1 Where did the dinosaur line come from (what were its ancestors) and when did t
ID: 295265 • Letter: 1
Question
1 Where did the dinosaur line come from (what were its ancestors) and when did this line diverge from ancestral reptiles?
2. What are the two main groups of dinosaurs and how are they distinguished from one another?
3. What other sorts of reptiles lived at the same time as the dinosaurs and what was their mode of life?
4. What ended the dinosaur lineage and the lines of many other species. including many reptiles lines? What was the triggering event and what were the global consequences?
5. Select a dinosaur group and write a short paragraph about its characteristics, what main group it belongs to, its age, and mode of life?
Explanation / Answer
1. As per the research, Dinosaurs evolved within a single lineage of archosaurs in the Ladinian age. It is said that the first known dinosaurs were bipedal predators. Reptilia is identical to Sauropsida. Around the end of the Carboniferous, when the terrestrial reptiliomorph labyrinthodonts were still present, It is believed that the synapsids evolved the first fully terrestrial large vertebrates such as Edaphosaurus.
2. The two main groups are: the Ornithischia and the Saurischia.
Ornithischia: They had bird shaped structure. They had a very similar hip structure to living birds.
Saurischia: They had Lizard shaped structure. They had the more primitive hip structure.
They can be visibly differentiated by observing the the orientation of the pubis.
3. There were so many reptiles who lived with dinosaurs during that era such as Ichthyosaurs, Plesiosaurs and Mosasaurs. They were meat-eating reptiles and depended on hunting to fill their stomach. Flying reptiles called Pterosaurs also existed during that time and they were carnivores or insectivores.
4. The Cretaceous–Paleogene (K–Pg) extinction event resulted in mass extiction of life during that time. It happened almost 66 million years ago. It is discovered that during that period a massive comet or aesteroid must have hit Earth which left the planet devastated. This resulted into huge loss of plants and animals and the weather in Earth also got affected during that time as claimed by some scientists.
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