Making the Connection TAXONOMY

science of describing, naming and classifying organisms

Traditional

• Linnaean System

Modern

• Systematics

• Phylogenetics

• Phylogenetic tree

• Cladistics

• Cladograms

TRADITIONAL

• Linnaean System – 1735, Systema Naturae ranks organisms by categories according to form & structure.

Represented by hierarchical levels

King Phillip Came Over For Ginger Snaps

MODERN • Systematics - Describing, classifying

and naming organisms in terms of their natural relationships

Natural relationships = physical features, embryos, genes in the

nucleus, DNA & RNA

Classification should reflect Phylogeny

• Phylogenetics - Hypothesis of the evolutionary history of species or taxonomic group

Compare visible similarities among current living or fossils or compare chromosomes and macromolecules

Represent hypotheses in the form of Phylogenetic diagram also called Phylogenetic tree

Phylogenetic tree – Evolutionary tree or Tree of Life

•Charles Darwin 1837 Transmutation of Species

•Charles Darwin 1859 The Origin of Species by Means of Natural Selection

•Ernst Haeckel 1866 Monophyletic tree of organisms

Darwin’s First Tree

This is alleged to be Darwin's first sketch of an

evolutionary tree of life (circa 1837)

taken from his First Notebook on Transmutation of Species, which is viewable at the the Museum of

Natural History in Manhattan, New

York City..

The Origin of Species, 1859

Origin of Species Ch 13 "The affinities of all the beings of the same class have

sometimes been represented by a great tree... The limbs divided into great branches, and these into lesser and lesser branches, were themselves once, when the tree

was small, budding twigs; and this connexion of the former and present buds by ramifying branches may well

represent the classification of all extinct and living species in groups subordinate to groups. . . As buds give

rise by growth to fresh buds, and these, if vigorous, branch out and overtop on all a feebler branch, so by generation I believe it has been with the Tree of Life,

which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever branching

and beautiful ramifications" (Charles Darwin, 1859).

Ernst Haeckel Monophyletic tree of organisms 1866

Evolutionary tree that included all forms of life with a universal

common ancestor

CLADISTICS Developed by Willi Hennig in 1966, A phylogenetic classification system that

uses shared & derived characters as the only criteria for grouping taxa

• Shared character – feature that all members of a group have in common

• Derived character – feature that evolved only within the group under consideration

CLADISTICS• Clad – group of organisms that include an

ancestor plus all of its descendants

Represented by a

• Cladogram – hypothesis phylogenetic diagram of evolutionary relationship between a group

NAILING CLADASTICS

• Take out your worksheets.

• What characteristics did you use to organize organisms?

• How did you design your table?

• Compare and contrast Cladograms.

Cladogram Group

Cladogram of vertebrate animals

Ingroup

Outgroup

Trees Portray Clades

Interpreting a Phylogenetic Tree

• Nodes: Organism at base of tree is common ancestor to all the others in the tree.

• Sister Groups: Branch points indicate the evolution of some characteristic that splits a group into two groups.

• Groups shown at tips of branches include organisms that have evolved most recently.

Major Revision of the Classification System

When looking at the cells of any living organism what 2 fundamental types of

cells can you identify?

EURKARYOTES

&

PROKARYOTES

NEW TREE OF LIFE • 1977, Carl Woese began grouping

organisms by their genetic (RNA) similarities

• Phylogenetic tree drawn from his RNA grouping shows that living things seem to fall into 3 broad groups or domains and an additional kingdom

Redrawing The Classifications of Life

Tree of Life

TREE OF LIFE FLOW CHART

• http://cmapsnasacmex.ihmc.us/servlet/SBReadResourceServlet?rid=1025200161531_1068066319_1715&partName=actualhtmltext

ANY QUESTIONS?

HOMEWORK

WHAT DO YOU THINK???

• Due 5/5/09 List three ways of how evolutionary trees are used.

• Read p 346 – 351

• QUIZ???