Here is the worksheet:

I have done most of them, I need help with 11-15.

Zahra Husseini Name LAB EXERCISE 4: Patterns of Natural Selection Introduction Natural selection is one ol the major forces of evolution acting on populations. The major requirements for selection to occur are that i] traits [or phenotypes) vary among individuals in populations, 2) some ot this variation among individuals is due to genetic ditterences among individuals. and 3] that variation in traits atfects some aspect at tness. It scientists know the distribution of a trait over time. they can identity changes in the population as a result of a change in the env' onment. Selective pressures can act on the variance of a population to result in stabilizing, disruptive. or directional selection. One way to visualize variance is using a histogram: a type of bar graph that looks at the abundance of a category. In the example to the right. the number of people who are different heights is graphed. In this case. we can look at the abundance of each phenotype of 0 Height \"I.\" trait. Number of people In today's lob. we will look at the mean and variance otshark tooth length in a population of sharks. The length of a tooth can be related to many factors such as size of shark, typical size of prey, difculty in catching prey. or sexual selection. We will then examine how natural selection can change the mean and variance of shark's teeth in a population and use these changes to interpret what type (it selection may have occurred. Experiment: Activity 1 1. Open up the following things on a computer: a. A Microw Excel workbook. Save it to the desktop. Rename the worksheet that is currently highlighted to read \"Exercise l\". b. The Natural Selection lab WDda provided by your instructor. We will be using this dataset at measured shark teeth to visualize the distribution of a population. whulkanylas To get an idea at how our data looks. we will create a a histogram. At rst glance. a histogram looks just like a E" bar chart (and it is) but the bars are right next to each 3, other. A histogram can look at the variation in a trait. s which in this case is tooth length. n was n7 Isms n Nmiul The rst thing we need to do is identity the highest and lowest values A of the dataset. Highlight the data values and select the sort button ZY to anange your values from smallest to largest. With the lowest SorIEL number. round down to the next whole number and with the highest lter" number. round up to the next whole number. this will give us a range of values for the Xeaxis on our graph. Be sure to include units. 22mm lowest number {rounded}: 36mm Highest number (rounded): Using the values from the previous step, Calculate the range of data {the highest value the lowest value). Be sure to include units. 14mm Range: There is no general rule tor how many bins, or bars. to create. Divide the range by the number of bins desired: in this case. we will use 8 bins. This will get you the bin size. Round this number to the next highest 0.1. Be sure to include the units. 1.8mm Bin size: Now that we have the highest and lowest values for the graph as well as the bin size. 6. Finally, let's graph this data. Usi the graph below. draw the Xeaxis using the we can gure out how many data value: can be found in each bin to create our bin values calculated in the previous question. Place the \"Frequency" or the histogram. number of data points found in each bin on the yeaxis. The max value on the yaxis should be close to the max value of the number of data points. Draw The first column \"Bin Values" are the values for the bars. Using the example histogram the bars that correspond with each bin, making sure that they touch. Include on the previous page. the first bin is 60 65 (the bin size is 5). The conventional way of axes labels. writing the bin size is [60, '5) where the rst numberhas a bracket, then a comma, and then the second number has a W. This notation helps in determining the / inclusivity lor the range. A bracket means that that value is included in that bin whereas the parentheses is not included in that bin. For example. if you have a data value of 5 and the two bins [60, 65) 8. [65. 