Joan Roughgarden facts for kids

Joan Roughgarden (born 13 March 1946) is an American ecologist and evolutionary biologist. She has engaged in theory and observation of coevolution and competition in Anolis lizards of the Caribbean, and recruitment limitation in the rocky intertidal zones of California and Oregon. She has more recently become known for her rejection of sexual selection, her theistic evolutionism, and her work on holobiont evolution.

Personal life and education

Roughgarden was born in Paterson, New Jersey, United States. She received a Bachelor of Science in biology (with Distinction and Phi Beta Kappa) and a Bachelor of Arts in Philosophy with highest honors from University of Rochester in 1968 and later a Ph.D. in biology from Harvard University in 1971. In 1998, Roughgarden came out as transgender and changed her name to Joan, making a coming out post on her website on her 52nd birthday.

Career

Roughgarden worked as an instructor and Assistant Professor of Biology at the University of Massachusetts Boston from 1970 to 1972. In 1972 she joined the faculty of the Department of Biology at Stanford University. After becoming full professor she retired in 2011, and became Emeritus Professor. She founded and directed the Earth Systems Program at Stanford and has received awards for service to undergraduate education. In 2012 she moved to Hawaii, where she became an adjunct professor at the Hawaiʻi Institute of Marine Biology. In her academic career, Roughgarden advised 20 Ph.D. students and 15 postdoctoral fellows.

Roughgarden has authored books and over 180 scientific articles. In addition to a textbook on ecological and evolutionary theory in 1979, Roughgarden has carried out ecological field studies with Caribbean lizards and with barnacles and their larvae along the California coast. In 2015, she wrote the fiction novel Ram-2050, a science-fiction retelling of the Ramayana.

Research

Caribbean Anoles & Interspecific Competition

Roughgarden's early work in the 1970s and 80s helped to develop the Anolis lizards of the Caribbean as an important model system for evolution and ecology. For example, she used two-species enclosure experiments on two Caribbean islands to demonstrate increasing strength of interspecific competition as resource partitioning decreases: a central tenet for competition theory. The Anolis system thus provided an early example of an eco-evolutionary feedback, and with further development by Jonathan Losos and others, has become an important example of adaptive radiation.

Barnacles & Recruitment Limitation

After setting up a lab at the Hopkins Marine Station, Roughgarden sought to extend her approach of combining theoretical with field research by studying intertidal acorn barnacles (Balanus and Chthamalus spp). Earlier work by Joseph Connell, Bob Paine and others had suggested that the characteristic zonation of rocky intertidal communities was predominantly structured by predation, (for example by Pisaster seastars) and by competition, wherein dominant Balanus species displaced Chthamalus species to the high intertidal zones. Together with her student, Steve Gaines, Roughgarden showed that these interspecific interactions were most important in intertidal localities and communities with a high density of barnacles, such as those Connell and others had studied in Scotland. At Hopkins in Central California, however, barnacle density was lower, and the amount of free space was best explained by periodic pulses of larval recruitment.  With her student Sean Connolly, she then showed, through both empirical observation and modeling, that a latitudinal gradient in upwelling along the west coast of North America created very dense barnacle recruitment in the north (Oregon and Washington), where upwelling was weak, and very sparse barnacle recruitment in the south (California), where upwelling was strong. This in turn explained why field studies in the north had found interspecific interactions to be important, while her own field studies in the south had found larval recruitment to be most important for structuring intertidal populations. This deft synthesis helped to drive a paradigm shift in marine ecology which emphasized larval dispersal and recruitment dynamics over adult interactions and favored demographic models of populations open to larval recruits from distant localities, which dominated the field during the 1990s.

Theistic evolution

Roughgarden has written on the relationship between Christianity and science. Her book Evolution and Christian Faith: Reflections of an Evolutionary Biologist presents scripture passages that emphasize her belief that the Bible does not conflict with evolutionary biology and relates Christianity and evolution by asserting that all life is interconnected, as members of a faith community are connected. Roughgarden opposes creationism and intelligent design, but asserts her belief in God's involvement in evolution. She was a speaker at the Beyond Belief symposium in 2006.

