PDF - Wallace Online

CONTENTSNATURAL SELECTIONI. ON THE LAW WHICH HAS REGULATED THE INTRODUCTION OFNEW SPECIESGeographical Distribution dependent on Geologic Changesfrom well-known Geographical and Geological factsA Law deducedThe Form of atrue system of Classification determined by this Law GeographicalDistribution of Organisms Geological Distribution of the Forms ofLife High Organisation of very ancient Animals consistent withthis Law Objections to Forbes's Theory of Polarity RudimentaryOrgans Conclusion . . . .Pages 3-19II.ON THE TENDENCY OF VARIETIES TO DEPART INDEFINITELYFROM THE ORIGINAL TYPEIntroductory Note Instability of Varieties supposed to prove the permanentdistinctness of Species The Struggle for Existence TheLaw of Population of Species The Abundance or Rarity of a Speciesdependent upon its more or less perfect Adaptation to the Conditionsof Existence Useful Variations will tend to Increase ; useless orhurtful Variations to Diminish Superior Varieties will ultimatelyExtirpate the Original Species The Partial Reversion of DomesticatedVarieties explained Lamarck's Hypothesis very differentfrom that now advanced Conclusion .... 20-33III.MIMICRY, AND OTHER PROTECTIVE RESEMBLANCES AMONGANIMALSTest of true and false Theories Importance of the Principle of UtilityPopular Theories of Colour in Animals Importance of Concealmentas Influencing Colour Special Modifications of Colour Theory