PALAEOZAIC ERA (pronounced as: pall-ay-oh-zoh-ick)
PRECAMBRIAN
(more than 4600 Million years ago)
Which includes the Proterozoic eon and the Archean eon spanning about 2000years each, that single celled organisms like blue-green algae and bacteria first appeared. Towards the end of the archean eon the first multicellular, soft bodied animals began to emerge such as jellyfish, sea pens, and worms.
CAMBRIAN
(more than 570 Million years ago)
The cambrian period of the Paleozoic era was characterized by adverse eruption of life in the seas. Life had not yet evolved on land.
- Trilobites (lengths up to 2 feet)- Green and Red Algae
- Gastropods
- Segmented worms
- Corals
- One-celled animals
- Shellfishes
ORDOVICIAN
(more than 500 Million years ago)
During the early Ordovican period the first vertebrate fish have been found. Graptolites and corals also flourished. The first nautiloids appeared.
- Radiolarians- Starfish
- Coral
- Jelly fish
SILURIAN
(more than 436 Million years ago)
The appearance of the first plants on land. Algae is an abundance in the seas, as well as marine invertebrates
- Spider- Sponge
- Eurypterid (giant sea scorpions)
DEVONIAN
(more than 436 Million years ago)
The first amphibians appeared.
As the Palezoic era continues, we see the first appearance of land creatures, such:
- mites
- ammonites
- crabs
- ground insects
- spiders
Towards the end of the Devonian period, amphibians began to colonize the land. The first ferns also grew and true seed plants eventually emerged. The Devonian period also saw many new groups of fish evolve.
- Placoderm- Ichthyostega
CARBONIFEROUS
(more than 350 Million years ago)
Great swamp forests covered the land. Insects and spiders appeared.
During this period snakes emerged as well as salamander type amphibians. Large amphibians roamed the lands now and fresh water fish and shark were now in abundance. Near the end of this period the first reptiles appeared on land.
- Insect- Pleuracanth
PERMIAN
(more than 270 Million years ago)
The first sailback reptiles.
The Permian Period, at the end of the Palezoic era, marked a great changes in the Earth's climate and appearance. Trilobites and other marine groups became extinct, and the group of small reptiles (diapsids) abound. These were the ancestors to most modern reptiles and the ruling dinosaurs as well as pterosaurs and crocodiles. Thriving also, were the early ancestors to mammals (synapdia), which included some large reptiles such as dimetrodon. Reptiles grew to dominance among vertebrates, because their special adaptations enable them to flourish in the drier climate. The warm zone spread in the northern hemisphere, where extensive dry desert appeared. The rock formed at that time are stained red by iron oxides, the result of intense heating by the sun of a surface devoid of vegetation cover. The old types of plants and animals dried out.
- Dimetrodon- Eryops
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MEROZAIC ERA (pronounced as: mezo-zay-ick)
TRIASSIC
(more than 225 Million years ago)
All the continents were joined together in one huge landmass. Climate was hot and dry but with rain seasons. The first Tree Ferns and Coniferous trees were starting to appear.
As the Mesozoic era begins, we see the rise of the what is known as the dinosaurs. Pterosaurs (flying reptiles) also made their first appearance here as well as :
- Coelophosis- Crocodiles
- Diplodocus
- Euskelosaurus
- Frogs
- Mammals
- Turtles
During the late Triassic period, many small mammals also arose.
JURASSIC
(more than180 Million years ago)
The earliest known birds appeared (e.g. Archaeopteryx)
The climate change as the huge continent was breaking up.
There were now forests of cycads, conifersand gingko.
The Jurassic period began the Age of Ruling Reptiles. During this period, vegetation was greener and more lush.
By late Jurassic, huge dinosaurs walked the lands such as:
- Archaeopteryx
- Allosaurus- Brachiosaurus
- Ceratosaurus
- Rhamphorhynchus
- Stegosaurus
- Brachiosaurus
- Tyrannosaurus
CRETACEOUS
(more than 135 Million years ago)
The Cretaceous period of the Mesozoic era may have seen more dinosaurs than ever before, like the:
- Ankylosaurus (heavyly armoured shell)
- Centrosaurus
- Duckbilled Parasaurolophus
- Muttaburrasaurus
- Quetsalcoatlus- Triceratops (3 horned dinosaurs)
- Tyrannosaurus (carnivorus and savage)
Birds became increasingly numerous and flowering plants were emerging. By the end of the Cretaceous period, all large and small ruling reptiles, except the crocodile went extinct.
The continents has separated and each has its own flora and fauna. However, Australia and Antarctica were still joined together. There were now flowering plants such as magnolias and waterlilies.
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CENOZOIC (pronounced as: sen-oh-zoh-ick)during many different species of animals appeared. This era ended with the Great Ice Age and the appearance of the first humans
Related topic:
ICE AGES
TERTIARY
(more than 63 Million years ago)
Part of the Cenozoic era, the Tertiary period is divided into five epochs:
• Paleocene
• Eocene
• Oligocene
• Miocene
• Pilocene
During this time mammals diversified quickly. Some examples are marsupials, insectivores, bears, hynas, dogs, cats, seals, walruses, whales, dolphins, early mastodons, hoofed mammals, horses, rhinoceroses, hippopotamuses, oreodonts, rabbits, monkeys, lemurs, apes, and humans (Australopithecus).
- Mammoth- Sabre-Toothed Tiger
- Eohippus
QUATERNARY
(recent to more than 8 Million years ago)
Quaternary period was the second and last period of the Cenozoic era. This period is divided into two (2) epochs:
• Pleistocene
• Holocene
Mammoths roamed the lands. Cattle, deer, and of course, Homo Habilis, Homo Erectus, and Homo sapiens.
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