Past DLS

Past Director’s Lecture Series

The Director’s Lecture Series has been offered each winter at the Arnold Arboretum since the arrival of Director William (Ned) Friedman in 2011. The series features experts addressing an array of topics related to Earth’s biodiversity and evolutionary history, the environment, conservation biology, and key social issues associated with current science. Past lectures are detailed here, with links to video or audio for select lectures.


Mutants in our Midst: Darwin, Horticulture, and Evolution

William (Ned) Friedman, PhD, Director, Arnold Arboretum and Arnold Professor of Organismic and Evolutionary Biology, Harvard University
Monday, January 12, 7:00–8:30pm
Director Ned Friedman spoke of the horticultural varieties that we grow in gardens as premier examples of the ongoing process of evolution: random mutations that lead, on the rarest of occasions, to novel and desirable biological characteristics. Throughout his life, Charles Darwin (as well as other nineteenth century evolutionists) looked to the world of horticulture and plant domestication to gain critical insights into the generation of variation and the process of natural selection that underlie evolutionary change. Dr. Friedman explained how horticulture played a central role in laying the foundations for discovering evidence of evolution as well as the process of evolution and also argued that modern botanical gardens can and should become a leading force for the promotion of evolutionary thinking.

The Oldest Living Things in the World

Rachel Sussman, Photographer
Monday, March 2, 7:00–8:30pm
Since 2004 Rachel Sussman has been researching, working with biologists, and traveling the world to photograph continuously living organisms 2,000 years old and older. Her work spans disciplines, continents, and millennia: it is part art and part science, has an innate environmentalism, and is underscored by an existential incursion into Deep Time. Her original index of millennia-old organisms, The Oldest Living Things in the World, has never before been created in the arts or sciences. Attendees enjoyed her awe-inspiring photographs and heard what it means to bear witness to organisms that perhaps predate human history and that may survive well into future generations.

China, Biodiversity, and the Global Environment

Peter Raven, PhD, President Emeritus, Missouri Botanical Garden
Monday, March 23, 7:00–8:30pm

China boasts not only the largest percentage of the world’s population (19%) but also one of Earth’s richest and most diverse floras. Yet its economic rise as an industrial nation and its population density, with the associated environmental degradation, put this biodiversity at risk. Add in climate change and it is a recipe for disaster. Professor Peter Raven, a leading botanist, advocate for the conservation of biodiversity, and one of the co-editors of The Flora of China, a joint Chinese-American census of all the plants of China, is uniquely qualified to assess the consequences of over-population, industrial pollution, economic inequalities, and natural resource exploitation in China—consequences not limited to that country but affecting the entire global environment. In this talk, Dr. Raven considered what it means for humanity to lose thousands of species to extinction, many before they are known or described by scientists. He presented his thoughts on reversing environmental degradation in China and around the globe and what is required to move all people toward an ethic of conservation and securing sustainability.

Environmental Lawlessness

Richard Lazarus, Howard and Katherine Aibel Professor of Law, Harvard University
Monday, April 20, 7:00–8:30pm

What happens when laws and regulations don’t keep pace with changes in technology, science, and society? The answer, according to Harvard Law School Professor Richard Lazarus, is lawlessness. Come learn some of the history and circumstances behind the country’s current but outdated environmental laws, how the original scope and intentions of these laws may no longer match the scope of the problems we face today, and the lawmaking challenges we now face as we seek to address the mounting environmental risks posed by deepwater drilling, natural gas fracking, and climate change. Professor Lazarus, who teaches environmental law, natural resources law, Supreme Court advocacy, and torts at Harvard Law School, was the principal author of Deep Water–The Gulf Oil Disaster and the Future of Offshore Drilling (GPO 2011), the Report to the President of the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling Commission. He spoke of lessons learned from this environmental disaster and how new regulations in line with current technologies are needed to better protect the environment as we tap our natural resources.


