The main difference between dichotomous key and polyclave key is that the dichotomous key compares two contrasting statements, whereas the polyclave key lists the presence and absence of all features.
The dichotomous and polyclave keys are two diagrams describing the relationships among organisms. They describe the characteristics of organisms.
Key Areas Covered
1. What is Dichotomous Key
– Definition, Features, Importance
2. What is Polyclave Key
– Definition, Features, Importance
3. Similarities Between Dichotomous Key and Polyclave Key
– Outline of Common Features
4. Difference Between Dichotomous Key and Polyclave Key
– Comparison of Key Differences
Key Terms
Dichotomous Key, Polyclave Key
What is a Dichotomous Key
A dichotomous key is a diagram that allows the identification of a group of organisms by dividing them into two categories repeatedly. These categories are called ‘leads’ while a set of leads at a given point is called a ‘couplet’. When an organism no longer shares its selected characteristics with any other organism, it has been identified. However, the above-selected characteristics have to be immutable; in other words, they do not change. For example, coloration, size, and behavioral features may vary among individuals and throughout their lifetime. However, physical structures, such as the number of limbs, and biochemical processes, such as reproduction methods, are better characteristics.
Figure 1: Dichotomous Key
Furthermore, there are two types of dichotomous keys based on the representation method. They are the diagrammatic representation as a branching flowchart and the descriptive representation as a series of paired statements laid out in numbers. However, the dichotomous key does not provide any trustworthy phylogenetic relationships of organisms in the diagram.
What is Polyclave Key
The polyclave key is a tool used in the identification of unknown species. Interactive computer programs help to generate the polyclave key. Importantly, the polyclave key uses a process of elimination. It has a series of choices that describe the features of the species. One can match the characters of the species with those features. If the features of the species match the characters, the species is included in the list. But if the features of the species do not match the characters, the species is eliminated from the list. Therefore, a polyclave key is a list of species with a certain characteristic. When more characters are used in the selection, more species are eliminated from the list.
Moreover, the polyclave key allows the rapid elimination of many species. The elimination process can be continued until only one species remains.
Similarities Between Dichotomous Key and Polyclave Key
- Dichotomous and polyclave keys are two diagrams describing the relationship between organisms.
- They describe the characteristics of organisms.
Difference Between Dichotomous Key and Polyclave Key
Definition
A dichotomous key refers to a key for identifying organisms based on a series of choices between alternative characters. In contrast, polyclave key refers to the tools used to help identify unknown objects or species.
Significance
The dichotomous key compares two contrasting statements, while the polyclave key lists the presence and the absence of all features.
Access to the Key
The dichotomous key has a single access, while the polyclave key has multiple access.
Identification Structure
The dichotomous key contains a series of identification steps, while the polyclave key allows the identification of organisms by elimination.
Importance
At each point of the dichotomous key, the multiple alternatives lead to a further choice, while each statement describes several species.
Conclusion
In brief, dichotomous and polyclave keys are two diagrams describing species according to their characteristics. The dichotomous key compares two contrasting statements. It has a single access. Also, it has a series of identification steps. Multiple alternatives lead to a further choice. In comparison, the polyclave key describes the presence or absence of all features. However, it has a multiple access. The process of identifying the species in polyclve key is by elimination. Also, each statement describes several species. Therefore, the main difference between the dichotomous and polyclave keys is the comparison type.
References:
- Taxonomic Keys. North American Network of Small Herbaria
Image Courtesy:
- “Extant Shark Orders” By Chris huh – Own Work (Public Domain) via Commons Wikimedia
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