Final answer:
The phylogenetic species concept relies on genetic differences and similarities to establish species boundaries. Genetic analysis would reveal more similarities between species that are closer on the phylogenetic tree. Additionally, speciation can occur through a variety of mechanisms, including geographic isolation, polyploidy, and ecological niches, with mutations and sexual reproduction being key sources of genetic variation.
Step-by-step explanation:
One important factor in using the phylogenetic species concept to determine species boundaries is genetic differences and similarities (E). This concept focuses on the evolutionary history and relationships among species, and genetic analysis is often used to discern these relationships. For example, if a scientist wishes to understand the genetic relationship between species A, B, D, and E, they would likely find that species D and E share more genetic similarities with each other than with species A or B, and vice versa, provided they are more closely related on the phylogenetic tree.
Moreover, with respect to mechanisms of speciation, geographic isolation is a key factor in allopatric speciation. Additionally, mechanisms such as polyploidy in plants, sexual selection, or ecological niches can lead to speciation. Lastly, genetic variation is crucial for speciation, with primary sources being mutations and sexual reproduction, which introduce new genetic combinations.