Write short notes on cladistic analysis.

Explanation

(i)It is one of the primary methods of constructing phylogenies, or evolutionary histories. Cladistics uses shared, derived characters to group organisms into clades.
(ii) These clades have atleast one shared, derived character found in their most recent common ancestor that is not found in other groups hence they are considered more closely related to each other.
(iii) These shared characters can be morphological such as, leaf, flower, fruit, seed and so on, behavioural, like opening of flowers nocturnal / diurnal, molecular like, DNA or protein sequence and more.
(iv) Cladistic accepts only monophyletic groups. Paraphyletic and polyphyletic taxa are occasionally consider when such taxa conveniently treated as one group for practical purposes. eg. dicots, sterculiaceae. Polyphyletic groups are rejected by cladistic.
(a) Monophyletic group Taxa comprising all the descendants of a common ancestor.
(ii)Paraphyletic group Taxon that includes an ancestor but not all of the descendants of that ancestor.
(c)Polyphyletic group: Taxa that includes members from two different lineages.
Need for cladistics:
(1) Cladistics is now the most commonly used and accepted method for creating phylogenetic system of classifications.
(ii) Cladistics produces a hypothesis about the relationship of organisms to predict the morphological characteristics of organism.
(iii) Cladistics helps to elucidate mechanism of evolution.
(b) Paraphyletic group : Taxon that includes an ancestor but not all of the descendants of that ancestor.