The Swerve: How the World Became Modern


Stephen Greenblatt, PhD, Cogan University Professor of the Humanities, Harvard University January 27
Stephen Greenblatt spoke about his book, The Swerve, an innovative work of history and thrilling story of discovery in which one manuscript, plucked from a thousand years of neglect, changed the course of human thought and made possible the world as we know it. This last surviving manuscript of an ancient Roman philosophical epic, On the Nature of Things, by Lucretius—was a beautiful poem of the most dangerous ideas: that the universe functioned without the aid of gods, that religious fear was damaging to human life, and that matter was made up of very small particles in eternal motion, colliding and swerving in new directions.

Déjà vu all over again: Denialism of Climate Change and of Evolution


Eugenie Scott, PhD, Former Executive Director,  Chair, Advisory Council, National Center for Science Education February 10
Both evolution and global warming are “controversial issues” in education, but are not controversial in the world of science. There is remarkable similarity in the techniques used by both camps to promote their views. The scientific issues are presented as “not being settled”, or that there is considerable debate among scientists over the validity of claims. Both camps practice “anomaly mongering”, in which a small detail, seemingly incompatible with either evolution or global warming, is held up as dispositive of either evolution or of climate science. In both cases, reputable, established science is under attack for ideological reasons. Eugenie Scott deconstructed the arguments and identified the ideologies that hinder widespread understanding of evolution and responsiveness to climate change. View the talk on WGBH’s Forum Network and read an article referenced in her talk.

Darwin in the City: How Modern Civilization Drives Evolution


Carl Zimmer, Columnist,The New York Times March 24
When we picture evolution, we think of fish crawling from the sea hundreds of millions of years ago, or birds evolving into new species on remote islands. But evolution takes place today, in the most unexpected places–in city parks, in farm fields, and in hospitals. Humans, scientists now recognize, are a powerful evolutionary force, pushing life in new directions. Now, researchers are wondering where we’re headed. Carl Zimmer, author of Evolution: Making Sense of Life, will present some of the ways that modern civilization drives evolution and current thinking about humans as a force of change.View the talk on WGBH’s Forum Network.

Uncorking the Past: The Quest for Wine, Beer, and Extreme Fermented Beverages

Uncorking the PastOB

Patrick E. McGovern, PhD, Scientific Director, Biomolecular Archaeology Laboratory for Cuisine, Fermented Beverages, and Health, University of Pennsylvania Museum April 14
Fermented beverages have probably been with the human race from its beginning in Africa. Following a tantalizing trail of archaeological, chemical, artistic, and textual clues, Patrick E. McGovern, the leading authority on ancient alcoholic beverages, will describe how enterprising our ancestors were in concocting a host of beverages from a vast array of natural products (honey, grape, barley, rice, sorghum, chocolate). As humans spread around the planet, this had profound effects on our cultural and biological development. Some of these beverages, including the earliest alcoholic beverage from China (Chateau Jiahu), the mixed drink served at the King Midas funerary feast (Midas Touch), and the chocolate beverage (Theobroma), have been re-created by Dogfish Head Brewery, shedding light on how our ancestors made them and providing a taste sensation and a means for us to travel back in time. The talk will be followed by a tasting of ancient beers recreated by Dogfish Head Craft Brewed Ales. Participants in the tasting must be 21 or older.


Plants, The First Three Billion Years: A Reflection on the Nature of Evolutionary History

Ned Friedman Director's Series

William (Ned) Friedman, Director, Arnold Arboretum, and Arnold Professor of Organismic and Evolutionary Biology, Harvard University January 14

Plant biodiversity. How did it all begin? And what are some of the key evolutionary twists and turns that have deposited us into a world teaming with photosynthetic life? Join us as we explore how lunch for a unicellular organism inadvertently laid the groundwork for the first plants, and how they then went on to produce exquisitely beautiful multicellular photosynthetic lineages dozens of times, only one of which made it out of the water and onto land 475 million years ago. And finally, we will reflect on what might have been (and what might be) if one or two of these twists and turns had gone differently in evolutionary history.

