Cretaceous Period 146 to 66 mya
The Cretaceous Period, named for the chalk often contained in its rocks. still ruled the land. continued to evolve.
During this period new plants and animals appeared possessing new methods of reproduction. were flying, plants had and had appeared by this time.
The end of this period saw the extinction of the dinosaurs.
The break up of Pangaea became more obvious. The Tethys Sea opened up between Laurasia in the north and Gondwana in the south. Within Gondwana, South America was still joined to Africa and Antarctica (EAn).
With continents separating instead of colliding there were few high mountains and the continents sank down below warm shallow seas. This was the Cretaceous period, the age of chalk. The continents moved towards their present positions.
The most dramatic movement was of India (Ind). Watch how it shoots northwards during the next 100 million years!
As Pangaea broke apart and spread the climate of many fragments became less tropical.
could not grow or spread very quickly. They needed the wind to carry the pollen to the egg. Also it took over a year for the plant to store enough food in the seed to make sure the baby plant could grow.
About 200 mya a new kind of plant evolved. It attracted insects using colored flowers, and gave them sugary nectar to eat. and other animals evolved to eat the nectar offered by the flowers. While eating they picked up pollen on their bodies which they carried to other flowers.
The pollen itself was different. It carried two sperm. One fertilized the egg. The second fertilized the flower which then grew rapidly into a fruit. The seed used this for food. These flowering plants could grow and make fruits in just a few weeks, so they spread much faster than the seed plants. Fruits, berries and nuts appeared, so there was lots of new food for animals. New animals evolved to eat the fruit. The land became filled with the color and scent of many beautiful blooms. The hardwood trees and other plants of the tropical rain forest, now being so rapidly destroyed by people, are of this kind.
Image courtesy Uwe H. Friese
were evolving new methods of . One method involved insects living together and helping to look after their brothers and sisters instead of reproducing themselves. Social colonies of bees, ants and wasps evolved in this way.
Image of bee courtesy of Jon Sullivan
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