EDWARD'S LECTURE NOTES:
More notes at http://tanguay.info/learntracker
C O U R S E
Dinosaur Ecosystems
Michael Pittman, University of Hong Kong
 |
C O U R S E L E C T U R E Dinosaur Life and Extinction Notes taken on February 10, 2017 by Edward Tanguay |
•
synapomorphies
•
features that are shared between groups of dinosaurs
•
autapomophies
•
anatomical features that are not found in other dinosaurs
•
Phanerozoic Eon (542 million years ago)
•
1. Paleozoic Era (524-251 Ma) ANCIENT
•
2. Mesozoic Era (250-65 Ma) MIDDLE
•
Triassic (250-200 Ma)
•
Jurassic (200-145 Ma)
•
Cretaceous (145-65 Ma)
•
3. Cenozoic Era (65 Ma - today) CURRENT
•
earliest dinosaurs
•
Nyasasaurus
•
Tanzania
•
235 million years ago
•
middle Triassic
•
Spondylosoma
•
South America
•
middle Triassic
•
bipedal
•
legs much more robust than their arms
•
appeared to have been carniverous
•
two meters long
•
much like the Velociraptor
•
lived much later: 75-71 Ma
•
but the first dinosaurs were probably covered in scales than feathers
•
South America is known for early dinosaurs
•
Saturnalia
•
Late Triassic
•
228 Ma
•
Herrerasaurus
•
231 Ma
•
Argentina
•
Staurikosaurus
•
Brazil
•
225 Ma
•
Eoraptor
•
231 Ma
•
Argentina
•
Pisanosaurus
•
228 Ma
•
South America
•
probably omnivores
•
dinosaurs have a acetabulum
•
characteristic hole in hip bone
•
250 million years ago, an extinction event occurred
•
wiped out almost 90 percent of all species of tetrapod
•
dinosaurs became dominant when non-dinosaurian reptiles became extinct
•
ornithosuchids
•
an extinct family of reptiles from the Triassic period that were distantly related to crocodilians
•
rauisuchians
•
a group of mostly large Triassic archosaurs
•
diet
•
Tyrannosaurus Rex
•
quintessential carnivore
•
one of the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event
•
found in a variety of rock formations dating to the Maastrichtian age of the upper Cretaceous Period, 68 to 66 million years ago
•
Diplodocus
•
focused on eating vegetation
•
North America
•
Jurassic period
•
the boundary between carnivory and herbivory is fluid in dinosaurs
•
the impressive range of diets found in living birds is a testament to the dietary diversity of their theropod ancestors
•
extinction of non-avian dinosaurs
•
impact event
•
10-kilometer wide asteroid or comet
•
extinct
•
dating of rock samples shows that non-avian dinosaurs went extinct at the same time as this event
•
formed the Chicxulub Crater in Mexico's Yucatan Peninsula
•
today partly buried
•
65.5-million-year-old clay layer deposited widely across the globe
•
high concentration of iridium
•
a chemical only found in meteorites or nuclear blast sites
•
generated tsunamis
•
triggered earthquakes with magnitudes of over 11 on the Richter Scale
•
debris that the explosion threw up, upon returning to earth encountered friction and started to heat up
•
raised Earth's surface temperature
•
firestorms likely caused a greenhouse effect
•
dust in the atmosphere hindered photosynthesis in the short term
•
led to collapse of ecosystems
•
the site of impact over sulphate-rich deposits released sulfuric acid aerosols that acidified the oceans
•
reduced sunlight getting to Earth's surface
•
effected ocean ecosystem and food chains
•
the non-avian dinosaurs were either killed instantaneously by the impact or died quickly in the extreme environment following it