Skip to main content
Close
Menu

Rediscovering Biology: Molecular to Global Perspectives

Evolution and Phylogenetics

Molecular techniques are reigning our perspective on evolution. This unit illustrates how molecular data are combined with fossil evidence to explore relationships between species that until now scientists have only been able to guess at. The unit takes a glimpse at the evolution of Phylogenetics as a field.

ONLINE TEXTBOOK
The online textbook chapters support and extend the content of each video. The Web version can be viewed as a full chapter or as individual sub-sections, and includes links to glossary terms and other related material.

ANIMATIONS & IMAGES
Explore the archive of animations, images and figures from the videos and online textbook. All of the images can be viewed online or downloaded as jpg files.

EXPERT INTERVIEW TRANSCRIPTS
Read profiles of the expert scientists featured in the video and find the complete transcripts of the interviews conducted for this unit.
Philip D. Gingerich, Ph.D.
Tim Read, Ph.D.
Carl R. Woese, Ph.D.

Chapter Contents

Introduction
A Brief History of Classification
Cladistics and Classification
Applications of Molecular Phylogenetics
HIV and Forensic Uses of Phylogenetics
The Origin of Bats and Flight
Challenges
Coda: The Renaissance of Comparative Biology

Unit Glossary

Clade
An organizational term used in cladistics to describe a group of related organisms being compared.

Conjugation
A method of gene transfer that occurs in bacteria, in which DNA copied from a plasmid or chromosome is transferred to a recipient cell. It can contribute to lateral gene transfer when it occurs between distantly related bacteria.

Convergence
The phenomenon where more distantly related lineages have similar features due to the operation of similar evolutionary forces.

Eukarya
The domain of all eukaryotic organisms. Eukaryotes are single or multicellular organisms with cells that have a membrane-enclosed nucleus and usually other organelles.

Homology
Similarity of features of organisms due to shared ancestry.

Lateral gene transfer
Also referred to as horizontal gene transfer. The transmission of genes directly between organisms, particularly bacteria, and not from parent to offspring.

Monophyletic
A clade, or group, of organisms that includes every member of the group and its shared common ancestor.

Outgroup
An unrelated group or organism used for the purpose of comparison.

Paraphyletic
An incomplete clade of related organisms from a common ancestor.

Parsimony analysis
A method used to create phylogenies of organisms based on the assumption that the evolution of characters occurs by the simplest (most parsimonious) path.

Phylogeny
A tree-like diagram used to represent evolutionary relationships between species or groups.

Reversal

A phenomenon wherein mutation or selection causes a derived character state to revert back to the ancestral state

Rooted tree

A phylogeny in which the evolutionary ancestor is known.

Sister taxa

The most closely related groups of organisms in a phylogeny.

Synapomorphies
Derived character states that are shared by two or more taxa.

Taxa
Groups or representatives of related organisms that are being compared; they can vary in hierarchical level (such as genus, family, order, and so on).

Unrooted tree
A phylogeny in which the evolutionary ancestor is not known.

Unit Animations

  • Cladogram
    An example of a cladogram, which depicts the relatedness of taxonomic groups; uses the Order Cetacea, whales, as an example.
    View Animation Still

 

  • shim.gifNew Theoretical Approach in Whale Phylogeny
    A phylogeny depicting the new picture of whale ancestry.
    View Animation Still

 

  • Genetic Data
    Demonstrates how scientists use genetic data to build a phylogeny and determine relatedness between a group of organisms.
    View Quicktime Movie
  • shim.gifTree of Life — Lateral Gene Transfer Diagram
    Revised “tree of life” with all groups divided into their domains. Includes information about lateral gene transfer and the endosymbiosis of bacteria that became mitochondria and chloroplasts.
    View Animation Still

Related Resources

Books
Freeman, S., and J. C. Heron. 2001. Evolutionary analysis. 2d ed. Upper Sable River, NJ: Prentice Hall.
An excellent inquiry-based college-level textbook on evolution. It is somewhat more accessible than Futuyma’s textbook.

Futuyma, D. J. 1998. Evolutionary biology. 3d ed. Sunderland, MA: Sinauer Press.
This is perhaps the most comprehensive textbook on evolutionary biology. It also provides an excellent entry into the primary literature of evolutionary biology.

Article
Hillis, D. M, J. P. Huelsenbeck, and C. W. Cunningham. 1994. Application and accuracy of molecular phylogenies. Science 264:671-77.
A technical review of the state of phylogenetic systematics as of the middle 1990s.

Series Directory

Rediscovering Biology: Molecular to Global Perspectives

Credits

Produced by Oregon Public Broadcasting. 2003.
  • Closed Captioning
  • ISBN: 1-57680-733-9