Duquesne University

Spiral of Life

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The Spiral of Life: All living things are connected by evolution.

Darwin's tree
First depiction of a phylogenetic tree-like diagram, in Charles Darwin's notes (1837).

Spiral of Life
Spiral of Life concept art, emphasizing the common origin and equality of all of Life .

The Spiral of Life series is an art and science collaboration designed to visually communicate both basic and cutting-edge concepts surrounding the phylogeny of life in an accessible manner.

A series of museum displays based on the Spiral were created for the Carnegie Science Center, the Pittsburgh Zoo and PPG Aquariums, the National Aviary, Phipps Conservatory, and the Children’s Museum. Each mural exploring a perspective on phylogeny complementary to the institution’s focus. 

See the mural series >

Posters of the displays are available for purchase >

Charles Darwin became famous for his realization that all species arise from a common ancestor; changing slowly overtime through the process he called natural selection. In one of Darwin’s notebooks (see right), we can find the first known depiction of a diagram that translates evolutionary relationships. This type of diagram is still used today, and Darwin’s science is the basis of modern evolutionary biology.

As the idea coalesced into a popular icon, misconceptions accumulated including that evolution is a linear process, that it culminates in Humans, and then stopped.

The Spiral of Life is an updated understanding of evolution that emphasizes the common origin and the equality of all livings things.

The Spiral's key principles:

  1. All livings things share a common ancestor.  The Spiral combines the ramification pattern seen in Darwin’s iconic tree with the circle theme, thus placing the origin at the center of the diagram, unequivocally communicating the common origin of life. Radial diagrams are increasingly used by researchers so it becomes important to prepare students to read these.
  2. All livings things are equally important, and have their own evolutionary track. The radius of the circle signifies time, like rings in a tree. This visualization helps equate living organisms at each given moment.
  3. Evolution is a history of events. The concentric circles are explicitly labeled with dates to help viewers order major evolutionary events.
  4. Evolution is on-going. A “future” ring tantalizes the imagination of the viewer, demanding that they project how branches will evolve.
  5. Evolution does not imply an increase in complexity. Using a radial diagram where all organisms existing today are depicted at the same size and at the same distance from the center, the Spiral helps (1) visualize that simpler organisms are not stepping stones in the evolution of complex organisms (or specifically humans) - they are the heirs of their own evolutionary path; and (2) address the misconception that simpler organisms living today are ancestors to more complex organisms.
  6. Evolution is not simply linear or vertical. Processes represented in a traditional tree of life are referred to as “vertical,” showing the passage of genetic material from a parent generation to an offspring generation. But in the late 20th century, researchers discovered that genetic material can also be passed between organisms of the same generation without reproduction. This process, called “horizontal gene transfer,” is expressed in the Spiral, showing that evolution is best understood as a pattern that combines vertical branching and horizontal crossing.

    Spiral of Life suggests the Web of Life
    Our work with the Spiral of Life suggests the diagram will become a Web, a combination of vertical and horizontal processes. Black dotted lines represent expected relationships between microscopic groups; grey dotted lines represent expected relationships across all domains, including multicellular organisms.

  7. The origin of life may be more primitive or more varied than previously thought. The Spiral represents the origin of life not as a neat single line, but as a large and knotted root, implying that the origin of the three domains may be more primitive or more varied than previously thought.
  8. Evolution led to a diverse ecosystem. As Lynn Margulis put it, "[for] most people today, life is readily divided into three categories: plants […], animals […], and germs (to be vanquished)." The Spiral includes the microscopic majority of the biosphere. The Spiral shows the top-level organization of life as the three domains: Archaea, Bacteria and Eukarya. Due to (1) the vastness of the intradomain diversity within Bacteria, and (2) that Eukarya includes animals, plants and fungi, which are organisms our audience is more likely to recognize, The Spiral shows each domain at different levels of detail. Bacteria is represented with a subselection of its kingdoms, while Eukarya is represented down to the phylum level. The colorful and large depiction of representative organisms of each branch is given more importance than its name, stretching the viewers’ conception of the diversity of life without the barrier of scientific nomenclature.

