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Tips on researching recent extinctions

Controlled subject words

When using an index or abstract to look for articles on a particular subject, always check to see if it has a controlled vocabulary or thesaurus indicating what subject words are recognized and used by that index. For example, consulting the controlled vocabulary will clarify whether one should look up the word "extinct," or "extinction," or "extinctions," or "animal extinctions," or "plant extinctions," etc.

Zoological Record offers an entire volume called the Zoological Record Search Guide, which is a guide to the controlled vocabulary used by that index. This guide indicates that the word "extinction" is the recognized subject word that you should use when searching for information on this topic.

If the index does not have a controlled vocabulary or thesaurus, or if one is searching for books in a library's online catalog, one can usually assume that the recognized subject headings will be those used by Library of Congress, and found in Library of Congress Subject Headings. The following subject headings are used by the Library of Congress for the topic of extinction:

  • Extinct animals
  • Extinct amphibians
  • Extinct birds
  • Extinct fishes
  • Extinct insects
  • Extinct mammals
  • Extinct plants
  • Plants-extinction
  • Extinction (Biology)
    • QE721.2.E97 (Paleontology)
    • QH78 (Natural history)
Try searching the American Museum of Natural History Online Library Catalog with these subject headings.

Database search strategies

When searching in an electronic database, non-controlled subject terms can be used as well as those that are part of the controlled vocabulary. Most databases also allow words to be truncated in order to quickly search for all possible variations. Terms can also be combined to refine the search strategy further.

Different databases have different symbols that represent word truncation, some use an asterisk, some use a question mark, etc. The chances of retrieving all possible relevant references may increase by utilizing truncation. For example, searching "extinct*" will retrieve any references containing the word "extinct," "extinction," or "extinctions."

Truncation should be used with care as some words can have different endings that change their meaning. For example, if one wanted to find information on insects and the search term "insect*" was used to pick up references containing both singular and plural forms of the word, one would also find that references containing the word "insectivore" or "insecticide" would also be retrieved. Some database offer features to help you avoid a situation like this, but if these features are not available, you can always combine the singular and plural form of the word with an "or" (see below).

Non-controlled subject terms:
The likelihood of picking up all possible relevant references is increased if the search query is as broad as possible and includes all possible words (synonyms) that are likely to be used by an author discussing the topic. For example, when looking for information on extinction, one might try using additional truncated words such as "exterminat*." Searching for the word "rediscover*" may help locate articles about species that were once thought to be extinct.

Combining terms:
Searching in electronic databases also allows one to combine terms using "or," and "and" to refine the search strategy, as in this search entry: "(extinct* or rediscover*) and mammal*"

If one is searching for information on recent extinctions, then searching for the word "extinct*" is likely to pick up numerous articles about dinosaurs and other less recent extinctions. Sometimes one can stipulate topics that one is not searching for, as in the following two search entries: "extinct* not dinosaurs" or "extinct* not (jurassic or cretaceous or ...etc.)."

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