sna a)s Peppered Moth SurveY +s d : rd d g+x \- X \LJ Modeling Camouflage and Natural Selection SS; d.nt' o-8 o ?-\ + =" lntroduction f,x(d tu cd

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Download "sna a)s Peppered Moth SurveY +s d : rd d g+x \- X \LJ Modeling Camouflage and Natural Selection SS; d.nt' o-8 o ?-\ + =" lntroduction f,x(d tu cd"

Philip Nelson
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1 Name Modeling Camouflage and Natural Selection lntroduction As part of his theory of evolution by natural selection, Charles Darwin proposed that organisms best adapted to their environment survive ind reproduce more successfully than other organisms. Camouflage, the concealment of an organism because of its color, is an example of an adaptation that can increase an organism's chance of surviving to reproduce. Organisms that are more difficult for predators to see are less likely to be attacked. In this investigation, you will examine the effect of camouflage on the survival of a prey species. Peppered Moth SurveY Industrial melanism is the term used to describe the adaptation of darkening by an organism in response to industrial pollution. One example of rapid industrial melanism occurred in the peppered moth, Biston betularia, in the area of Manchester, England, from 1845 to Before the Industrial Revolution, the trees in the forest around Manchester were Iight grayish-green due to the presence of lichens on their trunks' Peppered moths, which lived in the area, were Iighi-colored with dark spots. Their coloring served ai camouflage against predators, especially birds' As the Industrial Revolution progressed, the trees became covered with soot, which turned the trunks dark. Over a period of 45 years, a change took place in the peppered moth population in this area. In this investigation, you will simulate a predatorprey situation and determine if color contrast ^hur un effect on the ability of a predator to rapidly locate prey. In the second part of the investigation, you will study the data on peppered moth coloiation as actually reported over the course of several years. You will then determine the relationship between the environmental changes and the color variations of the peppered moths by using the research data to graph the results of an environmental adaptation. a)s il' \. oi \ t \ + r-t- -i.+ q = 6 \ e X \ - l +s d : SS; A \. \ v \u it?-\ + =" sna rd d C I C D } d.nt' o-8 o f,x(d J Y \ I > g+x \- X \LJ f.,, 'O tu cd - \ f,. graph paper. paper disks, Punched out of netspup"t with a hole Punch (60). sheet of newspaper. pencils, each with a different coior of lead (2) r paper disks, Punched out of white Paper with a hole punch (60). sheet of white Paper r rs-\"-\r- $it-" r) r lora{f ( bvf.b"*k )

2 PartA Simulating Predator-Frey Relationships 1. You will use the discs of white paper and newspaper to simulate prey. The paper discs will be placed on s that either match or contrast with them. You will use forceps to simulate a bird's beak and capture as many of your prey as possible in 15 seconds. Place a piece of white paper on your lab desk. While your teammate is looking away, scatter 30 white disks and 30 newspaper disks on the papet'. When your partner is ready with the forceps, let the hunt begin and start timing. 2. When 15 seconds have elapsed, count how many of each type of disk were picked up. Compare the number of captured disks of each type to the number that remained on the paper. Record the numbers in the data table in the Additional Records and Observations section 3. Replace the white paper with a sheet of newspaper. While your partner is looking away, scatter 30 newspaper disks and 30 white disks. Repeat the hunting procedure with your partner and record the number of disks picked up on the Additional Records and observations sectiorl Also record the numbers of each type remaining 4. Change roles. You play the role of predator, while your partner sets up the disks. Repeat Steps 1-3 above. Did you andysyy partner each pick up the sanle amount of "prey"? 5. After you have recorded data for one trial using a white and one trial using a newspaper for each lab partner, comlrute the Percentage of Available Prey Recovered for the contrasting and matching situations. 'Io do this, divide the total number of discs recovered that contrttsted with their by the total number of discs of that type. Repeat this procedure with the total number of discs recovered that motched their. For example if you scatter 30 newspaper discs and 30 white discs on a sheet of newspaper, and you recover 5 newspaper (matching) discs and 15 white paper (contrasting) discs, your recovery rate is ',ro x iooto = 17o/ofor the matching backgrouhd situation. Likewise, your recovery rate is * x 100% = 50o/o for the contrasting situation. Sh.ot, \o\^r qo.1 q.a\o.\ions 'rv\ {h- Spr^<- t"\o'pt \

3 Record your computed percentages in the table in the Additional Records and Observations section of your form. Comparing percentages rather- than raw numbers will give you a clearer picture of the effect or lack of effect that contrast has on predation. Background Gontrast and Predation Success I rral Number Backgrouod Total number of disks scattered Total number of disks plcked up Percentage of available prey recovered Newspaper White Contrasting Matching Contrasting Matching baakground Part B Graphing and Analyzing Predator-Prey Relationships 6. Table A represents data from a l0-year study of two varieties of the same species of peppered moths. The numbers represent moths captured in traps for L0 consecutive years. The traps were located in the same area each year. 1 Using the data provided in Table A, construct a graph Table A Year l{umber of light Moths Captured llumber of 0a* Moths Capturcd comparing the numbers of each variety of peppered moth. Label the axes with the years of the study (plotted horizontally) and the number of moths captured (plotted vertically). Use different colored pencils or a solid line and a dashed line to indicate the two color variations. Be sure to include a key beneath the graph. 8. Use your graph and the textbook, if needed, to answer the following questions. What prey s on the p eppered moth? lf the bark of trees is dark and the moths thot rest there are lishtcolored, what wlllhappen to the moths? What ts a mutation?

4 What could hav e c aus ed the ftr st dark- color ed moth to o ccur? What caused the tree trunks of many trees in England to turn from a light color to a dark color? Which variety of moth increased over the 7}-year period? What is the name of this type of evolutionary change? 1. Assume that you are selecting from a field of an equal number of light and dark "prey." You would expect to pick up an approximately equal number of each type, if coloration is not important to predation success. What did your experiment indicate? 2. Using the data on the graph, draw a conclusion concerning the population of peppered moths in the sampled area of England. 3. Explain the reason for the increase in the number of dark-colored moths. 4. What means could be used to return the environment of the peppered moth to its original state? 5. What effect would cleaning up the environment have on these moths? X n\+o-k 5l*" \^t\ o \h- \^b.

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Natural Selection: Peppered Moth Simulation and MRSA

Natural Selection: Peppered Moth Simulation and MRSA Name Date Period In this internet lesson, you will learn about a classic example of natural selection that occurred during the beginning of the industrial age and about modern issues with bacterial natural