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A Mini-Lesson


Solving a Phylogenetic Puzzle
With Molecular Geneics

R.P. Filson



 CLICK HERE for a quick but impressive and effective
Interactive Demonstration of How Speciation Can Occur


Using real data, students develop likely phylogenies for seven related populations of lizards living on the Canary Islands (off the West coast of Africa). Three phylogenetic charts will be constructed, each using different forms of data: geography, geology, morphology, and molecular genetics (DNA comparisons). Serves as an excellent example of MILE: Multiple Independent Line of Evidence, showing at least some degree of similarity of patterns and therefore mutual confirmation of the phylogeny.


1. Speciation involves genetic differentiation, ecological differentiation (niche separation) and reproductive isolation.

2. Scientists use a variety of criteria to compare explanations and select the better ones.


Scissors and tape
An atlas would be a desirable option


 (see end of lesson for the formatted handouts).

All information, preparation, and handouts can be found on the
University of California at Berkeley Museum of Paleontology web site in their "Learning From the Fossil Record" section.

This will take you out of the ENSIweb site, so to get back here, click on "Back", or select ENSIweb from the "Go" in your browser menu.



 SPECIAL NOTE: Click here to explore many of the different lines of evidence pointing to speciation and macroevolution.

MACROEVOLUTION DIAGRAM: See the Macroevolution Diagram and a page of directions for using that diagram on an overhead projector. This nicely shows how accumulated speciations can eventually form all the groups and subgroups of organisms. It also shows how classification is related to evolution. A very nice colorful version of this can be found on page 32 of that most useful resource: Teaching About Evolution and the Nature of Science, by the National Academy of Sciences (1998) (see our Resources section). A particularly interesting alternative diagram is the one Darwin included in The Origin of Species (chapter IV), the only diagram in that book! His discussion there of that diagram should be required reading for any biology teacher. Darwin's Tree makes a great overhead transparency for discussing his concept of evolution by natural selection, as well as how classification reflects that evolution.


Anoles Evolution Virtual Lab from HHMI BioInteractive
BioInteractive Short Films: (one DVD): Lizards in Evo Tree; Beak of the Finch; Making of a Theory
BioInteractive Virtual Lab Series (one DVD): Lizard Evolution Lab; Stickleback Evolution Lab; et al
BioInteractive Sheets: Teacher Materials and Student Worksheets for...
Four modules, two deal with analog comparisons (morphologies), two with measurement, calculations and graphing. Also, DNA comparisons, leading to likely phylogeny; looking for trends, patterns.
Measure leg lengths, toe lengths, tail lengths. Ecomorphs compared on each island. Questions raised, tested, and analyzed for most likely explanation. Leads to evidence for convergent evolution.
Excellent tutorial about how to do Think-Pair-Share
ENSI lesson: Case of the Threespine Stickleback

Science Daily article of interest; Support for controversial Darwin theory of 'jump dispersal' [e.g. "Rafting"] Science Daily, October 1, 2014.
" How did this lizard's ancestors arrive on the Caribbean island where they live? A new study affirms a long-controversial view that some organisms, like this Grand Cayman blue-throated anole, may have crossed oceans in creative ways." " A new computational method, published in the journal Systematic Biology, tested two competing theories about how species came to live where they do and found strong evidence for jump dispersal [e.g., rafting], especially for island species."

SeeBioInteractive for many more resources:
Many excellent resources, e.g., Short Films, Virtual Labs, Animations, Click & Learn and more resources for teaching Evolution, DNA, Geobiology, Infectious Disease

The Origin of Species: The Beak of the Finch
HHMI BioInteractive: Blumenrath
[Use this instead of the ENSI Oat Seed Lab]
Excellent (Meets several expectations in NGSS, AP Bio, and IB, all spelled out in Teacher Materials)
Four parts (With Short Film, Teacher Materials and Student Worksheets/Handouts):
Beaks As Tools: Selective Advantage in Changing Environments
Evolution in Action: Graphing and Statistics
Evolution in Action: Statistical Analysis (t-Test)
Sorting Finch Species: Click and Learn (includes analytical comparisons of finch sounds)


Some of the ideas in this lesson may have been adapted from earlier, unacknowledged sources without our knowledge. If the reader believes this to be the case, please let us know, and appropriate corrections will be made. Thanks.

1. Original Source: R.P. Filson, Edison High School, Stockton, CA


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