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Tracking Changes in Photoperiod Around the Globe Mystery Class Update: March 6, 1998 Mrs. Berger's 5th Grade Class Just as sure as the sun rises in the morning, Mrs. Berger and her students, have gathered this week's sunrise and sunset data for you. (This week's sunrise/sunset times are provided at the end of this report). Before we get to those times, though, we want to first take care of Challenge Question # 1 from last week, where we asked you to think about a food web and answer this: "How do seasonal changes in photoperiod affect your animal's food web?" Students in Mrs. Dwyer's 5th Grade Class have been researching robin behavior, and responded with an answer that does a nice job of showing how seasonal changes in photoperiod affect the food web for the robin. As a class, read their thoughts and discuss their conclusions: "Robins are affected by the seasonal changes in the photoperiod. Some of these changes are related to the arrival of spring - more sunlight, warmer air, ice melting, water becoming available, worms and insects becoming active when their food becomes available (fruits, soil nutrients, other insects, nectar)." Mrs. Dwyer's 5th Grade Class Surry Elementary School Surry, ME 04684 jdwyer@surryes.u92.k12.me.us Example of Webbing Activity (Click Image to Enlarge) Generally, the longer the photoperiod, such as in spring and summer,the more food that will be available. This is because the added sunlight and heat in spring and summer make plants grow, and the plants provide food for plant-eating animals, and these plant-eating animals can then be available as food for animals which prey on them. Also, the added sunlight and heat warm the air and thaw frozen soil and lakes, making other foods such as worms, insects and fish available too. On the other hand, the shorter the photoperiod, such as in fall and winter, the less food that will be available. The reduced amount of sunlight and heat means fewer plants are available for plant-eating animals, and fewer worms, insects and fish too, and therefore less food is available for animals that prey on these food sources. Now, back to this week's sunrise and sunset times from Mrs. Berger's class. Remember, this information was recorded on Monday, the same day you collected your sunrise/sunset data Here Are This Week's Data: Journey North Mystery Class Sunrise/Sunset Data Data For: Monday, March 2, 1998 Mystery Class Sunrise Sunset # 1 6:41 19:29 # 2 6:52 18:06 # 3 5:39 22:45 # 4 7:05 18:12 # 5 7:02 20:04 # 6 7:08 18:09 # 7 6:44 18:27 # 8 5:55 18:21 # 9 7:14 19:19 # 10 7:52 17:30 The Next Mystery Class Update Will be Posted: March 13, 1998 Copyright 1998 Journey North. All Rights Reserved.