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 The Cretaceous period was between 127-65 million years ago. The continental drift continued at a fast pace which was accompanied by many volcanic activities. The supercontinent separation of Laurasia and Gondwana was completed. The world began their modern-day look as animals and plant life flourished.
This was the time when the first placental mammals appeared. It was a period where the rise and extinction of the toothed birds occurred. Fossilized remains shows that birds resembling today’s common pelicans, flamingos, ibises and many more were from the period of cretaceous.
 It was a time when prehistoric flowering plant such as angiosperm continued to develop. Many other flowering plants like sassafras, credneria, magnolia, ficus, viburnum rapidly outnumbered ferns, horsetails, trees like conifers and gingkos, and cycads, hence, changing the environment vastly.
During the early stages of Cretaceous, temperatures were warn, seasonality was low, and global sea levels were high (there was no polar ice). Towards the end, there were severe climate change, lowered sea levels, and greater volcanic activities.
About 65 million years ago, Cretaceous period ended. It was a time where a mass extinction wiped out all dinosaurs except for birds and many other animals and half of all invertebrate marine organisms. There has been much explanation to the reason why this wiped out occur. The two most probable are:
Gradualistic Hypothesis (the habitat loss and regression hypothesis) - The gradualistic hypothesis suggested that climate changes of cooler weather and fall in the sea level reducing dinosaurian and shallow water marine animal habitats causing extinction.
Catastrophic Hypothesis (the extraterrestrial impact hypothesis) – There is good geophysical evidence for the incidence of an asteroid impact at the end of the Cretaceous. This impact would have triggered a nuclear winter scenario that would have caused the extinction.
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