Phylogenetic tree

The phylogenetic tree, or phylogram, is a graphical representation of phylogenesis, the gradual divergence of species from a common ancestor. In addition to the order of divergence of the individual species, a time scale can also be designated on the phylogenetic tree, permitting dating of the individual events in phylogenesis. For some purposes, it is useful to denote changes in the properties of the studied organisms on the phylogenetic tree, termed anagenesis. If the graph is used to depict not genealogical relationships between organisms, but their mutual similarity, then this is called a phenogram. Mutually unrelated species living in a similar environment and exposed to similar selection pressures (fish, dolphins, sharks, ichthyosaurus) can gradually become more similar (i.e. converge to a similar body structure) and can be placed close to one another on a phenogram (but not on a phylogram).

Was this information useful for you?
The classical Darwinian theory of evolution can explain the evolution of adaptive traits only in asexual organisms. The frozen plasticity theory is much more general: It can also explain the origin and evolution of adaptive traits in both asexual and sexual organisms Read more