How is a certain species chosen to grace the cover of a textbook? While we would love to think that all species have an equal chance, the truth is that the subjects on the cover are usually selected because of their artistic appeal. After all, even though I am a Drosophila geneticist by training, and love pictures of fruit flies, I realize that most people would prefer to see something like butterflies, flowers or wolves. Dull insects and parasites are out, color is in.
However, for the 11th edition of Biology, I decided to mix it up a bit. The authoring team and I decided that not only would we choose a pretty picture (we are not complete rebels), we would integrate the theme of that picture throughout the text. Why? Because students, like everyone else, like a good story, and educators are probably the best story-tellers on the planet. Our job as teachers is to take a series of usually uninteresting facts and find a way to engage the students. So this edition, we picked a really cool story….
And here is the story…..
The wolf on the front cover is a subspecies of the North American gray wolf called Canis lupus arctos, or the arctic gray wolf. Wolves, like the one shown here guarding a skeleton of a caribou (Rangifer tarandus), historically occupied almost the entire United States. However, wolves were viewed as a hazard by many human groups, and by the 1930s, almost all of the wolf packs in the continental United States had been exterminated. But this is not just the story of the loss of another animal species.
The removal of the wolves began to have a ripple effect on the Yellowstone ecosystem. Without a natural predator, the population size of elk began to expand, and as it did, the preferred food sources of the elks – cottonwood and willow trees – began to dwindle. Cottonwoods especially serve an important role in the Yellowstone ecosystem. This species of tree prefers the banks of streams, where its root system helps stabilize the stream banks, thus preventing erosion and the accumulation of sediment. With the loss of the trees, the aquatic habitats suffered, and for decades ecologists documented the decline of aquatic insect, fish, and bird populations. Over time, scientists were becoming concerned that the food web of the Yellowstone ecosystem was moving towards collapse.
In order to understand the role of the wolves in ecosystems such as Yellowstone, scientists had to piece together information on the evolutionary history of the organisms in the community with an understanding of how the ecosystem functions as a biological system. Coupled with this was some fascinating detective work, with experimental results suggesting that it was the demise of the wolves, and not other ecological factors, that were responsible.
The story of the wolves is a positive one for science. By reintroducing wolves back into Yellowstone in the late 1990s, and closely monitoring not only the health of the wolf population, but also the size and composition of the elk herds, conservation ecologists have been able to document that the Yellowstone ecosystem is beginning to return to a healthy status.
So why did we do this?
Well, within this text you will find that these three same themes – the nature of science and biological systems- form the threads that connect the content together. We integrated the cover into the story of biology, and then we built assets around the themes to help the instructors engage their classes. Throughout the text, unit level learning outcomes, feature readings, and new digital assets, are all combined to integrate the themes into the course content. The goal is to enforce the idea that, like the complex interactions of the species in the Yellowstone ecosystem, the many parts of the biological sciences are interconnected, and that by understanding these connections, students can grasp the importance of biology to their lives.
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