The mass extinction ended the Palaeozoic Era and as a result great change was brought to the Mesozoic Era. With as little as 5% of all living things surviving the extinction, it was now time to adapt or perish.
This period in time is arguably the greatest known time to humans, as this Era saw the dawn of the dinosaurs. It is broken up into 3 distinct periods: 1) Triassic Period (250 - 203 MYA) Sauropsids such as the Archosaurs dominate. First Cynodonts such as Cynognathus evolve. Marine reptiles also evolve. 2) Jurassic Period (203 - 135 MYA) Dinosaurs start to dominate the land and the first mammals evolve 3) Cretaceous Period (135 - 65 MYA) This is the age of the dinosaurs. Dinosaurs are at their peak in size, variety and numbers and as a result they dominate every continent. JURASSIC PERIODLife during the Jurassic period took a very different approach to anything seen before. Most crocodile groups and synapsids were wiped out at the end of the Triassic period. Only a few early mammals survived. Giant dinosaurs took over and dominated the land, this started what is referred to as the "rule of the dinosaurs". It was a time where long-necked Sauropods and grazing herbivores were prayed on by large carnivorous theropods.
In the air, pterosaurs evolved and the first birds evolved from small predatory dinosaurs. Aquatic life also evolved with important marine animals such as ammonites, belemnites and sharks and rays becoming greater in numbers. On land cycads, conifers and ginkgoes were all important plant groups throughout the Jurassic. |
TRIASSIC PERIODThis time in history is very significant. It is the start of the "Age of Reptiles" and the very fist time where animals of different families lived alongside each other. The synapsids (relatives of the mammals) were being driven to the point of extinction. Ruling reptiles dominated the land and the first crocodiles, pterosaurs and dinosaurs all came to rise at the end of the Triassic.
In the oceans, Triassic reefs were formed by modern type corals while new groups of molluscs appeared. Slower older marine life were replaced by modern sharks and sting rays. Dolphins were evolving from primitive creatures such as Ichthyosaur, some being as big as modern whales. Conifers dominated the landscape and evergreen forests became more important. CRETACEOUS PERIODThis period of time was certainly the age of the dinosaurs. Dinosaurs are at their peak in size, variety and numbers, dominating every continent and land mass. New groups of dinosaurs including the tyrannosaurs, duck billed hadrosaurs and horned dinosaurs developed and spread across the land masses. Birds evolved that resemble the modern kinds while snakes developed from lizard ancestors. A new group of insects including butterflies, ants and bees emerged, feeding on and pollinating the newly evolved flowering plants.
Marine invertebrates adapted a modern look during this period, with crabs and other modern crustaceans appearing. Fish species undertook great diversity and the relatives of modern carps, herrings, perches and eels were all born. The first marine turtle and aquatic birds also evolved. Flowering plants continued to grow, however were still evolving as they were just weeds that grew in disturbed lands. Later in the period, flowering plants such as willows and magnolias formed forests in which dinosaurs lived in. Ferns remained important as long as rainfall was high. |
THE END OF THE DINOSAURS "KT EXTINCTION"
Although not the biggest extinction in terms of the species lost, at the end of the crustaceous period 65 million years ago, saw the most famous mass extinction event of all time. All large land animals disappeared as did numerous invertebrate groups. All dinosaurs became extinct. In the oceans, plesiosaurs and mosasaurs died out, and many molluscs, plankton and bivalves suffered the same fate. In the air, some bird species survived but most experienced what the dinosaurs did.
Scientists are uncertain as to what could have caused this mass extinction. Some evidence indicated that a large asteroid struck the Earth at this time. Experts speculate that this could have caused a lot of dust and debris to be thrown into the air, blocking out the sun for years or even decades causing life to cease to exist. Another theory is perhaps this period of darkness and coldness caused plants and animals to die out. However the most likely cause is that the climate change in the crustaceous periods, may have cause some groups of living things to go into decline.
Scientists are uncertain as to what could have caused this mass extinction. Some evidence indicated that a large asteroid struck the Earth at this time. Experts speculate that this could have caused a lot of dust and debris to be thrown into the air, blocking out the sun for years or even decades causing life to cease to exist. Another theory is perhaps this period of darkness and coldness caused plants and animals to die out. However the most likely cause is that the climate change in the crustaceous periods, may have cause some groups of living things to go into decline.
(above) An artists impression of the common theory as to what caused the 'KT Extinction', ending the reign of the dinosaurs. Meteors hit the earth, causing total destruction and chaos, while wiping out the dinosaurs. The destructive winds thrash the seas upon land while T-Rex and a few Brachiosaurus' try to avoid extinction. Photo source: http://fineartamerica.com