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- The Dinosaur Era
- Did Dinosaurs Live In The Antarctic?
- The Giants Within The Dinosaur Age
- Ruling The Skies
- Within The Seas

When dinosaurs made their first appearance on Earth which was about 230 years ago, the world was a lot different than what it is today. There wasn’t too many of the animal groups that we recognize today. There weren’t any birds, mammals, or lizards. However, there were some lizard-like reptiles.

The difference was also recognizable in the plant area. There wasn’t any flowering plants or the common shrubs and trees that we see in this day in age. The trees looked very different and were set apart from what we’re able to see today. However, some trees were relatives of the modern podocarps and modern-day ferns. Also, there wasn’t any grass. Low ground would have been covered by mosses and ferns.

The Triassic world was very unique for another reason. About 20 million years ago, before the existence of the first dinosaurs, the biggest extinction in history had occurred. Over 90% of animal species and plant life had died out at this time. Even during the Late Triassic, the world was still in recovery. There wasn’t an existence of the usual assortment of life normally found on earth.

It took over 10 million years before ecosystems were able to recover. Animals and complex ecosystems took even longer than 10 million years in order to recover. A majority of the dominant land animals that were around when dinosaurs evolved were products of long and established lines of descent.

The Late Triassic was a very ground-breaking time within the animal kingdom. By the end of this period, not only had dinosaurs appeared, but, also pterosaurs (flying reptiles), the first turtles and crocodiles, various kinds of marine reptiles, and the earliest true mammals had also made an appearance. 220 million years ago, which was towards the end of the Triassic period, there was yet another extinction. This extinction cleared out many of the non-dinosaurs including the dicynodonts, such as Placerias and primitive archosaurs such as Postosuchus. After this is when dinosaurs began to radiate and diversify.

It was often understood that the reasons that dinosaurs had survived was due to their greater speed and agility. It is now thought that they were simply lucky as they were not hit as hard by the extinction that had occurred. After the extinction towards the end of the Triassic period, dinosaurs were the largest land animals that remained.

At the end of the Cretaceous period, which was 65 million years ago, all the dinosaurs had died out. There has been a variety of ideas put out to explain why dinosaurs died out. The two most likely assumptions are that their habitat slowly changed, and that a meteor impact triggered their extinction.

Unfortunately, while these hypotheses are reasonable, and they can both explain how many animals became extinct, neither of them can explain why certain animals died out while some were able to survive. It is assumed that the dinosaurs all became extinct at the same time all over the world. The truth is that we only have high resolution data for North America. Within other parts of the world, there is either no terrestrial record or we don’t have good enough age resolution.