Life in the Mesozoic (cont.)

The Age of Dinosaurs

Saurischia“Reptile-Hipped

Dinosaurs”

1.Sauropods (Herbivores)2.Theropods (Carnivores)• Aves (Birds)

Sauropods

Seismosaurus

Sauropods

Barapasaurus

Sauropods

apatosaurus

Theropods

Tyrannosaurus

Velociraptor

Theropods

allosaurus

Theropods

Small Theropods

Compsognathus

How do we know about Dinosaur Behavior?

Dino Nests

Dinosaur Trackways

How do we know about Dinosaur Color and

Soft “Stuff”?

Skin Imprints

Triceratops

Brain Casts & Gizzard Stones

Color?

Ceratosaurus

Warm vs. Cold Blood(Endotherms vs.

Ectotherms)

Predator/Prey Ratios

Bone Structure

Upright Posture & Fast Speeds

Problems - Food & Heat Loss

Bottom Line

Some dinosaurs were endotherms (small

theropods) and others were ectotherms (large

sauropods)

Adapting to the Skies

First in Flight - Pennsylvanian

Cretaceousdragonfly

Meganeura monyi (roughly to scale)

The largest insect in history

More to come in the Mesozoic…

Second - The Flying Reptiles Pterosaurs

Criorhynchus

Pterosaurs

Pteranodon

Pterosaurs:

Pterodaustro

Third - First Birds (Aves)

Jurassic

archaeopteryx

Share Characteristics with Theropods

Deinonychus

Caudipteryx

Feathered Dinosaurs

Dilong paradoxus

Last…Mammals (Cenozoic)

Bats

Mesozoic Mammals

Synapsids(Mammals)

Anapsids(Turtles)

Diapsids

Lizards& Snakes

Crocodiles

Pterosaurs

MarineReptiles

Dinosaurs& Birds

Archosaurs

Triassic - Lystrosaurus

Mammals vs. Reptiles

1. Development of jaw and ear bones2. Secondary palate3. Teeth differentiate4. Evidence for warm-blood

Mesozoic Mammal Teeth

Cynodonts (Triassic)

Small Insectivores

Mesozoic Mammals: Bigger than previously

thought

Repenomamus

More with the Cenozoic…