A gene pool refers to the combination of all the genes (including alleles) present in a reproducing population or species. A large gene pool has extensive genomic diversity and is better able to withstand environmental challenges. Inbreeding contributes to a smaller gene pool, making populations or species less able to adapt and survive when faced with environmental challenges.
Gene pool refers to thorough genetic diversity that exists within a population. The larger the genetic pool, the more the diversity and the more opportunity this population will have to survive environmental stress that may impact on them. So gene pool is really good in the sense that the larger the gene pool, the more the survival of that particular population in terms of withstanding different things that may come in terms of environment.