Endosymbiosis: A Friend Within
Type of activity:
- Inquiry lab
- A hands on activity that can be used for review/reinforcement of the ecological principle of symbiosis.
- AP Bibolgy
- Life Sciences
- Inegrated science level 4.
This activity answers these questions:
- What is symbiosis?
- How do termites obtain nutrition?
- It gets them to question how endosymbiosis and symbiosis differ? And how are they related?
- What is mutualism?
This activity is a class activity that requires one class period of a mininium of fifty minutes to complete. It is possible to obtain termites through a couple of scientific supply houses, but I am always able to collect them from the surrounding area. Look in rotting logs and stumps for these insects. This helps to reduce the cost of the lab. Preparation time is limited to collection time and set up of the lab for microscope work. The termites can be kept in a jar with dirt and a rotting log for several weeks if it is watered down occasionaly.
This activity deals with the symbiotic relationship of mutualism between termites and flagellates. This activity utilizes the common ground termite, Reticulitermes flavipes and the protozoan Tricohonympha to show the symbiotic relationship of mutualism. It is a relatively easy procedure that requires only minimal materials and supplies.
- Compound microscope
- Slide and cover slip
- Two needles or sharp probes
- Protoslo and Reticulitermes flavipes
Each student should obtain a microscope slide, coverslip, compound microscope and two needles or sharp probes from the supply area. They are then ready to collect one live termite and place it on the microscope slide. Using the two needles place one on the front end of the termite and one on the abdomen. When these needles are pulled in opposite directions, the alimentary canal will open and reveal the wealth of protozoans within. A drop of distilled water should be added to the slide and a coverslip place in a normal wet mount fashion. This will allow the protozoan to swim from the alimentary canal and allow the students much easier viewing. If the compound microscopes are equipped to operate using the darkfield technique, the Tricohonympha can be seen with great ease.
Method of Evaluation:
The students should be expected to complete a lab write up on the activity. This lab report will provide information about the success of this activity and be the method of evaluation. It is also useful to monitor the excitement level as they discover these flagellates. Always a good measure.
This lab can then be followed up with class discussion about the broader principles of ecology, and symbiosis. It can also lead to research papers on the life cycle of termites. Social behavior and the method of transmission of the flagellates to the termites is also an interesting follow up discussion.