Designs in Nature: Investigate the Branching Structure of Trees
Nature is full of objects with many different shapes. Some of these shapes display obvious regularities or distinct patterns, such as stripes, waves, symmetry, or spirals. Each of these natural patterns has evolved over a very long time and serves a specific function that usually helps a plant, animal, or other organism to survive. In this lesson plan, students explore the branching pattern of trees, plants, and leaves. They will make drawings and a leaf rubbing to compare different branching patterns and do an experiment to investigate why this structure could be useful for a tree or other organisms.
- Identify common shapes and patterns that occur in nature.
- Make drawings of branching patterns based on a natural object.
- Explain the function of branching patterns in trees and other living organisms.
NGSS AlignmentThis lesson helps students prepare for these Next Generation Science Standards Performance Expectations:
- K-2-ETS1-2. Develop a simple sketch, drawing, or physical model to illustrate how the shape of an object helps it function as needed to solve a given problem.
|Science & Engineering Practices||Disciplinary Core Ideas||Crosscutting Concepts|
|Science & Engineering Practices||Developing and Using Models.
Develop a simple model based on evidence to represent a proposed object or tool.
Analyzing and Interpreting Data. Use and share pictures, drawings, and/or writings of observations.
Use observations (firsthand or from media) to describe patterns and/or relationships in the natural and designed world(s) in order to answer scientific questions and solve problems.
|Disciplinary Core Ideas||LS2.A: Interdependent Relationships in Ecosystems.
Plants depend on water and light to grow.
||Crosscutting Concepts||Structure and Function.
The shape and stability of structures of natural and designed objects are related to their function(s).
Patterns. Patterns in the natural and human designed world can be observed, used to describe phenomena, and used as evidence.
Materials for educator:
- Example tree pictures
- Example pictures of branching structures in nature
- Example pictures of shapes and patterns in nature
- One tree leaf with prominent veins for each student
- Colored pencils or crayons for students to share
Materials for each group of 2 students:
- Two branched stems of curled parsley
- Flashlight (can also be shared between groups)
- Two sheets of white printer paper or graph paper
Background Information for TeachersThis section contains a quick review for teachers of the science and concepts covered in this lesson.
Nature creates fascinating shapes and patterns. Spirals, stripes, dots, symmetry, waves; these are all forms and regularities that we can observe in nature (Figure 1). Animals and plants have evolved to have these forms and patterns as they serve a special function that usually increases their chances of survival. Stripe or dot patterns, for example, can help camouflage animals or plants so they are not easily spotted by predators.
Figure 1. Shapes and patterns that can be found in nature include symmetry, spirals, fractals, dots, stripes, meandering, waves, and many more.
One very interesting pattern is the branching pattern that can be found in several living organisms in nature. The branching structure of trees, for example, include its trunk, branches, twigs, and leaves. The fascinating part about this branching pattern is that it repeats itself at different scales. The trunk of a tree splits into branches, each of these branches then splits into new branches, and each of these new branches splits again into newer branches, etc. At each split, you could cut off a branch, hold it up, and see a smaller version of the original tree. Similar branching patterns can be observed in a tree's leaves and roots, as shown in Figure 2.
Figure 2. Trees show characteristic branching patterns in their branches, leaves, and roots.
Why have all of these different patterns evolved in nature? The branching structure in trees is crucial for their survival. To be able to grow, trees need resources such as water, carbon dioxide (CO2)— the gas we breathe out—and sunlight. The leaves of a tree are doing photosynthesis, which is a process that converts light, CO2, and water into energy used to fuel all its growth. In the search for sunlight and water, a tree stretches out over a larger surface, both above ground and underground. This is why it creates branches that grow outward from its trunk, to allow the tree to access more resources, which increases its chances of survival. Branching is a common strategy in nature to capture more resources. It can also be found in the leaves of a tree. The veins that run through the leaf and create its branching pattern provide structural support for the leaf and transport water, minerals, and energy through the leaf and the rest of the plant. This means a branching structure is not only advantageous for accessing resources, but also for distributing resources to many different places. The roots of a tree, on the other hand, have to absorb water and nutrients from the soil, which the tree needs to grow. Again, branching of the roots allows the tree to spread out in different directions and access more water and nutrients from its surroundings.
Branching as a way to obtain more resources from the environment is not limited to trees. You can observe this phenomenon in other plants, fungi, animals, and even within in our body (Figure 3).
Figure 3. Branching also occurs in the vascular system and nervous system within a human body.
Many designs that can be found in nature can also be useful in the human world. Biomimetics is a specific discipline in which engineers, researchers, and other scientists develop designs and technologies inspired by nature to solve complex human problems. The branching structures of trees or leaves, for example, has been copied from nature to build infrastructure networks, such as highways, pipelines, or support arches in architecture.
In this lesson plan, students will explore the branching structures in a tree, a plant, and within a leaf. They will make a drawing and leaf rubbing of the different branching patterns and investigate how branching helps the tree to solve its problem of accessing enough resources to survive.