![\"\"](\"http:\/\/ardillas.anipedia.net\/images\/foto-ardilla-voladora.jpg\")
<\/p>\n<\/p>\n
El autor entiende que la ardilla voladora puede llegar a ser perfecta por acci\u00f3n de la selecci\u00f3n natural. Otro ejemplo dogm\u00e1tico que recuerda el comentario de Thompson:<\/p>\n
<\/p>\n
\u201cThis situation, where scientific men rally to the defence of a doctrine they are unable to define scientifically, much less demonstrate with scientific rigour, attempting to maintain its credit with the public by the suppression of criticism and the elimination of difficulties, is abnormal and undesirable in science.<\/em>\u00a0 \u201c<\/p>\n <\/p>\n <\/p>\n <\/p>\n Quedar\u00eda por discutir, entre otras muchas cosas,\u00a0 qu\u00e9 significa \u00abla m\u00e1s delicada gradaci\u00f3n\u00bb, cuando el autor menciona esta palabra:<\/p>\n <\/p>\n the finest gradation from animals with their tails only slightly flattened, and from others, as Sir J. Richardson has remarked, with the posterior part of their bodies rather wide and with the skin on their flanks rather full, to the so-called flying squirrels;<\/em><\/p>\n \u00a0<\/em><\/p>\n la m\u00e1s delicada gradaci\u00f3n desde animales con la cola s\u00f3lo un poco aplastada, y, seg\u00fan ha se\u00f1alado Sir J. Richardson, desde animales con la parte posterior del cuerpo un poco ancha y con la piel de los lados algo holgada, hasta las llamadas ardillas voladoras;<\/em><\/p>\n \u00bfSignifica la m\u00e1s fina gradaci\u00f3n que no hay discontinuidad entre especies? Si as\u00ed fuese no estar\u00eda de m\u00e1s que el autor viniese a documentarlo. Ser\u00eda un caso bien excepcional. Por lo tanto no parece que exista la m\u00e1s fina gradaci\u00f3n sino diferencias entre especies. A saltos. Como las ardillas.<\/p>\n <\/p>\n 267<\/em><\/p>\n \u00a0<\/em><\/p>\n Look at the family of squirrels; here we have the finest gradation from animals with their tails only slightly flattened, and from others, as Sir J. Richardson has remarked, with the posterior part of their bodies rather wide and with the skin on their flanks rather full, to the so-called flying squirrels; and flying squirrels have their limbs and even the base of the tail united by a broad expanse of skin, which serves as a parachute and allows them to glide through the air to an astonishing distance from tree to tree. We cannot doubt that each structure is of use to each kind of squirrel in its own country, by enabling it to escape birds or beasts of prey, or to collect food more quickly, or, as there is reason to believe, to lessen the danger from occasional falls. But it does not follow from this fact that the structure of each squirrel is the best that it is possible to conceive under all possible conditions. Let the climate and vegetation change, let other competing rodents or new beasts of prey immigrate, or old ones become modified, and all analogy would lead us to believe that some, at least, of the squirrels would decrease in numbers or become exterminated, unless they also become modified and improved in structure in a corresponding manner. Therefore, I can see no difficulty, more especially under changing conditions of life, in the continued preservation of individuals with fuller and fuller flank-membranes, each modification being useful, each being propagated, until, by the accumulated effects of this process of natural selection, a perfect so-called flying squirrel was produced.<\/em><\/p>\n \u00a0<\/em><\/p>\n Consideremos la familia de las ardillas; en ella tenernos la m\u00e1s delicada gradaci\u00f3n desde animales con la cola s\u00f3lo un poco aplastada, y, seg\u00fan ha se\u00f1alado Sir J. Richardson, desde animales con la parte posterior del cuerpo un poco ancha y con la piel de los lados algo holgada, hasta las llamadas ardillas voladoras; y las ardillas voladoras tienen sus miembros, y aun la base de la cola, unidos por una ancha expansi\u00f3n de piel que sirve como de paraca\u00eddas y les permite deslizarse en el aire, hasta una asombrosa distancia, entre un \u00e1rbol y otro. Es indudable que cada conformaci\u00f3n es de utilidad para cada clase de ardilla en su propio pa\u00eds, permiti\u00e9ndole escapar de las aves y mam\u00edferos de presa y procurarse m\u00e1s r\u00e1pidamente la comida, disminuyendo el peligro de ca\u00eddas accidentales, como fundadamente podemos creer. Pero de este hecho no se sigue que la estructura de cada ardilla sea la mejor concebible para todas las condiciones posibles. Supongamos que cambien el clima y la vegetaci\u00f3n; supongamos que emigren otros roedores rivales o nuevos animales de presa, o que los antiguos se modifiquen, y la analog\u00eda nos llevar\u00eda a creer que algunas por lo menos de las ardillas disminuir\u00edan en n\u00famero de individuos o se extinguir\u00edan, a menos que se modificasen y perfeccionasen su conformaci\u00f3n del modo correspondiente. No se ve, por consiguiente, dificultad -sobre todo si cambian las condiciones de vida- en la continua conservaci\u00f3n de individuos con membranas laterales cada vez m\u00e1s amplias, siendo \u00fatil y propag\u00e1ndose cada modificaci\u00f3n hasta que, por la acumulaci\u00f3n de los resultados de este proceso de selecci\u00f3n natural, se produjo una ardilla voladora perfecta. <\/em><\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" El autor entiende que la ardilla voladora puede llegar a ser perfecta por acci\u00f3n de la selecci\u00f3n natural. Otro ejemplo dogm\u00e1tico que recuerda el comentario de Thompson: \u201cThis situation, where scientific men rally to the defence of a doctrine they are unable to define scientifically, much less demonstrate with scientific rigour, attempting to maintain its credit with the public by the suppression of criticism and the elimination of difficulties, is abnormal and undesirable in science.\u00a0 \u201c Quedar\u00eda por discutir, entre otras muchas cosas,\u00a0 qu\u00e9 significa \u00abla m\u00e1s delicada gradaci\u00f3n\u00bb, cuando el autor menciona esta palabra: \u2026<\/p>\n","protected":false},"author":86,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[467,14323,14331],"tags":[22775],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":4}},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/posts\/136301"}],"collection":[{"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/users\/86"}],"replies":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/comments?post=136301"}],"version-history":[{"count":7,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/posts\/136301\/revisions"}],"predecessor-version":[{"id":136682,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/posts\/136301\/revisions\/136682"}],"wp:attachment":[{"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/media?parent=136301"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/categories?post=136301"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/tags?post=136301"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}