Question | Answer |
what are the adaptations for burrowing moles? | some have lost incisors and canine, and one premolar. |
forelimb:
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 |