Copy of Allocation and Simple Statistics Lab

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Arizona State University *

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182

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Biology

Date

Feb 20, 2024

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docx

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Uploaded by ProfessorAlbatross4136

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

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.

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