How to Teach the Crosscutting Concepts with Wisconsin Fast Plants

by Carolina Staff
Hedi Baxter Lauffer, PhD Director, Teaching & Learning Wisconsin Fast Plants Program University of Wisconsin-Madison The Next Generation Science Standards* (NGSS) recommend we build our lessons to unify learning in 3 dimensions: scientific and engineering practices, disciplinary core ideas, and crosscutting concepts. However, it can be challenging to include crosscutting concepts explicitly. Lessons taught with Wisconsin Fast Plants engage students with natural phenomena, and they are some of the easiest to design with crosscutting concepts as the foundation.

Support for learning the crosscutting concepts

The NGSS describe 7 unifying scientific principles that we need to explicitly teach. These principles, or crosscutting concepts, need to be included alongside our objectives for learning disciplinary ideas and practices. Though previous standards and many science textbooks typically referred to these principles as something students build understanding about “without any specific instructional support (National Research Council, 2012),” the NGSS place them in the foreground.

So, we are faced with an important question: What does explicit instructional support for learning crosscutting concepts look like? Here we describe examples of explicit instruction using Fast Plants for each of the crosscutting concepts.

Crosscutting concepts

Observed patterns of forms and events guide organization and classification, and they prompt questions about relationships and the factors that influence them.

Phenomena that students can observe when growing Fast Plants

Life cycle stages begin with planting a seed and consistently follow a sequence of events (develop leaves, grow taller, develop flowers, produce seeds in pods).

For every seed planted, a plant develops that has a characteristic form (leaf shape, number of leaves, flower type and color, etc.). Although there is variation among individual plants, there are patterns in their forms that make them recognizable as Fast Plants.


Questions students may ask Elementary

What do all Fast Plants need to survive?

How similar (and different) are the [offspring] Fast Plants that we grow from seed produced by our mother Fast Plants.

Questions students may ask Secondary (6–12)

Can a Fast Plant grown without nutrients still complete the same life cycle pattern that we observe when a plant is grown with fertilizer, as the planting instructions recommend?

How do the patterns in phenotypes that we can observe in a population of Fast Plants compare to the genetic patterns that we can infer by producing and growing their offspring?

Events have causes, sometimes simple, sometimes multi-faceted. A major activity of science is investigating and explaining causal relationships and the mechanisms by which they are mediated. Such mechanisms can then be tested across given contexts and used to predict and explain events in new contexts.


Phenomena that students can observe when growing Fast Plants

When Fast Plants seeds get wet, they absorb the water and swell (imbibe). Wet seeds may germinate if the embryo inside the seed is alive and receives the oxygen and temperature conditions needed to grow. Therefore, water triggers (causes) seed germination, but its effects are mediated by oxygen and temperature.

The purple color observed in the purple stem variety of Fast Plants is caused by the underlying genetics: the allele for the purple stem trait is dominant over the allele for non-purple stems. In addition, how purple a purple stem looks is affected by the light intensity it receives.


Questions students may ask Elementary

Do Fast Plants need sunlight and water to grow?

How does an environmental factor affect an observable trait? Example: How does the number of hours the lights are on or distance the plants are from the light affect plant height, leaf size, or number of days until the first flower opens?


Questions students may ask Secondary (6–12)

What effect does the amount of nutrients (fertilizer) available in the soil have on the sequence of life cycle events?

What evidence can be collected and used to support or refute claims about what causes the inheritance pattern observed when a purple stem Fast Plant is crossed with a non-purple stem Fast Plant?

In considering phenomena, it is critical to recognize what is relevant at different measures of size, time, and energy and to recognize how changes in scale, proportion, or quantity affect a system’s structure or performance.

Phenomena that students can observe when growing Fast Plants

Comparing Fast Plants to the many varieties of Brassicas that humans have bred to suit their needs and preferences for food (e.g., broccoli, cabbage, cauliflower, and turnips) offers evidence of how different environments, over long time periods, resulted in plants that look very different but are related.

Dissections of Fast Plants (or microscope-aided observations) provide evidence that plants–like other living things—are made up of many different types of cells.

Questions students may ask Elementary

What are the similarities and differences we see when comparing Fast Plants to other Brassicas that we eat or see in stores, and how long did it take for them to become so different?

What evidence can we collect as evidence of what we can and cannot see happening to plants when they take up water (or dry out)?

Questions students may ask Secondary (6–12)

What mathematical representations are useful for figuring out what is happening at the molecular level (that we cannot observe), and how are those patterns related to the inheritance patterns in Fast Plants that we can observe?

What statistical analyses are useful for figuring out if our Fast Plants breeding project successfully affected the trait we tried to increase?

Defining the system under study—specifying its boundaries and making explicit a model of that system—provides tools for understanding and testing ideas that are applicable throughout science and engineering.

