Presentation on theme: "Dinosaurs From Your Questions. What events separate the periods of the Mesozoic Mass extinctions – mainly of cephalopods First appearances of new."— Presentation transcript:
Dinosaurs From Your Questions
What events separate the periods of the Mesozoic Mass extinctions – mainly of cephalopods First appearances of new cephalopods First appearances of various types of “plankton”
Dinosaur Distribution Where are they found? United States, Argentina, Mongolia, China, Central Asia, Africa, Antarctica, etc. Did dinosaurs live in NY? If so, which ones? Footprints of Coelophysis Why did they first appear in S. America? Favorable environmental conditions/Ecological opportunity
Dinosaur Distribution What environments did they inhabit? River Valleys, plains, coastal lowlands, etc. Did they live in cool climates? Probably, but still under investigation
Dinosaur Distribution How abundant were they? Probably at least as abundant as Mammals are now. Some indications of large herds of hundreds of individuals What were the relative abundances of terrestrial and aquatic forms? Majority were terrestrial
What was the vegetation like? Seed Ferns Gingkos Flowering plants in Cretaceous
What ecologies existed (food chains)? Terrestrial vegetation Herbivorous insects, amphibians, reptiles, dinosaurs, mammals Carnivorous amphibians, reptiles, dinosaurs and mammals Scavenging amphibians, reptiles, dinosaurs and mammals Decomposers: fungi, bacteria, etc.
What is the difference between reptiles and dinosaurs? Reptiles and dinosaurs descended from “primitive” “stem reptiles” Major differences in skull structure Major differences in pelvic structure and leg orientation Probable differences in thermal regulation
Dinosaur Systematics & Biostratigraphy What is the oldest dinosaur known? Triassic From what are they descended? Early “stem” reptiles To what are they related? Reptiles and probably birds How many species have been found? Hundreds, and counting! How long were they around? Approximately 180 Ma!
Ornithischians and Saurischians Differences in pelvic structure Functional differences? Relationship to bipedalism?
Paleobiology of Dinosaurs Why were they so large? Why not? Were they warm or cold blooded? Strong evidence favors warm- blooded: Trackways – speed Haversian canals in bones Skeletal morphology – active habits Affiliation with birds Feathers as insulation on some
Paleobiology of Dinosaurs What do we know about their diet and how do we know it? Herbivores and carnivores: Distinction made on dentition, skeletal structure, gastroliths Tooth morphology – clues to diet Coprolites – direct evidence Morrison Formation – a dinosaur lagerstatte What do we know about their internal systems? Rare instances of preservation: Italian Alps specimen How die they communicate? Vocalization with and without “reverb” chambers in skull. How do we know what we know? The fossils!
Paleobiology of Dinosaurs Has any soft tissue been found? Have any babies ever been found in eggs? Did they have scales or feathers? How long did it take them to grow so large?
Paleobiology of Dinosaurs Have any babies ever been found in eggs?
Dinosaur Fact File What was the first dinosaur? Herrarasaurus from Argentina What was the smallest dinosaur? Micropachycephalosaurus - 20 inches long Echinodon - 24 inches long Saltopus - 24 inches long Microceratops - 30 inches long Pisanosaurus - 36 inches long
Dinosaur Fact File: Largest Diplodocids and Titanosaurs Seismosaurus 84 feet (25.6 m) 150 feet (45.7 m) 200,000 pounds (90,720 kg) Seismosaurus - diplodocid Argentinasaurus - titanosaur Bruhathkayosaurus - titanosaur
Dinosaur Fact File Could dinosaurs swim? Yes, evidence includes toe scratches on bottom sediments. Did “Cave men” and dinosaurs co-exist? NO!!! They are separated in time by nearly 65 Ma (with apologies to Fred Flintstone and Dino) Was the Loch Ness Monster real? NO!!! It has been exposed as a hoax by the person that faked the most widely cited photographic “evidence.”
What caused their extinction? Multiple hypotheses: Bolide impact Volcanism Climate change All of the above Do they have any living descendents? Maybe!
Is There a Dinosaur in Your Backyard? Archaeopteryx Caudiopteryx Confusciornis Early Baby Bird 135 Ma
Miscellaneous and/or Unanswerable Questions What was their average life span? How intelligent were they? Could they talk? – probable vocal abilities Were they“mean”? Why is the source of children’s fascination with dinosaurs? How would dinosaurs and humans coexist? What color were they? Did they have territorial battles? Were some dinosaurs monogamous?
Reptiles and Mammals Reptile Adaptive Radiation included: Dinosaurs Therapsids – mammal-like reptiles Therapsids gave rise to mammals
What does it mean to be a mammal? Characteristics of mammals?
Early Mammals Small, rodent-like creatures Possibly nocturnal Some lines became extinct in Cretaceous Late Cretaceous to Early Cenozoic Adaptive Radiation
Major Groups of Extant Mammals Placentals Marsupials Monotremes Edentates