Signs-of-life

Signs of life

  Planet Earth was formed from a cloud of space rock, dust, and gas. For millions of years it was a mass of hot molten rock with a poisonous atmosphere. But eventually its crust cooled to the point where water could form vast oceans. The shallow fringes of these oceans were probably where life began, about 3.8 billion years ago , in a series of chemical reactions that assembled the first living cels

Early Earth

  For 500 million years ,Earth was a giant furnace of searingly hot rock, constantly bombarded by asteroids and meteorites. As each lump of space rock crashed into the plany, its energy was converted these impacts alos delivered. Chemical elements that were to be vital ingredients.

Chemical cauldron 

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   As the planet cooled huge volcanoes filled the air with .toxic gases. But they alos erupted vast quantities of water vapour that cooled and fallas rain. Filling the oceans. Lightning may have then triggered chemical reactions in thewater, forming complex molecules thet ware able to make copies of themselves the basis of life.

Farst cells

   The chemical processes that were essential to life needed to occur in a protected place. This was provided by a substance that could form tiny, tough walled bubbles. These were the first living cells microscopic packages of lifr=e giving chemicals that became bacteria, the simplest surviving life forms.

Energy from light


   Life needs energy.The fist cell used chemical energy, but about 3.5 billion years ago cells called cyanobacteria started using solar energy. They used it to make food from water and carbon dioxide, releasing vital oxygen. Similar cyanobactreia created these stromatolites on the coast of western Australia.

Deep heat

  It is likely that the first living cells developed in warm,coastal pools of salty water. However, life may have begun in the deep ocean, around hot volcanic vents that gush energy-rich chemicals from the ocean floor. Simple organisms that still live around these vents are probably vary like the earliest living cells