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56 Cards in this Set

  • Front
  • Back
The three periods of the Mesozoic.
Triassic, Jurassic, Cretaceous
The Triassic denotes _________ million years ago.
250 mya
The Jurassic denotes ___________ million years ago.
200 mya
The Cretaceous denotes __________ million years ago.
140.
Name two significant events in the Mesozoic.
Pangaea breaks up

Sea-level change
At its peak warmth, ca. 100 my ago, Mesozoic climate was
2 to 6 degrees C warmer at the Equator

> 20 degrees C warmer at the poles.
ca. _______ my ago lush ferns and alligators resided in Siberia.
100
Dinosoaur skeletons have been found north of ______________
the arctic Circle in Alaska.
What is the primary cause believed to have causes global warming during the Mesozoic?
higher atmospheric CO2 levels – possibly by a factor of 4 from present levels
what is the evidence of higher atmospheric CO2 during the mesozoic?
Paleomagnetic evidence that sea floor was spreading faster at that time (can estimate the spreading rate by looking at the magnetic patterns on sea floor – spacing of magnetic reversals; faster rates would have resulted in faster subduction rates of carbonate sediments, which would have lead to increased rates of CO2 production and increased CO2 from mid ocean ridges
Other possible influences/causes of warming during Mesozoic...
During the height of the Mesozoic, equator-pole temperature contrast was only 20 to 30 degrees C, while today it is 50 to 60 degrees, so circulation was different – more mixing back then.

Absence of Polar ice, changing albedo of regions, warming them
Two reasons for the higher sea-level in the Mesozoic:
climate warms

increased tectonic activity
Early Mesozoic dominated by ______, _______, __________, and others not widely seen today
ferns, cycads, ginkgophytes
Modern gymnosperms (e.g. conifers), first appeared in their current recognizable forms in the ___________.
early Triassic
By the middle of the __________, the earliest angiosperms (flowering plants) had appeared and began to diversify - became dominant.
Cretaceous
From the Carboniferous--Permian = _________ plants
big spore bearing plants
During the Mesozoic the evolution of _________ plants was seen.
pollinating
Early Mesozoic -Cycads,.Ginkgoes, Seed Ferns, Conifers =
seeds, but no flowers
Cretaceous = what kind of plants?
Flowering plants (angiosperms) with enclosed seeds
Name the four reptile groups of the Mesozoic.
Anapsid, Diapsid, synapsid, euryapsid
Describe anapsid.
one orbital lobe, no temporal lobe
describe synapsid.
one orbital lobe, one temporal lobe (lower cranium)
describe diapsid.
one orbital lobe, two temporal lobe.
describe euryapsid.
one orbital lobe, one temporal lobe (higher cranium)
Anapsids gave rise to the ___________.
synapsids and diapsids
diapsids gave rise to the ___________.
euryapsids.
synapsids gave rise to the ______________.
therapsids.
therapsids gave rise to the ____________.
cynodonts.
cynodonts gave rise to _______________.
mammals.
a pelycosaur (fin back) is an example of a _____________.
synapsid.
What was the first bird?
Archaeopteryx
List the four criteria of a dinosaur:
1. belong to the mesozoic era
2. reptiles
3. terrestrial
4. parallel gait (not sprawling)
List the two groups of Dinosauria:
Saurischian and Ornithischian.
Two groups of Saurischian:
Theropoda and Sauropodomorphs
Theropods =
Tyrannosaurus
Deinonychus
Sauropodomorphs =
Diplodocus
Apatosaurs
The five groups of Ornithischian:
Ceratopsians
Stegosaurs
Ankylosaurs
Pachycephalosaurs
Ornithopods
Ceratopsians =
Tricerotops
Ornithopods =
Maiasaurus
What are some of the proposed causes of the Cretaceous/Tertiary (K/T) Extinction?
Asteroid impact
Effects of the asteroid impact that caused the Cretaceous/Tertiary (K/T) Extinction?
volcanic activity
climate change
sea level changes
Predatory dinosaurs =
theropods
Theropods =
Ceratosaurs and Tetanurans
Tetanurans =
Carnosaurs and Coelurosaurs
very large Tetanurans w/ short necks and small forelimbs
carnosaurs
small Tetanurans, long-necked w/ long forelimbs
Coelurosaurs
Primitive theropods
Skeletal elements in hind limb fused
Sacrum totally fused & is fused to ilium
Adaptations for fast running w/ narrow gait
Includes Dilophosaurus and Coelophysis
Ceratosaurs
Non-ceratosaurian theropods
Ancestors to birds in this group
Have bird-like features
All teeth are in front of orbit
Second fenestra opened in front of eye
Hind limb modified for speed
Expanded distal end of pubis bone
Tetanurae
Lightly constructed skull w/ ridge in front of orbit
Rounded rostrum (face)
Medially flattened tip of lower jaw
Allosauridae
Three groups of Carnosaurs:
Tyrannosauridae, Allosauridae, and Gorgosaurus
D-shaped x-section of teeth in premaxillary
Opening in the jugal bone
Very small forelimbs w/ 2 functional fingers
Tyrannosauridae
Small, long-necked theropods
Evolutionary novelties
Extra fenestra in the palate
Elongate forelimbs >50% of hind limbs
Long slender hand with long second and third digits
Arctometatarsalian ankle
Coelurosaurs
Coelurosaurs include which groups?
Ornithomimosaurs
Dromaeosaurs
Oviraptorosaurs
Troodontids
Resemble flightless birds ; no teeth (beak?)
Very lightly built skull w/ very large orbits and shallow snout
Ornithomimosaurs
Large head w/lots of serrated teeth
Long forelimbs w/elongate 3 fingered hands
Tail w/ ossified tendons
Very large claw on digit 2
Dromaeosaurs
Early reptiles vs. Amphibians =
reptiles = more massive hip girdle, larger hind limb, larger forelimb, stronger vertebral column, more massive shoulder girdle.