BIO211H5 Final: BIO211 Exam Study Notes (includes Term 1-2 content)
15 - Some History:
● Earliest report from Sichuan, known as “dragons”
● Megalosaurus = first valid named dinosaur, found by Buckland
● Iguanodon = first herbivorous dinosaur, found by the Mantells, thumb spike, possibly tree
climber
● Dinosaur = terrible lizard, coined by Richard Owen, no longer dragon
●Waterhouse Hawkins then created life-sized models in Crystal Palace, Darwin published his
papers, other dinosaur collectors besides the two below: Sternberg, Brown, Andrews
● Bone Wars/GDR: Marsh and Cope started as collaborators but ended as bitter rivals due to
mistake of putting head on tail of plesiosaur (not a dinosaur btw)
● Once thought to be cold-blooded, slow and dumb, chunky and tail-dragging
○ until Deinonychus (Ostrom argued for relationship between ^ and birds)
○ Bakker: endothermic and some may have been feathered
■ Theropod dinosaurs likely had integumentary filaments (but not “feathers”)
■ All birds are dinosaurs, not all dinosaurs are birds
● Now: most dinosaurs moved with bodies roughly horizontal to ground, bipedal could stand
diagonal or near vertical, quadrupedal species could be semi-erect too
16 - Mesozoic I: Triassic
● Marine invertebrates
○ Stromatolites recover + Sea urchins diversify + Reefs built by modern corals (hexacorals)
○ Molluscs abundant
■ Rapid evolution of ammonoids -> index fossils
■ Belemnoids: squid-like relatives of ^ + Bivalves also diversified
● Triassic and Jurassic plant life
○ Tree-forming gymnosperms: cyads and Ginkgos
○ Mesozoic forests looked very different from modern forests, pollen evidence for
angiosperms (flowering plants), but not a good macrofossil record
● Early Mesozoic fishes
○ Radiation of actinopterygians (ray-fin) in Triassic-Jurassic, slightly more mobile jaws
○ Teleost fish (Tri) have highly mobile jaws and thin rounded scales, strong tails w/
uroneurals (ossified plate helping to support the tail fin) ~= modern fish
● Triassic amphibians
○ Temnospondyls still diverse, but no more lepospondyls or anthracosaurs
○ Modern amphibians (lissamphibians) did not appear until next period/Jurassic
● “Euryapsids” derived from loss of lower opening in diapsids?
○ Sauropterygians (aquatic reptiles)
■ Placodonts “tablet teeth” shallow water, duophagous (eats hard stuff)
■ Pacypleurosaurs: small and primitive, marine
■ Nothosaurs: thought to be ancestral to plesiosaurs
●Marine forefoot-paddlers and pelvic limbs, Pachyostotic (thickened) ribs,
webbed feet, elongated necks
■ Plesiosaurs: fully marine, Tri-Creta
● Rowing, “subaqueous flight”, hyperphalangy (finger bones) in paddle-like
limbs, deep bodies, gastroliths (stomach stone) to control buoyancy
○ Ichthyopterygians (also marine reptiles)
■Ichthyosaurs and relatives, prim had dorsal fins, increasing speed as they
evolved
● Vertebrae: spool -> puck-shaped, reduction of pelvic girdle, streamlined
and deep-bodied, hyperphalangy, hyperdactyly (excessive fingers),
hypocercal tail, viviparity
● “Anapsids”: Testudianians = turtles, terrapins, etc. terre, fresh and marine, sister to who?
