Biology dissections have been staple in high school classrooms. Dating back to when I was a student in biology, dissections were often the most exciting part of biology class. Students were placed in small groups with a dissection tray, dissection kit, and a series of cookbook instructions of what to look for in the specimen. We would go through the instructions step by step making cuts and incisions and drawing the parts as we go. Once all the steps are completed with all the diagrams labeled, the clean up process begins, and that was the dissection. There may be a post dissection series of questions for students to complete or how the dissections could be found on the next test, but in a nut shell, that was a typical dissection.
This year, I tried to have my students lead the dissections instead. The dissections were incorporated into the gr.12 biodiversity unit when most of the dissections take place. The unit took 4 weeks in its duration including basics of evolutionary history, classification, and research on the conservation efforts. I broke down the Unit into a project-based learning where the question is
“Are the efforts being conducted by conservation adequate in sustaining the population of a/an endangered animal (select your own___________________)?”
The project contains 4 parts
1) Learning portfolio on the classification of organisms
2) Leading a dissection
3) Presentation of the findings of the conservation efforts
4) Creating a cladogram and dichotomous key assignment.
In the learning portfolio, the students are to create their own notes, take down information discussed in class, and create a portfolio describing how biodiversity is organized. The students have to clearly identify, explain, and annotate with diagrams the various domains, kingdoms and phyla and their individual characteristics.
In the leading a dissection, I had the students prepare a presentation to guide through their peers step by step in the dissection, a diagram (blank and completed), and questions that follow the dissection. Many students chose Kahoot, and prepared various questions for their peers to complete. The remarkable part of this process was seeing the students answer questions and facilitate the dissections. Moving forward, I would create a more structured expectations of the diagrams, and a more concrete list of items needed from the students. Some of the diagrams, or instructions were not as clear, or that the diagrams were simply printed off an internet site without any use to them during the dissection.
The presentation of the conservation efforts of an endangered animal involved the students to individually prepare a formal presentation of an animal of their choice and to research on the current conservation efforts, techniques, and what more can be done to the efforts.
Lastly, the cladogram and dichotomous key is a simple assignment where the students create their own instead completing one. Some of the cladograms, and dichotomous were very creative in the topics that the students had chosen.
All in all, I think the student led dissection was a great success and will definitely try it again for my next biology class.
In the digestive system unit, a very unique way of getting the students to see the organization of the organs and how compact it is to fit all the organs is to use a layered digestive system model. In this project, the students have to generate a layered digestive system with any materials they want. The key for this is for the students to have the accurate depiction of the various organs, the order of the digestive flow, and the placement of each of the organs.
To get the students started with this project, every student should have been exposed to the various organs in our digestive system. To make their project layered, they have provided with 3-4 large sheets of paper, and have 1 of the sheets be the “exterior”, with the subsequent sheets of paper being the internal organs. They are to imagine that they are performing surgery, and that if they were to cut open and create an opening, what would they see? and what would be underneath?
This is a great anatomy video to show: Dr.Gunther – Digestion
Extension: Other students have used other materials such as using cardboard and velcro to show the 3 dimension aspects of the digestive system, while others made a cake. Creativity for this project was great!
In the Gases and the Atmosphere unit of gr.11 chemistry, the gas laws (Boyle’s, Charles, and Gay-Lussac) are often taught in a sequential and systematic manner. The first formula of Boyle’s law is introduced, followed by the formula (pv = pv), and then a bunch of busy work practice questions and on to the next law. I remember teaching this during my practicum, and as a new teacher, I followed the curriculum order to the tee. But how does teaching the gas laws, and having students complete series and series of questions beneficial to their conceptual understanding of the content. The students may have discovered the quickest way of completing the busy work, but when provided a conceptual question relating the pressure and volume, how do they measure up? Lin et al (2000) discovered that many students who have done the mathematical calculations of the laws failed to understand many conceptual real life situations. Gr.11 chemistry students were presented a series of real life conceptual questions where students who supposedly completed the gases unit still did not understand the relationship of pressure, volume and temperature. (fig.1)
To combat and encourage conceptual understanding, I exposed the 3 gas laws by introducing the 3 variables in a series of demonstrations, and examples. Simple demonstrations such as looking at the relationship of the size of a balloon in a cool vs hot environment suggests a direct correlation between the variables. Another example is using a closed off syringe to illustrate the inverse relationship between the volume and pressure. After the students have visually seen the relationships, and example calculations, a summary of the 3 laws with their mathematical relationships is provided. Then their task is to design an experiment to prove one of the 3 gas laws quantitatively. I have found that the most challenging task for a high school student in science classes is to prove something with supported data. Their experiments can vary, and can explore different ideas. I have seen failing experiments, to ones with Ward’s data hub with data hooked up inside a vacuum to collect data of pressure. The important aspect here is not to have students design a flawless experiment, but to have them design, experiment, and revise their experimental design to encourage critical thinking and teamwork.
At the end of the “experimental week”, the students were provided with conceptual questions to see their conceptual understanding of various gas law topics. I was amazed to see their depth and reasoning in applying their knowledge to the questions.
Lin, H., Cheng, H., & Lawrenz, F. (2000). The Assessment of Students and Teachers Understanding of Gas Laws. Journal of Chemical Education,77(2), 235