Biodiversity 2013: Crisis and Opportunity

James Hanken, Alexander Agassiz Professor of Zoology, Curator in Herpetology, and Director, Museum of Comparative Zoology; and Professor of Biology, Department of Organismic and Evolutionary Biology, Harvard University February 25

Biodiversity 2013: Crisis and Opportunity

The state of biodiversity in 2013 presents a tremendous paradox. Biodiversity science is more productive today than ever before; the rate of new species discovery, for example, is higher than it’s ever been. At the same time, the rate of species extinction is increasing dramatically due to human-mediated environmental degradation on a global scale. This crisis for the future of biological diversity offers unparalleled challenges and opportunities for the professional scientific community, which is responding with new approaches and a heightened sense of urgency, with increasing focus both on conservation of species and their habitats and on the major drivers of extinction.

Plastic: A Toxic Love Story

Plastic: A Toxic Love Story

Susan Freinkel, Science Writer and Journalist March 11

As coal fueled the industrial revolution, one could say that plastic built the modern world. But a century into our love affair with plastic, we’re starting to realize it’s not such a healthy union. Plastics draw on dwindling fossil fuels, leach harmful chemicals, litter landscapes, and destroy marine life. And yet each year we use and consume more; we’ve produced as much plastic in the past decade as we did in the entire twentieth century. Journalist Susan Freinkel will speak about our dependence on this material, guiding us through history, science, and the global economy to assess the real impact of plastic in our lives. She’ll present a new way of thinking about a substance that has become the defining medium—and metaphor—of our age. Her book, Plastic: A Toxic Love Story, will be available for purchase and signing.

The New You: How Symbiosis Studies Have Undercut Biological Views of Individuality

How Symbiosis Studies Have Undercut Biological Views of Individuality

Scott Gilbert, Howard A. Schneiderman Professor of Biology, Swarthmore College April 8

What defines an individual? Can an animal be construed an individual if its anatomy, physiology, development, and even its immune systems depend on symbiotic microorganisms? What becomes of the genetic and evolutionary individual when inherited symbionts provide selectable variation for the host? Animal plus symbiont equals…what? Super-animal? Team? Holobiont? Have we been lumping and sorting erroneously only to learn through advances in biotechnology that individuals are really communities or, perhaps, relationships? Join us for a mind-bending presentation that may leave you reassessing your place in the biosphere.


The Evolution of Big

Ned Friedman, Director, Arnold Arboretum, and Arnold Professor of Organismic and Evolutionary Biology, Harvard University January 9

The Evolution of Big

Think you know trees? Ned Friedman reveals an amazing period when there were no trees, and then, in the blink of a geological eye, several different groups of plants evolved the ability to increase their girth and qualify for placement in an arboretum. Get a sense of what forests looked like over three hundred million years ago. Learn about the (sad) extinction of all but one of the early arborescent lineages of plants and find out which evolutionary group of trees survived to populate the Arnold Arboretum and today’s forests.

The Global Forests of Greenhouse Earth

Kirk Johnson, Vice President of Research & Collections and Chief Curator, Denver Museum of Nature and Science
February 6

The Global Forests of Greenhouse Earth

Earth’s climate has passed from times characterized by huge ice caps to times when there was almost no ice at all and both Greenland and Antarctica were covered by forests. Kirk Johnson studies fossil leaves to refine geologic time, reconstruct ancient landscapes, track climate change, and document the evolution and extinction of species and ecosystems. For 30 years he has been chasing the 50–100 million year-old-forests of the last great global greenhouse period. In this lecture, he takes you on a journey to an entirely different Planet Earth—an environment that may help us to better understand changes occurring in our own time.

Art as a Source of Information on Horticultural Technology

Jules Janick, James Troop Distinguished Professor of Horticulture, Purdue University
March 5
Watch the lecture on YouTube »

Art as a Source of Information on Horticultural Technology

Works of art from antiquity to the present constitute an alternate source of information on horticultural technology and science, providing significant information on subjects such as the history of technology, crop evolution, lost traits, and crop dispersal. Sources include ancient mosaics, sculpture, illustrations of medieval manuscripts, renaissance paintings, and illustrations from illuminated and printed herbals. The uses of art as a source of horticultural technology are illustrated using examples of Paleolithic sculpture and painting, Egyptian and Mesopotamian sculpture and painting, ancient Greek paintings, Roman mosaics, Medieval illuminated herbals, and Renaissance art in its many manifestations including illustrated prayer books, frescoed ceilings, paintings, drawings, sculpture, and woodcuts from printed herbals.

