Phenetic versus phylogenetic systems

24,622 views 16 slides Aug 08, 2018
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About This Presentation

clasification types/
phenetics system
phylogenetic system characters


Slide Content

Phenetic versus Phylogenetic systems Presented by :- Prajapati Dimple B. M.sc sem - 2 CBO - 404 Department of life sciences, Patan

Content Classification types Phenetic system characters Phylogenetic system characters

Classification Types Artificial system Natural system Phylogenetic system

What is phenetic system of classification ? In Biology ,phenetics (Greek: phainein - to appear ) , also known as taximatrix is an attempt to classify oraganism based on overall similarity , usually in morphology or other observable traits , regardless of their phylogeny or evolutionary relation.

Phenetic System Phenetic classification makes no attempt to reflect evolution ; taxa are related based on similarity and difference of character states regardless of the evolutionary content of the characters and states reflected . The characters of choice in phenetic is the unit character or single character. Phenetic classification are based on overall similarities of characters.

Dendrogram : It is branching diagram in the form of tree and depicts degree of relationship . Phenogram : It is representation of phenetic relationship. Cladogram : It is the depiction of cladistics relationship.

What is Phylogenetic system of classification ? Classification of organisms based on their assumed evolutionary histories and relationship .Expand - Also called Phyletic classification , phyletics , origin of Phylogenetic classification.

Phylogenetic system A Phylogenetic system proposed subsequent to the acceptance of the theory of descent. A primary objective of Phylogenetic studies in botany is the determination of origins and relationship of all taxa of both extinct and living plants. Phylogeny deals with the evolutionary history of all taxa. It is a function of taxonomic research at all levels of classification.

The ultimate goal of Phylogenetic research is the production of a Phylogenetic system of classification. The Phylogenetic system shows the genetic and time relationship of any one taxon to another. A Phylogenetic system of classification for plants would provide the answer to questions of (1) their origin (2) to their modes of evolution (3) to problems of monophyleticism vs. Polyphyleticism (4) the identity of primitive and advanced characters etc.

Cladistic Characters The characters have developed from the cladistics approach to classification attempting to determine branching sequence of evolution and base a classification upon them. Useful cladistical characters are called compatible characters where evolutionary directionality of the states within each characters is the same.

Problems with Phylogenetic classification. Convergent evolution Lack of fossils Strict evolutionary classification

Logical Conclusion All angiosperms arose from single common ancestors.

References A textbook of Botany Angiosperms by B.P.Pandey https://en.m.Wikipedia.org https://www.slideshare.net www.biologydiscussion.com

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