Vernier Software and Technology
Vernier Software & Technology

Introduction to Molecular Evolution

Figure from experiment 21 from Investigating Biology through Inquiry


An evolutionary tree shows the evolutionary lineages of different species over relative time. Evolutionary trees, (also called cladograms), can be based on many different types of data. The traditional way of constructing evolutionary trees was to look at the physical morphology of organisms, including sizes, shapes and developmental structures of both living organisms and fossils. Today, similarities and differences in molecular data (protein and DNA sequences) are also being used. Both methods are valuable and often complement each other.

You will use the evolutionary tree to make predictions about the relatedness of the species you will examine in this investigation. Following the analysis and interpretation of your electrophoresis results, you will create a cladogram from your own results and compare your cladogram with your predictions.

For this investigation, it is useful to compare both closely related and distantly related fish. In addition to using the tree below to make your predictions, we recommend that you research additional information on the evolutionary histories of fishes, using the Internet, and biology and zoology books.

The data used to construct the evolutionary tree was obtained from the cladograms on the tree of life web page from the University of Arizona ( (Please note that the field of phylogenetics is ever changing and different methods used to construct a phylogenetic tree often result in differences between trees, hence the data on the tree of life web page may not concur exactly with “textbook” evolutionary trees.)


In this Preliminary Activity, you will (1) extract proteins from muscle tissue, (2) conduct electrophoresis of the resulting protein extracts, (3) analyze the results using Logger Pro, and (4) construct a cladogram using the results.

After completing the Preliminary Activity, you will first use reference sources to find out more about protein gel electrophoresis before you choose and investigate a researchable question. Some topics to consider in your reference search are:

  • protein
  • amino acid
  • gel electrophoresis
  • fish
  • evolutionary tree
  • cladogram
  • phylogenetic relationships
  • denature
  • molecular weight
  • dalton
  • kilodalton (kD)

Sensors and Equipment

No probeware required for this experiment.

Download Complete Experiment

The downloadable file contains the student instructions in PDF and Word format as well as the teacher information.

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Investigating Biology through Inquiry

See other experiments from the lab book.

1Buffer Investigations
3Investigating Osmosis
4Chemistry of Membranes
5Investigating Protein
6ATesting Catalase Activity (O2 Gas Sensor)
6BTesting Catalase Activity (Gas Pressure)
6CTesting Enzyme Activity (Spectrometer)
7Introduction to Biofuels: Enzyme Action
8Analysis of Enzymes using Tyrosinase
9Cellular Respiration
10ASugar Metabolism with Yeast (Carbon Dioxide Gas)
10BSugar Metabolism with Yeast (Ethanol)
11Fermentation with Yeast
12Photosynthesis by Chloroplasts
13Transpiration of Plants
14Plant Pigments
15Heart Rate
16Investigating Dissolved Oxygen
17Investigating Primary Productivity
18Modeling Population Dynamics
19Water Monitoring
20Evolution of Cellobiase in Fungi
21Introduction to Molecular Evolution
22Evolution of Yeast

Investigation 21 from Investigating Biology through Inquiry Lab Book

<i>Investigating Biology through Inquiry</i> book cover

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