Copy of Allocation and Simple Statistics Lab

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Arizona State University *

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182

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Biology

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Feb 20, 2024

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Bio 182 Lab, Arizona State University Group name: Summer Shade Team Names of members: Overview Angiosperms (flowering plants) are the most diverse plant group on earth with approximately 300,000 described species. Angiosperms are distinguished from other seed- producing plants by producing flowers and fruits . The ancestors of the angiosperms diverged from other seed-producing plants about 300 mya diversifying extensively during the Cretaceous (beginning approx. 135 mya) and replaced conifers as the dominant trees on earth by the end of the period (approx. 65 mya). The appearance of the angiosperm fruit is viewed as a key innovation that accelerated speciation and led to the primacy of angiosperms on earth. Flowers and fruits frequently possess traits that attract animals to promote pollination (flowers) and seed dispersal (fruits). Specialization between plants and their mutualist pollinators and seed dispersers is thought to have driven divergence of plant forms. But how are plants, sessile and unthinking, able to manipulate animal pollinators and seed dispersers? It could be argued that plants unwittingly adjust the investment of resources into larger or sweeter fruits to attract seed dispersers at the expense of more or larger seeds. The “decision” to invest in fruits versus seeds sets up a potential trade-off , or compromise in which investing more in fruit could be correlated with investing less in seeds. In today’s lab, we will test a few of these trade-offs to see if they hold up in two common fruits. We will begin with a study of the anatomy of the domesticated fruit, apple ( Malus domestica Borkh., Rosaceae), then compare its resource allocation decisions to a close relative, pear ( Pyrus commonus L., Rosaceae). Lastly, we explore these questions of trade-offs with a few simple statistics: correlation and t-test. Learning Objectives: 1. Develop basic bench skills, learn lab protocols, and practice lab safety Lab 2: Evolutionary trade-offs and a few statistics.

Bio 182 Lab, Arizona State University 2. Formulate a null and alternative hypothesis, the first step in experimental design 3. Calculate statistical tests and interpret the outcomes I. Flower and Fruit Anatomy Discussion: 1. Coevolution is a broad term used to describe the interactions between species that occur over long periods of time (generations) and affect key characters of both species. As you know, biological interactions range from adversary to mutualistic, and from incidental to essential. Use the space below to describe some of the different interactions that you are already familiar with (you can give examples, definitions, etc.) . How would you describe the interaction between pollinating insects and flower plants? Bees and flowers, bees get their food from the flowers and in the form of nectar. the flower would then get pollinate. 2. Imagine your group has been given the task of developing a completely new flowering plant (angiosperm). You will decide which adaptations this plant possesses by choosing from the list below. However, each of these adaptations has a cost associated. Your group has a spending limit of $100 dollars and you must pick at least one adaptation from each category: flower, seed, and fruit . Discuss with your group how you will design your new plant, keeping in mind the role of flowers, seeds, and fruits . Be prepared to share your plant with the class: Flower Fruit Seed Colorful petals $20 Colorful flesh $25 Colorful seeds $30 Sweet odor $25 Sweet tasting $45 Bitter taste $40 Nectaries $45 Tough outer flesh $20 Edible $20 Large petals $30 Large fruits $40 Large, nutrient-rich $35 Cluster of flowers $30 Samara (“wing”) $25 Many seeds per fruit $25 Edible petals $20 Buoyant $25 Tough outer coating $35

Bio 182 Lab, Arizona State University II. Fruit dissection In the next activity, we will begin to observe fruit anatomy by looking at an apple ( Malus domestica) or pear (Pyrus communis) . Prepare to record your observations. Procedure: 1. Weigh the entire fruit. Record the biomass. 2. Cut the fruit in longitudinal-section (see the sketch on the left in the figure below) . Identify and sketch notable structures in this section: calyx, stamens and styles, carpel, endocarp, seed and floral tube. 3. Cut one half of the fruit in cross-section. Identify and sketch notable structures in this section: sepal bundle, petal bundle, carpel, endocarp, seed and floral tube. Measurements of Fruits Apple: fruit biomass: 131.7 g seed biomass: 0.5051 g seed number: 8 mean seed biomass: 0.063 g Pear: fruit biomass: 134.9 g seed biomass: 0.294 g seed number: 6 mean seed biomass: 0.049 g

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Bio 182 Lab, Arizona State University 4. Carefully remove all of the seeds from the fruit. a. Remember to zero (“tare”) the empty weigh boat before adding seeds. b. Record the number of seeds and total seed mass for each fruit. c. Calculate the mean seed mass for each fruit (total seed mass/number of seeds). 5. Record your measures (fruit mass, seed number, mean seed mass) in the class data sheet. 6. Repeat steps 1-5 with pear.

