The First Life on Earth.

The first life on earth appeared not on the land but in the oceans. The atmosphere was still thin, so there wasn’t enough oxygen in the air to sustain life. Ultraviolet radiation, lethal to life forms, was also still at dangerous levels. Neither problem affected life underwater.

Life probably arose 3800 million years ago, although the earliest fossil evidence found was 3500 million years old. No one knows how life probably began but scientists think warm water, and shallow pools at the edges of the oceans would have been ideal for the formation of chemicals that would eventually be the founding blocks of life. The vital chemical reactions would have been triggered as a result of a meteor shock or impact.

The earliest life forms were of the very simple kinds- bacteria. The oldest fossils are known as ‘stromatolites‘, bands of blue-green algae that grew in shallow water.

It was another 2500 years before complex life forms, or seaweed finally appeared. The first known animals existed around 580 million years ago. Fossils of soft-bodied sea creatures, among them sea pens, jellyfish, worms and crab-like animals, found in the Ediacaran Hills, Australia give evidence of life in the Precambrian.

The largest and fiercest of all living creatures in the Cambrian creatures was the ‘Anomalocaris’ a 60-centimetre long ‘odd shrimp’. It had a clock-like body, two large eyes on stalks, and pair of pincer-like arms. Other smaller marine life forms had defences to repel such giant predators. ‘Hallucigenia‘ which moved about on the sea bed on seven pairs of stilts, had an additional row of spines on its neck.

One of the Burgess Shale animals may be of particular significance to us, as humans. It is named Pikaia, after Mount Pika. This small worm-like creature had a stiffening rod backbone running down its body, with the cells arranged in V-shaped segments similar to the ones in modern fish. Pikaia may have been ane early ancestor of vertebrates to which fish, reptiles, birds and mammals like us belong.

The emergence of life from water asserts its dominance as the prime element for life. It is interesting to discover and read about animals that may have formed the origin of our existence as vertebrates and mammals. The life that began 3800 years ago in the oceans has now evolved to become the world as we known it today!


Author: Digital Onca

Digital Onca is a blog that documents the concepts of Digital Marketing and Public Relations. Digital Onca is the effort to stay with the times, understand more deeply, more closely the working of a digital space that is steadfastly emerging around us.

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