Variation resulting from the appearance of mutations is called variation through mutation while that conditioned by subsequent recombination of genes as a result of interbreeding is called variation through recombination.roup variation includes the differences among aggregates of any rankâfrom differences among small groups of individuals within a population to differences among the kingdoms of living nature (animals and plants). In essence, the entire taxonomy of organisms is constructed on the comparative study of group variation.
The best known animal phyla are the Mollusca, Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Echinodermata, and Chordata, the phylum to which humans belong.
The major divisions of the plant kingdom are the mosses, ferns, conifers (gymnosperms) and flowering plants (angiosperms). The major phyla of the animal kingdom are the cnidarians, mollusks, annelids, arthropods, echinoderms, and chordates.