - 359Ma) but they were still restricted to the waters edge because the need to keep the skin wet and also they lay eggs in water.

By the Carboniferous Period(359 - 299Ma) arthropods were fully established. Also this is the 1st evidence of reptiles in the fossil record. For the 1st time vertebrates had broken there bonds with water.