| GENEPOOL | The total genetic information within a population of animals or plants, usually within a single species (4, 4) |
| POOL | Gene ___ (total genetic information in the gametes of all a population's individuals) |
| CULL | Eliminate, to reduce a population (of animals) (4) |
| EXPOSITION | The insertion of background information within a story or narrative (10) |
| INSIDER | One who has access to confidential information within a group (7) |
| CULLER | One reducing population (of animals) |
| FIFTHCOLUMN | Organised group of enemy sympathisers within a population; originally, Franco supporters in Madrid during the Spanish Civil War (5,6) |
| GENEFLOW | Result of cross-fertilization within a population |
| CITADEL | Stronghold usually within the walls (7) |
| ENDEMIC | Widespread within a population |
| SCALE | Series of musical notes, usually within an octave (5) |
| ALP | Start to assess record that's usually within range (3) |
| HEDGEROW | A line of bushes, trees and plants, usually growing along a bank bordering a country lane or between fields (8) |
| ANATOMY | (Science of) physical structure of animals or plants (7) |
| NATURAL | ___ history, the traditional observational study of animals or plants (7) |
| TAXONOMY | The classification of animals or plants (8) |
| FORMALDEHYDE | Colourless, poisonous, pungent gas used to preserve parts of animals or plants (12) |
| VOLE | With a population of around 75 million, a field mouse-like animal which is one of Britain's most common mammals; or, in ecarte the winning of all the tricks in one deal (4) |
| RELUQUIAE | Fossil remains of animals or plants (9) |
| RELIQUIAE | Fossil remains of animals or plants (9) |
