Carrying capacity refers to the maximum population size of a species/population in a particular habitat. The carrying capacity depends on abiotic (e.g., shelter, water) and biotic factors (e.g., food, presence of mates). According to the evolutionary theory, individuals better adapted to their environments are more likely to survive and reproduce (i.e., produce more offspring) than other members of the same species. These 'better adapted' individuals will have more chances to pass their 'beneficial alleles' to the next generation.