Abstract
WE find it very difficult to follow the hypotheses made by Mr. Pantin in his interesting letter, and cannot agree that they accord with reality. We can not see how, for example, the hypothesis that natural selection is the dominant factor affords any explanation of the fact that the numbers and proportions of local species increase towards the south; nor how it can explain the fact that in New Zealand (of. Ann. of Bot., vol. 32, 1918, p. 339) a great many families show their maximum number of endemics in every genus at the far north, all these families being Indo-Malayan; while a second group of families, characteristic of the northern hemisphere, show their maximum number at the south of New Zealand, and a third group at the centre. The northern families and genera diminish as one goes southward in New Zealand, and pass over, without paying any attention to, the regions where the maxima of the central and southern groups occur. These groups in the same way show no unusual change when they reach the region where the northern maximum occurs. Are the environmental conditions so peculiar at these points that those of the north should cause a multiplication of species only in Indo-Malayan families and those of the south only in families of the northern hemisphere?
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WILLIS, J., YULE, G. Statistical Studies of Evolution. Nature 109, 274 (1922). https://doi.org/10.1038/109274a0
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DOI: https://doi.org/10.1038/109274a0
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