arrector pilli, sebaceous (oils) glands, scent glands, sweat glands (evaporative cooling), mammary glands

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temporal fossa, mammal like reptiles, paleozoic abundance, carnivores (Triassic), primitive tetrapod eye, glandular skin w/o scales, most likely oviparous

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precursor evolutionary events leading to C. Mammalia lost temporal shield (upper bones of skull roof), exposing zygomatic arch and sagittal crest (allowing for muscular attachments), beginnings of heterodonty, probably had hair, beginnings of upright posture

Paraphyletic group!

O. Tricodonts (E), Dicodonts (E), Monotremata

S.C. Prototheria (E)

small, insectivorous, nocturnal, braincase 3-4x larger than similarly sized therapsids

S.C. Prototheria (E)

Most complex teeth of the Jurassic

retain reptilian jaw articulation

S.C. Protheria

compared to therians: primative ear (no pinnae, less coiled cochlea), mammary glands but no nipples, endothermic but lower metabolic rate, lack sweat glands (not good at evap. cooling)

O. Multituberculata (E)

single pair of lower incisors, large molariform teeth, rodent-like herbivores (extinction via competitve exclusion with rodents?), shows evidence of tooth wear suggesting backwards drawing of molars (similar to the forward drawing of rodents!)

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I.C. Metatheria, I.C. Eutheria

Tribosphenic molars (shearing and grinding)

animal based diet

cecum: junction between sm. and lg. intestine that holds bacteria

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plant based diet

extremely long guts

non-ruminant herbivores: long sm. intestine (foregut) (to stew a while to pull out nutrients), cecum, long hindgut

ruminant herbivores: crazy stomachs, avg. cecum, emphasis on foregut digestion

2 sets of reversed triangles, edges shear, protocone and talonid basin form a crushing interface

*Difference btn pseudotribosphenic molars and tribophenic molars: 

Tribosphenic: trigonid is in the FRONT, talonid is in the BACK

Pseudo: trigonid is in the BACK, talonid is in the FRONT

evolved convergently

non ruminant

coprophagy: feeding on feces, make up for a quick gut passage rate by passing food twice (rabbits, rodents, shrews...)

cecal pellets soft and reconsumed, fecal pellets left aside

feeding on feces, make up for a quick gut passage rate by passing food twice (rabbits, rodents, shrews...)

cecal pellets soft and reconsumed, fecal pellets left aside

circular cycle that maximizes occlusion between heterodont teeth

powerstroke: transverse movement of lower molars across uppers, leads to distinct shearing and grinding surfaces

Early synapsid: adductor muscle created an upward vector allowing for opening and closing of jaw

Mammals: temporalis and masseter/pterygoid muscles create more potential vectors leading to a diversity in jaw directionality (see: mammalian masticatory cycle)

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depending on food type, different muscles have been adapted to different sizes

 ie: carnivore vs. herbivore (different muscle regions being enlarge gives information regarding what the animal eats, and how its jaw is specialized to process that food)

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Searching = time spent looking for food

Handling = time spent digesting the food

L-R: 

specific food source: hard to find, easier to adapt and specialize to food source

varied food source: easier to find, but harder to recieve nutrients (less digestive adaptations)

running

digitagrade: have elevated meta/carpals leaving only the phalanges to make contact with the substrate, long limbs

unguligrade: elevated the phalanges, as well as the meta/carpals so that only the tips of the phalanges are in contact with the ground, also reduced the number of digits (3,2, or 1), longest limbs

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limbs act as levers, muscles provide the power

To increase the force output, shorten the out lever and lengthen the in lever (ie: lions/tigers)

To increase the velocity, lengthen the out lever and shorten the in lever (ie: horses)

with out lever being tibia/fibula and in lever being femur

• muscle inserts near joints they move
• bring limbs directly under body (potential loss of clavicle)
• morphology of limb joingt limits movement to force and aft (minimizing energy spent controlling transverse movements)
• tendons/ligaments can store E and function like springs (elasticity)
• decreasing the weight of distal limb segments
• muscle mass is near body w/long tendons to reach insertion

alter gait so both legs are in front/back, or one side touch the ground simultaneously (ungulates) 

allows for rapid changes in direction

spinal flextion to run and alter direction

propulsion by all 4 limbs

stotting or pronking

hopping, propulsion by hindlimbs only

lengthening one or more hindlimb segment, shift of body mass posteriorly, enlargement of hip muscles, large hind feet for take off and landing, long tail for balance

burrowing; live entire life under ground

enlarged radius and ulna, robust humerous, enlarged claws, small eyes, leathery nose

expensive endeavor: safety provided by living underground outweighs energetic cost (also a more stable environment with many resources)

[+]: water>air (density), bouyancy

[-]: h2o current--> drag, evolved streamlined bodies to reduce drag

[-] gravity

no generation of lift

energetically cheap

energetically expensive, though extremely efficient

morphologically complex

study of animal distributions and ranges

• nearctic, palearctic, neotropical, oriental, ethiopian, australian