I once approached a physics teacher to lend me his expertise and opinion on my sequence of lessons for Gravity, Mass, and Weight. His main concern: Not enough time for student to grasp the concept. In this post I will explore the same concern for biology education, with a focus on Year 7 (first year of secondary school in the UK).
In my social media world & experience, I tend to see Year 7 focused on the cell principle, human reproductive system, the digestive system (or other organ system), and possibly some work on food webs. Aside from the content learnt during these topics, what are the deep concepts that connect them?
The topic of Gravity, Mass, and Weight, adds more nuance to the organised network of knowledge that helps students understand forces. The cell principle, however, appears more focus on what life contains. More of a descriptive account of life rather than anything explanatory that help students make meaning of their world.
Human reproduction is often presented in a fashion that sees students learn a series of causal mechanisms, such as the menstrual cycle, fetilisation, or pregnancy. But what of the bigger picture?
What about the digestive system, a popular early biology topic? While physics builds conceptual knowledge of the fundamental patterns of nature, forces, energy, or motion, beginning with the digestive system seems analogous to beginning with physics with the engineering of the combustion engine. We have digestive systems, this is how they work, is akin to we have cars with engines, this is how they work.
Aside from these causal mechanisms, how does the topic help students organise their knowledge into a meaningful network, arranged around the deep patterns found in life? How do the contents of living organisms, or the functioning of organ systems help our young students make meaning of being part of life on Earth?
Ausubel's theory of assimilation suggests that learning progresses, and knowledge is further organised, by progressive differentiation. In other words, learning begins with the more general (big picture) concepts, and progresses by the continual addition of detail and nuance.
My opinion is that the cell principle, or human reproduction, the digestive system (inset other organ system here) do not stand as the deep explanatory concepts in biology. I focus my curricular narrative around these deep patterns:
The circular logic of life: The organisation of organisms allows them to draw upon flows of energy and matter, which enables them to maintain their organisation. (Dupré & Nicholson, 2018)
Evolution: Inheritance, natural selection, common descent.
I think the latter requires less explanation here, except that I believe it should never be far from discussion throughout secondary biology education including the first lessons of Year 7. The former I shall explain next.
There are many misconceptions that are well known for their persistence, such as the presence or not of mitochondria and chloroplasts. Whether plants take in or release oxygen or carbon dioxide. I think these are directly related to other misconceptions that are typically not apparent in the current curricular focuses.
For example, that students do not know what happens to the biomass lost when a person successfully loses weight, and typically attribute the phenomenon to simply doing exercise. Nor do they have good ideas about why a middle aged human appears to have maintained their weight for a couple of decades, despite eating so much food. In my experience, this is typically attributed to the loss of faeces, or sweat.
Students struggle with the carbon cycle in general, and it is mostly rote learnt, as if an extra to learn beyond the important stuff.
I believe that these misconceptions are connected, principally because students do not have a deep understanding of the flow of energy and matter. Students are biased to seeing themselves, and other life, as enduring substance, rather than a dynamic system that is in constant maintenance, resisting entropy (Dupré & Nicholson, 2018). The latter is the concept that students need to grasp, and it will take time, lots of time.
This is not to mean that the cell principle or human reproduction must be lost from Y7, but for their contents to viewed under a different light. For example, rather than a show case of cellular components and their functions, the process of cellular respiration must be connected to the larger flows. The flows within the body, and the flows within the ecosystem.
Maybe, even, organelles need not be learnt so early, when we can simply attribute cellular respiration to the whole cell, or indeed the whole organism early on, in that same way we do to the whole mitochondrion. What do organelles add to the meaning of their learning at this point? it's an important question.
What really needs tackling is what organisms do with flows of energy and matter and how they procure them. In my experience, as simple as this may seem, students appear to struggle with these concepts: that they are built from the molecules they consume, that organic molecules are used for building the organism, and are broken down to provide energy. Overtime, all molecules 'break down', are excreted, and will require replacing.
Year 7 should take a focus more on this superordinate concept of the flow of energy and matter. Year 7 topics should be planned with this, and evolution, in mind. The details of the causal mechanisms of the organ systems can wait (how many times are they covered currently in secondary biology in the UK?).
First, we must task students with making meaning of how their bodily processes are connected within a larger flow. Not how their digestive system works in detail, but how it fits into the larger flow of nature. Thus, it is to connect the human, the animal, the plant, the organism, the act of living, to a larger, more encompassing flow of energy and matter, the food web, the community, the ecosystem.
It is to encourage our students to feel, with every breath, a deep connectedness with nature and the flow of energy and matter. To imagine the incorporation of newly acquired matter into their bodies, and ponder about the matter's history, and possible future once released again. To visualise the trace of molecules through an ecosystem, and then through the systems of their body, imagining the ongoing dynamic maintenance of muscle, bone, and tissue, before, one day, their eventual excretion back to the larger flow in the environment.
To be living is to be connected in this pattern. The pattern of organisation, self maintenance, and the flows of energy and matter, can be seen at all scales, from the bacterium to the ecosystem. So what we invest early with our secondary students will pay dividends as they encounter new contexts and new scales.
Consequently, why begin at the scale of the cell? Why zoom into the digestive system or any other organ system? Why not begin at the concrete scale of the whole organism, begin with organismal ecology, begin with flows of energy and matter in the community, begin with feedback and self-regulation of food chains, begin with the patterns that connect at the organismal level before applying them at other scales.
We should not be blinded by progress of lesson by lesson accrual of knowledge, especially of numerous causal mechanisms. It's important to zoom out continually and encourage students to make meaning of curricular content within the patterns that connect all life. Biology is not a subject with a lot of content to get through, it is a subject with deep explanatory concepts that students need to wrestle with continually. Let's begin there. If you've enjoyed this—check out my book. Download chapter 1 here—English edition—edición española—or check out my other posts.
Christian Moore-Anderson
@CMooreAnderson (twitter)
References
Dupré, J., and Nicholson, D. 2018. “A Manifesto for a Processual Philosophy of Biology.” In Everything Flows, edited by D. Nicholson and J. Dupré, 3-48. UK: Oxford University Press.