Cretaceous period is the last era, the final Mesozoic era.He replaced the Jurassic, geologists estimated, somewhere around 145 million years ago and lasted for about eighty million years, after which the beginning of the Tertiary period is different, the Cenozoic, the era - "the era of a new life."The name of this rather long stage of development of the Earth has received in connection with the fact that she left us a legacy of powerful deposits of chalk, marl and sand.Although during these eighty million years on Earth occur any disaster on a planetary scale, and hence the extinction of a large number of plant and animal species, yet the movement of tectonic plates, the change in global sea level and climate change has made the amendments to the process of evolution of living beings.
Cretaceous period usually divided into sub-sections: the lower and upper Cretaceous.To understand how life evolved in the seas, on land and in the air space of time, you should briefly describe the passage, since the Jurassic stage tectonic orogenic processes.In the lower cretaceous era Gondwana and Laurasia kept separate from each other.Exactly the same process occurred with Africa and South America.Thus, the Atlantic Ocean is becoming increasingly familiar to us now outline.But in eastern Gondwana it merged with Laurasia.Australia was where it resides, and now, but the water rose only a third of the present area.
Upper Cretaceous is characterized by the fact that in the Northern Hemisphere ocean levels began to rise, and large areas of Eastern Europe, Western Siberia, the whole of Arabia, and almost all modern Canada were under water.However, by the end of the Cretaceous period the Earth began to resemble its shape modern globe.
in the Cretaceous period and the climate has changed.It is, of course, was much warmer than modern.Space in Europe today covered a tropical jungle.However, at high latitudes have alternated seasons, and in winter snow fell.Such climate change gave rise to that, along with spore and gymnosperms appeared zakrytosemennye plants.Such trees are beech, birch, ash and walnut, appeared in the era of the Cretaceous, have survived to this day unchanged.Land acquired the first flowering plants - first magnolia, then rose.In flowering it had the advantage that their pollen is carried not only wind but also insects.Fruit plants, putting the seed in the fruit spread via animal eats fruit.Thus, fruit and flowering plants flooded the entire planet.
flora changes in the Cretaceous period, and led to the emergence of new species of fauna.The air became the first butterfly to flit and fly bee feeding on the nectar of flowers.The dominance of the sea comes foraminifera, dead and crumbled shells of which gave the name of all this geological time.Along with them there are other mollusks, ammonites.The kingdom is dominated by fish sharks and bony fish.Animals Mesozoic era - especially the dinosaurs and early mammals - safely "moved" from the Jurassic period in the Cretaceous.But for some chalk dead end birdlike dinosaurs extinct, such as archeopteryx.But there are birds - the ancestors of modern geese, shorebirds, ducks and loons.
Mesozoic Era (Jurassic period in particular), according to the famous film, known as the era of the dinosaurs.In general, the rule of ancient dinosaurs preserved in chalk.But during the last period of Stegosaurus disappears from the face of the earth, and it occupies a niche Tyrannosaurus.The rich flora contributed to the emergence of new types of herbivorous dinosaurs: triceratops, Iguanodon ankylosaur and others.We can say that in the era of the Cretaceous dinosaur species diversity peaked.And at this time, hiding from the giants in their burrows, lives and future rulers of the Earth - mammals.These animals, like rats, rarely reach one meter in length, most of the species were small egglayers, testaceous or marsupial animal, weighing up to 500 grams.But behind them was the future.
