dinosaurs 🦖🦕

• Dinosauria stand upright with a straight knee and ankle joint. 
• They evolved during the Triassic from archosaurs. 
• The first dinosaurs were bipedal predators 1-2 metres long. Found in Patagonia and Argentina, fossils are rare. 
• During the Triassic Pangea made a large hot and dry environment. Archosaurs survived well here. Pangea breaks apart during the Jurassic with a few land bridges. The climate became warm and humid so large dinosaurs evolved. 
• During the cretaceous land bridges disappeared and the climate cooled. The size of the dinosaurs decreased, perhaps due to a change in diet due to the evolution of flowering plants and grass or climate change. 
• Dinosaurs are split into saurischian and ornithischian. 
• Sauropods and therapods are two groups within saurischians. 
• Saurischian dinosaurs were reptile-hipped (pubis bone points forward) shape of pie 
• Ornithischian dinosaurs were bird-hipped (pubis bone points backwards) shape of equals 
• Theropods were two legged and meat eaters, they evolved into birds. 
• Theropods ranged in size from 5 tonnes or larger to turkey sized. 
• Tyrannosaurus was the largest of all terrestrial predators during the late cretaceous. 
• Scavenger:

  • Short arms 
  • Large back legs - distance walkers 
  • Large olfactory lobes - good sense of smell 
• Predator:

  • Modern predators scavenge
  • Not all predators don’t need forelimbs 
  • Few trace fossils - cant determine speed 
  • Predator and scavenger 
  • Large teeth - CARNIVORE 
• Sauropods were very large - 30 meters long, 50 tonnes- with four legs and a long neck and tail. 
• Sauropods were herbivores found in the Jurassic and cretaceous. They had a long neck and long and thin skull. They had no grinding teeth so swallowed stones to aid digestion. They had extra bones beneath their spine to support the neck and tail. Their long tail helped with balance and was a weapon.