Marsh Madness Highlights Symbiosis
What began as an introduction to the salt marsh ecosystem, ended with students understanding that there are many different relationships between organisms. This new lesson, It's a Mutual Thing, was first introduced to 4th grade classes at Surf City Elementary School in Pender County. Then, we took it to the 4th-6th grade classes at Island Montessori School in New Hanover County a few days later.
It's a Mutual Thing delves into symbiosis, or the relationships between two organisms, outside of the traditional predator-prey relationship we all know. Our introduction highlighted some of those, using visual representations of those species. We discussed how the marsh is a nursery for small fish and shellfish and how some of our larger commercially harvested fish begin their lives there. Then we explored other symbiotic relationships.
We began with Mutualism. A great example would be a sea anemone and the anemonefish (think Finding Nemo). The anemonefish is protected from predators by hiding among the tentacles and the sea anemone gets food the anemonefish leaves behind. The anemonefish has a mucus layer over its scales that protects it from being stung by the tentacles as it swims around them. Win-win!
Next, we discussed Commensalism. Barnacles are sessile organisms and can't swim to find their food. They use feather-like projections to filter the water of small plankton. Being attached to a mobile organism allows them better access to food everywhere they wouldn't normally swim. They do not harm the other organism by being attached, but a whale receives nothing from the barnacle being there.
Finally, we discussed Parasitism. Parasites can be found internally or externally, and we explored both. A hookworm that attaches to the small intestines of a fish (or human) will take up important nutrients that the host is trying to digest. A tick or a leech will attach to the outside of the body and feed on the blood.
After our in-depth look at some of these relationships, it was time to get to the activity. Each group was given a packet of species cards, clues, and symbiosis identification cards. The object was to use the clues to match the species together and then decide which type of symbiotic relationship they collectively had in front of them. This was a challenge, for both the students and the instructor.
As a developer of lessons and activities, it was my role to have clear-cut instructions for the students to follow, as well as clues that made sense to them, but weren't necessarily easy. We ran into a bit of a snag with the first class from Surf City Elementary School, when I realized that the clues in our lesson plan book had been changed, but the clues given to the students were not. So after the first class, I quickly went to the main office to make a copy for the students. Then I came to the realization that the clue were too difficult for that age group. This was easily remedied at home, where I changed each and every clue to make more sense to the students.
When you go into a classroom and you teach a lesson for outreach, the information may stay the same but the execution may be different. Each lesson you teach can be tweaked depending on the age of the students, their prior knowledge of the subject, and what tools you use to teach the lesson. In the past, it has been recommended to me to use larger photographs of organisms for Kindergarten students. For 4th-6th grade, this lesson works when the clues are clear, precise, and using language they are used to reading in their textbooks.
It was a great two days of introducing symbiosis to students in two different counties, and it was the first time we got to teach in Pender County so far. We hope to continue to grow our relationship with these schools, and become more mutualistic with them.