Creation of Dichotomous Keys From a BioBlitz

This activity is designed for students to develop an appreciation for their environment and strengthen observational skills. The student will also demonstrate the ability to observe and report findings using descriptions and drawings. Identification of unknown plants will be done using field guides. Experience using and creating a dichotomous key will be accomplished. Vocabulary words to be "discovered" will be scientific investigation, dichotomous key, population, biodiversity.

This brief description is for integration into a 7th grade life science lesson. It is extremely adaptable to all grade levels and class sizes. There is no special equipment needed. Field guides help. A book to place collected plants would be helpful. A science notebook is also a needed tool. The original BioBlitz was designed to see how many organisms could be identified in a 24 hour period. This lesson will use one hour in the field and one hour in the classroom. The lesson fits into the beginning of the year to teach observational skills or could be done numerous times throughout the year to compare differences over time.

The first day of the activity students will be briefed on the expected outcome. They will be taken to a particular corner of the school property and broken into teams. Each team will travel in a different direction and cover 1 city block. They will walk on the right side of the street and observe, list, draw and/or collect a sample of every organism that is within arms reach of the sidewalk. The main idea is to discover the diversity of organisms living around us. Materials needed are simple and include a notebook, field guides, and something to collect plant specimens in, old textbooks work well.
The second day will be spent in the classroom counting the number of species and comparing results. The students will be given time to identify ten plant species using provided field guides and they will use these plants to develop a dichotomous key for identification.
The third day can be used to discuss what was discovered. How many organisms did they identify? What were the different characteristics of the organisms? What characteristics did the students use in their dichotomous keys? Have the students discuss ways to make this experiment different or adapt to different environments. Use this as a lead into a discussion on populations and ecosystems. What type of organisms would we have found if we went to a bog? etc.
This lesson was adapted from a lesson taught by Mike Link at the Audubon Center of the North Woods in Sandstone, Minnesota. It was part of a Minnesota Science Teachers Education Project (MnSTEP) Biology/Environmental Education course.

Safety tips are obvious for this type of activity. If you have an outdoor area close to your school you could choose to do transects instead of walking along a sidewalk. Give each group a compass and have them record every plant species they encounter along their transect for a given amount of time. If you have money for field trips you can go to different areas and compare plant species and diversity. Another nice addition to this project is to have students create a poster with the plants they collected and display them for the rest of the class to enjoy.

The discussions and enthusiasm students display will be the main assessment whether the goals of this activity are being achieved. The level of questions they ask and interest in the activity will be a guide of the success or failure or this lesson. In order to check for student understanding, the dichotomous keys will be collected and student notebooks will be checked for involvement.

7.IV.B.4—dichotomous key
7.IV.C.2 - populations
7.IV.C.3 - ecosystem
7.IV.C.4—factors affecting types and numbers of organisms