NIMBioS Investigative Workshop
Information and Entropy
Topic: Information and entropy in biological systems
Meeting dates: April 8-10, 2015
Location: NIMBioS at the University of Tennessee, Knoxville
- John Baez, Mathematics, Univ. of California, Riverside
- Marc Harper, Educational and biotechnology consultant
- John Harte, Environmental Science, Policy and Management, Univ. of California, Berkeley
Objectives: Information theory and entropy methods are becoming powerful tools in biology, from the level of individual cells, to whole ecosystems, to experimental design, model-building, and the measurement of biodiversity. The aim of this investigative workshop is to synthesize different ways of applying these concepts to help systematize and unify work in biological systems. Early attempts at "grand syntheses" often misfired, but applications of information theory and entropy to specific highly focused topics in biology have been increasingly successful. In ecology, entropy maximization methods have proven successful in predicting the distribution and abundance of species. Entropy is also widely used as a measure of biodiversity. Work on the role of information in game theory has shed new light on evolution. As a population evolves, it can be seen as gaining information about its environment. The principle of maximum entropy production has emerged as a fascinating yet controversial approach to predicting the behavior of biological systems, from individual organisms to whole ecosystems. This investigative workshop brought together top researchers from these diverse fields to share insights and methods and address some long-standing conceptual problems.
Goals of the workshop:
- To study the validity of the principle of Maximum Entropy Production (MEP), which states that biological systems - and indeed all open, non-equilibrium systems - act to produce entropy at the maximum rate.
- To familiarize all the participants with applications to ecology of the MaxEnt method: choosing the probabilistic hypothesis with the highest entropy subject to the constraints of our data. We will compare MaxEnt with competing approaches and examine whether MaxEnt provides a sufficient justification for the principle of MEP.
- To clarify relations between known characterizations of entropy, the use of entropy as a measure of biodiversity, and the use of MaxEnt methods in ecology.
- To develop the concept of evolutionary games as "learning" processes in which information is gained over time.
- To study the interplay between information theory and the thermodynamics of individual cells and organelles.
Summary Report. At this workshop experts on biodiversity, ecology, evolution, game theory and biochemistry traded insights on the many ways the concepts of information and entropy are useful in their work. Information is measured in bits and was made into a precise concept in Claude Shannon's work on communication and codes. Entropy is a measure of disorder or randomness and first arose in work on chemistry and physics: the "second law of thermodynamics" says that entropy increases over time. We now realize that entropy is the flip side of information: it is the information not known about a complicated random situation, that would need to be known to completely describe it. Living organisms use information to make decisions and cleverly exploit the tendency for entropy to increase while preventing themselves from falling into disorder. The workshop participants, coming from many fields, worked to synthesize the different ways in which the mathematics of entropy and information can be used to understand biology from the level of molecules to the level of individual organisms and even whole ecosystems.
NIMBioS Investigative Workshops focus on broad topics or a set of related topics, summarizing/synthesizing the state of the art and identifying future directions. Organizers and key invited researchers make up half the 30-40 participants in a workshop, and the remaining 15-20 participants are filled through open application from the scientific community. Open applicants selected to attend are notified by NIMBioS within two weeks of the application deadline. Investigative Workshops have the potential for leading to one or more future Working Groups. Individuals with a strong interest in the topic, including post-docs and graduate students, are encouraged to apply. If needed, NIMBioS can provide support (travel, meals, lodging) for Workshop attendees, whether from a non-profit or for-profit organization.
A goal of NIMBioS is to enhance the cadre of researchers capable of interdisciplinary efforts across mathematics and biology. As part of this goal, NIMBioS is committed to promoting diversity in all its activities. Diversity is considered in all its aspects, social and scientific, including gender, ethnicity, scientific field, career stage, geography and type of home institution. Questions regarding diversity issues should be directed to Dr. Ernest Brothers, the NIMBioS Associate Director for Diversity Enhancement (firstname.lastname@example.org). You can read more about our Diversity Plan on our NIMBioS Policies web page. The NIMBioS building is fully handicapped accessible.