Origins of complexity

Life is organized hierarchically: societies are made up of organisms; organisms of organs, tissues and cells; cells of organelles and molecules. These teaching modules explore the origins of this basic principle of biology. 

Our understanding of life is being transformed by the realization that evolution occurs not only among individuals within populations, but also through the integration of groups of individuals into new higher-level individuals—that is, through evolutionary transitions in individuality (ETIs). 

The major landmarks in the diversification of life and the hierarchical organization of the living world are consequences of a series of ETIs: from genes to gene networks to the first cell, from prokaryotic to eukaryotic cells, from cells to multicellular organisms, from asexually reproducing individuals to sexually reproducing pairs, and from solitary individuals to societies. How and why do groups evolve into individuals?

About the modules

These teaching modules were created by biology teachers and biologists with the support of the National Science Foundation. We want you to use them, modify them to suit the needs of your class, and redistribute them to anyone you like. If you do find them useful, please let us know so that we can show the NSF that we did something worthwhile with their money. 

If you have questions, we are happy to help. If you have suggestions for us, we'd like to hear them, too. Share your experiences so that we can improve the modules for everyone!

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