Photosynthetic organisms appeared between three.2 and 2.four billion years in the past and started enriching the ambiance with oxygen. Life remained largely small and microscopic till about 580 million years ago, when advanced multicellular life arose, developed over time, and culminated in the Cambrian Explosion about 541 million years ago.
Some scientists believe that instead of a single organism being the last universal widespread ancestor, there have been populations of organisms exchanging genes by lateral gene switch. By the beginning of the Archean, the Earth had cooled significantly. Present life types could not have survived at Earth’s floor, as a result of the Archean atmosphere lacked oxygen hence had no ozone layer to dam ultraviolet light.
This article is about scientific evidence in regards to the history of Earth. Venkatraman Radhakrishnan was born on May 18, 1929 in Tondaripet, a suburb of Chennai.
Nevertheless, it is believed that primordial life … Read MoreRead More »