Bacterial phylogeny is the study of the evolutionary relationships among different bacterial species. Scientists use genetic information, such as DNA sequences, to construct a "family tree" that illustrates how various bacteria are related to one another. This helps in understanding the diversity and evolution of bacteria over time. By analyzing these relationships, researchers can identify common ancestors and track the evolution of specific traits, such as antibiotic resistance. Tools like phylogenetic trees and molecular techniques are essential in this field, allowing scientists to classify bacteria and explore their ecological roles in environments like soil, water, and the human body.