1.   Humans are not the centre of life, nor is any other single species.

2.   So, think wisely before you devote all your time to carp - or any other single species.

3.   The cryptocorynes occur mainly in cultures of single species on overgrown river beds and are exposed to the conditions of amphibious life.

4.   The genus contains only a single species.

5.   There is debate about whether a single species can split into two without geographical isolation.

6.   The single species of veterinary importance is not found in lung tissue, but in the heart and associated pulmonary vessels.

7.   American goldfinches in their dull-yellow winter plumage outnumbered any single species of sparrow.

8.   And biologists persist in confronting the collaborators with single species in which quarter-power scaling laws do not seem to hold.

9.   Between extinction spasms, in the background hum of evolution, single species winked out here and there to be replaced by new ones.

10.   Bond and Kamil were interested in the longstanding question of why members of a single species may have very different color patterns.