Dino-KT

• Dinosaurs - Name literally means “terrible lizards." Land reptiles that lived from the Late Triassic to the Cretaceous (65-230 million years ago)
• Dinosaurs arose from the thecodonts of the archosaur group of reptiles to become the most dominant vertebrates on land in the Mesozoic
• Aside from the dinosaurs, the thecodonts gave rise to the crocodiles, pterosaurs and birds
• Where did the other reptiles we know today come from?

  Cotylosaurs
• Stem reptiles - gave rise to mammals
• The dinosaurs are divided into two groups based on the differences of their pelvic bones: the Ornithischian (bird-hipped) dinosaurs, the Saurischian (lizard-hipped)
• What is the earliest known bird called wherein the lineage of this earliest bird is traced to the saurischian (lizard-hipped) dinosaurs?

  Archaeopteryx
• Ammonites - were similar in shape and form to the modern Nautilus •very common in the oceans of the Paleozoic and Mesozoic eras, 400 to 65 mya; “fish of the Mesozoic seas." Became extinct at the same time as dinosaurs, about 65 million years ago.

  
• These strange-looking bivalves (pelecypods) called rudistids also went extinct by the end of the Cretaceous. These are related to the present-day mollusks such as clams, mussels, etc.
• What is the most popular theory that caused the extinction of the dinosaurs at the end of the cretaceous?

  Bolide impact
• How big an asteroid do you need to destroy a continent in meters?

  16000
• What are some evidences of asteroid impact that killed the dinosaurs?

  Crater, iridium layer, shocked quartz.
• Shocked quartz - only found in high-yield nuclear test sites or in impact areas
• Rubble bed - in the K-T boundary layer evidence for the deposition of boulders and coarse material along the coasts of the Gulf of Mexico by a large wave, like a tsunami during the K-T
• Tektites - are quartz grains which are vaporized under intense heat and pressure, and cool into glass beads with no crystalline structure. There were probably formed during a meteorite or comet collision and are abundant in the K-T layer.
• Deccan traps - may have played a role in the extinction of the dinosaurs. Most of the basalt was erupted between 65 and 60 million years ago. Gases released by the eruption may have changed the global climate and led to the demise of the dinosaurs 65 million years ago. These are flat- lying basalt lava flows and covers an area of nearly 200,000 square miles
• Deccan (region of India) Traps (means staircase) produced over 500,000 years, as the Indian subcontinent drifted north to collide with Asia