

reminder..major extinctions at the end of the
Permian; same thing at the end of the Mesozoic.
Ammonites were very common during the Jurassic and Cretaceous (some up to 2
meters).
Note difference between the nautiloids and the ammonites (sutures).
Echinoids (sea urchins) were also common during the late Mesozoic.
planktonic foraminifera very common (Fig. 15.4)
coccolithophores were responsible for the large chalk beds formed during the
Cretaceous.
Plants-GYMNOSPERMS dominated Trassic & Jurassic (Cycads)
ANGIOSPERMS showed up during early Cretaceous. (90% of all land species today)
REPTILES--the BIG story
2 major families of dinosaurs: LIZARD-HIPPED (Saurischia) and BIRD-HIPPED (Ornithischia)
For the Saurischia, the Pubis bone parallels the Ischium. Fig. 15.9
Saurischians: Theropods: Tyrnnosaurus, Alosaurus, Veliciraptor
Sauropods: Apatosaurus, Iguanodon, Stegoceras
Ornithischians: Ankylosaurus, Stegosaurus, Triceratops, Protoceratops,
Pachycephalosaurs, Hadrosaurs
Brachiosaurus (75 metric tons!)
Still a controversyas to whether or not dinosaurs were warm-blooded.
Flying reptiles: Pterosaurs (wing supported by
the "baby finger". Fig. 15.14
Swimming reptiles: Ichthyosaurs (very fish-like), Mosasaurs (short-necked,
lizard-like)),
Plesiosaurs (long-necked, some short-necked) FIg. 15.5 & 15.6
Birds: Archaeopteryx (like feathered dinosaurs)
Mammals: jaw is different from a reptile-only a single bone and hinged
different.
Mammals have two sets of teeth and are specialized and double-rooted.
(Mammals chew their food.)
Three groups of mammals: Monotremes, Marsupials, Placentals.