Natural Selection Gizmo Answer Key

Name: Makena Combs Date: 06-12-2022 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? On a black tree trunk, the light, speckled morph would be the most visible. 2. Which morph do you think would be easier to see on a light tree trunk? On a light tree trunk, the dark morph would be the clearest to see. 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? 11 moths B. How many light moths did you capture? 5 moths 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. The light, speckled moth If a forest contained mostly light-colored trees, which type of moth would you expect to be most common? The light, speckled moth rather than the black moth. 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? Over time, I believe the light moths will persist and procreate as the dark moths start to fade. 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 50% 50% 2 41% 59% 3 39% 61% 4 28% 72% 5 29% 71% 3. Analyze: What do your results show? According to my findings, the population of light moths is steadily rising while that of dark moths is steadily declining. 4. Apply: Which type of moth do you think was more common before the 19th century, when most trees were light in color? Before the 19th century, light-colored moths were probably more prevalent since they blended in with the trees as opposed to the black moths, which stood out. 5. Extend your thinking: What strategies did you use to hunt for moths? I used teh ability to see the different colored moths by a colored background that would contrast with their own color. 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? In my opinion, the number of light moths will decline while that of dark moths will rise. 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 57% 43% 2 88% 13% 3 77% 23% 4 100% 0% 5 100% 0% 3. Analyze: What do your results show? According to the findings, the population of dark moths is rapidly growing until it reaches 100%, whereas the population of light moths is rapidly declining until it reaches 0%. 4. Apply: Which type of moth do you think was more common during the 19th century? Why? The industrial revolution caused black soot from coal businesses to pollute the air during this time, which led to a rise in the dark moth's prevalence. The lichens were killed by the soot, turning the light-colored trees into dark-colored ones. As a result of the white moths being exposed, they were individually taken off, leaving the back moths. 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? Natural selection is demonstrated in this experiment between the peppered moth and tree colors. Which moth populations grew in contrast to which populations shrank was decided by the color trait. The white moths would stand out against a dark tree, making them more visible to predators. The black moths would then be left to live and procreate. If the tree color were light, the dark moths would stand out to predators and become extinct while the light moths would blend in and thrive, leading to an increase in population. 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. The changes I observed in the moth populations result from the best camouflaged moths who survived and reproduced, passing their colors along the way to their offspring. The moth themselves cannot change color but rather it is a trait that is passed on to them. The moths that blended in with the tree survived and were able to reproduce, passing the color they had to their offspring. The moths that did not match the tree did not survive, unable to reproduce and pass their color trait to their offspring. 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. Because only the most suited survive through natural selection, it can result in evolution. This implies that the feature that is most suited to a particular environment will flourish and grow, while another will decline. The feature examined in this experiment included color and how well-integrated moths were with their surroundings. The lighter-colored moths on the tree would blend in if the trees the moths were on were white, but the darker-colored moths would be eaten by predators, reducing their population over time. The lighter-colored moths, on the other hand, will live, allowing them to reproduce, pass on the genes that cause them to have a lighter hue, and grow in number. Darker-colored moths will gradually decline in population while lighter-colored moths will become more widespread. The black moths may eventually go extinct or less dark coloring may be inherited.