El Centro College ENVR 1401 Online Natural Selection
__________________ ___________________________ ___________________ _________________ _________________ ___________________ ___________________ ____________________ ___________________ ______________ _____ Objective 1. Students will demonstrate the principle of natural selection. 2. Students will explain how the process of natural selection operates. 3. Students will describe how particular traits increase the success of an organism in its environment.
__________________ ___________________________ ___________________ _________________ _________________ ___________________ ___________________ ____________________ ___________________ _______________ ______ Please Highlight or type answers in a different color.
Activity 1: Natural Selection Simulation Background Natural selection is selection is the theory proposed by Charles Darwin Darwin as a mechanism of evolution. The overall concept is that populations become adapted to their particular environment over time. This leads to differential survival and success in reproduction. In general, individuals with traits that are well suited to the current environment survive and produce more offspring than other members of the population.
Traits are also known as adaptations as adaptations.. They increase the reproductive success of individual organisms in a given environment. If the environment should undergo changes then the the reproductive success of populations will shift. One well known example is the Peppered Moth. The moth is usually pale with black black speckles across the wings. This coloring gives it the ability to camouflage itself among trees in the area. One mutation that naturally occurs gives the moths a dark, nearly black appearance that stands out against the trees. The number of these individuals is small in the wild due to predation. They do not survive long enough to reproduce. However, during the nineteenth century, it was noticed that in specific areas the dark moths outnumbered the moths with a speckled appearance. This is because of industrialization in urban areas and higher levels of air po llution that actually darken the tree trunks thus making the pale speckled moths easier prey. Adapted from Dobson, C., and S. Burton. 2006. Spork and Beans (Natural Selection, Microevolution and Adaptation). Biology Dept., Grand Valley State University. Introduction For this lab you will use various utensils to determine which one is the “best adapted” to collect the beans. Question Which group will be the most reproductively fit? Bare Hands Hypothesis (Before beginning the lab, type your hypothesis here.) Using bare hand will collect the large amount of beans Materials cups spoon knife loose glove or oven mitt fork bare hands
beans, any dry variety *amount varies
El Centro College ENVR 1401 Online Natural Selection NOTE: In this lab you will be collecting beans using different utensils. To obtain better data, each utensil will be used three times for a total of 3 trials. This lab may be done by one person with a different utensil each time and repeated for a total of three trials per utensil or it may be performed my multiple people each with a different utensil and then repeated for a total of three trials. Individual tester uses 200 beans ( ½ cup). Multiple testers use 1000 beans (1 ¼ cups).
Procedure Individual testers 1. Find an open area to perform the lab (outside or inside will work fine). 2. Spread out approximately 200 beans (1/2 cup) in the area. Set a timer for 15 seconds. 3. At the signal pick up the fork, collect beans for 15 seconds and place in the cup. 4. Count the number of beans collected and record data. Put back the beans collected. 5. Reset timer for 15 seconds. Repeat collection and recording for a total of 3 times. 6. Using a different utensil, collect beans for 15 seconds, record data and repeat for a total of 3 times. 7. Continue until all utensils have been tested 3 times. Have fun! Multiple testers 1. Find an open area to perform the lab (outside or inside will work fine). 2. Spread out approximately 1000 beans (1 ¼ cups) in the area. Set a timer for 15 seconds. 3. At the signal, each person pick up a different utensil, collect beans for 15 seconds, and record data. 4. Put back collected beans, repeat collection and recording for a total of 3 trials. Have fun!
Results REQUIREMENT: Submit a clear picture of the lab in progress here. This ensures the lab was performed. Credit will not be given if no picture is submitted.
Table 1: The amount of prey (beans) captured per adaptation.
Groups Trial 1
Fork
Knife
Spoon
Glove
Bare Hand
75
35
155
82
188
2
89
29
164
94
192
3
104
42
171
102
200
Totals
268
106
490
278
580
Rank the groups based on their extinction rates from ancient to modern. Populations that have smaller numbers left in the wild will become extinct first while groups with larger numbers in the wild will last longer throughout evolutionary history. 1.Knife 2.Fork 3.Spoon 4.Glove 5.Bare Hand
Conclusion 1. Which groups became extinct first? WHY? Knife, because the beans collected using the knife not too much 2. What is the best suited (“best fit”) trait in this experiment? WHY? The Bare Hand is the best fit for this experiment because hand can collect more than any other group 3. How does this experiment relate to naturally occurring animals, e.g., birds, for example? This experiment relates to naturally occurring animals by showing the amount of food animal eats, the nature of the animal, and how animal get the food will help to survive. 4. Explain the statement “Individuals are subjected to natural selection, but it is populations that evolve .” individuals do not evolve - because of our genes already set, but populations' genes can evolve 5. How might a group of organisms in nature avoid extinction due to competition? Need enough space, able to produce, energy from food, and water
