Slide 1 / 27 New Jersey Center for Teaching and Learning Progressive Science Initiative This material is made freely available at www.njctl.org and is intended for the non-commercial use of students and teachers. These materials may not be used for any commercial purpose without the written permission of the owners. NJCTL maintains its website for the convenience of teachers who wish to make their work available to other teachers, participate in a virtual professional learning community, and/or provide access to course materials to parents, students and others. Click to go to website: www.njctl.org Slide 2 / 27 AP BIOLOGY Investigation #1 Artificial Selection Summer 2014 www.njctl.org Slide 3 / 27 Investigation #1: Artificial Selection Click on the topic to go to that section · Pacing/Teacher's Notes · Pre-Lab · Guided Investigation · Independent Inquiry
Slide 4 / 27 Pacing/Teacher's Notes Return to Table of Contents Slide 5 / 27 Teacher's Notes Lab procedure adapted from College Board AP Biology Investigative Labs: An Inquiry Approach Teacher's Manual Click here for CB AP Biology Teacher Manual Note: This investigation will be assessed in the Evolution & Classification Unit (lab quiz located with Evolution/Classification assessments). This investigation takes approximately 7 weeks to complete, thus it is planned to begin during the Cell Cycle unit. However, plants required regular watering and fertilization so please plan accordingly, keeping in mind any school breaks/holidays. Slide 6 / 27 Pacing General Reference Day (time) Activity to Unit Plan Notes Description Day 1 (HW) CC Day 2 Pre-lab Pre-Lab HW Day 2 (40) Set up and Steps 1-2 CC Day 3 planting Selecting trait, measurements, This can occur anytime between Day 3 (80) Step 3-7 CC Day 11 and statistical days 7-12 analysis Preparing bee Prepare Bee Day 4 (40) sticks for H Day 1 Sticks pollination This can occur anytime between Steps 8-10 Day 5 (80) Pollination H Day 2 days 14-16. Bee sticks may need to be constructed prior to pollination This can occur anytime between days 28-36, look for yellow Day 6 (20) Steps 9-10 Begin drying EC Day 4 seedpods 2nd generation This should occur after about a week Day 7 (40) Step 11 EC Day 9 planting of drying seeds This can occur when the new plants Step 12-13 Reexamine trait are between 7-12 days old, but Day 8 (80) EC Day 19 should be done at the same age as the original analysis of generation 1 Day 9 (40) Step 14 Analysis EC Day 20 Day 10 (20) Assessment Lab Quiz EC Day 21
Slide 7 / 27 Pre-Lab Return to Table of Contents Slide 8 / 27 Question/Objectives Can extreme selection change expression of a quantitative trait in a population in one generation? In this lab we will: · Investigate natural selection as a major mechanism of evolution. · Convert a data set from a table of numbers that reflects a change in the genetic makeup of a population over time and apply mathematical methods and conceptual understanding to investigate the cause(s) and effect(s) of this change. · Apply mathematical methods to data from a real population to predict what will happen to the population in the future. · Investigate how natural selection acts on phenotypic variation in populations. · Evaluate data-based evidence that describes evolutionary change in the genetic makeup of a population over time due to changes in the environment. · Design an investigation based on your observations and questions related to the importance of a single trait in the life history of a plant. Slide 9 / 27 Pre-Lab Questions Read the background information and answer the following questions in your lab notebook. 1. Define natural selection and contrast it with artificial selection. 2. What will happen over time to a population exposed to artificial selection? Give a example. 3. What does it mean to "quantify several traits"? 4. Give a brief outline of this investigation.
Slide 10 / 27 Safety When growing plants under lights, be careful to avoid any situation where water or fertilizer could come in contact with electrical wires. Slide 11 / 27 Guided Investigation Return to Table of Contents Slide 12 / 27 Materials · Lighting · Bee sticks for pollination · Growing system · Digital cameras to record the · Wicking investigation · Fertilizer · Plastic magnifiers · Soil · Laboratory notebook · Vermiculite · Fast Plant seed
Slide 13 / 27 Plant Cultivation: First Generation Plants Step 1 Prepare growing containers. If using plastic soda bottles click her for instructions Slide 14 / 27 Plant Cultivation: First Generation Plants Step 2 Each day, check your plants and make sure that the reservoirs are full, especially on Fridays. As your plants grow, record your observations daily. Also try to identify a trait that you could measure or observe reliably. Look for variation in the plants you are growing and describe any you see in your notebook. Observe your classmates' plants as well. Note: Carefully read Step 3-7 before the plants begin to flower. Slide 15 / 27 Plant Cultivation: First Generation Plants Step 3 When the plants are about 7 to 12 days old, the class needs to choose 1-2 variable traits for artificial selection. Several variable traits can work for this. Compare your observations with those of other students. You want a trait that varies between plants in a single bottle/ pot but also varies between containers. The trait should not be something that is Yes or No, but rather something that varies within a range. That is, look for traits that you can score on a continuum (length, width, number, and so on). In your lab notebook, compile a list of all the possible traits your class identified. As a class, pick a trait you want to try to affect.
Slide 16 / 27 Plant Cultivation: First Generation Plants Step 4 Score each of your plants for the trait that your class chose to evaluate. You may need a magnifier to do this accurately. Don't be surprised if some plants are not very different from one another. Slide 17 / 27 Plant Cultivation: First Generation Plants Step 5 Calculate appropriate descriptive statistics for the class data for the first generation: mean, median, range, standard deviation, etc. Slide 18 / 27 Plant Cultivation: First Generation Plants Step 5 cont'd Create a histogram (such as the one below) that shows the frequency distribution of the trait that you have selected.
Slide 19 / 27 Plant Cultivation: First Generation Plants Step 6 You are now ready to make selection decisions. Directional selection tends to move the variability of a trait in one direction or the other (increase or decrease the trait in the next population). Find the top (or bottom) 10% of plants with the trait in the entire class's population (e.g., out of a population of 150 plants, the 15 hairiest plants), and mark any that are in your plant containers. Using scissors, cut off the tops of the remaining plants in that container (those not in the top 10%). Note: Containers with no individuals in the top 10% will be kept as a control population. Do not cut these plants. Slide 20 / 27 Plant Cultivation: First Generation Plants Step 7 Just as you did in Step 5, construct a new histogram and calculate descriptive statistics for the selected population of plants. Record the data in your lab notebook. Once you have finished, isolate these selected plants from the rest of the population. Move the containers of selected plants to another light system so that the plants can finish out their life cycle in isolation. This population will serve as the parents for the new generation. Slide 21 / 27 Plant Cultivation: First Generation Plants Step 8 On about day 14-16, when several flowers are present on each of the selected plants, cross-pollinate the selected plants with a single bee stick or pollinating device. Fast Plants are self-incompatible - each plant must be fertilized by pollen from another plant. Collect and distribute pollen from every flower on every plant in the selected population. Reserve this bee stick for only the selected population.
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