○ Grandfather turtle (pappochelys) had turtle-like features such as expanded ribs (becomes
plastron/shell) shows that turtle ancestors were diapsids, lost hole
● Diapsids
○ Thalattosaurs: aquatic, near-shore, feet NOT paddle, compressed tails, needle-like teeth
○ Lepidosauromorphs: sphenodontians: -recent includes tuatara and others, NZ
○ Longisquama
“long scales” debatable group
○ Archosaurs
■1. Anterior fenestrae (in front of orbit/eye socket, housed air sinuses)
■ 2. Lateral lower jaw fenestrae for muscle attachments
■ Thecodonts = Ancestors of dinosaurs, crocodiles and other extinct groups
● More upright posture than more primitive forms
■ Phytosaurs (crocodile like) variations in snout, nares/nostrils very posteriorly
placed
■ Rauisuchians = agile predators with (pillar) erect stance (independently derived
from dinosaurs, with ventrally-directed hip socket)
■ Aetosaurs = herbs w/ heavy dermal armour, index fossils
■ 1st Crocodylomorphs (recent) but modern crocodilian forms evolved later in
Meso
■ Pterosaurs (-Cre), first vertebrates with powered flight (flapping), hollow bones
●Primitive: fifth toe, short neck and metacarpal, but long tail
●Derived: no fifth toe, long neck and metacarpal, but short tail
● Evolutionary trends: reduced dentition and stiff tail (modern birds)
● Elongated 4th digit + pteroid bone (supported propatagium/wing
membrane) + actinofibrils (strengthened wings) + pycnofibres (hair-like)
●
■ Dinosaurs
● Upright posture with laterally-directed hip socket and turned in femur
● Reduced 4th and fifth digits
● Two major groups: “bird-hipped” and “lizard-hipped”
● (true) Mammals (synapsids) evolved from therapsids like reptiles
○ Have 3 middle ear bones and jaw joint between dentary and squamosal
○
○ Diphydonty: 2 sets of teeth, deciduous (milk/baby) and permanent
○ precise dental occlusion: near perfect fit btw top and bottom
○ Secondary palate separates nasal and oral cavities
■ Allow for simultaneous respiration and feeding for high metabolic rate
○ Metabolism
■ Endothermy: internal reg of body temp
■ Homeothermy: maintenance of constant body temp
■ Tachymetabolism: maintenance of high metabolic rate
○Fur helps maintain body temp, earliest evidence from mid Jura
○ Turbinates seen in modern mammals = Thin, delicate bone structures in nasal cavity
(hard to preserve) -> Warm and moisten air can maintain higher breathing rate w/out
drying lungs
○ Muscular diaphragm assists with respiration; reduced ribcages
○ More efficient erect locomotion w/ dorsoventral flexion (excld. Monotremes semi-erect)
○ Morganucodontids among earliest mammals
■ Small, agile insectivores with double jaw joint (dentary-squamosal +
quadrate-articular), heterodonty, diphyodonty, precise occlusion
● Palaeogeogrpahy
○ Pangea began to split up
○Triassic mass extinction affected marine and terre, but esp marine
■ Casualties: conodonts and placodonts, Heavily affected: bivalves, ammonoids,
plesiosaurs, ichtyosaurs, temnospondyls...
■ Dinosaurs not severely affected
■ Rifting + volcanism -> increased CO2 -> global warming
17 - Mesozoic II: Jurassic
● Teleost fish contd. (advanced actinoptergians/ray-finned fish)
○ Eels & tarpon: elongated, lost caudal fin, pelvic girdle, ribs and scales
● Sarcopterygian fishes (lobe-fin): coelacanths and lungfish still around
●1st Lissamphibians/Modern amphibians
○ Pedicellate teeth: crown and base lies ontop small pedicell (tooth layers); also
bi/multi-cus
○ Caecilians most are fossorial/burrowers, chemoreception thro sensory tentacles
■legless, reduced eyes and tails, mouth terminal to subterm, heavily fused skulls
○ Salamanders, newts, mud puppies some paedomorphic or w/ limb reduc, term mouth
○ Frogs and toads: short trunks, loss of ribs and tails, hopping, wide flat skulls
● Diapsids: champsosaurus (not dinosaur nor crocodile/gharial, sim to phytosaur^)
○ Dorsal orbits, secondary palate, terminal nares (snorkeling behaviour convergent w/
croc)
● Archosaurs: dinosaurs
○ “Bird-hipped” = Ornithischians = pubis bone points posteriorly
■ Horned, duck-billed, armoured
○ “Lizard-hipped” = Saurischians = pubis anteriorly
■ Bipedal carni, long-necked, birds
● Ornithischians bird
○ Thyreophorans “armoured”
■ Stegosaurs: herb, hind longer than fore, small head/brain
● almost all had bony dorsal plates + spikes on tail
■ Ankylosaurs: ankylosaurids had clubbed tails, nodosaurids didn’t
● Herb, Short powerful limbs + wide back covered with bony armours
○ Ornithopods “duck-billed” (mostly Cret tho)
Document Summary
Earliest report from sichuan, known as dragons . Megalosaurus = first valid named dinosaur, found by buckland. Iguanodon = first herbivorous dinosaur, found by the mantells, thumb spike, possibly tree. Dinosaur = terrible lizard, coined by richard owen , no longer dragon. Waterhouse hawkins then created life-sized models in crystal palace, darwin published his. Bone wars/ gdr: marsh and cope started as collaborators but ended as bitter rivals due to. Once thought to be cold-blooded, slow and dumb, chunky and tail-dragging papers, other dinosaur collectors besides the two below: sternberg, brown, andrews mistake of putting head on tail of plesiosaur (not a dinosaur btw) Until deinonychus (ostrom argued for relationship between ^ and birds) Bakker : endothermic and some may have been feathered. Theropod dinosaurs likely had integumentary filaments (but not feathers ) All birds are dinosaurs, not all dinosaurs are birds.