Exploring Terra Incognita: The Extraordinary Diversity of Microbes on Us, in Us, and All Around Us

Noah Fierer, Assistant Professor, Department of Ecology and Evolutionary Biology and Fellow at the Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder March 19
Watch the lecture on YouTube »

Exploring Terra Incognita

Microorganisms are ubiquitous and abundant on Earth. You inhale thousands of microbial cells in every breath and your body is home to 100 trillion of them. Only in the past few years have we been able to describe the enormous diversity of microorganisms that live in familiar environments, including your forehead, your computer keyboard, plant leaves, and the soil in your garden. In this lecture, Noah Fierer speaks about recent work exploring microbial diversity on the human body, the effects these organisms (most of which are not pathogenic) may have on our health, and how we may be able to use bacteria for forensic identification. He also discusses ongoing work exploring bacterial diversity in the atmosphere through which unexpected sources of airborne bacteria in U.S. cities have been identified. His presentation highlights some future research directions in the burgeoning field of microbial ecology and how this research will likely alter how we think about ‘germs’ and human-microbe interactions.


A Darwinian Look at Darwin’s Evolutionist Ancestors

Ned Friedman, Director, Arnold Arboretum, and Arnold Professor of Organismic and Evolutionary Biology, Harvard University January 10

A Darwinian Look at Darwin's Evolutionist Ancestors

For over a century before the publication of On the Origin of Species, naturalists, theologians, atheists, horticulturists, medical practitioners, poets, and philosophers had advanced evolutionary concepts for the diversification of life through descent with modification. The early history of evolutionary thought will be examined through the lens of Charles Darwin’s highly personal views of his evolutionist ancestors. We will examine the question of what set Darwin apart from the dozens of advocates of evolution who preceded him. Is Darwin truly deserving of his place in history? Come find out!

Restoring Hawaii’s Marvels of Evolution

Robert Robichaux, University of Arizona February 7

Restoring Hawaii's Marvels of Evolution

Evolving in splendid isolation over millions of years, Hawaii’s native plants exhibit patterns of diversity that are unrivaled elsewhere on Earth. Especially striking are the many examples of adaptive radiation, in which original immigrants to the islands evolved into dazzling arrays of plants exhibiting great variation in form and habitat preference. Yet Hawaii’s native plants face an uncertain future. Many native plants, such as the exquisitely beautiful silverswords and lobeliads, now teeter on the edge of extinction. Join botanist Robert Robichaux of the University of Arizona and the Hawaiian Silversword Foundation as he discusses recent efforts to restore Hawaii’s marvels of plant evolution.

The Good, the Bad, and Occasionally the Dead: Humanity’s Relationship with Earth’s Nitrogen

Alan Townsend, University of Colorado, Boulder, University of Arizona February 28

The Good, the Bad, and Occasionally the Dead: Humanity's Relationship with Earth's Nitrogen

How do we lead the lives we want while maintaining healthy ecosystems that can support future generations? These challenges will define the coming century, and one of them lies at the heart of the most fundamental of human needs: the need to eat. Come hear about the occasionally odd and often dramatic history of humanity’s relationship with phosphorous and nitrogen, the good these chemical elements do and the harm they cause, and ultimately, the reasons we can have hope for a better future.

Our Constitution’s Intelligent Design

U.S. District Judge John E. Jones III March 28

Our Constitution’s Intelligent Design

In 2005, Judge John Jones presided over the landmark case of Kitzmiller v. Dover, and thereafter rendered an opinion holding that it is unconstitutional to teach the concept of intelligent design as an alternative to the theory of evolution. In the aftermath of that ruling, Judge Jones, an appointee of former President George W. Bush, was subjected to intense criticism. Judge Jones will highlight some of the lessons he learned from these experiences, including the development of his passion for judicial independence, and a belief in the need for better civics education, particularly related to our three branches of government.