SG - Natural Selection SE Classwork

lOMoARcPSD|23780900 Name: Date: Student Exploration:Natural Selection Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. 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 Morphs because it would be on a dark background 2. Which morph do you think would be easier to see on a light tree trunk? Dark Morphs because it would be on a light background 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 ( for one year. ), and hunt moths A. How many dark moths did you capture? 0 B. How many light moths did you capture? 2 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? 2. Light morph If a forest contained mostly light-colored trees, which type of moth would you expect to be most common? Lighter colored camo ones because it would help to conceal them better. lOMoARcPSD|23780900 Get the Gizmo ready: Activity A: ● Click Reset ( ). ● Check that the LIGHT TREES tab is selected. Light trees 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? The light ones would flourish because of their ability to blend in and the dark ones would stand out. 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 46% 54% 2 45% 55% 3 38% 62% 4 32% 68% 5 0% 100% 3. Analyze: What do your results show? The light moth population grew because I could not find them and the Dark ones died out because I could see them easily. 4. Apply: Which type of moth do you think was more common before the 19th century, when most trees were light in color? I would think that the light color moth would be more dominant given the lighter trees so that they could blend into the trees. 5. Extend your thinking: What strategies did you use to hunt for moths? lOMoARcPSD|23780900 The dark ones were easy to see but the light ones I had to strain my eyes to see the outline of the mouth in order to hunt them. Get the Gizmo ready: Activity B: ● Click Reset. ● Select the DARK TREES tab. Dark 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? I think that the light moth population would dwindle down because it would be easier to see them and the dark moth population would grow in population. 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 54% 46% 2 55% 45% 3 75% 25% 4 88% 12% 5 100% 0% 3. Analyze: What do your results show? Black moth population grew because they were harder to spot on the trees. 4. Apply: Which type of moth do you think was more common during the 19th century? Why? I would say that the light moth population was more common because the trees were lighter in color. lOMoARcPSD|23780900 5. Draw conclusions: Natural selection is the process by which favorable traits tend to increase in frequency over time. How does this experiment illustrate natural selection? The moth would adapt their camo because of the tree color which would help them survive. 6. Think and discuss: Did the changes you observed in the moth populations result from individual moths changing colors? Or did they occur because the best-hidden moths survived and reproduced, passing on their colors to their offspring? Explain your answer. I would think that the moths that survived went and reproduced and passed on their traits to their offspring because the moths were not changing colors on the tree to my knowledge. 7. Extend your thinking: Biological evolution is the process by which populations of organisms change over time. How could natural selection lead to evolution? If possible, discuss your answer with your classmates and teacher. Natural selection could lead to evolution because the organisms survive and reproduce to pass on their traits and over time more traits that are superior will show up which could lead to the whole population of moths having these traits which is evolution.