The following points highlight the four major steps involved in the construction of taxonomic groups. The steps are: 1. Operational Taxonomic Units 2. Unit Characters 3. Estimation of Resemblances 4. Cluster Analysis. Taxonomic Group: Step # 1. Operational Taxonomic Units (OTUs): Operational taxonomic unit is the basic unit in numerical taxonomy. It can be an individual, species, genus, family, order or [...]
The following points highlight the seven hypotheses of origin of monocots. 1. According to Engler and his associates, Isoetales, Ophioglossales and a few other pteridophytes are ancestors to monocots. The herbaceous monocots have been considered to be more primitive than woody dicotyledons by them. However, this view is contradicted by the fact that, the woody habit is now generally accepted [...]
The following points highlight the three main lines of evolution in angiosperms. Angiosperm: Evolution # 1. The First Line: I. It consists of Rhoeadales, Sarraceniales, Parietales, Malvales, Geraniales, Sapindales, Rhamnales and some Tubiferales. In this case the hypogynous condition remained unchanged. II. Labiatae is the most advanced family of this line. It is characterized by fusion of sepals, petals and [...]