Phenomena that students can observe when growing Fast Plants

Populations of Fast Plants are a wonderful example of interacting systems–each plant is an individual working system (like humans, plants are made up of systems that meet their needs), and the population (even if it’s only a few plants) is a system of interacting roots and shoots.

A Fast Plant is a model organism, or system model, that was bred specifically for research. Fast Plants have the typical characteristics of other flowering plants (dicots). However, as model organisms, they were selectively bred to complete their life cycle quickly and thrive in laboratory conditions.

Questions students may ask Elementary

What structures develop through the life cycle of a Fast Plant that interact to support survival, growth, or reproduction?

What needs to be included in a Fast Plants growing system for the plants to have what they need to grow and reproduce?

Questions students may ask Secondary (6–12)

What are the interacting systems within Fast Plants that support nutrient uptake, water delivery, gas exchange, or reproduction?

How can a model of the processes taking place during reproduction that we cannot see explain and predict the phenotypes and inheritance patterns across generations that we can see?

Tracking fluxes of energy and matter into, out of, and within systems helps one understand the systems’ possibilities and limitations.

Phenomena that students can observe when growing Fast Plants

Fast Plants planted (or germinated) and grown in recommended light conditions versus dark conditions exhibit easily-observed differences in color and size of structures. These differences are caused by the impact of the dark environment.

First, we see that pigments stimulated to develop by the flow of energy from the light source to the seedling do not develop in the dark (the seed leaves are pale yellow). In addition, we see that matter cycling from the environment (air and soil) to the plant is not supported in the dark. Without the cycling of matter from the environment, the growth and development of plant material (roots, shoots, leaves, and food needed by the seedling) is limited to the matter and energy reserves contained in the seed.

Questions students may ask Elementary

What happens to a 10-day old Fast Plant if it is closed into a sealed glass jar to limit the air it can receive?

What does a growing Fast Plant take in that could be the source of materials it needs to grow roots, stems, leaves, and flowers?

Questions students may ask Secondary (6–12)

What happens when Fast Plants are planted in the dark and don’t receive any energy from light when they are young seedlings?

Does a germinating seed need light? Where does the matter and energy come from that enable a seedling to grow before it grows above ground?

The way in which an object or living thing is shaped and its substructure determine many of its properties and functions.

Phenomena that students can observe when growing Fast Plants

Fast Plants are living models of myriad structures with observable functions, many of which are measurable. Just a few of the structures students can observe and measure over time include: stem height; hypocotyl length; number of leaves; number of flowers; rate of development; and size, placement, and sequence of development of reproductive structures contained within flowers.

Evidence about interdependence and evolution are observable in the structures of Fast Plant flowers relative to structures on bees, which co-evolved and serve important pollination functions.

Several available Fast Plant varieties have a heritable mutation that results in an easily-observable phenotype that is sometimes detrimental or neutral. For example, rosette-dwarf, tall, and yellow-green Fast Plants typically germinate and develop slightly slower than standard Fast Plants because their mutations have some deleterious effects. On the other hand, non-purple stem Fast Plants grow and develop at the same rate as purple stem or standard Fast Plants.

Questions students may ask Elementary

What structures on a bee’s body are important for transferring pollen among the flowers of Fast Plants?

What happens to the development of shoots, leaves, and flowers in Fast Plants if root growth is limited? This could be tested by growing Fast Plants in containers with minimal soil volume (e.g., the cell of a quad vs. a bottle growing system).

Questions students may ask Secondary (6–12)

How do environmental factors affect the growth and development of structures throughout the Fast Plants life cycle? Environmental factors can include chemical, biological, and physical components; structures observed can include anything measurable whose function students can explain.

Do the mutations in (choose any of the different varieties of Fast Plants) result in harmful, beneficial, or neutral effects to growth and development? Which structures and functions appear to be affected, and what might be a plausible model for those effects at the molecular level?

For natural and built systems alike, conditions of stability and determinants of rates of change or evolution of a system are critical elements of study.

Phenomena that students can observe when growing Fast Plants

When physical or biological components of the environment are changed, Fast Plant populations show effects in growth, development, and/or reproductive success.

Comparisons between bottle or deli growing systems with and without Fast Plants growing in the potting mix (soil) show visible differences in the type of run-off when watered from the top. When fertilizer is included in both systems, differences in algal growth may also be observed (systems without plants typically have greater fertilizer run-off into the water reservoir, supporting algal growth).

Questions students may ask Elementary

How will a population of Fast Plants that we grow from seeds we produce ourselves be similar to or different from the parent plant population?

What effects do plants have on changes to the soil they grow in?

Questions students may ask Secondary (6–12)

How do changes in the physical or biological components of the environment affect Fast Plant populations?

What feedback mechanisms in Fast Plants allow the plants to maintain homeostasis in response to low or high temperatures, low or high nutrient availability, salinity, etc.?

*Next Generation Science Standards® is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of, and do not endorse, these products.

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