70) the 65 STDEV : 3.59 would be included in the [65, 70) range because the 65 has the bracket. Your first minimum number should be the minimum calculated in step #5. MEAN = 29.75 E Then in the second column, count the number of data points that tall within each bin. If 3 your data isn't already sorted from smallest to largest in Excel, do this now to make this 1' E; \\ step easier. I' u" \\ J x' K bin Values [min it, max 1:) Frequency {number at data points in bin] [22,219) 4 [11935) mm) [25,273, [25,2950 [30:13) [32,33 9) [34,3150 [35,3150 [24,259) 5 Length afsharktaathlmm] [26,27,9) 9 In addition to a histogram, we can describe data using descriptive statistics. [2839-9) 11 Specifically. we will look at the mean and the standard deviation of our data set. 30 ]_9 13 emeanls eaverageo e aase. ecancacuael ya Inga evaues [)3 ) Th 'th fth dt tW l lt'lb dd' Ilth l [3233 9) 9 together and dividing it by the number at values. [34359) 7 Anotherwoy we can measure the difference between datasets is looking at the [36,37 9) 1 slundard deviation. which is a measure of the spread at the data. The standard 7 deviation gives us an idea of how close or far apart data is from the mean. 7. Let's use Excel to calculate both the mean and the standard deviation. In the cell to the right of on the word \"Mean", write the following formula: =AVEMGE(m.Q.QLQmJ Write your tarmula and the mean of this dataset in the space below. Round to 2 decimal places. :AVERAGElAZ:A53): 23.79 8. Draw a vertical line through the Xeaxis on the graph to denote the mean. a] Stabilizing Selection How 11065 the data lookln comparison to the med"? '5 the mew" 0'50 Where Both sharks withtinvteeth and sharks with large teeth died orhad a hard time the highest frequency 0f VGIUGS i5? '5 the mean elsewhere? surviving so now there are manysharks with medium sized teeth. The mean is notwhere the highest frequency ofvalues is. It is where the second highest b] Disruptive Selection "ENEMY value '5- The environment changed overtime and now there only sh that either sharks with 9. the cell to the right at the word \"Standard Deviation". write the formula: ""V'EE'\" \"W'd nd Wham Wit\" \"'E'ee'\" WW eat- =5TDEVltammaaLa) c] DirectionalSelection Write the formula anal the standard deviation at this dcltaset in the space The sharks with tiny and medium siled fish couldn'teat the sh that were there below. Round to 2 decimal places. because they were too big for them. Create a new worksheet [tab] in Microsott Excel and rename it to \"Exercise 2\". Copy =5TDEle2:A63]= 3.55 and paste the shark tooth data into this new worksheet. 10' We \"OW have ih'e'emc '0 look at our data: 0 histogram, the mean, and IE. Now choose one of the three selective pressures and change this data to the standard devratlan. LE? 5 put all Of these values in the some place. lie-xi simulate the selective pressure that you chose to occur in this population. To to your graph on the preVIoUs page, wnte the mean and standard deVIatIon. do so delete 20% atthe data points lii you choose disruptive selection delete 30% at the data points]. What is the range forthis new data set? Elm: ACliVil'l' 2 Round up to the next whole number. Show your work. ll. in the table below. hypothesize how the mean and standard deviation will 3512:14mm change it this shark population undergoes various types of selection. Mean: l4. Calculate the mean and standard deviation of this data set. Color these cells in yellow so they are easier to nd. Round to 2 decimal places. Type of Selection Hypothesis {circle one) Actual results (circle one) Directional {toroerl ncreos Decrease Stay same D ase Stay some 2935 Directional {smaller} increase ecrease Sta some increase reas Sta same Mean = 4.18 Disruptive increase im Sta some increase Decrease Stabilizing increase Decrease W increase Decrease Standard Deviation = Standard deviation: l5. Calculate the percent change in the mean and standard deviation from the original dataset. Reportyourvalues in the appropriate location on the board. Type of Selection Hypothesis {circle one) Actual results c'rcle one) Directional ltaraerl increase Decrease m increase Stay same Values \"'0' 0'3 greater \"\"0\" 10% orsrnaller "W\" 'i 0% are COMideied Directional {smaller} increase Decrease i 9 Stay some signicant changes. Do the changes that you see make sense for your Disruptive W Decrease Stay same ecreose Stay some change in population? Why or why not? Stabilizing increase Sta some increase crease Sta same 12. Describe a scenario a 5 natural selection to explain why the length at l Ed I 100 sharks' teeth would change to reect the selective pressures listed below. '2', change : w = 119an Re