Who would have thought that the number of cats in a particular area would impact Red Clover density?
He who believes in the struggle for existence and in the principle of natural selection , will acknowledge that every organic being is constantly endeavouring to increase in numbers, and that if any one being vary ever so little, either in habits or structure, and thus gain an advantage over some other inhabitant of the country, it will seize on the place of that inhabitant, however different it may be from its own place.
There are geese and frigate-birds with webbed feet either living on the dry land or most rarely alighting on the water, there are long-toed corncrakes living in meadows instead of in swamps; there are woodpeckers where not a tree grows, there are diving thrushes and petrels with the habits of auks.
The bee can't withdraw its sting owing to the backward serratures and causes the death of the insect by tearing out its viscera. If we looking at the sting of the bee as having originally existed in a remote progenitor as a boring and serrated instrument, like that in so many members of the same great order and which has been modified but not perfected for its present purpose, with the poison originally adapted to cause galls subsequently intensified, we can perhaps understand how it is that the use of the sting should so often cause the insect's own death.