ZOL Aquatic Enviornment
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16 terms
Terms | Definitions |
|---|---|
 Pakicetus | Early cetacean (50 mya), skull of cetacean, body for amphibious, artiodactyl ankle, astragalus (double pulley shaped) |
| Basilosaurus | Fully aquatic cetacean (37 mya), body elongated, hind limbs greatly reduced (pelvic girdle present) |
| Regulating Body Temperature | Large body size, blubber is 70% of mass |
| Locomotion | Torpedo shaped, little hair, cervical vertebrae compressed or fused, no external ears, glands recessed, pelvic girdle absent, 40 mph |
| Fluke | One of two horizontally flattened divisions of a whale's tail |
| Breathing | Nostrils shifted to top of head, must breath air |
| Staying Underwater | High blood volume (2-3x), more red blood cells per volume (2x), more myoglobin (2-9x), high tolerance to lactic acid, ability to reduce HR, circulatory can bypass regions (except brain, heart, lungs) |
| Coping with Pressure | Flexible thorax, ribs not attached to sternum or vertebral column, lungs with elastic fibers, hard auditory bullae |
| Odontoceti Hearing and Vision | Auditory bullae not attached to skull, vibrations come through jaw, echolocate (can stun fish), good eyesight (except river dolphin), sonar can confuse |
| Mysticeti Hearing and Vision | Poor eyesight, use low frequency sounds |
| Sirenia | Herbivorous, broad cheek teeth, muzzle directed downward, dense bones (to sink), low metabolic rate |
| Carnivora | Excellent vision, vibrissae, streamlined body, short neck, nostrils high on face, all four limbs modified |
| True Seals | Sleek hair, no external ear flaps, hind limbs directed backwards; not used on land |
| Eared Seals | Thick coat of fur, small external ear flaps, hind limbs rotated under body to walk |
| Walruses | No external ear flaps, hind limbs can be rotated |
| Amphibious Mammals | Dense fur, well groomed, streamlined body, webbed feet or distinct hair, nostrils high and can be closed, flattened tail |
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