Darwin’s thinking was greatly influenced by Charles Lyell and his “Principles of Geology,” of which he carried a copy during his voyage on the “Beagle”. In addition to collecting biological specimens contemporary to his time, Darwin also used fossils and geological observations to support his theories. 

• Geology of The Voyage of the Beagle, Charles Darwin

_{Photo: Live filamentous cyanobacteria from the North Sea. Micro fossils dated 3,500,000,000 years ago have a similar morphology to these organisms (Homayoun Bagheri, 2008).}

_{Graphics are reproduced with permission from John van Wyhe ed., The complete Work of Charles Darwin Online.}