Exam (elaborations) GIZMOS Student Exploration Natural Selection

Exam (elaborations) GIZMOS Student Exploration Natural Selection Vocabulary:biological evolution, camouflage, Industrial Revolution, lichen, morph, natural selection, peppered moth Prior Knowledge Questions (Do these BEFORE using the Gizmo.) The peppered moth (Biston betularia) is a common moth found in Europe, Asia, and North America. It is commonly found in two forms, or morphs: a dark morph and a light, speckled morph. Birds are a frequent predator of the peppered moth. 1. Which morph do you think would be easier to see on a dark tree trunk? The light morph 2. Which morph do you think would be easier to see on a light tree trunk? The dark morph Gizmo Warm-up The Natural Selection Gizmo™ allows you to play the role of a bird feeding on peppered moths. The initial population of 40 moths is scattered over 20 tree trunks. Click on moths to capture them. Click the Next tree button or hit the spacebar on your keyboard to advance to the next tree. 1. Check that LIGHT TREES is selected. Click Start and hunt moths for one year. A. How many dark moths did you capture? 4 B. How many light moths did you capture? 5 C. Camouflage is coloring or patterns that help an organism to blend in withthe background. Which type of moth is better camouflaged on light bark? The lighter moth is better 2. If a forest contained mostly light-colored trees, which type of moth would you expect to be most common? I’d expect light-colored moths to be more common because of evolution. Activity A: Light trees Get the Gizmo ready:  Click Reset.  Check that the LIGHT TREES tab is selected. Introduction: Before the 19th century in England, the air was very clean. The bark on trees was usually light in color. Abundant lichens growing on tree trunks also lightened their appearance. How many moths can you find? This study source was downloaded by from CourseH on :56:27 GMT -05:00 This study resource was shared via CourseH GIZMOS Student Exploration Natural Selection Question: How does the color of a peppered moth affect survival? 1. Predict: Over time, what will to happen to the populations of light and dark moths on light trees? The amount of light-colored moths will increase, and the number of dark-colored moths will decrease. 2. Experiment: Click Start and hunt peppered moths on light tree trunks for five years. In each year, try to capture as many moths as you can. (Hint: Use the spacebar on your keyboard to advance to the next tree.) After 5 years, select the TABLE tab and record the percentages of each moth type. (Note: The table shows current populations of each moth, not the number of captured moths.) Year Dark moths Light moths 0 50% 50% 1 41% 59% 2 40% 60% 3 52% 48% 4 53% 47% 5 45% 55% 3. Analyze: What do your results show?They show an increase in the amount of light moths, but after the 2 nd year, their numbers decrease, only to pick up again in the 5th year. I believe this is because there was a shortage in the amount of dark moths, and predators had to work harder in order to find their food. 4. Apply: Which type of moth do you think was more common before the 19th century, when most trees were light in color? I believe light colored moths were more common before the 19th century. Extend your thinking: What strategies did you use to hunt for moths?I looked for their outline against the tree bark. Activity B: Dark trees Get the Gizmo ready:  Click Reset.  Select the DARK TREES tab. Introduction: The 19th century was the time of the Industrial Revolution in England. Most of the new industries used coal for energy, and the air was polluted with black soot. In forests near factories, the soot coated trees and killed lichens. As a result, tree trunks became darker. Question: How did air pollution affect moth populations? This study source was downloaded by from CourseH on :56:27 GMT -05:00 This study resource was shared via CourseH 1. Predict: Over time, what will to happen to the populations of light and dark moths on dark trees? Light colored moths will decrease and dark colored moths will increase. 2. Experiment: Click Start and hunt peppered moths on dark tree trunks for five years. In each year, try to capture as many moths as you can. (Hint: You can use the spacebar on your keyboard to advance to the next tree.) When you are done, select the TABLE tab and record the percentages of each moth type. Year Dark moths Light moths 0 50% 50% 1 43% 57% 2 41% 59% 3 35% 65% 4 30% 70% 5 36% 64% 3. Analyze: What do your results show? The amount of light moths being found increased steadily until the 5 th year. 4. Apply: Which type of moth do you think was more common during the 19th century? Why? I think the black moth was more common during the 19th century. 5. Explain why industrial melanism is an example of transient polymorphism. Transient polymorphism is one form gradually being replaced by another. Industrial melanism is when the dark colored moths started taking over the light colored moths as a result of the industrialization in England. This study source was downloaded by from CourseH on :56:27 GMT -05:00