Structural patterns exist all around us, especially in living systems. A common example in the biology classroom is bone structures which show evolutionary similarities between species.
My biology courses begin at the cellular level and explore the basic structures of life. Phosopholipids, for example, make up our cell membranes. Each individual molecule has the same structure and in aggregate, they serve a critical function in regulating the life of every cell in our bodies.
Patterns in the scientific sense often lend clues to the function of the system they belong to, and they can help us make insightful observations of new systems. New questions arise as patterns emerge and are analyzed in new ways. I want my students to look for similarities in observable features (particularly in biology) and use those observations to build hypotheses about new systems. The skill of pattern-finding is important in itself, but it becomes more powerful when applied in context with the content.
Patterns dictate every aspect of biology, and we are inextricably part of those patterns.
Traditionally, freshman biology curricula begina with atoms, molecules, and cells, and work their way to larger structures and systems. This is a very abstract approach which most ninth grade students are not prepared for (prerequisite science is usually a physical science of some kind). Rather than looking at structural patterns and their functions, it makes more sense to begin with patterns which affect their lives.
Consider the changing seasons: life on earth is made possible by energy from the sun. As energy availability changes, patterns in living things also change appropriately. Plants and animals move into (or out of) dormancy; part of the shift to dormancy may include structural change (ex. losing leaves) due to those functional shifts. The seasonal shifts physically affect students - they can connect the pattern to their own lives. This can be extended to the cycle of life and death, both in a macro- and micro-biome. When natural patterns are disrupted, problems emerge, and they can now be approached with a concrete frame of reference.
What does this mean?
Patterning is important in science because it can help set a frame of reference for further study. Typically, this is done by studying the microstructures which dictate systemic functions of plants and animals. While effective in some situations, may biology courses are built starting with small (cells) structures and leaving the big (plants, animals) to the end of the year. But, with exam pressure and other end-of-year stress, many of the macro-level units are touched in spirit only.
Rather than focusing on structural patterns first, focus should be given to identifying and observing patterns students are more familiar with. Exploring environmental factors which can influence an organism is more in line with them empirical science they've done in years prior and helps build an answer to the question, "why?". I understand the danger in making blanket statements like this, especially because each student comes to class ready to engage in different ways.
@bennettscience Students developed in abstract thinking, micro to macro works well. More concrete thinkers need macro to micro (difficult).— Chi Klein (@chi_molecule) October 5, 2014
So, while I would prefer to start with recognizable patterns to help forge connections to the content, it really comes down to knowing my environment and adjusting as needed. It takes a blend of ideas - giving opportunities for concrete exploration as well as abstract can help bridge the gap created when one method is used exclusively over another. As the teacher, it is my responsibility to help students make those connections, regardless of the particular content. Spiraling, scaffolding, and exploration can all be used in the process. The key is to be aware of what patterns exist congruently and work to take advantage of each.