Diverse Placental Mammals

Question Answer
what are the adaptations for burrowing moles? some have lost incisors and canine, and one premolar.
rotated so that digits point to side, palms face backwards, and elbows pint upward.
phalanges: short, claws long.
clavicle and humerus short and robust.
manubrium of sternum greatly enlarged and extends forward to beneath base of skull.
adaptations in burrowing moles
moves shoulder joint forward so that forepaws can loosen soil beside the snout. clavicle provides secondary articular surface with humerus. adaptation for burrowing in moles
double articulation provides hinge-like movement and strong bracing for rotation of humerus that accompanies digging stroke. adaptation for burrowing in mole
bat skulls and teeth are shaped by their diet
insect-eating bat microchiroptera
fruit-eating bat megachiroptera
bats that have alrge canines nd incisors for trapping and puncturing eat what? large beetles
less specialized bat that eats moths and beetles hoary bat
the upper fourth premolar and three molars. comparable lower teeth. cheek teeth of insectivorous bat
second and third upper molars. comparable lower teeth cheek teeth of nectarivorous bat
upper fourth premolar and three molars and the comparable lower teeth. cheek teeth of frugivorous bat
the most successful mammals rodentia
long middle branch from beneath front of zygomatic arch to back of jaw. deeper portion vertically directed between zygomatic arch and lower portion of jaw. protogomorph
middle branch from front of orbit on side of face. sciuromorph
deep branch from inside zygomatic arch and forward through infraorbital opening in fromt of eye. hystricomorph
both forward. deeper portion through infraorbital foramen. middle portion in front of orbit. myomorph
what are the specializations for herbivory in rodents? teeth are rough grinding surface with long lasting molars, for breaking cell walls and grinding seeds.
high crowned with grinding surfaces complicated by folding of enamel derived hypsodont
low crowned with blunt cusps primitively bunodont
enamel ridges connect the cusps and expanded. lophodont
two upper pairs of incisors, one lower pair. no specializations of masseter muscle. cheek teeth with ridged crowns for cutting. lagomorpha, rabbits
changes in cetaceans from terrestial mammals: forelimb now a steering device
hindlimb missing
tail now a horizontal caudal fin
dorsal fin
Porpoises, dolphins, sperm whales, baleen whales; 20 to 120,000kg; worldwide in oceans and in some rivers and lakes in Asia, South America, northern America, and Eurasia. Molecular data place whales within the order Artiodactyla. Cetacea
bones of arm and hands (except thumb) are elongate and slender. distal portion of ulna reduced, so looks like single bone in lower limb. chiroptera: bats
extends from body and hind limbs to arm and fifth finger, between the fingers, form hind limb to tail, and from arm to occipitopollicalis muscle bat wing membrane
bat flying mechanism airfoil as in bird wings
upstroke stopped by lock of enlarged greater tuberosity of humerus against the scapula
muscles that bind scapula to axial skeleton ultimately responsible for stopping the upstroke
anteaters, sloths, armadillos; 20g to 33kg; Neotropical region (plus some armadillos in southern United States of America) xenarthra

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