When are anatomical traits more useful in phylogenetics Whe

When are anatomical traits more useful in phylogenetics? & When is it better to use a molecular approach?

Solution

Answer:

Inferences from phylogenetic analysis should be based on all available evidences. Most of the phylogenetic studies have been limited to either anatomical and morphological traits or molecular analysis. Recently, attempts are being made to combine anatomical and molecular data, called total evidence analysis.

Total evidence analysis commonly treat individual base pairs as equivalent to anatomical characters. Because a single gene may consist of hundreds of base pairs, this always results in the molecular characters outnumbering anatomical characters, thus potentially biasing the outcome.

Anatomical traits from fossils plays the predominant role in resolving the phylogenetic positions of extinct taxa and clades for which molecular data are unavailable.

The anatomical evidences for higher level groupings are weak. In such cases, molecular approach is superior. With respect to two conventional orders- Lipotyphla and Artiodactyla, molecular data suggests that neither is monophyletic. According to molecular analysis, the traditional lipotyphlan families- Tenresidae and Chrysochloridae form a monophyletic group along with Macrosceledia, Tubulidentata, Proboscidea, Sirenia and Hyracoidea, which has been called Afrotheria.

No morphological or anatomical evidence supporting Afrotheria has been found.