Dichotomous Keys PDF

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Holly Marie Bernardino April 9th, 2020 BIO1220L BIO 1220L Lab 10 — Creating and Using Dichotomous Keys EXERCISE 1: USING A DICHOTOMOUS KEY The identification of five unknown plant species. Include with each the leads you selected to arrive at your answer (for example—1, 2, 3’ for brittlebush, Encelia farinosa). Unknown Species A: 1’, 7, 8’ for California black walnut, Juglans californica Unknown Species B: 1, 2’, 4’, 6 for coast live oak, Quercus agrifolia Unknown Species C: 1, 2’, 4’, 6’ for white alder, Alnus rhombifolia Unknown Species D: 1’, 7, 8 for blue elderberry, Sambucus mexicana Unknown Species E: 1, 2, 3’ for brittlebush, Encelia farinosa EXERCISE 2: CONSTRUCTING A DICHOTOMOUS KEY Using the space below, construct a bracketed dichotomous key using hypothetical creatures. Select eight of the Caminalcules and give them names (as opposed to the numbers currently used to identify hem). Use the characteristics in the provided diagram below to help write the leads of your dichotomous key.

EXERCISE 3: WHY ARE DICHOTOMOUS KEYS ARTIFICIAL? 1. Are dichotomous keys used for the same purpose as phylogenetic trees? Dichotomous keys could be used as the same purpose as a phylogenetic tree. However, dichotomous keys are used to determine and identify certain characteristics and to split up species. Phylogenetic trees show the lineage of species throughout time, as well as the organization of organisms. Phylogenetic trees show how things have changed over time, while dichotomous keys are highlighting the specific changes. Phylogenetic trees display the evolution of traits. 2. Do dichotomous keys reflect evolutionary histories and relationships? No, they do not. They only reflect certain characteristics that distinguish organisms into specific categories. They allow for humans, especially scientists to distinguish and identify organisms that are unknown as if they were trying to find clues to solve the puzzle. You could have an organism that is completely unrelated to another organism, but they would be “connected” through having a certain trait that does not even define a history or direct relationship. They could hint at relationships if one notices similarities amongst certain traits....