Color and Purpose in Plants Lesson Plan (2 Parts)
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Overview
Lesson 1- The Seed
The lesson should begin by handing out sunflower seeds (Helianthus) and a small, clear container filled with soil to groups of students.
The students should then be asked to crack open and observe. Then asked to write down the observations such as the colors and shapes they see of the seed. They should also be asked about the relationship between the seed and light once the seed is planted in the soil. An emphasis should be placed on the storage function of a seed.
A picture should then be shown illustrating the anatomy of a seed with attention towards the color of the cotyledons (embryonic leaves).
The main function of a seed should also be discussed by showing a picture of a seed stained with iodine showing purple starch granules. Ask the students to write down where they think the starch came from.
After placing the 3-4 seeds about half an inch into the soil, the students should be asked to theorize what they think will happen within the next week and write it down. The main points of understanding in this exercise are the purpose of colors and the seeds' relationship with light.
The term “phototaxis” can be broken down after their predictions are written down. “Photo” meaning light and “taxis” meaning orientation and movement of an organism to a light source. The word “phototropism'' can also be established meaning the movement of an organism in the direction of external stimuli. In this case it will be the light.
The students should then water the seeds just enough to where water begins to drop out of the bottom. It should then be asked which place in the room the seeds should go. The seeds should then be placed by a window with their names written on the container that holds their seeds.
A discussion should be had about the color green and three theories about why plants are green will be briefly discussed (in powerpoint with pictures).
Daily observations should be written down for the proceeding 7-14 days. Typical germination in Helianthus occurs within 7-10 days. What the students should notice with successful germination is that the roots will begin to go downwards in the soil. This is actually due to gravity through a process called geotaxis which can also be explained. Then the shoot with the cotyledons will begin going upwards towards the light. This is caused by phototropism. The color of the new, embryonic leaves should be emphasized as they now have developed chloroplasts filled with the green pigment chlorophyll. A note should also be made of the pale color of the roots which have pretty much remained the same color as the initial inner seed.
Important Vocabulary in Lesson 1- Starch, phototaxis, phototropism, cotyledons, geotaxis, stimuli, chloroplasts, chlorophyll
Lesson 2- The Flower
After the seeds have been growing for about 2-3 weeks, a second lesson will be presented. First the students should be asked what will ultimately happen if the plants they’re growing continue to grow. The answer obviously being a flower will develop. Then the lesson should begin by handing out a small plant that is flowering.
Observations should be written down on the colors and shapes they see. A picture showing basic leaf structure can be displayed.
The first point of emphasis should be the size of the leaves compared to the ones they have been growing. Let the students notice the increase in surface area. The process of photosynthesis should then be discussed explaining chloroplasts and the green pigment chlorophyll as well as the root words of photosynthesis. Recall the concepts of phototaxis and phototropism. The connection of starch in the seeds should also be made by explaining the conversion of light to sugar. A brief explanation of the roots uptake of water and nutrients from the soil can be discussed.
The students should then be asked to write down what the purpose of the flower's color is. Then a diagram of basic flower anatomy can be presented. The main point here will be the purpose of a flower's color which is to draw in pollinators such as insects. The point that insects are in the animal kingdom such as us can be discussed. Explain how they are able to see different wavelengths of light such as ultraviolet light. A diagram showing the spectrum of light with the small section of visible light should also be shown.
They should then be asked to draw the different structures they see on the inside of the flower. Then they need to swab the flower’s anthers with something white to reveal the yellow pollen. By using the flower anatomy display, a distinction should be made between the male (anther) and female (stigma) parts of the flower. Let the student see and draw each.
It should be asked what they think will happen after an insect visits one flower and goes to another. Questions should be asked such as “what does the insect get from the flower? What do the insects help to spread?” The process of symbiosis, pollination, and fertilization should be summed up. A sequence of images from an insect visiting a flower to a developing fruit can then be shown. This will help visualize the life cycle of flowering plants and bring it all together by showing what the students started with; a seed.
Students will be asked what they think certain flower colors symbolize/represent. The powerpoint also includes more general associations with the given colors (i.e., money = green)
Students will be asked to write a poem that connects their favorite color with what they perceive as their purpose in life. It will be important to note that purpose is different than goals, because goals can be accomplished and completed while purpose is more of a direction or theme they can apply to their life.
For example, for a student that may say “I want to become a doctor,” their purpose would be better outlined as “My purpose is to help heal others”
There can be discussion about what goals they can achieve with their purpose and what it would take to accomplish them.
Important Vocabulary in Lesson 2- Surface area, photosynthesis, chloroplasts, chlorophyll, light spectrum, ultraviolet light, compound eyes, anthers, stigma, symbiosis, pollination, fertilization, life cycle