PHENETIC, CLADISTIC, CLADOGRAM,

By: Geonyzl L. AlviolaDavao Doctors College

OUTLINE- Introduction :History of Biological

Classification- Phenetic Classification- Cladistic Classification- Cladogram

BIOLOGICAL CLASSIFICATION HISTORY

1. Biological Taxonomy - Aristotle - mid 300’s BCE2. Hierarchical Taxonomy & Binomial nomenclature - Linnaeus - early to mid 1700’s3. Phenetic taxonomy - Adanson - 1750s4. Phylogeny - Darwin, Haeckel - mid 1800’s5. Evolutionary taxonomy - Mayr and Simpson -mid 1900’s6. Phenetic taxonomy - Sneath and Sokal - 1960’s7. Cladistic taxonomy - Hennig - 1960’s

SPECIES CLASSIFICATION

Phenetic: physical attributes, numerical taxonomy

(resemblance: Based on phenotypic similarity)Cladistic (Phylogenetic): evolutionary relationships (descent: Based exclusively on the branching patterns of phylogeny )Evolutionary: synthesis of the two

PHENETICS Does not necessarily reflect genetic

similarity or evolutionary relatedness. Instead, groups are based on convenient, observable characteristics.

Is based on the organism characters, compared to give the expression of similarities and differences.

TWO TYPES OF PHENETIC CLASSIFICATION Artificial Classification - based on one or few easily observable characters of plants such as plant habit People who used the system: - Theophrastus - Herbalist - Linnaeus

Natural Classification based on similarity, but this method

used different characters. People who used the system: - de Jessieu – Genera Plantarum - de Candolle – Prodromous Systematis Naturalis Vegetabilis - Hooker & Bentham – (Genera Plantarum)

CLADISTIC (PHYLOGENETICS)

Phylogenetics is the science of the pattern of evolutionEvolutionary theory states that groups of

similarorganisms are descended from a common ancestor.

Phylogenetic systematics is a method of taxonomic

classification based on their evolutionary history.

Phylogenetic Classification System:Groups reflect genetic similarity and

evolutionaryrelatedness

PHENETICS VS CLADISTIC Phenetics: (Principles

of Numerical Taxonomy,1963) by Peter Sneathnd Robert Sokal Cladistics:(Phylogenetic Systematics, 1966) by Willi Hennig

all out war in the….1960s and 1970s!

W. Hennig

R. Sokal

Within the field of taxonomy there are two different methods and philosophies of building phylogenetic trees: cladistic and phenetic

Phenetic methods construct trees (phenograms) byconsidering the current states of characters without regard to theevolutionary history that brought the species to their currentphenotypes;dendrograms are based on overall similarity

Cladistic methods construct trees (cladograms) rely on

assumptions about ancestral relationships as well as on current data;cladograms are based

ASSUMPTIONS OF CLADISTICS All species in a group must have share

a common ancestor. All species derived from a common

ancestor must be included in the taxon.

PHENETICS VS CLADISTIC

• Phenetics uses “overall similarity” - all characters Used• Graphical representation is called a phenogram, dendrogram, network

PHENETICS VS CLADISTIC

• Cladistics uses only phylogenetically informative characters• Derived state is shared by 2 but not all taxa - “shared derived character states

PHENETICS VS CLADISTIC

phenogram is not equal Cladogram

CLADOGRAM (PHYLOGENETIC TREE)

Node: a branchpoint in a tree (a presumed ancestral OTU)• Branch: defines the relationship between the taxa in terms of

descent and ancestry• Topology: the branching patterns of the tree• Branch length (scaled trees only): represents the number of

changes that have occurred in the branch• Root: the common ancestor of all taxa• Clade: a group of two or more taxa or DNA sequences that includes both their common ancestor and all their descendent

PARTS OF THE CLADOGRAM

Monophyletic pertains to a taxon that is derived from a single ancestral species. only legitimate cladogram type!

  Polyphyletic pertains to a taxon whose

members were derived from two or more ancestors not common to all members.

Paraphyletic pertains to a taxon that excludes some members that share a common ancestor with members included in the taxon.

Basic steps in Cladograms

1) select group of organisms2) determine characters & states3) for each character, classify ancestral & derived comparison to outgroup traits shared with outgroup = ancestral4) group by shared derived characters (synapomorphies)5) choose most parsimonious tree (fewest evolutionary transitions)

EXAMPLE : SEED PLANTSTaxa Cotyledo

nCarpels Perianth Seeds

Conifer 2 present

Dicot 2 Present Present Present

Gnetales 2 Present Present

Monocot 1 Present Present Present

outgroup - - - -

PRACTICE PROBLEM Imagine that we have landed on the planet of the

potato heads, and want to perform a phylogenetic analysis of the different taxa that we have found. Natives tell us that taxon A is very distantly related to the others, so we choose it as our outgroup. We now score our matrix using the systematist's convention that "0"=ancestral and "1"=derived.

REFERENCES

Boylan, M. 2016. Aristotle: Biology. The Internet Encyclopedia of Philosophy, ISSN 2161-0002, http://www.iep.utm.edu/ Chisholm, Hugh, ed. (1911). "Adanson, Michel". Encyclopædia Britannica. 1 (11th ed.). Cambridge University Press. p. 183.Goswami, S. 2016. Systems in Plant Classification: 3 Types. http://www.biologydiscussion.com/plants/classifications/system-of-plant-classification-3-types/30330Grieve, M. 2016. Bloodroot. A Modern Herbal. http://www.botanical.com/ McNeill, J. (1979). Purposeful phenetics. Systematic Biology, 28(4), 465-482.Mayr, E., & Bock, W. J. (2002). Classifications and other ordering systems. Journal of Zoological Systematics and Evolutionary Research, 40(4), 169-194.Saupe, SG. 2007. Phenetic Classification System. Biology Department, College of St. Benedict/St. John's University, Collegeville. http://www.employees.csbsju.edu/ssaupe/Sokal, R. R. (1986). Phenetic taxonomy: theory and methods. Annual Review of Ecology and Systematics, 17(1), 423-442.Stuessy, T. F. (2009). Paradigms in biological classification (1707–2007): has anything really changed?. Taxon, 58(1), 68-76.UCMP. nd. Carl Linnaeus. http://www.ucmp.berkeley.edu.history/linnaeus.html

Chapman (2009)

Christenhusz & Byng (2016)

Pimm & Joppa (2015)

Plant species 310,129 308,312 450,000vascular 281,621 295, 312

Thank you