Evo Edu Outreach (2010) 3:206–214 DOI 10.1007/s12052-010-0213-5 EDUCATION ARTICLE How to Win the Evolution War: Teach Macroevolution! Kevin Padian Published online: 10 March 2010 # The Author(s) 2010. This article is published with open access at Springerlink.com Abstract If the American public understood what is what most worries creationists is that the average K-12 actually known about the major evolutionary transitions in student will learn about how we know about the major the history of life and how we know about them, transitions in the history of life. Currently, the system works uncertainty about evolution would drop precipitously, for the creationists, and for four main reasons. First, nothing creationist arguments would fall on deaf ears, and public substantial about macroevolution is in the framework or education in biology would make much more sense than it syllabus of any state, so not only will it not be taught, it will now does. Macroevolution must take a much more be discouraged from being taught. Second, very few prominent place in K-12 science teaching. To do so, a evolutionary biologists have a first-hand understanding of curriculum must be redeveloped at both K-12 and college macroevolution, and they do not spend substantial time on it levels, so that preparation in macroevolution is a required in their college courses. This is because most of them are part of K-12 biology preparation. population biologists and population geneticists, and they have had little or no training in macroevolution. Third, as a Keywords Creationism . Evolution . Macroevolution . result, college biology students, including those who become Evolution education . Intelligent design teachers, have a very poor background in macroevolution. And fourth, for all these reasons, textbooks in all grades from The war of entrenchment and retrenchment in American K-16 fail completely to convey an understanding of how public schools has gone on long enough. Pendulums swing; evolution works in the long run. yearly skirmishes result in gains and losses for each side, often In this essay, I want to explain why a full and straight- in the same state; just when the last bunch of anti-intellectuals forward exposition of macroevolution in seventh-grade life- has been voted off the school board, along comes another science texts, high school biology texts, freshman-level ’ group to take their places. It s educating a parade, as Genie college biology texts, and upper division texts in evolution Scott often says. But it’s time for the parade to get smarter. 1 and related subjects is the single most effective advance that We are fighting the same battles over and over again. To can be made in educating the public about evolution. This change this, evolutionists have to shift the ground. For too means convincing a large proportion of that “undecided” or long scientists and educators have been on the defensive, uneducated middle portion of the American spectrum about trying to preserve the teaching of the same K-12 canon that Darwin’s principles of common descent and diversification is keeping the populace ignorant about how evolution works of life through time. State curricula have to be revised; in the long run and how we know about it. Make no mistake: textbooks have to be rewritten; teachers have to be better educated; and selection committees at the state and local 1 This language may seem overly pugnacious, but I’m deliberately level have to insist on these improvements. I do not pretend borrowing it from the creationists, who have used the “battle” and that this will be easy; I do not suggest that we stop teaching, “ ” war metaphors incessantly for over half a century (Numbers 2006). teach less of, or de-emphasize what we are already teaching K. Padian (*) about evolution; I do not say that no one anywhere is doing Department of Integrative Biology and Museum of Paleontology, any of this. I am saying that much more of it has to be done, University of California, Berkeley, CA 94720-3140, USA and it has to be instituted far more strongly. This work has to e-mail: [email protected] start now, and on several fronts at once. Evo Edu Outreach (2010) 3:206–214 207 What is Macroevolution? not predict why cervids (the deer family) are far less diverse and numerous than bovids (the antelope family)—which they Macroevolution means the patterns and processes of have been for the latter part of the Age of Mammals. evolution above the level of populational change and Analogies are tricky, but hierarchical concepts work differentiation. These patterns and processes follow upon much the same in evolution and economics. There are many speciation events. What that means, in effect, is that facets to microeconomics and macroeconomics, just as to speciation—the production of new species—is the raw microevolution and macroevolution. Let’s consider some material of macroevolution, just as the production of new simple ones. Microeconomics could describe the operation mutations is the raw material of change at the population of mom-and-pop groceries, supply and demand of small level. Of course, once species are separated by speciation companies, and economic interactions in relatively self- events, they still contain populations, and these populations contained towns or principalities. Macroeconomic topics generate mutations that continue to be the raw material of would include international monetary policy, the Federal further evolutionary change that separate the sister species Reserve System, and questions of wage and price controls. even more. The important thing is that when we talk about In both macro and micro senses, there is a common currency. macroevolution we are discussing the patterns and process- It is—well, currency. Dollars, that is. It unites the levels, es that happen using species and other larger clades (groups even though the problems are very different. In evolution, comprising related species) as the units in play—not genetics is the common currency: that is, genes. Populations individuals in populations with gene flow and shifts in of a species share a genetic currency that allows interchange allele frequencies. The difference between micro- and and evolution of the genetic and phenotypic structure of a macroevolution is much like the difference between how lineage; above the species level, the genetic material is your town votes in an election and how the whole country hardly ever interchanged, but within distinct lineages it votes: there are lots of agendas in different regions that continues to evolve and differentiate them. don’t play out on every local stage, and how your town Here are five components of macroevolution that every votes is not a necessary predictor of how the nation votes. student of biology should understand: That’s what keeps political scientists busy. And the relation- ships—which are not necessarily fractal—between micro- 1. The rates of origination and extinction of species shape and macroevolution keep evolutionists similarly busy. the history of life. These rates are exactly analogous to Examples of macroevolutionary events, processes, and the interplay of births and deaths in populations, which patterns would include the rise of the dinosaurs (and their structure the history of these populations through time. extinction); how grasses came to dominate most continents, Because in a population there will always be deaths and how mammalian herbivores responded; how flight (extinctions at the species level), the birth rate evolved in insects, pterosaurs, birds, and bats; and why (speciation rate) must keep up with the death rate artiodactyls (even-toed ungulates) replaced perissodactyls (extinction rate) on average through time or else the (odd-toed ungulates) increasingly during the Tertiary population (clade) will die out (become extinct). Period. These phenomena cannot be predicted just from Population size (diversity of species in a clade) can knowing about Hardy–Weinberg equilibria, runaway sexual decrease for two reasons: the birth rate (speciation rate) selection, or the “rare male effect,” important though all can decline or the death rate (extinction rate) can those are to some populations of living organisms. increase. (Conversely, the diversity of species in a clade The reason why we study macroevolution as a separate can increase either because the speciation rate increases subject from population biology is that the things that or the extinction rate decreases.) In macroevolution, we happen at the population level do not translate very see both processes and all four combinations of patterns predictably to the level of the clade. They are different shaping the diversity of clades through time. hierarchical levels, as Niles Eldredge, Stephen Jay Gould, 2. As a species-lineage evolves, its morphology may and many other paleontologists have pointed out for change in many ways or hardly at all. The best- decades (e.g., Eldredge 1985). It is not that these levels documented fossil sequences show a variety of modes are inconsistent or incompatible. It is simply that what of evolution. Some—actually very few—change in a happens at one level does not predict or describe what will slow and steady directional way. A great many show happen at the other. Imagine a species of deer in which statistically minor fluctuation of features in one individuals in populations in some areas are favored because direction and then another, but generally centering they can forage more efficiently for food in winter, whereas around a fairly steady mean. Others show almost no individuals in other populations elsewhere are favored change at all for most of their histories, then substantial because they can elude predators more effectively. These are change in a very short period of time. When we can see interesting phenomena at the populational level, but they do these lineages separate into two distinct lines in the 208 Evo Edu Outreach (2010) 3:206–214 fossil record, we are witnessing a speciation event.