Keys in the traditional sense are a type of taxonomic literature (see Figures 25-1 & 25-2).
require the time, materials, or experience involved in comparison and recognition. The use of keys or similar devices (synopses, outlines, etc.) is by far the most widely used method and does not. The reliability is, of course, dependent on the accuracy and authenticity of the specimens, illustrations, or descriptions used in the comparison. Even though this is a reliable method, it may be very time consuming or virtually impossible-due to the lack of suitable materials for comparison. A third method is by comparison of an unknown with named specimens, photographs, illustrations or descriptions. In some groups this is virtually impossible.
This is based on extensive, past experience of the identifier with the plant group in question. Recognition, according to Morse (1971) approaches expert determination in reliability. Although of great reliability, this method presents problems by requiring the valuable time of experts and creating delays for identification.
#Modern bio study guide answers 25 1 manuals#
In general the expert will have prepared treatments (monographs, revisions, synopses) of the group in question, and it is probable that the more recent floras or manuals include the expert's concepts of taxa. In terms of reliability or accuracy the best method of identification is expert determination. For a thorough and technical discussion of specimen identification see Sneath and Sokal (1973). The methods of identification include (1) expert determination, (2) recognition, (3) comparison, and (4) the use of keys and similar devices.
#Modern bio study guide answers 25 1 how to#
For further information see Harrington and Durrell's book How to Identify Plants. The practical aspects and methods of plant identification and identification systems are discussed in this chapter. According to Blackwelder (1967) "identification enables us to retrieve the appropriate facts from the system (classification) to be associated with some specimen at hand" and is "better described as the recovery side of taxonomy." In practice one commonly identifies a plant by direct comparison or the use of keys and arrives at a name. Identification is, therefore, a basic process in classification with nomenclature playing an essential role in the retrieval of information and as a means of communication. Both processes-identification and classification-involve comparison and judgment and require a definition of criteria of similarities. The comparison of an unknown plant with a named specimen and the determination that the two elements are the same also involves classification, i.e., when one correctly decides that an unknown belongs to the same group (species, genus, family., etc.) as a known specimen, the information stored in classification systems becomes available and applicable to the material at hand. Identification is simply the determination of the similarities or differences between two elements, i.e., two elements are the same or they are different. Although identification is a separate activity or process, in practice it involves both classification and nomenclature. Identification is a basic activity and one of the primary objectives of systematics.
Chapter 25: Plant Identification CHAPTER 25.