PALEO200 Lecture Notes - Lecture 4: Quadrupedalism, Hadrosaurid, Caudofemoralis
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Erect relatively straight legs directly underneath it (cat) Sprawling legs out to either sides of the body (lizard: all animals with backbones and forelegs came from the same ancestor (fish-like) that had muscular fins. Evolved a more salamander-like creature gain a sprawling stance and moved around on land. Later, two lineages evolved (birds and mammals more upright stance) In general, the upright erect stance is more efficient, and uses less energy to move around o. Plenty of cases where a sprawling stance can be just as good or better. Erect stance is more efficient when moving on land o. Posture of animals are well imprinted in the bones. Articulation: where two bones are in contact with one another. Comparative morphology: comparing shapes of one animal to another o. Dinosaurs walked with limbs held directly beneath them. Limbs: generally, adaptations of any animals represent a trade-off, graviportal: limbs adapted to support heavy loads.