Final answer:
Today, genetic sequencing technology allows for a more detailed understanding and classification of organisms than the Linnaean system that was based on observable traits. This has led to significant reclassifications, such as the recognition of Archaea as a distinct domain, separate from bacteria.
Step-by-step explanation:
Organisms are classified today using a system that has evolved significantly from past methodologies. Historically, classification systems were based mostly on physical traits and observable features, such as those used in the Linnaean classification system, developed by Carl Linnaeus. This system is rooted in taxonomy and organizes life into a hierarchical structure, including levels such as domain, kingdom, phylum, class, order, family, genus, and species.
A crucial scientific advancement that has changed our understanding of classification is genetic sequencing technology. With the sequencing of DNA, scientists can uncover the genetic relationships between organisms, which may not be apparent through physical characteristics alone. This has led to a more accurate understanding of evolutionary relationships, and as a result, the reclassification of some species.
For example, the evolutionary history of microorganisms has been greatly clarified through genetic sequencing. This has enabled scientists to better classify these organisms, often leading to the discovery of entirely new groups or domains of life, such as the Archaea, which were once thought to be a type of bacteria due to superficial similarities. Now, they are recognized as a distinct domain of life.