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51 Cards in this Set

  • Front
  • Back
11 soft anatomy characteristics of mammals
1. lactogenic
2. viviparous
3. hair
4. sweat and sabaceous glands
5. endothermic
6. four-chambered heart
7. anucleate red blood cells
8. separate renal artery
9. muscularized diaphragm
10. facial muscles
11. expanded cerebrum expanded from dorsal pallium
-nourish young with milk produced by mammary glands
-give birth to live young which are nourished in the uterus
-exception of egg-laying monotremes
three layers of hair
-medulla - insulation
-cortex - pigment
-cuticle - scales (pattern species-specific)
sebaceous glands
-associated with hair follicles
-produce oils that condition hair
significance of four-chambered heart
-separates pulmonary from systemic circulation
renal artery
-blood flowing into kidneys is supplied by renal artery from aorta
-vs. renal portal system
muscularized diaphragm
-separates abdominal cavity from thoracic cavity
-expands rib cage during inhalation
facial muscles all derived from what?
-constrictor colli (throat muscle)
8 cranial characters of mammals
-double occipital condyle
-modified atlas/axis complex
-tympanic bone
-3 ear ossicles
-single pair of bones in mandible
-single nares
-secondary palate
-respiratory turbinates
double occipital condyle
-point on skull that articulates with first cervical vertebra
atlas/axis complex in mammals
-first and second cervical vertebrae
-atlas reduced to simple ring that stays fixed when skull moves up and down
-axis has post that goes through hole, on which skull rotates
tympanic bone
-supports tympanum (eardrum)
-forms auditory bulla in many mammals
-non-mammals have angular bone in lower jaw
3 ear ossicles and their ancestral homologs
-malleus - articular
-incus - quadrate
-stapes - stapes
secondary palate
-separates nasal from oral cavities
two points to respiratory turbinates
-olfactory turbinates support epithelium for scent
-large surface area for recovery of exhaled water vapor, therefore required for endothermy
5 characteristics of mammalian teeth
-restricted to margins of the jaw
-two growths (baby and adult teeth)
-socketed (tooth anchored)
-contrasts: acrodont (on jaw, not socketed) and pleurodont (on shelf, not socketed)
-different shapes for different functions
-many bumps
-especially cheek teeth
-upper teeth acclue with lower teeth
2 characteristics of mammalian axial skeleton
-extreme regionalization of vertebral column
-rib distribution restricted to thoracic vertebrae
5 regions of vertebral column in mammals
-cervical (7 bones in neck)
-thoracic (13 bones in chest)
-lumbar (varied # in lower back)
-sacral (varied # in pelvic area)
-caudal (varied # in tail area)
four characteristics in appendicular skeleton in mammals
-limb orientation
-reduction in bones of limb girdles
characteristics of mammalian axial skeleton
-extreme regionalization of vertebral column
-Rib distribution - restricted to thoracic vertebrae
characteristics of mammalian appendicular skeleton
-epiphyses - bony caps at tips of limb bones (permits stress at joints)
-calcaneum (allows calf musculature)
-limb orientation - rotated under body (most of weight supported by skeleton vs. musculature)
-reduction of bones in limb girdles
mammal pectoral girdle
-scapula and clavicle
-vs. anterior and posterior coracoids and interclavicle
-monotremes still possess the latter
mammal pelvic girdle
-fusion of three ancestral elements into single pelvic bone: illium, ishium, and pubis
-remain unfused in monotremes
-carboniferous period
-temporal region- solid shield of bone
-jaw closing muscles attach onto ventral surface of solid shield of bone
-"together arch" - arch of bone formed by opening of fenestra
-fenestra - below suture of postorbital and squamosal, much of musculature passes through and anchors on dorsal surface of skull
modified synapsid condition
-temporal fenestra expands
-brain case expands
-non-therapsid synapsids
-early permian - 320 mya
-ex. Dimetrodon
-3 m long
-small temporal fenestra
-weakly heterodont
-small dentary with post dentary bones (articular and angular)
-quadrate articular jaw joint
-lacked secondary palate
-single occipital condyle
-advanced synapsids
-mammal-like reptiles
-became dominant by 265 mya
-all large (up to 5m) and very active
-cynodonts evolved from therapsids in the late Permian
what happened at the end of the Permian?
-mass extinction - 90% of all species, including nearly all therapsids
-cynodonts survived
-"dog teeth"
-strongly heterodont dentition
-gradual evolution of mammalian characters
-gradual evolution of secondary palate
-double occipital condyle
-expansion of dentary in posterior direction, postdentary bones shrinking
-expansion of temporal fenestra and brain case
key character approach
-used jaw joint - mammals have joint between squamosal and dentary
-vs. quadrate and articular
-approach confused by Probainognathus and Diarthragnathus, perfect transitional forms (possessed both types of jaw joints)
suite of characters approach
-jaw joint - dentary/squamosal articulation
-strongly heterodont dentition
-precision of acclusion
-alternate side chewing
-well-developed inner ear region (expanded petrosal, which houses inner ear)
-small size (rat-sized or smaller)
-axial flexes (dorso-ventral in mammals, lateral in non-mammals)
grade-based approaches
key character and suite of character approaches
-based on some perceived level of organization
requirements of classifications
-must reflect evolutionary history - monophyletic groups (allow us to make better predictions about unknown groups)
-stable to the largest degree possible
implications for endothermy
-energy requirements
-increased efficiency of cardio/pulmonary activities
-behavior implications
energy requirements for endothermy
-10 times more energy than ectotherm
-increased efficiency of food gathering and processing
--complex, specialized dentition and precise acclusion
--specialized jaw musculature (masseter)
--secondary palate (allow animal to eat and breathe simulataneously)
increased efficiency of cardio/pulmonary activities
-extrusion of nuclei from red blood cells
-separation of pulmonary from systemic circulation, four chambered heart
-restriction of ribs to thoracic region
-muscularized diaphragm
behavioral implications for endothermy
-permits nocturnal behavior
-hair for insulation
-increased auditory capacity
-increased olfactory capabilites
lineage of mammals
-synapsida - therapsida - cynodontia - mammalia
morganucodontids - morganucodon
-small size
-large nasal cavity, respiratory turbinates, well developed ear region
-dentary expanded (D/S jaw joint, articular still present)
-no tympanic bone (angular still present)
-3-cusped teeth, labial off-set lingually
-alternate side chewing
-shearing teeth (insectivorous)
-diphyodont (infer lactation)
-ancestral condition of pectoral girdle
-possessed vibrissae
-infer endothermy
-3 cusped teeth, linear
-ex Jeholedens in China
-large nasal cavities
-well-developed inner ear
-limb bones lacked epiphygeal plates
-has derived mammalian pectoral girdle
-pectoral limb not rotated under body
-pelvic girdle retained ancestral condition
-"rodents of the mesozoic)
-coexisted with modern mammals
-chisel-like incisors
-large diastema (char. of herbivores)
-complex cheek teeth (many cusps)
-diversified simultaneously with angiosperms
-some arboreal, some may have been gliding
-multiple lineages - non-monophyletic
-progressively more "therian"
-bifunctional teeth
--single tooth with two functions
--tribosphenic molars
newly discovered fossils
-Ausktribosphenos (closely related to monotremes)
-Hadrocodium (oldest known mammalian fossil - 195 mya)
-Eomaia (verl well-preserved Eutheriam mammal - 125 mya)