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Transcript of Dinosaurs From Your Questions. What events separate the periods of the Mesozoic Mass extinctions...
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 Bird135 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