EPS SCI 17 Midterm: Midterm Study Guide
3 May 2018
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MIDTERM STUDY GUIDE
DINO TERMS
●ornithischian
(bird-like hips = pubis pointed backward): start off pretty small, primarily
herbivores
○ include Thyreophora
(“the armored dinosaurs”) and cerapods
○ thyreophora
: “the armored dinosaurs” (early Jurassic - end Cretaceous)
■ osteoderms running down the back modified into plates, spikes, and
armor
■ Examples
:
● stegosaurs
●ankylosaurs
○ Cerapods
■ ornithopods
: “the duck-billed dinosaurs” (mid Jurassic - Cretaceous)
● herbivorous
● novel-chewing mechanisms
● Examples
: miasaurus, Corythosaurus
■ marginocephalia
: “bone-headed dinosaurs” (late Jurassic - Cretaceous)
● herbivorous
● Example
: Pachycephalosauria
- thick domed skulls
● Example
: Ceratopsians
- elaboration of skull bone into shields &
evolution of horns
○ increased size → came with quadrupedal body plan
●saurischian
: (lizard-like hips = pubis pointed forward)
○ sauropods
: (mid Triassic - Cretaceous)
■herbivores
■increased size → came with quadrupedal body plan
■ Examples
: Brachiosaurus, Diplodocus
○ theropods
: carnivorous (specialization of teeth changed diet), generally bipedal
(shortened forelimbs compared to hindlimbs)
■ maniraptors
: includes living birds, as well as their close relatives (such
as Velociraptor
)
●Dimetrodon (“two measures of teeth”)
: evolved from the lineage that includes
mammals, because it is a synapsid
(1 post-orbital fenestra) → not a dinosaur, though
reptile-like in appearance
○diapsids
(2 post-orbital fenestrae) = includes dinosaurs, birds, living reptile
○ a cousin of mammals (not a direct ancestor)
○ discovered by Edward Cope in the Bone Wars
■extinct ≈40 million years before the 1st dinosaurs
■possibly used the sail for thermoregulation
● oviraptor
: theropod with unusual morphology (found in an area with many Protoceratops
nests)
○ had no teeth → thought to steal eggs (“egg thief”), because we misidentified eggs
near them as eggs stolen from other species
○ images / views of the dinosaur have changed over time
■ new evidence (eggs contained developing oviraptor skeletons) emerged
that they protect their own eggs
●Iguanodon
: originally believed to be meat-eating → later found to be herbivorous
○ named by Gideon and Mary Anna Mantell
● Deinonychus (“terrible claw”)
(1969, John Ostrom): small, carnivorous dinosaur with
similarities to Archaeopteryx
→ reignited the hypothesis that dinosaurs & birds are
closely related
○ ossified tendons running along tails
● Anomalocaris
(“abnormal shrimp”): predator that captured animals with its appendages
to pull towards its circular mouth
○ did not seem to fit in with any living organisms (something quite unique)
● Opabinia
: segmented body, has mouth on the end of trunk and 5 eyes (also a strange
predator)
●Dunkleosteus
: very large fish, kinetic skulls covered in bone, gianted saw-like hard
sheaths
●Tiktaalik
: (discovered in 2004, lived ~375 Mya) has shoulder-blade & neck → shows
transition from fins to limbs
●Pikaia
(worm-like animal): has a nerve cord along its back (which is found in chordates)
○ has same basic body plan that connects it with other vertebrates
●agnathans (jawless fishes)
: includes lampreys, hagfishes, and several extinct groups
● sarcopterygii (lobe-finned fishes)
: fins more muscular with small bones for support
(homologous to the bones in early tetrapod limbs)
○ 2 extant groups: lungfishes & coelacanths (much more abundant & diverse in the
Paleozoic)
○ ancestors of the first tetrapods
GEO TERMS
● Mesozoic
(~65 - 245 Mya): the time period where dinosaurs lived → includes the
following:
○ increasing diversity throughout the Mesozoic
■ Triassic
: dinosaurs first emerged → limited diversity of dinosaurs
■ Jurassic
: increasing diversity
■ Cretaceous
: most diverse
○ much warmer time, than modern-day
● Cambrian
(≈541 - 485 Mya): the rapid first appearance of most major groups of animals
(rapid diversification of multicellular animal life)
●Ediacaran
: occurs just before end of Pre-Cambrian → evidence of 1st multicellular life
(very morphologically simple)
●Devonian
: probably many independent colonizations of:
○ chelicerates (ex. spiders, mites, etc.)
○ insects
○ crustaceans (ex. crabs, lobsters, shrimp)
● Permian
: dominated by synapsids → ends in mass extinction event
○ much diversity of synapsids
(ie. mammals with 1 post-orbital fenestra)
■Dimetrodon
■therapsids
- Inostrancevia
has complex teeth (3 kinds of teeth) → on the
way to becoming a mammal
■ Pelycosaurs
○trilobites, eurypterids (scorpion-like animals), rugose corals = extinct
○only a handful of therapsids survive → from these ashes, dinosaurs will rise (all
evolve convergently)
■occupy similar ecological niches and look similar
● trace fossils
: our only preserved record of behavior of fossil organisms (ex. footprints)
○ sponges produce certain chemicals (cholesterol) that are very rare otherwise in
nature → even if body has decayed away, we can use geochemical trace fossils
●principle of superposition
: in a sedimentary sequence that has not been overturned,
the oldest rock units are always at the bottom
● principle of original horizontality
: sedimentary layers are originally deposited lying flat
(ie. parallel) to the Earth’s surface
● principle of cross-cutting relationships
: if one rock cuts across another, it is younger
● rule of inclusions
: if a unit contains a clast, or inclusion of another rock unit → the clast
or inclusion is older
Document Summary
Ornithischian (bird-like hips = pubis pointed backward): start off pretty small, primarily. Include thyreophora ( the armored dinosaurs ) and cerapods. Thyreophora : the armored dinosaurs (early jurassic - end cretaceous) Osteoderms running down the back modified into plates, spikes, and armor. Ornithopods : the duck-billed dinosaurs (mid jurassic - cretaceous) Marginocephalia : bone-headed dinosaurs (late jurassic - cretaceous) Example : ceratopsians - elaboration of skull bone into shields & evolution of horns. Increased size came with quadrupedal body plan. Saurischian : (lizard-like hips = pubis pointed forward) Examples : brachiosaurus, diplodocus (shortened forelimbs compared to hindlimbs) Theropods : carnivorous (specialization of teeth changed diet), generally bipedal. Maniraptors : includes living birds, as well as their close relatives (such as velociraptor ) Dimetrodon ( two measures of teeth ) : evolved from the lineage that includes mammals, because it is a synapsid (1 post-orbital fenestra) not a dinosaur, though reptile-like in appearance.
