I have taught biology in some form for the last 14 years and I see one mistake over and over. Students often have the misconception that there are only two types of (eukaryotic) cells: animal and plant cells. I know that sometimes students don’t hear everything we say, but this is definitely a misconception we need to be working on.
This creates a mental block for students in higher level science courses. This post contains affiliate links for your convenience. You can read my full disclosure here.
I suspect it revolves around presentation and their preteen and teenage brain development. Tweens and teens tend to see things very black and white. The way that we typically present animal and plant cells only provides two generic cells for comparison. Unfortunately, it isn’t a complete set of information and there is a reasonable chance that another instructor later in their life will have to rewire their brain.
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When students are presented with only two generic cells for comparison, they struggle to wrap their heads around the diversity of cells. The diversity of cells is enormous.
This is a particularly difficult area of struggle for students going on to take Anatomy & Physiology and/or higher level biology courses. This is a diagram of some cell types found in the human body and it is just a sampling.
Instead of limiting students to thinking of cells falling into two generic categories, we can focus on answering the question of what do all cell have in common and why do differences exist?
Don’t create more work.
Science can feel overwhelming and our natural response can be to over simplify. The result is that the brain works so much harder to understand new material. That is right. When we give students incorrect or incomplete information we create a scaffold that is falling down. Now when they get the new information that doesn’t fit into the scaffold they built previously they have to destroy the previous schema (fancy word for how the knowledge is being stored in the brain) and create a new one from scratch.
Have you ever been working on a big project only to realize that one of the foundational pieces has not been done well enough? It completely blows! Have you ever tried to just push through and get it done without fixing the problem? Students do that too, which makes laying those strong foundations so very important. Student learning decreases as frustration increases.
Animal and Plant Cells come in a variety of shapes and sizes just like people.
I can’t tell you how many students look at me completely stumped when I have tried to discuss the differences between a skeletal muscle cell and a neuron. Sometimes they even draw the fried egg looking thing they have been shown for years to illustrate to me that “This is an animal cell”.
That is a generic animal cell. It is not what all the cells in animals look like. Actually very few of the cells in animals look like that. Why? Because animals are complex organisms. Animals, including humans, need our cells to do different jobs in our bodies.
Each cell has a specific function. The reason we provide the generic animal and plant cells as comparison is to show the striking differences between the two. For instance, an animal cell will never have a cell wall.
I encourage you to teach that cells are divided and organized in many ways depending on what structures are present. While these divisions, help make categorizing cells easier they are not a complete view of all cells.
A person can come in many shapes and forms and still be recognized as a person. The same is true for cells. There is so much more to cell biology. Check out all the options for cell models.
We haven’t even mentioned the differences between prokaryotes and eukaryotes or the variety of modifications for different organisms. I suggest that we put an emphasis on diversity. For instance, animal cells will not have cell walls. Then show students lots of different cells and explain that by looking for a few structures we can determine which are animal and plant cells. Just like people look different so do cells (even animal cells).