| African slaves were needed to replace Native American populations that had been decimated by European conquest. |
| So the spermatogonia of an endangered species could be kept preserved and used to produce male and female broodstock to help rebuild populations. |
| In the estuaries, where the bed is more sandy or muddy, the number of species is smaller but the size of their populations is larger. |
| London has one of the most ethnically diverse populations in the world. It absorbs more than half of all immigrants to Britain. |
| This leads to differing populations of plankton in different parts of the sea and varying communities of animals that feed on these populations. |
| There are important populations of seals and internationally significant nesting grounds for a variety of seabirds such as gannets. |
