What is Life?

Lecture Series: Life In The Universe

Guy J. Consolmagno, SJ, Planetary Scientist, Vatican Observatory Research Group

Throughout history, our definition of 'life' reflects our assumptions about how the Universe works – and why we ask the question. The ways different human cultures, ancient and current, have talked about life provide some sense of how we have defined life, and illustrate the aspects of life that fascinate us. Many cultures used life as an analog to explain the movement of winds and currents, or the motions of the planets. Today we use those mechanical systems as analogs for life. Ultimately, we may not really know what life is until we have discovered more than one independent example of it on places other than Earth – we need many diverse examples before we can generalize. But without a definition of what we're looking for, and why we're looking, we may have a hard time recognizing life when we find it.

Planet Formation and the Origin of Life

Lecture Series: Life In The Universe

Dante S. Lauretta, Professor, Planetary Sciences/Lunar and Planetary Laboratory

It is generally accepted that planets or their satellites are required for life to originate and evolve. Thus, in order to understand the possible distribution of life in the Universe it is important to study planet formation and evolution. These processes are recorded in the chemistry and mineralogy of asteroids and comets, and the geology of ancient planetary surfaces in our Solar System. Evidence can also be seen in the many examples of ongoing planet formation in nearby regions of our galaxy. Finally, the variety of observable extra-solar planetary systems also provides insight into their origins and potential for life. These records will be discussed and compared to summarize our current understanding of planet formation and the accompanying processes that may lead to the origin of life throughout the Universe.


Life on Earth: By Chance or By Law?

Lecture Series: Life In The Universe

Brian J. Enquist, Professor, Ecology and Evolutionary Biology
Life on Earth is amazing and multifaceted. Ultimately all of life has descended from one common ancestor and has been guided by evolution by natural selection. On the one hand, the evolution of modern-day diversity and ecosystems may have been contingent on the initial chemical building blocks of life and the historical events that have characterized our planet over geologic time. On the other hand, there are numerous aspects of life pointing to regular and deterministic processes that shape the complexity and diversity of life. This talk will touch on those examples where the laws of chemistry and physics, in addition to evolutionary rules, have resulted in general properties of life. These properties ultimately determine how long we live, the diversity of life, the function and regulation of ecosystems and the biosphere, and how life will respond to climate change.

Complexity and Evolvability: What Makes Life So Interesting?

Lecture Series: Life In The Universe

Anna R. Dornhaus, Associate Professor, Ecology and Evolutionary Biology

Life is particularly fascinating in its ability to create complex and ever-changing forms out of simple building blocks. How does such complexity arise, and what are the conditions that allow never-ending evolution of new and more intricate forms of life? We now know that one of the main processes that allows this is that life consists of modules that interact with and feed back on one another. In the history of life on Earth, new levels of complexity have often arisen out of new types of such interactions, and continued evolution has been driven by life interacting with other life. We even find that man-made systems can develop a 'life' of their own when such feedback interactions among many modules occur. Life, it seems, is more about rules of interaction than special materials. We have only begun to understand the power of this algorithmic nature of life.

Time Traveling: What Our Brains Share with Beetle Brains

Lecture Series: The Evolving Brain

Nicholas J. Strausfeld, PhD, Director, Center for Insect Science and Regents’ Professor of Neuroscience

Emerging evidence suggests that distantly related animals such as mice and flies manifest similar behaviors because they have genealogically corresponding brain centers. The view is that a common ancestor had already evolved circuits for behavioral actions, memory of such actions, and their consequences more than half billion years ago. Evidence that those circuits have been inherited through geological time challenges how we as a species relate to animals that we view as wholly different from ourselves. 

A Window into the Brain: Viewed through the Evolution of MRI Technology

Lecture Series: The Evolving Brain

Diego R. Martin, MD, PhD, Chair, Department of Medical Imaging and Professor of Medicine, UA College of Medicine
The evolution of MRI technology and its use to study brain structure and function has revealed much of what we know today about the evolving brain and has revolutionized clinical care. Rich visual content will be used to illustrate the technical elements that have been pieced together over time to form the modern MRI scanner. Each element of MRI technology will be introduced from the historical timeline as the scanner system is built piece-by-piece for the audience. Milestones and personalities will be introduced to add meaning and significance showing the innovative spirit and creativity of this technology’s development.

The Evolution of Modern Neurosurgery: A History of Trial and Error, Success and Failure

Lecture Series: The Evolving Brain

G. Michael Lemole, Jr., MD, Chief, Division of Neurosurgery and Professor of Surgery, UA College of Medicine

The science and art of neurosurgery has advanced dramatically in the past few decades, and yet its history is firmly grounded in a paradigm of surgical trial and error.  Collaborations with allied specialties have made these “trials” safer, but much of what we know of functional brain anatomy comes from disease or iatrogenic perturbations.  This lecture will explore the keen observations and dogged persistence that led to our current state of the art.  We will explore how this surgical knowledge of the brain makes our current practice safer and how future technologies will advance our understanding with less invasive but more meaningful impact.

The Literate Brain

Lecture Series: The Evolving Brain

Pélagie M. Beeson, PhD, Professor and Head of Speech, Language and Hearing Science

Written language represents a relatively recent cultural invention, and unlike the development of spoken language, literacy requires explicit and prolonged instruction. How is this accomplished? Do unique regions of the brain develop in support of reading and spelling, or are these skills dependent upon brain regions involved in other perceptual and cognitive processes? By studying disorders that arise following brain damage in previously literate adults, and by using brain imaging techniques to examine neural activity as healthy individuals engage in reading and spelling, a new understanding of the brain is being revealed. Further clarification comes from rehabilitation research that promotes the return of written language skills and provides a view of the brain’s plasticity.

The Ancestors in Our Brains

Lecture Series: The Evolving Brain

Katalin M. Gothard, MD, PhD, Associate Professor of Physiology, Neurobiology, and the Evelyn F. McKnight Brain Institute

The human brain retains ancestral neural circuits that support behaviors geared toward satisfying basic biological needs. Superimposed on these core circuits are newly evolved structures that specialize in complex computations. These specializations convey flexibility to the brain and the ability to distill information into abstract thought. The ancient molecules and core circuits that make us social and emotional beings interface harmoniously with the newly evolved structures that make us thinkers and inventors of technology. 

More Perfect Than We Think

Lecture Series: The Evolving Brain

William Bialek, PhD, John Archibald Wheeler/Battelle Professor in Physics, Princeton University

From its ability to appreciate beauty, to the reassembly of distant childhood memories, to our almost unthinking ability to respond to the unexpected, is our brain really "doing a good job" at solving the problems we confront as we move through the world? Has evolution granted us a rich inheritance of tools, or saddled us with artifacts of a distant past, limiting our ability to solve new problems? Many other animals, from insects to our fellow primates, do many equally remarkable things, but several examples will be presented allowing us to see how the human brain solves problems in an essentially perfect way — no machine operating under the same physical constraints could do better. Examining what is common among the problems that the brain is good at solving begins to suggest a more general principle that may be at work.