December 4, 2009
http://dsc.discovery.com/dinosaurs/?campaign=dsc-cod-1-bbc006
 Reading Ch. 14
 Final Exam date: TU, Dec. 15
• Material covered: Ch. 13, 14, 15, 16 + movie
Marine Vertebrates
 Bony fishes
• Primitive sturgeons dominant early
• Teleosts evolved
mobile jaws, swim bladders
– Ex: Xiphactinus
 Sharks (cartilagenous)
• Megaladon
http://www.fossilien.de/seiten/haizaehne/megalodon.htm
http://www.bbc.co.uk/science/seamonsters/factfiles/xiphactinus.shtml
Plesiosaur
Marine
Vertebrates
 Reptiles
• Nothosaurs and placodonts
 http://www.youtube.com/watch?v=-JJdKhGW-HY
• Plesiosaurs
• Ichthyosaurs
• Mosasaurs
Nothosaur
Ichthyosaur
Mosasaur
http://biology.fullerton.edu/life/hol/hol_ch14.html
http://www.exn.ca/dinosaurs/story.asp?id=2000032152&name=creaturs
http://current.com/items/91095972_ancient-sharks-fed-on-plesiosaurs.htm
http://www.palaeos.com/Vertebrates/Units/220Lepidosauromorpha/220.300.html
http://www3.interscience.wiley.com:8100/legacy/college/levin/0470000201/chap_tutorial/ch12/chapter12-08.html
Triassic
Mass
Extinction
(#4)
 Wiped out ~30% of
genera
• Mostly archosaurs
 Cause?
http://universe-review.ca/R10-19-animals.htm
Mesozoic Land Plants
Cycad
 Gymnosperms (non-flowering)
• Cycads
Look like palm trees
• Ginkgos
Ginkgo biloba survived
• Conifers
Conifers
http://faculty.ncwc.edu/ekosal/arboretum/gingko.htm
http://www.galenotech.org/ginkgo.htm
http://www.plantoftheweek.org/week241.shtml
http://www.science.siu.edu/landplants/Cycadophyta/cycadophyta.html
Ginkgo
Mesozoic Land Plants
 Evolution of angiosperms (flowering)
• Flowers help pollination
Double fertilization
• Faster recovery and growth
• Fertilization of same species guaranteed
Coevolution with insects
Faster evolution
http://www.museum.vic.gov.au/prehistoric/fossils/koonwarra.html
http://www.amnh.org/exhibitions/dinosaurs/gallery/diorama.php?image=1&p=forest&a=sino
http://www.pbase.com/gaocus/image/18369846
Mesozoic Land Reptiles
 Two major reptile groups:
• Lepidosaurs
 Ancestors of snakes, lizards
• Archosaurs
 Ancestors of crocs, birds
Early archosaur
http://higheredbcs.wiley.com/legacy/college/levin/0471697435/chap_tut/chaps/chapter14-06.html
Age of the Dinosaurs
 Dino distinctions:
• Upright posture
• Ankle joint
 Two major groups:
• Saurischia group
Lizard-like pelvis
• Ornithischia group
Bird-like pelvis
http://universe-review.ca/R10-19-animals.htm
Saurischians
(lizard-hipped)
 Sauropods
• Giant herbivores
Brachiosaurus
Apatosaurus
(“Brontosaurus”)
 Theropods
• Carnivores
Tyrannosaurus
Caudipteryx
• Ancestors of birds
http://www.nhm.uio.no/palmus/wwd/brachiosaurus.html
http://blogevolved.blogspot.com/2009/09/sauropods-in-art.html
http://www.amnh.org/exhibitions/dinosaurs/gallery/diorama.php?image=1&p=forest&a=sino
Archaeopteryx
Dino-to-Bird
 Transitional fossils
• Archaeopteryx
• Limusaurus
http://rst.gsfc.nasa.gov/Sect20/A12d.html
http://www.pbs.org/wgbh/nova/microraptor/prod-04.html
http://www.abc.net.au/science/articles/2009/06/18/2601531.htm
http://www.cosmosmagazine.com/news/2469/earliest-dinosaur-feathers-shed-light-avian-development
Limusaurus
Ornithischians (bird-hipped)
Hadrosaurus
 Armored
• Stegosaurus
• Ankylosaurus
 Duck billed
• Hadrosaurus
 Rimmed head
• Triceratops
Ankylosaurus
http://www.ftschool.org/fourth/s_studies/sg.unit3.html
http://www.geologicresources.com/dinosaur_place.html
Flying Reptiles
Jeholopterus
 Pterosaurs (flying reptiles)
• Pterodactyls
Likely rode on updrafts due to size
http://www.amnh.org/exhibitions/dinosaurs/gallery/diorama.php?image=1&p=forest&a=sino
http://www.ucmp.berkeley.edu/diapsids/archosauria.html
http://instruct1.cit.cornell.edu/courses/biog105/labs/deuts/homolanalogy.html
Evolution of Mammals
 Evolved from synapsids
(mammal-like reptiles)
 Skeletal distinctions:
Repenomamus
•
•
•
•
Middle ear--3 bones
Lower jaw--1bone
Teeth were differentiated
Palate
http://www.calstatela.edu/faculty/acolvil/dino_reptile.html
http://ib.berkeley.edu/courses/ib173/lectures/lecture3/173-jaws.html
http://www-rohan.sdsu.edu/~rhmiller/chordates2/Chordates2.htm
http://www.sciam.com/article.cfm?articleID=00016D38-9B8F-11E5-9B8F83414B7F0000
Evolution of Mammals
 Egg layers
• Monotremes (Platypus)
 Live birth
• Marsupials (pouched)
Premature births
Safer for mom
• Placentals
Birth when ready
Mom at risk
http://www.australianfauna.com/platypus.php
K/T Extinction
 3rd largest
• Wiped out ~1/2 life
 Puzzling evidence:
• Marine environment
Total loss of ammonites & reptiles (both in decline)
Tropical groups hit hard
– Water cooling and regressing
• Land environment
Decline of angiosperms
Dinosaurs in decline
Not affected
– Mammals--placentals became dominant
– Turtles, snakes, lizards
http://we.vub.ac.be/~dglg/Web/Claeys/Chicxulub/Chixproject.html
Extinction Hypotheses
 Impact hypothesis
• Based on iridium anomaly
• Chicxulub crater
• Global cooling, acid rain, fires
 Volcanic hypothesis
• Gigantic lava floods in India, Brazil
• Ash and CO2 production
 Regression
• Altered habitats, climate
http://we.vub.ac.be/~dglg/Web/Claeys/Chicxulub/Chixproject.html
http://evolution.berkeley.edu/evosite/evo101/VIIB1dMassExtinctions.shtml
http://www.geo.uu.nl/ngv/geonieuws/images/600q.jpg