\u00a0<\/em><\/p>\n the most favoured or improved varieties will have been enabled to spread; there will have been much extinction of the less improved forms, and the relative proportional numbers of the various inhabitants of the reunited continent will again have been changed; and again there will have been a fair field for natural selection to improve still further the inhabitants, and thus to produce new species.<\/em><\/p>\n <\/p>\n \u00a0<\/em><\/p>\n las variedades m\u00e1s favorecidas o perfeccionadas habr\u00e1n podido extenderse, se habr\u00e1n extinguido muchas de las formas menos perfeccionadas, y las relaciones num\u00e9ricas entre los diferentes habitantes del continente reconstituido habr\u00e1n cambiado de nuevo, y de nuevo habr\u00e1 habido un campo favorable para que la selecci\u00f3n natural perfeccione todav\u00eda m\u00e1s los habitantes y produzca de este modo nuevas especies.<\/em><\/p>\n <\/p>\n <\/p>\n 153.<\/p>\n <\/p>\n To sum up, as far as the extreme intricacy of the subject permits, the circumstances favourable and unfavourable for the production of new species through natural selection. I conclude that for terrestrial productions a large continental area, which has undergone many oscillations of level, will have been the most favourable for the production of many new forms of life, fitted to endure for a long time and to spread widely. While the area existed as a continent the inhabitants will have been numerous in individuals and kinds, and will have been subjected to severe competition. When converted by subsidence into large separate islands there will still have existed many individuals of the same species on each island: intercrossing on the confines of the range of each new species will have been checked: after physical changes of any kind immigration will have been prevented, so that new places in the polity of each island will have had to be filled up by the modification of the old inhabitants; and time will have been allowed for the varieties in each to become well modified and perfected. When, by renewed elevation, the islands were reconverted into a continental area, there will again have been very severe competition; the most favoured or improved varieties will have been enabled to spread; there will have been much extinction of the less improved forms, and the relative proportional numbers of the various inhabitants of the reunited continent will again have been changed; and again there will have been a fair field for natural selection to improve still further the inhabitants, and thus to produce new species.<\/p>\n <\/p>\n Resumiendo, hasta donde la extrema complicaci\u00f3n del asunto lo permite, las circunstancias favorables y desfavorables para la producci\u00f3n de nuevas especies por selecci\u00f3n natural, llego a la conclusi\u00f3n de que, para las producciones terrestres, un gran territorio continental que haya experimentado muchas oscilaciones de nivel habr\u00e1 sido lo m\u00e1s favorable para la producci\u00f3n de nuevas formas de vida, capaces de durar mucho tiempo y de extenderse mucho. Mientras el territorio existi\u00f3 como un continente, los habitantes habr\u00e1n sido numerosos en individuos y especies, y habr\u00e1n estado sometidos a competencia rigurosa. Cuando por depresi\u00f3n se convirti\u00f3 en grandes islas separadas, habr\u00e1n subsistido muchos individuos de la misma especie en cada isla; el cruzamiento en los l\u00edmites de la extensi\u00f3n ocupada por cada nueva especie habr\u00e1 quedado impedido; despu\u00e9s de cambios f\u00edsicos de cualquier clase, la inmigraci\u00f3n habr\u00e1 estado evitada, de modo que los nuevos puestos en la econom\u00eda de cada isla habr\u00e1n tenido que ser ocupados mediante la modificaci\u00f3n de los antiguos habitantes, y habr\u00e1 habido tiempo para que se modificasen y perfeccionasen bien las variedades en cada isla. Al convertirse, por nueva elevaci\u00f3n, las islas otra vez en un territorio continental, habr\u00e1 habido de nuevo competencia riguros\u00edsima; las variedades m\u00e1s favorecidas o perfeccionadas habr\u00e1n podido extenderse, se habr\u00e1n extinguido muchas de las formas menos perfeccionadas, y las relaciones num\u00e9ricas entre los diferentes habitantes del continente reconstituido habr\u00e1n cambiado de nuevo, y de nuevo habr\u00e1 habido un campo favorable para que la selecci\u00f3n natural perfeccione todav\u00eda m\u00e1s los habitantes y produzca de este modo nuevas especies.<\/p>\n","protected":false},"excerpt":{"rendered":" El autor cree que las variedades que sobreviven lo hacen por que se lo merecen, es decir, que son m\u00e1s perfeccionadas: \u00a0 the most favoured or improved varieties will have been enabled to spread; there will have been much extinction of the less improved forms, and the relative proportional numbers of the various inhabitants of the reunited continent will again have been changed; and again there will have been a fair field for natural selection to improve still further the inhabitants, and thus to produce new species. \u00a0 las variedades m\u00e1s favorecidas o perfeccionadas habr\u00e1n podido extenderse, se habr\u00e1n\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":[467,14321,14326,521],"tags":[],"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\/135145"}],"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=135145"}],"version-history":[{"count":3,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/posts\/135145\/revisions"}],"predecessor-version":[{"id":135181,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/posts\/135145\/revisions\/135181"}],"wp:attachment":[{"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/media?parent=135145"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/categories?post=135145"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/biologia_pensamiento\/wp-json\/wp\/v2\/tags?post=135145"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}