28 terms

Mammalogy

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Red-shanked douc langur
Phylogeny
the relationships by ancestry among groups of organisms
convergent evolution
Evolution toward similar characteristics in unrelated species
Relative dating
Method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock
radiometric dating
Dating using decay of radioactive isotopes.
triassic era
advent of mammals
KT Event
cretaceous->tertiary extinction of dinosaurs
Tetrapod
four feet
-historically amphibians
Synapsida
-mammal precursor
-"together arch"
-zygomatic arch creates opening
-cranial frenestra
-temporal fossa
-one temporal opening
Anapsid
no temporal opening
Diapsid
lizards, snakes, dinosaurs, crocodiles, and birds, two fenestrae/temporal opening
Therapsids
270 mya
-middle permian
-active/diverse
-dominant terrestrial lifeform
-went extinct during PT extinction
Theraspid characteristics
enlarged temporal fenestra
partial, evolving secondary palate
changes to jaw and skull structure
Cynodont
"dog teeth"
-advanced theraspids
-survived PT
-interacted w dinosaurs
-small and inconspicuous
Cynodont evolution
-many transitional fossils
-complete secondary palate
-enlarged dentary
-shrinking post-dentary
-braincase expansion
closed bar lines on evolutionary line
extinction
quadrate-articular jaw joint
old extinct
Dentary-squamosal jaw joint
current
key character approach
using one characteristic
4 suite of characteristics for mammals
3. Occlusal cheekteeth for grinding
4. Well-developed inner ear
5. atlas and axis complex C1, C2 verts
6. two occipital condyles
7. regionalized vertebrae with thoracic ribs
8. mammalian posture
extant mammals
Prototheria (monotremes-first-one opening)
Metatheria (marsupial-middle)
Eutheria (placental-new)
Theria
beast
What allowed mammal radiation
-pangea breaking
-plant diversity and fruiting
-insect diversity
-loss of dinos
How did mammals survive?
-fur
-climbing/speed
-nocturnal
-insect eating
-efficient eating (special dentition/masseter/secondary palate) to supply 10x cal.
-efficient cardiopulminary efficiency (anucleated rbc/separated ox and deox blood/diaphragm/thoracic ribs/respiratory turbinates)
Eating survival
...
Cardiopulminary survival
...
Behavior survival
Nocturnal
-hair
-olfactory/auditory
Location survival
Exploiting marginal environments
-near arctic
-marine mammals