#EARTH DURING THE CRETACEOUS PERIOD FULL#

However, they are nothing compared with what swims around in these oceans, they are undoubtedly the meanest collection of predators ever assembled by mother nature quite simply, this is HellвЂ™s Aquarium. This is the Cretaceous, on land walk some of the most fearsome landlubbing predators ever known, giant predatory dinosaurs such as tyrannosaurus and its even bigger South American relative giganotosaurus, the largest land predator of all time. But imagine diving into an ocean filled with not just one ferocious predator, but several, and not just belonging to one group of animals, but again several. In my two previous hubs I profiled two prehistoric seas dominated by just one super predator, a huge marine reptile and the biggest shark that ever lived. Flightless and unable to walk properly, Hesperornis spent most of its time at sea hunting fish and squid, coming on to land to mate and lay eggs.Дiet: A marine predator eating fish, ammonites and belemnites.Д®vidence: Thus far fossils have only been found in North America.ДЇact: While birds might be famous for having tiny brains, the brains of Hesperornis were small even by bird standards. One of the so called 'toothed birds' commonly found in the Cretaceous of North America and elsewhere. Nobu Tamura, CC-BY-1.2, via Wikimedia Commons Hesperornis The Upper Cretaceous Period has been referred to as a 'greenhouse world' and much of the predictions of what could happen to the environment in the future has been based on our understanding of what the world was like during this time.Modern birds do not possess teeth, although genetic experiments carried out on hens, have shown that they still possess the genes required to evolve teeth. These higher temperatures were as a result of two things: a significantly different layout of the continents that allowed for improved heat circulation in the oceans and a much higher level of carbon dioxide in the atmosphere at the time, four times higher than today. The Mean Surface Temperature across the Earth during this time has been estimated as being 11В°c warmer than now. The most extreme was the earth's climate in the Upper Cretaceous Period (86 million years ago), which was far warmer than today. Higher temperatures on earth are not unknown. Over a period of millions of years, as volcanic activity reduced, carbon dioxide levels and global temperatures gradually dropped, eventually leading to the formation of the polar ice caps around 20 million years ago. The huge amount of carbon dioxide created from this volcanic activity is believed to be the main reason for the Cretaceous Period being so warm. This huge amount of volcanic activity went on throughout the Jurassic and Cretaceous Periods, from 125 million years ago until 75 million years ago. The Western Pacific also has thousands of volcanos.

#EARTH DURING THE CRETACEOUS PERIOD FULL#

In the middle of the Atlantic Ocean is the Mid Atlantic Ridge: a long chain of extinct volcanos that stretches the full length of the American continent. New oceans were being created and all these oceans had volcanically active ocean ridges.Д®vidence of this massive volcanic activity can be seen in the oceans of our world today. The high levels of carbon dioxide in the atmosphere were due to volcanic activity and the break up of the huge Pangean land mass into different continents during the Jurassic and Early Cretaceous Period. Much of the UK and Western Europe was a large, shallow tropical sea: only isolated areas in the Highlands of Scotland and Wales were land. Global sea levels were over 200 metres higher than they are today. Large deciduous forests covered the North and South Poles and there were no polar ice caps. North America, Europe and Asia were a single land mass to the North, whilst Africa, South America, Antarctica and Australia were a second land mass to the South. Whilst many of the continents had already started to arrange themselves in the way we see them today, the land mass was divided into Northern and Southern continents with a vast sea across the Equator. The world during the Upper Cretaceous Period looked very different than it does today. To answer this we need to understand the world during this Period. This fact has lead a number of people to question whether todays temperature increase is not simply part of the natural climate cycle. The Upper Cretaceous Period was much warmer than today. Why was the upper Cretaceous period so warm?Дoes this prove Global Warming is part of a natural climate cycle?

Earth during the cretaceous period