5.4 - C - Reclassification
Constructing cladograms based on physical structures can often be problematic as structural similarities do not always reflect evolutionary relationships. Similar structures can be one of two types:
As using structures can be problematic, clades are now establishing using DNA or amino acid sequences. This technology has shown many traditional classifications did not match the evolutionary origin of species. As a result, scientists reclassify species as new evidence emerges. Although time-consuming, the process of reclassification gives biologists more insights to biodiversity and the relationships between species.
The figwort is an angiosperm and an example of reclassification based on evidence. Until recenty, the figwort family was the eighth largest family of angiosperms. The family was originally proposed in the late 1700's and newly discovered plants were added to it until is reached over more than 5,000 species.
Taxonomists set out to study the chloroplast DNA of the family and discovered that what was known as the figwort family actually contained five families combined. After a major reclassification effort, the original figwort family was divided into the five new families (some shown to the left):