Final answer:
Traits that exhibit a continuous range in a population are likely due to polygenic inheritance and environmental factors. Gene flow and natural selection can affect how these traits are distributed within a geographically continuous population.
Step-by-step explanation:
Traits that occur as a continuum in a population are likely due to polygenic inheritance, where multiple genes contribute to a single trait resulting in a range of phenotypes rather than discrete categories. Environmental factors can also influence these traits, contributing to the variation we observe. When populations are geographically continuous, gene flow maintains a relatively homogeneous gene pool, allowing alleles to move freely within the population. However, when populations are geographically separated, they can evolve differently due to natural selection, genetic drift, and varying mutations. These genetic variations contribute to the continuous traits seen in populations.
New traits can also appear in populations through mechanisms such as mutations and genetic drift. These traits must be advantageous for natural or sexual selection to increase their frequency in the population. Lastly, the frequency of beneficial alleles in a population is determined by a combination of genetic factors, including mutation, gene flow, and natural selection, as well as the impact of environmental changes.