Search Engines and Databases
PubMed is maintained by the U.S. National Library of Medicine. Although focused on medicine, it covers almost all of the journals relevant to evolutionary biology. PubMed searches can be limited to reviews. Web of Knowledge covers the whole of science; major journals are covered back to 1900. It is possible to search for specific articles or for articles that cite chosen articles. Requires subscription by library. Google Scholar is very simple to use, but it does not allow such sophisticated searches as PubMed or Web of Knowledge. It may often be the fastest way to find relevant articles but may not be as complete. JSTOR is an excellent way to explore the older literature: It includes long-established journals such as Evolution, American Naturalist, Science, and Nature, back to their first issues. (For the Philosophical Transactions of the Royal Society, back to 1665.) In most cases, the full text can be searched. Requires subscription by library. Scirus searches the Web specifically for science and finds both Web pages and journal articles. Requires subscription by library. Wikipedia is an online encyclopedia that has extensive entries on evolutionary topics, which are on the whole balanced and accurate. Anyone can provide entries and can edit them, which can lead to extensive rounds of corrections and countercorrections (as, e.g., with the entry on Evolution). Unlike papers in scientific journals, Wikipedia articles are not formally peer-reviewed. For information on peer review, see Sense about Science and Wikipedia. Bear in mind that no one source of information can be entirely reliable: It is best to critically compare multiple sources whenever possible.
Many publishers maintain their own databases (e.g., Elsevier’s ScienceDirect, Wiley’s InterScience, BioMedCentral, or Highwire Press). However, because these cover only a subset of journals, they are not very useful for exploring the literature.
Searching databases by subject is not straightforward. Words can be used in a variety of ways. For example, searching for “evolution” in a title or abstract will pick up many articles that use the word in its original sense, to mean an unfolding through time: evolution of rock formations or the evolution of solutions to mathematical equations. (The surprising variety of uses is illustrated here). Conversely, it may be hard to sum up a topic in one word or phrase. For example, many studies in evolutionary biology would not use the word “evolution” in a title or abstract: Only 69% of 2006 papers in the journal Evolution do so. Your librarian may be able to provide useful advice on efficient searching and guidance on other databases.
Be warned: Searches can produce thousands of results, and it is not at all easy to judge which are worth reading. It is now simple to export search results to reference management software such as EndNote or Reference Manager and to download papers. Ultimately, however, there is no substitute for carefully reading the best papers—and doing this properly will take many hours. It is therefore crucial to learn how to divide the time it takes to scan the literature and to actually read it.
In Further Reading and in the Web Notes, we have given references to what we believe are the best sources. To go further and to check on recent developments, a good strategy is to look at papers that cite key articles. These may be identified from our Web Notes or by looking for reviews that are cited by recent papers. It may be helpful to begin by reading the “classic” papers, since these may identify the key concepts without being obscured by a mass of later developments. It is also useful to have a sense of which journals are the most useful: We give a brief guide here.
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