...rule will invariably be found to hold good. All varieties will therefore fall into two classes — those which under the same conditions would never reach the population of the pamit species, and those which would in time obtain and keep a numerical superiority. Now, let some...

...rule will invariably be found to hold good. All varieties will therefore fall into two classes — those which under the same conditions would never...of drought, a destruction of vegetation by locusts, tlie irruption of some new carnivorous animal seeking " pastures new " — any change in fact tending...

...rule will invariably be found to hold good. All varieties will therefore fall into two classes—those which under the same conditions would never reach...some alteration of physical conditions occur in the district—a long period of drought, a destruction of vegetation by locusts, the D 2 Irruption of some...

...rule will invariably be found to hold good. All varieties will therefore fall into two classes—those which under the same conditions would never reach...some alteration of physical conditions occur in the district—a long period of drought, a destruction of vegetation by locusts, the D 2 irruption of some...

...rule will invariably be found to hold good. All varieties will therefore fall into two classes — those which under the same conditions would never...destruction of vegetation by locusts, the irruption of some fresh carnivorous animal seeking " pastures new " — any change in fact tending to render existence...

...rule will invariably be found to hold good. All varieties will therefore fall into two classes—those which under the same conditions would never reach...some alteration of physical conditions occur in the district—a long period of drought, a destruction of vegetation by locusts, the irruption of some...

...depiction of struggle not in terms of grains of sand, but in terms of drastic environmental shifts: "Now, let some alteration of physical conditions occur...locusts, the irruption of some new carnivorous animal. . . ." And such striking changes have drastic outcomes: "it is evident that . . . those forming the...

...existence of varieties, and that most changes would affect survival ability, one way or the other. Next: let some alteration of physical conditions occur in...district — a long period of drought, a destruction of the vegetation by locusts, the irruption of some new carnivorous animal seeking "pastures new" —...

...Wallace's view of namral selection: Let some atieration of physical conditions occur in the district—a long period of drought. a destruction of vegetation...any change in fact tending to render existence more dilficult to the species in question. and tasking its utmost powers to avoid complete extermination:...

...zunachst zur Aufstellung des Satzes, dass alle Varietaten einer Art in zwei Klassen zerfallen — « Those which under the same conditions would never...would in time obtain and keep a numerical superiority » (p.28). Wenn nun eine Aenderung derLebensbedingungen eintritt, so ist es klar, « that, of all the...