Source Newsroom: University of Wisconsin-Madison
Newswise — With Charles Darwin's 200th birthday coming up in February, several University of Wisconsin-Madison experts are available to talk about the evolutionary biologist and related research.
— Humans: Still evolving, only faster
When many people think about evolution, they may think about ancient apes morphing into humans, or perhaps Darwin's famous Galapagos finches. But modern humans are just as subject to the pressures of natural selection and, in fact, human evolution has accelerated during the past 5,000 years, according to UW-Madison anthropologist John Hawks. Hawks uses modern-day variation among human populations to understand and reconstruct our evolutionary history. Though people from around the world are genetically very similar, with individuals differing by only around 0.1 percent of their DNA, a handful of genes are very highly variable. The present distribution of such genes provides a living record of our evolutionary past.
Hawks is currently expanding his studies to the evolution and spread of human languages and other cultural "hitchhikers" that reflect the movements and influence of ancient populations. The Bantu family of languages, for example, is distributed across central Africa in a pattern that matches well with the spread of farming. He is investigating links between genetic changes and cultural innovations throughout human evolutionary history.
— Evolving germs
Perhaps the most relevant and observable forms of evolution in action occur in the microorganisms that cause disease. Tony Goldberg, a professor in the UW-Madison School of Veterinary Medicine, studies the ecology and evolution of disease and disease-causing organisms. Most famously, disease-causing bacteria that survive antibiotic regimens can evolve resistance to the drugs used to fight infection. Viruses evolve to adapt to new hosts and environments. The AIDS virus, for example, was not always adapted to humans. The virus that infects humans today and that sparked a global epidemic evolved from a simian virus found in chimpanzees that was first transmitted to humans through the bush meat trade in central Africa no later than the 1930s. The virus's first human victim, explains Goldberg, was probably infected through a wound exposed to animal blood.
The challenge, according to Goldberg, is to discover what other types of harmful microbes could enter the human population in similar ways. Only by understanding how, where and why humans and other species exchange pathogens can such transmission be averted. Goldberg's research on this topic spans several continents and disease systems, from bacteria in Ugandan primates to West Nile virus in the suburbs of Chicago.
— What's the trouble with intelligent design?
Intelligent design (ID) is embodied in the idea that some of nature's adaptations — the vertebrate eye, for example — are too complex to have evolved on their own and required the intervention of an "intelligent designer" : God. The catch with ID, argues UW-Madison philosophy professor Elliott Sober, is two-fold. First, it isn't true that complex adaptations could not have evolved by natural selection. Second, the ID hypothesis itself isn't testable. In science, testing a hypothesis requires figuring out what the hypothesis predicts. What features of the eye does the ID hypothesis predict? Without information about the goals and abilities that the designer has, this question can't be answered, Sober explains. The ID hypothesis can "accommodate" any observation, he says. "If you observe X, you can construct the hypothesis that an intelligent designer made X exist. But accommodating what we observe isn't the same as predicting what we should observe."
— Coping with evolution
There is no escaping that evolution is a pillar of modern biology. And while some major religions can and do accommodate the tenets of evolutionary science, how do spiritually minded scientists and others integrate the ideas of evolving life, geological time and the big questions of cosmology into their spiritual worldviews? For UW-Madison historian of science Lynn Nyhart, the pages of history offer insight that can be especially valuable for students and others wrestling with the apparent conflicts between evolution and biblical interpretation. If you take evolution as a fact, says Nyhart, what do you do about your spiritual inclinations and needs?
The experiences of scientists in the first generations after the publication of Darwin's "On the Origin of Species" reveal a burst of spiritual creativity as they sought to address this problem. Evolutionists seeking to maintain their spiritual lives adopted new readings of the Bible, looked to older traditions that relied less directly on the Bible, discovered non-Western spiritual traditions, or found new spiritual meaning in art, music, poetry, and philosophy. Belief in the truth of evolution, Nyhart shows, has never required scientists to abandon the spiritual realm.
— The yeast we can do
Darwin may have gotten his evolutionary insight from observing nature's stunning breadth of forms, but assistant genetics professor Audrey Gasch finds hers inside the tiny sphere of the yeast cell, whose basic, cellular physiology closely resembles our own. A geneticist and biochemist by training, Gasch had been studying the genetic and cellular responses of yeast to environmental stress in the lab for years, when the thought occurred to her: Perhaps her lab strains were wimps compared to wild yeast — or, at least, different.
Her research on wild cells taken from locations worldwide, including Wisconsin soils, has now confirmed the hunch. Wild yeast differ tremendously from lab strains — and each other — in their ability to survive environmental stresses, including freezing and thawing, and high concentrations of ethanol, which they produce as they ferment wine, beer and biofuels. She's now probing this natural variation to understand how the traits of cells evolve at the most basic level: that of genes. Her work has implications for everything from cancer biology to biofuels production.
— Through history's lens
Ronald Numbers, Hilldale Professor of the History of Science and Medicine, is one of the world's leading authorities on the collision of science and religion, from Galileo to the recently opened creation museum in Kentucky. The son of a Seventh-Day Adventist minister, he grew up believing his church's literal reading of the Bible; his studies in science eventually challenged those beliefs. His publications include "The Creationists," Science and Christianity in Pulpit and Pew," "Galileo Goes to Jail, and Other Myths About Science and Religion," and "Darwinism Comes to America." Numbers can comment on the mainstream responses to Darwinism, what Darwin really wrote about in "On the Origin of Species" (there is only one sentence on humans in the book), and what we usually get wrong about Darwinism, natural selection and evolution. He is sought by critics and believers alike for his expertise and is in high demand in this anniversary year, including a lecture at the Vatican in March.
— Detailing the origin of species
One hundred fifty years after Charles Darwin published "On the Origin of Species," UW-Madison assistant professor of genetics Bret Payseur is working to answer the same basic question posed in that seminal work: How do new species arise? While Darwin could only speculate about biological mechanisms to explain the diversity he observed, Payseur is tackling the question with an arsenal of modern molecular tools to identify genetic barriers that can lead to the evolution of new species.
He also studies genetic variation responsible for the evolution of differences within a single species. Among humans, for example, different populations can show distinct physical characteristics, disease susceptibility, and lifestyle adaptations such as the ability to digest lactose. Other differences can be more extreme, as seen in a population of house mice found on remote Gough Island in the south Atlantic. In just 200 years of isolation, the Gough Island mice have become twice as large as their mainland counterparts and are also the only known carnivorous mice in the world, preying on seabird chicks and driving at least one species, the Tristan albatross, toward extinction. Payseur is currently working to understand the evolutionary history of this unusual mouse population.
— Invasive species: Evolving a path to success
In the rough-and-tumble world of biology, a tiny fraction of species have developed a very useful trick: the ability to invade and make themselves at home in environments very unlike their home turf. For example, zebra and quagga mussels native to Eurasia normally thrive in saline or brackish water but have established freshwater populations in the U.S. Great Lakes. They are so successful that they now threaten our native freshwater ecosystems and are driving native mussels to extinction. Evolutionary geneticist Carol Lee calls such species "weedy" for the ability to spread and thrive under a variety of environmental conditions. Her research as an associate zoology professor focuses on two main questions: What traits allow some populations to invade new habitats, and how do such traits evolve? In addition to the mussels, she studies an invasive species of copepod, a tiny crustacean that has also made the leap from salt to fresh water. She is working to identify the genes and types of mutations that allow such invasive species to adapt so readily to different conditions. Understanding species' evolutionary potential may also hold the key to predicting how species will respond to environmental and climate changes.