Given that evolution is a field in enormous expansion, our literature survey was complemented by consultation with a board of experts from Duquesne University and the Carnegie Museum of Natural History.

A series of evaluation efforts accompanied the development of the Spiral, please see a list of publications to the right. Changes were made to the images based on the findings and a series of accompanying educational materials were developed including hand-outs (see below) and activities.

Evolutionary Art and Darwin: Handouts for Spiral of Life
All murals were accompanied by hand-outs or activities that helped visitors discover the Spirals.

Spiral of Life: Co-Evolution of Plants and AnimalsDetail for "Spiral of Life II: Co-Evolution of Plants and Animals". The Tui bird co-evolves with a kind of red mitlestoe that has explosive flowers.


Executive Producer - John A. Pollock

Artist and Lead - Joana Ricou


Scientific advisors: Dr. Brady Porter, Associate Professor of Biological Sciences, Dr. John F. Stolz, Director, Center for Environmental Research and Education, Professor of Biological Sciences, Dr. David Lampe, Associate Professor of Biological Sciences, Dr. Michael Seaman, Associate Professor of Biological Sciences, from Duquesne University, and Matthew C. Lamanna, Ph.D. Assistant Curator Section of Vertebrate Paleontology Carnegie Museum of Natural History.

Principal funding was provided by Science Education Partnership Award from the National Center for Research Resources, a component of the National Institutes of Health (R25 RR020403) to JAP. Partial funding for "The story of life: reading a sculpture" performance and public interaction at the Children's Museum from the F.I.N.E. Artist Residency Series, funded by the Fine Foundation.

Research assistants Brinley Kantorski, Allison Pogue.

Additional art by Robert Hoggard and Laura Gonzalez.

Thank you to Angela Seals, Lois Winslow, Penny Lodge at the Children's Museum of Pittsburgh; Erin Estell, Todd Kazner, Steve Sarro and Caitlin Stone at the National Aviary; Dave Mintz, Connie George, Tracy Gray, Jennifer Hicks, Mark Reardon, Margie Marks and Kevin O'Connell at the Pittsburgh Zoo & PPG Aquariums; Laura Micco, Sarah Presogna, Margie Radebaugh and Kelliann Walsh at the Phipps Conservatory; Dennis Bateman, Azur Cherin, Mike Hennessy and Brad Peroney at the Carnegie Science Center.





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Posters for Spiral of Life: Evolution and Darwin art

GEV is a distribution partner of Darwin2009. Visit our store to purchase posters of the Spiral of Life!

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Darwin 2009: Exploration is Never Extinct!Presented by Regenerative Medicine Partnership in Education.

Spiral of Life

Mural series



1. Ricou, Joana, Danielle Commisso, Laura Lynn Gonzalez, John A. Pollock. Evaluation of a Mural Series on the Evolution of Life. International Journal for Cross-Displinary Subjects in Education, Volume 2, Issue 3, ISSN 2042 6364 (submitted by invitation)

2. Ricou, Joana, John A. Pollock, Danielle Commisso. The Evolution Of Evolution: The Tree, The Spiral And The Web of Life. Extended Abstract. Proceedings of the Canada International Education Conference (2010).

3. Ricou, Joana, John A. Pollock (2010). The Tree, the Spiral and the Web of Life: A Visual Exploration. Leonardo Magazine (accepted for publication 2011/2012).

Please e-mail jiricou@gmail.com for a copy.


MacDonald, Teresa E. (2010). Communicating Phylogeny: Evolutionary tree diagrams in museums. University of Kansas Natural History Museum. Paper presented at the 2010 annual meeting of the National Association for Research in Science Teaching, Philadelphia, PA.

Sources for Spiral of Life mural series

Please download the document below for sources consulted to created this project:
Bibliography for Spiral of Life Download sources for the Spiral of Life project (pdf)