Natural Selection Gizmo Latest Updated 100% Correct, Rated A+ Download Now

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? light-colored moth 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 the spacebar on your keyboard) to advance to the next tree. 1. Check that LIGHT TREES is selected. Click Play ( ), and hunt moths for one year. A. How many dark moths did you capture? _5 dark moths B. How many light moths did you capture? 0 light moths were captured How many moths can you find? Get the Gizmo ready: • Click Reset ( ). • Check that the LIGHT TREES tab is selected. Activity A: Light trees C. Camouflage is coloring or patterns that help an organism to blend in with the background. Which type of moth is better camouflaged on light bark? light colored moth 2. If a forest contained mostly light-colored trees, which type of moth would you expect to be most common? light-colored moth would be most common 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. 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? light moths would increase while the dark moths would begin to decrease. 2. Experiment: Click Play and hunt peppered moths on light tree trunks for five years. In each year, try to capture as many moths as you can. Note: You can use the spacebar on your keyboard to quickly 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 23% 77% 2 24% 76% 3 31% 69% 4 35% 65% 5 26% 74% Get the Gizmo ready: • Click Reset. • Select the DARK TREES tab. Activity B: Dark trees 3. Analyze: What do your results show? That the dark moth population decreased throughout the years while 4. Apply: Which type of moth do you think was more common before the 19th century, when most trees were light in color? light-colored moth was more common 5. Extend your thinking: What strategies did you use to hunt for moths? By randomly hitting random spots on the trees 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? 1. Predict: Over time, what will to happen to the populations of light and dark moths on dark trees? light moth population would begin to decrease while the dark moths begin to increase 2. Experiment: Click Play and hunt peppered moths on dark tree trunks for five years. In each year, try to capture as many moths as you can. 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 50% 50% 2 47% 53% 3 63% 37% 4 69% 31% 5 86% 14% 3. Analyze: What do your results show? throughout the 5-year period the percentage of the dark moth population increased while the light moths were reduced drastically 4. Apply: Which type of moth do you think was more common during the 19th century? Why? The dark moth was more common because of the darker trees allowing them to live longer and reproduce more than their lighter