In Conclusion Darwin was right on the mark: "As the species of the same genus usually have much similarity in habits and constitution, and always in structure, the struggle will generally be more severe between them, if they come into competition with each other, than between the species of distinct genera."
(the species of the same genus; have; much similarity in habits and constitution; T:usually) (the struggle; will generally be; more severe) (they; come; into competition with each other)
the species of the same genus the struggle they
have will generally be come
much similarity in habits and constitution T:usually
more severe
into competition with each other