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Geologists use trilobites to tell the age of rocks? When a geologist uncovers a trilobite, he finds out what geological time period it's from, and this gives him a good estimate of the age of the surrounding rock layers that the trilobite was found in.
IN THE BEGINNING
Nobody knows for sure when or how life began, however some scientists believe it may have begun some 3.5 to 4 billion years ago in the form of bacteria.This bacteria is called Cyanobacteria,or blue-green algae.These bacteria lived in large masses that formed what's known as Stromatolites.Stromatolites are the oldest known fossils.Cyanobacteria was responsible for the formation of much of the oxygen in the early atmosphere thru a process called photosynthesis.Photosynthesis is a biochemical process in which plants, algae, and some bacteria harness the energy of light to produce food.Nearly all living things depend on energy produced from photosynthesis for their nourishment, making it vital to life on Earth.
THE PROTEROZOIC ERA
(2.5 billion years ago)
Cyanobacterias
(Chroococcalean)
(Palaeolyngbya)
Stromatolite
(Collenia sp.)
Segmented worm
(Windermeria aitkeni)
(An early relative of the trilobite)
Naraoia
(Naraoia compacta)
(An early relative of the trilobite
thought by some to be a soft-bodied trilobite)
Photo copyright©1996-1997
The Peabody Museum Of Natural History
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