Transcript Organizing Biodiversity with Evolutionary Trees

• Summer 2008 Workshop
• in Biology and Multimedia
• for High School Teachers
Organizing
Biodiversity with
Evolutionary Trees
Classification & Taxonomy
• Aristotle - first classification system
• John Ray - developed classification
system and a new concept of species
• Carolus Linnaeus - system of hierarchical
classification and binomial nomenclature
What is Systematics?
• Systematics is the branch of Biology
that seeks to classify biodiversity using
everything known about an organism in
order to understand its evolutionary
relationship to other organisms.
Early Classification vs. Modern Analysis
Pre- Darwinian
Post-Darwinian
Organisms are
grouped
according to
similar
physical
characteristics
Organisms are
grouped
according to
evolutionary
relationships
Tree of Life
• All organisms are related, but some are
more closely related than others.
• To represent the idea that all living things,
despite their diversity, share a common
ancestor, Darwin used the metaphor of a
“tree of life”.
Tree Thinking
“The affinities of all the beings of the same class
have sometimes been represented by a great
tree…The green and budding twigs may
represent existing species; and those produced
during each former year may represent the long
succession of extinct species… As buds give rise
by growth to fresh buds, and these, if vigorous,
branch out and overtop on all sides many a
feebler branch, so by generation I believe it has
been with the great Tree of Life.”
Charles Darwin, On the Origins of Species (1859)
This “tree”
illustration
was the
only one
included in
Darwin’s
Origin of
Species.
Darwin’s Tree
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Image taken from http://commons.wikimedia.org/wiki/Image:Darwins_tree_of_life_1859.gif
• Ernst Haeckel’s
tree diagrams
continued to
develop the idea
that all living
organisms are
related.
Haeckel’
s Tree
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
• He included
microorganisms
and was the first
to use the term
“Protista”.
http://en.wikipedia.org/wiki/Image:Tree_of_life_by_Haeckel.jpg
Evolutionary trees are
hypotheses!
• Different sources of evidence may lead to
the development of competing trees
• The principle of parsimony (choosing the
least complex hypothesis) guides
systematists in their reconstruction of trees
Fossils
Morphology
Behavior
Physiology
Data Sources
Geography
Geology
Molecular Evidence
Ecology
Creating Evolutionary Trees
• Comparative studies and fossils may be used
to create initial phylogentic hypotheses
• Molecular techniques may be used to test or
refine initial hypotheses
• Computer programs are readily available to
analyze vast amounts of phylogenetic data
Tools
• Available Software for Phylogenetic Analysis
Biology Workbench - http://workbench.sdsc.edu/
NCBI Blast - http://workbench.sdsc.edu/
ClustalW - http://www.ebi.ac.uk/Tools/clustalw2/index.html
• Molecular Data Bases on the Web
Genbank - http://www.ncbi.nim.nih.gov/Entrez
Ribosomal Database Project II - http://rdp.cme.msu.edu/
Using Molecular Data
“Old” World View of Biodiversity
• In 1977, Carl Woese
used molecular data from
ribosomal RNA to classify
microbes. Previously,
microbes classification
was limited due to their
lack of identifiable
characteristics.
Plantae
Fungi
Animalia
Protista
Monera
Drawn by Christine Rodriguez
• Woese’s work led to the
current three “domain”
system of classification:
Archaea, Bacteria,
Eukarya
QuickTi me™ and a
T IFF (Uncompressed) decompressor
are needed to see thi s pi cture.
http://evolution.berkeley.edu/evolibrary/article/_0_0/evo_01
The Tree of Life Project
• The Tree of Life Web
Project (ToL) is a
collaborative effort
of biologists from
around the world.
The project seeks to
create a “super
tree” which
organizes the
diversity of
organisms on Earth
through their
evolutionary history.
Figure courtesy of David Hillis
http://www.zo.utexas.edu/faculty/antisense/DownloadfilesToL.html
Resources
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“A Science Primer: Classification and Phylogenetics” http://www.ncbi.nih.gov/About/primer/phylo.html
Baum, D.A.,et al. “ The Tree Thinking Challenge” Science 310:979-980.
Campbell, N.A. and Reece, J. B. Biology 6th edition. San Francisco: Benjamin Cummings, 2002.
Clos, L.M. “What is Cladistics?” [6/8/06] http://www.fossilnews.com/1996/cladistics.htm
Filson, R. “Island Biogeography and Evolution: Solving a Phylogenetic Puzzle with Molecular Genetics”
http://www.accessexcellence.org/AE/AEPC/WWC/1995/simulation_island.html
Kramer, B. and Flammer, L. “Making Cladograms: Phylogeny, Evolution, and Comparative Anatomy”
Evolution & Nature of Science Institutes (ENSI/SENSI), University of Indiana. [6/8/06]
http://www.indiana.edu/~ensiweb/lessons/mclad.html
“Names & classifying living things” http://www.backyardnature.net/names.htm
Singer, F., et al “The Comparative Method, Hypothesis Testing & Phylogentic Analysis” The American
Biology Teacher 63(7): 518-523.
Skelton, P. W., A. Smith, et al. (2002). Cladistics a practical primer on CD-ROM. Cambridge, The Open
University; Cambridge University Press.
“The Tree of Life Web Project’ http://www.tolweb.org/tree/
“Tree-thinking Group” http://www.tree-thinking.org
“Understanding Evolution: An Evolution Web Site for Teachers” http://evolution.berkeley.edu/
“What did Trex taste like? An introduction to how life is related”
http://www.ucmp.berkeley.edu/education/explorations/tours/Trex/guide/index.html
Dawson, Scott “Creatures from the Black Lagoon: Lessons in the Diversity and Evolution of Eukaryotes”
http://www.ucmp.berkeley.edu/education/events/eukevol.html