A tale of shipwreck and delicious beans Reproduced from Tieman & Haxer, 2007 Even in the same species, there are differences between individuals Some variations are good, some are not so good. One kind of good variation helps organisms avoid being preyed upon The environment helps determine what a “good variation” is. Captain Dan and his crew were sailing from South America to Australia when they encountered a severe storm. The ship tossed in the sea for days before coming to rest on an island somewhere in the South Pacific. The ship was badly damaged and most of the supplies had fallen overboard during the storm. Dan and his crew were very hungry and the island didn’t promise much in the way of food. After looking around, the crew discovered tiny organisms hiding in the grass. They named them Jelly bellicus because the organisms reminded them of a sweet treat back home. Upon closer inspection the crew realized that there were eight different varieties of Jelly bellicus. The crew began gobbling up as many of the delicious critters as they could find. The crew split into three groups to find food on the island. The ground looked very different from one part of the island to the next. Eight different specimens ◦ ◦ ◦ ◦ White White w/spots Red Pink w/spots ◦ ◦ ◦ ◦ Tan w/spots Light brown w/spots Dark brown w/spots Black Red and dusty Beige and fluffy Grey and bumpy Arrange into three groups with appx equal numbers Each group gets a bag of jelly beans In each bag: ◦ 10 of each colour ◦ 80 beans total Dump the bag of beans into the terrain and mix them up Each crew member can only use one hand to hunt No picking up handfuls of terrain and sorting through Wait for the signal before hunting All hunting stops when Captain Dan says so Don’t actually eat the beans! Ready? Record how many of each type of bean you found. Which beans were easier to find? Which ones were harder to find? Why? As a group, decide which jelly bean is the easiest, and which is the hardest to find. Make sure to write it down. Red and Dusty Group ◦ Easiest bean – Red and Pink ◦ Hardest bean – Tan w/spots Grey and Bumpy Group ◦ Easiest bean – Red ◦ Hardest bean - Black Beige and Fluffy Group ◦ Easiest bean – Black ◦ Hardest bean - Pink Different colours do better in different environments, just like the beans. What would happen to black rabbits in the grass? Brown rabbits in the snow? Good thing there are different colours! Hawks like to eat rabbits! What might it look like to a hawk, way up high, to see different colours of rabbits on the ground? Will some be easier to see than others? What might happen to the dark rabbits on the green grass? If all the dark rabbits get eaten, how can they have dark babies? There might not be very many dark rabbits left on the green grass! Connection to computer model (foxes and rabbits) Mimicry – The red beans are poisonous! ◦ Kids will probably avoid the pink beans too ◦ Real-world connection to wasp mimics ◦ None of these insects can sting! Population Shift ◦ After first round of hunting, surviving beans reproduce ◦ Have many rounds, many generations ◦ Represent results in bar graph Simpler variations ◦ Use only one type of terrain This will reduce complexity ◦ If you want to focus only on predation or selection pressure ◦ Could work up to the different terrains and realworld connections Computer model Writing activity Multi-day activity?