Origin of Species Variorum

→ like 1859 1860 1861 1866 1869

in the same manner as 1872

→ sorted. 1859 1860 1861 1866 1869

preserved in due proportion. 1872

→ species of the same genus, when 1859 1860 1861 1866 1869

them, if 1872

→ climates! In Russia the small Asiatic cockroach has everywhere driven before it its great congener. 1869 1872

climates! 1859 1860 1861 1866

↑ 1 blocks not present in 1869 1872; present in 1859 1860 1861 1866

In Russia the small Asiatic cockroach has everywhere driven before it its great congener.

→ has been known to 1866 1869 1872

will 1859 1860 1861

generations, if they were allowed to struggle together, →like beings in a state of nature, and if the seed or young were not annually →sorted.

Struggle

for

Life

most

severe

between

Individuals

and

Varieties

the

same

Species.

the species

species

of the same genus

usually have,

have usually,

though by no means invariably,

some

much

similarity in habits and constitution, and always in structure, the struggle will generally be more severe between →species of the same genus, when they come into competition with each other, than between

the species

species

of distinct genera. We see this in the recent extension over parts of the United States of one species of swallow having caused the decrease of another species. The recent increase of the missel-thrush in parts of Scotland has caused the decrease of the song-thrush. How frequently we hear of one species of rat taking the place of another species under the most different →climates! In Russia the small Asiatic cockroach has everywhere driven before it its great congener. ↑ In Australia the imported hive-bee is rapidly exterminating the small, stingless native bee. One species of charlock →has been known to supplant

another,

another

and

species; and

so in other cases. We can dimly see why the competition should be most severe between allied forms, which fill nearly the same place in the economy of nature; but probably in no one case could we precisely say why one species has been victorious over another in the great battle of life.

A corollary of the highest importance may be deduced from the foregoing remarks, namely, that the structure of every organic being is related, in the most essential yet often hidden manner, to that of all

other

the other

organic beings, with which it comes into competition for food or residence, or from which it has to escape, or on which it