Holobiont Evolution

As professor emerita, Dr. Roughgarden turned her attention to the emerging concept of the holobiont, which she defined as “an animal or plant host together with all the microbes living on or in it, exosymbionts and endosymbionts, respectively.” The concept, which originated in 1943, has had increasing recognition with the rise of second and third-generation DNA sequencing methods that allow the microbial communities (i.e. the microbiome) of a host to be examined. The close association between the microbiome and its host has led many  to suggest that the holobiont may be an evolutionary unit of selection, in which the combination of the host’s genes with those of its microbiome produce an extended genome, or hologenome. However, the hologenome concept has been criticized on the grounds that microbiomes are usually not vertically transmitted from parent to child, thereby violating what is commonly thought to be one of the key principles of natural selection: variation inherited in a Mendelian fashion.

Together with other proponents of the holobiont concept, Roughgarden wrote a 2018 review of the topic in which they examined the evidence for the holobiont as a biological entity. They considered the tight integration of physiological, developmental, reproductive and even immunological components between host and microbial symbionts to provide a foundation for this concept. For example mammalian mothers’ milk contains sugars that appear to be for the benefit of the microbial symbionts, because they cannot be metabolized by the newborn.  They also cite the horizontal acquisition of DNA coding for syncytin, a protein that allows formation of the placenta, as a key step in the evolution of placental mammals, which also demonstrates adaptive evolution in the holobiont.

In this review, Roughgarden begins to sketch a population genetic model of holobiont evolution, containing a host species, and a single microbial symbiont, and in which selection is based only on the number of copies of the symbiont genome acquired by the host. The model contains three sequential processes per generation: microbes can move between hosts, they can proliferate within hosts and holobionts can survive or perish dependent on the number of symbionts acquired. This model was enough to show that, with vertical transmission, a deleterious symbiont will reduce the number of holobionts (and symbionts), while a beneficial symbiont will tend to increase the sizes of both groups. However, horizontal transmission “binds the collection of microbiomes into a unified system, a meta-community, rather than a collection of independent communities”.

Roughgarden followed this review with two papers that further fleshed out her model of holobiont evolution. The first showed that, when microbes colonize hosts following a Poisson distribution, horizontal transmission can still lead to holobiont evolution when beneficial symbionts increase the success of their hosts and thus flood the microbial source pool (the converse case with parasitic microbes also holds true). She calls this phenomenon “collective inheritance” as opposed to lineal Mendelian inheritance. The second paper adds a second microbial species to the model, as well as a “colonization parameter” d, which partially determines the Poisson rate parameter. The d parameter approximates the density of the symbiont strain around the host, or the host’s selectivity for the symbiont species, depending on context. Because microbial colonization of the host follows a Poisson distribution, there is no Hardy-Weinberg analog, and directional selection tends to be more diffuse than expectated under vertical transmission. She then reasons from this two-microbe model that the host is likely to use antibodies and “probodies” to modulate d for each microbial species, in effect orchestrating things so that only microbes that provide some minimum amount of altruism toward their host are allowed to remain in symbiosis with the host. From the microbe’s standpoint, those species that provide the minimum amount of altruism to clear the host’s threshold will tend to outcompete those that provide more. This paper carefully demonstrates that this host-orchestrated species selection process is conceptually distinct from co-evolution or multi-level selection and can predict and explain the tight integration of hosts and their microbial symbionts found throughout the eukaryotic tree of life.

Awards and honors

• Stonewall Book Award, 2005
• Center Fellow, National Center for Ecological Synthesis and Analysis, University of California (Santa Barbara), 1998
• Dinkelspiel Award for Undergraduate Teaching, Stanford University, in 1995
• Visiting Research Fellow at the Merton College, University of Oxford, in 1994
• Elected Fellow of the American Academy of Arts and Sciences in 1993
• Fellow of Guggenheim Foundation in 1985
• University Fellow, Stanford University in 1978

Roughgarden has served as associate editor of several academic journals, including Philosophy and Theory in Biology (since 2008), American Naturalist (1984–1989), Oecologia (1979–1982), and Theoretical Population Biology (1975–1986). She was the vice-chair and Chair of Theoretical Ecology Section of the Ecological Society of America during 2002–2003. She has served on the Nonprofit Organization Board for the Oceanic Society (San Francisco), the EPA Science Advisory Board Committee on Valuating the Protection of Ecological Systems and Services, and the science advisory boards of the Pacific Ocean Conservation Network (California), and the Channel Islands National Marine Sanctuary (Santa Barbara).

See also

In Spanish: Joan Roughgarden para niños