Precambrian to Devonian periods

 

About 4,600 million years ago the Earth was formed, the atmosphere consisted mainly of volcanic gases with little oxygen. It was a very hostile place for most forms of life.

Over the southern polar region one super large continent Gondwanaland was situated. The other continents were spread over the rest of the Earth. The crustal plates constantly moved, meaning the continents would be carried across the Earth's surface.

Primitive life forms started to emerge around 3,400 million years ago in warm shallow seas. The oxygen began to build up and created a shield of ozone. This protected living organisms from the sun's harmful rays, and also helped life sustain itself by providing an atmosphere.

About 470 million years ago the first Vertebrates began appearing, and the first land plants emerged around 400 million years ago (Devonian period) and the first animals around 30million years ago.

 

 

 

Some Examples of Precambrian to Devonian Trilobites

Name Size (Length) Family
Acadagnostus 8 mm Agnostidae
Phacops 4.5 cm Phacopidae
Olenellus 6 cm Olenellidae
Elrathia 2 cm Ptychopariidae

Some Examples of Devonian Fish

Name Size (Length) Family
Cephalaspis 22 cm Cephalaspidae
Cheirolepis 17 cm Cheirolepidae
Pterichthyodes 15 cm Asterolepidae
Cheiracanthus 30 cm Acanthodidae
Botheriolepis 40 cm Bothriolepidae
Coccosteus 35 cm Coccosteidae
Pteraspis 25 cm Pteraspidae
Rhamphodopsis 15 cm Ptyctoontidae

Carboniferous to Permian Periods

363 - 290 million years ago was the Carboniferous period. The name of this period comes from the thick carbon rich layers that now have turned into coal, produced by tropical forests repeatedly being drowned by shallow seas. This is the period when the first dense plant cover formed on Earth, around the equatorial continents. The early part of this period saw the first reptiles appearing.

Towards the end of the Carboniferous times two continents Laurasia and Gondwanaland collided, thus resulting in a large land mass named Pangaea. The southern hemisphere was covered by Glaciers during the Permian period. Ice held much of the World's water and large areas in the northern hemisphere experienced a drop in sea level. Traveling away from the poles deserts predominated and hot dry climates resulted in a great mass extinction of life.

Some Examples of Carboniferous and Permian Trees

Name Size (Length) Family
Pecopteris 4 m Marattiaceae
Paripteris 5 m Medullosaceae
Mariopteris 5 m Unknown
Medullosa 5 m Medullosaceae
Lepidodendron 30 m Lepidodendraceae
Cordaites 10 m Cordaitacea
Glossopteris 8 m Glossopteridaceae
Alethopteris 5 m Medullosaceae

Triassic Period

Around 245 - 208 million years ago was the Triassic Period, the is know as the beginning of the Dinosaurs. The land mass during this period was experiencing extremes of climate filled with lush green areas around the cost with lakes and rivers. The inner land contained huge deserts. The plant life was limited only non flowing plants lived. Dinosaurs first appeared around 230 millions years ago this was the late Triassic period. The earliest know Dinosaurs were the flesh eating carnivorous, Herrerasaurus and Staurikosaurus. The earliest plant eating Dinosaurs appeared in the late Triassic period for example the Plateosaurus and Technosaurus. By the end of the Triassic Period Dinosaurs dominated the land mass.

 

 

Triassic Dinosaurs

Name Size (Length)  
Melanorosaurus 12.2 m A melanorosaurid
Mussaurus 2-3 m A plateosaurid
Herrerasaurus 3 m A herrerasaurid
Pisanosaurus 90 cm Aprimitive ornithischian
Plateosaurus 7.9 m A plateosaurid
Technosaurus 1 m A primitive ornithischian
Coelophysis 3 m A coelophysid
Staurikosaurus 2 m A staurikosaurid

Plateosaurus

Coelophysis

Herrerasaurus