PENNSYLVANIAN

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Paleo-Geography

• Pangea supercontinent forms as all continents collide - significant mountain building worldwide
• High sea levels form broad, shallow continental seas
  and vast coal swamps
• Climate hot & humid but glaciated at the poles
• Oxygen level 40% above today - abundant wildfires
• Much of the world's coal formed in the Carboniferous
  

Life

• Amphibious tetrapods (below) continue to flourish
• Amniote egg appears which allows certain tetrapods
  (below right) to live on land full-time
• Reptiles appear and diversify wildly; first ancestor of mammals appears also
• Giant dragonflies, cockroaches and myriapods continue
  to flourish in the high humidity and oxygen
• Giant, primitive horsetail, club moss and fern 'trees'
  dominate. Dense layers of dead wood form coal beds.
• Sea life dominated by sharks, corals, bryozoa, brachiopods, ammonoids, crinoids and foraminifera
  

  
  Eryops (left), a huge   6-foot salamander,   dominated the coal   swamps, but still had   to lay eggs in water

            (Image:
     Jeolojik Devirler)

Hylonomus (near right), ealiest known Sauropsid, and Archaeothyris (far right), ealiest known Synapsid, layed their eggs on land. In so doing, they became the ancestor of every reptile, bird and mammal on earth.

               (Image: Dinosaurier von A bis Z)

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