Ernst Mayr identifies the ‘One Long Argument’ in The Origin of Species (“Origin’) as a compound theory of two independent activities: modification over time and diversification in geographical space (Mayr 86). This paper will focus on the second element of Darwin’s compound theory, species diversification in geographical space as argued by Jerry Coyne in Why Evolution is True.
My thesis is twofold: First, Coyne incorporates Darwin’s geographical space theory into four biogeographical inductive arguments and includes a fifth argument using a theory of convergent evolution. This hybrid five-part inductive argument allows Coyne to explain some attributes of island species that remained puzzles for Darwin. Secondly, this hybrid …show more content…
Coyne develops the inductive argument for each of the species he cited and Darwin completed a number of experiments to test the theory that plants could survive an ocean voyage. Birds and insects can fly to an isolated island and carry plant seeds with them either internally or externally. In contrast most land mammals and the other creatures cited could not swim to an isolated island or they would be killed by the salt water. However, there are certain mammals which have been noted on these oceanic island: flying mammals and aquatic mammals. Both examples would have ready paths to colonize these …show more content…
Secondarily, there is no reason that certain species of mammals be found on these islands while their related but functionally different species are not. This is a very strong observation.
3.4 Observation 4 – Species on Oceanic Islands are Similar to Nearby Mainland Species Coyne introduces the final Origin observation, “…with few exceptions, the animals and plants on oceanic islands are most similar to species found on the nearest mainland” (Coyne 115). This is a close paraphrase of Darwin’s original observation in Origin.
…it is obvious that the Galápagos Islands would be likely to receive colonists from America, whether by occasional means of transport or (though I do not believe in this doctrine) by formerly continuous land ...such colonists would be liable to modification,—the principle of inheritance still betraying their original birthplace. (Darwin