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Your Inner Fish
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Mid C19 Richard Owen looked at bones from all over the world brought to him by explorers. Saw clear pattern in all arms of animals - all arms 1 bone upper arm, 2 bones forearm, lotsa bones 'hand', then 5 fingers. And legs same. All creatures with limbs - wings, flippers or hands - have this common design.
Owen was convinced that this was bc God was using a common prototype. Then along comes Charles Darwin, who suggests that more likely reason is that they all share a common ancestor.
Major diff bt 2 theories is that Darwin's can be tested - makes prediction that blueprint will have a development history.
Tiktaalik, a fossil fish from 375 m years ago, had a neck (which meant head cd move independantly of body), and had fins which still had fin webbing, but inside had 1 bone, 2 bones, lotsa bones, digits arrangement.
Tiktaalik's bones showed it cd band at both wrists and shoulders. In a world filled with fishy predators, the only defence was to get big, get armour, or get out of the water.
Most of the bones humans use to walk, grasp, throw, first appeared in fish millions of years ago. First bits of our upper arm and leg in Eusthenopteron 380 mya. Tiktaalik reveals early stage of wrists and pelvi 375 mya. First true fingers and toes 365 mya amphibian Acanthostega
SonicHedgehog gene orig discovered in fruit flies, but then found in all animals.Exactly same protein controls way limbs and digits develop.
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