The mass extinction of dinosaurs randi leigh thomas


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The mass extinction of dinosaurs randi leigh thomas

  1. 1. What They Didn’tTell YouThe Mass Extinction of DinosaursRandi Leigh Thomas
  2. 2. Origins• The rise of the dinosaurs was not an overnight sensation.• Dinosaurs took about 50 million years to develop into the species we recognize today.• Unlike the images from Jurassic Park, not all of the dinosaurs lived in one climate or time period.
  3. 3. Popular Extinction Theories-Cosmic radiation from a nearby explodingsupernova star killed them.-Acid rain from volcano activity wasresponsible.-Continental drift altered the climate.-Disease ravaged dinosaur populations.-Small mammals appeared that fed ondinosaur eggs.
  4. 4. Most Widely Accepted Theories• Baptistina: The Meteor Meltdown• Deccan Traps: The Indian Volcanoes• Resistance Issues: Bugs and Illness• The Double Whammy: A Catastrophic Series
  5. 5. Meteor Meltdown
  6. 6. • In the 1980s, Luis and Walter Alvarez discovered Iridium in the K-T boundary.• Iridium is rare on Earth but abundant in meteors.• The duo theorized that a gigantic meteor or comet struck the Earth at the end of the Cretaceous era causing many deathly events to ensue.
  7. 7. • The impact caused:-A massive explosion-Dust cloud formation-No visible light-Massive forest fires-Smoke in the atmosphere-A general cooling of the planet• There is an observable crater along the Mexican Yucatan Peninsula that coincides with the K-T Boundary.
  8. 8. • The asteroid was imagined to be 6 to 12 miles in diameter causing a crater 130 miles across.• The Southwest Research Institute has named it “Baptistina” and traced the meteors path:-160 million years ago a 100 mile wide asteroid was headed forthe planet.-A smaller and unnamed asteroid struck and shattered Baptistinasending fragments toward the atmosphere.-95 million years later, the fragments reached Earth destroyingthe dinosaurs.
  9. 9. Volcanoes and Greenhouse Gases
  10. 10. • The Deccan Traps are an active lava bed in India.• These volcanoes were extremely active over a long period of time but the most massive eruption coincides with the K-T Boundary.• Those eruptions could have released 10 times as many harmful gases into the atmosphere as the meteor crash.
  11. 11. • These substances include:-Extreme quantities of dust-Sulphuric Acid-Carbon Dioxide• Leading to the extreme temperature swing at the end of the Mesozoic.• The existing 2/3 of these lava beds covered almost a million square kilometers. That’s about half of India!
  12. 12. Dinosaur Disease
  13. 13. • Because of the climate of the late Cretaceous, insects were able to flourish.• Many of the bugs from that era were preserved in amber and that has allowed scientists to exam them for diseases.• It was determined that some of the smallest animals we know today could have taken down giants.
  14. 14. • Some bugs carried leishmania and malaria that could easily infect reptiles.• Fossilized dung revealed the ingestion of nematodes, trematodes, and protozoa that could have caused dysentery.• These diseases were relatively new so the dinosaurs had little resistance to these pests.
  15. 15. Catastrophic Coupling
  16. 16. • The mass extinction of the dinosaurs is not the only one to have happened in history.• A bigger extinction occurred 250 million years ago known as “The Great Dying”, or the Permian-Triassic.• It eliminated 90% of known species from the face of the Earth.
  17. 17. • Scientists observed periods of time when there were asteroid impacts, volcanic eruptions, or neither happening.• The results showed that there were more deaths when both impacts and eruptions happened.• This led them to believe that a large scale chain of events was the most probable cause for the end of the dinosaurs.
  18. 18. Other PossibilitiesIt is also highly suggested that around the timeof the K-T boundary, dinosaurs were already indecline.• The herbivores main food source, vegetation, was dying off because of reduced oxygen levels and higher temperatures.• As herbivores died, carnivores followed suit without nutrition.• There was already a sharp decline in dinosaur population and it is proposed that perhaps the asteroid just finished them off.
  19. 19. Can We Bring Them Back?
  20. 20. Iconic movies like Jurassic Park have alwaysmade us wonder whether bringing backdinosaurs is possible. In theory, it is. But here’swhy it would never work:• The habitat dinosaurs lived in is destroyed. A national park just isn’t big enough for 4 or 5 large carnivores!• Finding a suitable host for the DNA would be almost impossible. Yes, birds are dinosaurs too. But I don’t foresee them hatching raptors any time soon.• Do we really want T-Rex marching through our backyards?
  21. 21. • If we could find perfectly preserved dinosaur DNA, extract and sequence it with little error, organize it into chromosomes, place it into the living egg of the correct species (wait...that would mean we already had the egg and its own DNA!), and raise the egg successfully, then we could all have pet Triceratops. Yeah, right. • Visit this website:
  22. 22. Please watch this video in your own time!“Jurrassic Park: How it Should Have Ended”
  23. 23. Keep in Mind…• Not all dinosaurs are extinct! Take a look at birds.• Theories of how the dinosaurs disappeared are still disputed. There’s not many proven facts on the subject yet.• And last but certainly not least:Dinosaurs are cool whether you’re 4 or 40.