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vertebrate forelimbs (1 Viewer)

party gal

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hey if anyone has any info to help me analyse and compare the structure of vertebrate forelimbs it would b much appreaciated!! thanx
 

*sarah*

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Just look at some textbooks.
Basically the pentadactyl limb (ie 5 'fingered') is a homologous structure in many vetebrates.
Compare the finer details of the limbs of some animals in relation to their function. Eg the bones of the whale limb are large and heavy to help propel it through the water while the human hand has a finer, more flexible structure to help in gripping etc
 

silvermoon

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i think the Charles Stuart University site probably has some good stuff on this but...in case it doesnt...
vertebrate forelimbs are homologous structures. in a range of vertebrate you can find the same basic bone structure: radius, ulna, metacarpals and phalanges.
human: reasonably slender ulna, rows of close fitting metacarpals and phalanges with an opposable thumb for movement and fine manipulation
bat: very thin, hollow ulna, fused together one row of metacarpals and long thin phalanges that support the membrane of the wing
crocodile: thick ulna for support and power to propel through water and on land, thick metacarpals fused together for power and stability, phalanges attached so that they can bend at right angles for walking.
horse: 'leg' tapers, walk on one phalange

homologous structures suggest common ancestry. examination of the similarities of bone structure support the idea of evolution in that it is easy to see how the structure has changed to support different lifestyles - such as the human and the crocodile or the whale (whicb has metacarpals and phalanges fused together to form the support for a flipper)
 

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