Bio 182 Lab, Arizona State University III. Investigating resource allocation to reproductive effort. When resources are limited, some organisms shift allocation of scarce resources among essential functions to optimize the chances of surviving and reproducing. When something happens at the cost of something else, it is called a trade-off . It could be argued that, when resources are limited, investment in flowers and fruits (to attract mutualists) may come at the cost of making more or bigger seeds (to ensure seeds survive to make a new plant). That is, there may be a trade-off between fruit biomass and seed biomass. In the next activity, we will investigate trade-offs in our fruits using two research questions: Question 1: Do bigger fruits make smaller seeds? Question 2: Do apples and pears differ in their resource allocation decisions? That is, do they invest the same amount of resources in seeds (mean seed mass/total fruit mass)? Procedure 1. For each research question above, write a hypothesis that states the imagined outcome (the alternate hypothesis). Then write its opposite (the null hypothesis). Question 1: H 0 : Fruit biomass and total seed mass of apples/pears are positively correlated. H A : Fruit biomass and total seed mass of apples are negatively correlated. Question 2: H 0 : Apples and pears do not differ in the ratio of mean seed mass/total fruit mass. H A : Apples and pears differ in the ratio of mean seed mass/total fruit mass. 2. Analyze data from the class. Use Google Sheets for this (see below) a. Google Sheets i. You have access to Google Sheets with any google account (including your ASU student account). ii. Go to https://google.com/drive and select “Go to Drive” iii. Go to “New” > “Google Sheets”

Bio 182 Lab, Arizona State University iv. Enter the data from our class including columns for: fruit biomass, fruit type (apple or pear), seed number, and seed biomass. Record this data here, or include a screenshot. v. For Question 1 we are going to calculate a correlation between fruit biomass and seed biomass: 1. In an empty cell type =CORREL() 2. Select your column for “fruit biomass” as data_y 3. Select your column for “mean seed biomass” as data_x 4. =CORREL( ) will return a correlation coefficient for these two variables 5. Record this number here. 0.5252421584 vi. For Question 2 we are going to calculate a t-test for fruit type and seed biomass: 1. Select the column for “fruit type” 2. Go to “Data” > “sort sheet by column X, A to Z” 3. In an empty cell type “=TTEST( )” 4. Select “seed biomass” for apples as range1 5. Select “seed biomass” for pears as range2 6. Enter “2” for tails 7. Enter “3” for type (this tells excel that our variables are unpaired) 8. Sheets will return a p-value for the relationship between fruit variety and seed biomass 9. Record this number here. 0.02899544156 3. Finally, we can visualize our data by creating a graph. Use Google Sheets for this (see below). a. Google Sheets: i. For Question 1: 1. Select the columns for “fruit biomass” and “seed biomass” 2. Go to “Insert” > “Chart” 3. Change the “Chart Type” to “Scatter” 4. Include an image of this graph here. Be sure to label your graph and axes.

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Bio 182 Lab, Arizona State University For Question 2: 5. Calculate the average seed weight for each fruit type. Go to an empty cell and type “=AVERAGE( )”. Select the seed weights for apples. 6. Go to an empty cell and type “=AVERAGE( )”. Select the seed weights for pears. 7. Select the two averages 8. Go to “Insert” > “Chart” 9. Upload an image of this graph here. Be sure that the graph and axes are properly labeled. IV. Interpret your results. 1. You have now completed your evaluation of the experimental results. Time to interpret them:

Bio 182 Lab, Arizona State University Question 1: Examine the graph of your results and the magnitude of the correlation. Do your results support the null hypothesis for question 1? That is, is there a correlation between fruit mass and seed mass? Is it negative? Explain. Yes, the correlation is positive because the correlation meaning is greater than 0.5. Question 2: Examine the graph of your results and the p-value resulting from the t-test. Do apples and pears make the same relative investment in seeds? Do your results support the null hypothesis? Why or why not? Yes, apples and pears make relatively the same amount of seeds. Because the p-value is below 0.5, we reject the null hypothesis.

Bio 182 Lab, Arizona State University Resource Allocation to Reproduction Grading rubric Total - 40 pts Rating Scales Rating Scales Rating Scales Criteria Exceeds expectations (10 points) Meets expectations (8 points) Needs revision (5 points) Observations Sketches include a description of the specimen (e.g. apple - cross section) and attempt to identify notable features Entry includes sketches for each of the following: - fruit - longitudinal sc - fruit - cross sc Sketches include a description of the specimen (e.g. apple - cross section) but do identify notable features Entry includes sketches for at least one of the following: - fruit - longitudinal sc - fruit - cross sc Sketches do not include a description of the specimen Entry is missing sketches or sketches are rudimentary and fail to identify notable characters. Data entry includes each of the following: - fruit biomass - number of seeds - seed biomass - mean seed mass Data entry includes at least two of the following: - fruit biomass - number of seeds - seed biomass - mean seed mass Data entry is missing two or more of the following: - fruit biomass - number of seeds - seed biomass - mean seed mass Entry includes two graphs : - a bar graph comparing seed mass between fruit varieties - a scatter plot illustrating the relationship between seed mass and fruit mass Graphs include a title and correctly labeled axes. Entry includes at least one graph: - a bar graph comparing seed mass between fruit varieties - a scatter plot illustrating the relationship between seed mass and fruit mass Graphs are missing a title and/or labeled axes Entry does not include graphs. Conclusion Entry makes a conclusion for each research question, based on the data collected: - Is there a relationship between seed size and fruit size? Entry makes a conclusion for at least one research question, based on the data collected: - Is there a relationship between seed size and fruit size? Entry does not make a conclusion on either research question asked or fails to refer to statistical outcomes.

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Bio 182 Lab, Arizona State University - Do apples and pears differ in their investment in seeds? Conclusion references whether data support the null or alternative hypothesis . - Do apples and pears differ in their investment in seeds? Conclusion does not reference either the null or alternative hypothesis .

Copy of Allocation and Simple Statistics Lab

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