IB Biology Lab Report Name ______________________________ Date lab was done ____________________ Title: Construction of a Dichotomous Key Purpose: To understand the use of binomial nomenclature; to use structural characteristics of organisms in the construction of a dichotomous identification key. Notes: Construction of a Dichotomous Key A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish. Keys consist of a series of choices that lead the user to the correct name of a given item. "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step. In constructing keys, keep the following in mind: Use constant characteristics rather than variable ones. Use measurements rather than terms like "large" and "small". Use characteristics that are generally available to the user of the key rather than seasonal characteristics or those seen only in the field. Make the choice a positive one - something "is" instead of "is not". If possible, start both choices of a pair with the same word. If possible, start different pairs of choices with different words. Precede the descriptive terms with the name of the part to which they apply. Manipulative skills Levels/marks Complete/2 Partial/1 Not at all/0 Aspect 1 Aspect 2 Following instructions* Carrying out techniques Follows instructions accurately, adapting to new circumstances (seeking assistance when required). Follows instructions but requires assistance. Competent and methodical in the use of a range of techniques and equipment. Pays attention to safety issues. Usually competent and methodical in the use of a range of techniques and equipment. Rarely competent and methodical in the use of a range of techniques and equipment. Usually pays attention to safety issues. Rarely follows instructions or requires constant supervision. Aspect 3 Working safely Rarely pays attention to safety issues. Construction of a Dichotomous Key Study the physical characteristics of the 10 mythical creatures in the diagram provided. Give each organism an appropriate name using correct binomial nomenclature format. Design a dichotomous key for the identification of all 10 species. Dichotomous Key: Answers: Number 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Name