Evolution by means of hybridization / by J.P. Lotsy.

  • Johannes Paulus Lotsy
Date:
1916
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Evolution by means of hybridization / by J.P. Lotsy. Source: Wellcome Collection.

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    144 THE EVOLUTION OF LIVING BEINGS. them different, and that we can do this just as well with members of very different classes as with members of the same class, by trimming their differences a little more yet. It is easy, in this way, to construct a general ground- plan even between a sea-urchin and a hedgehog, by abstraction of all the differences they show, until we have nothing left than the one point they have in common: the covering with spines and then claim that the groundplan of Echinus and Erinaceus al¬ lows us, to unite them to the group of the Spiniferae, which is not very much worse than the group of the Chordata as defined in the Handwörterbuch of the Naturwissenschaften II p. 623 as: „die durch den Be¬ sitz einer Rückensaite, Chorda dorsalis, ausgezeichne¬ ten Tiere: Tunicaten, Amphioxus und Vertebraten. Man's mind is a curious one, because, after having thus divested the different individuals he sees in na¬ ture, of all their differences, he assigns such immense importance to the shabby rest thus obtained, that he proceeds to explain the differences (he has just succeeded in explaining away) by speculations about the causes which could have changed this common rest to all the different structures which are actually presented by the different organisms, forgetting enti¬ rely, that there is not the slightest reason to consider this rest as ever having been transformed. It is always the same mistake : looking for the (non existing) single origin of different types. So one reaches all kinds of attractive, but quite un¬ founded, conclusions as f. i. that the flapper of a seal