6/27/2023 0 Comments The inner fishWhat’s more, these great revolutions in the history of life, and others like them, could never have happened otherwise. Feathers did not arise during the evolution of flight, nor did lungs and limbs originate during the transition to land. Extending this message, Shubin states “biological innovations never come about during the great transition they are associated with. Fish were breathing air with lungs well before animals ever stepped onto terra firma.” (p. Shubin follows: “Lungs aren’t some invention that abruptly came about as creatures evolved to walk. Lungfish, Shubin notes, have lungs in addition to gills. Shubin provides several examples of this gradual change with change of function beginning with lungs in fish and feathers in the ancestors of birds. The key insight is that the function that the nascent characters provide often is distinct from the function they provide the organism when fully formed. Darwin responded in the sixth edition of The Origin of Species that characters change gradually, “often accompanied by a change of function”, a phrase that Shubin highlights (p.
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