Lesson: Natural Selection Part II
This lesson follows the previous lesson where students camouflage and try to find a lizards or butteflies. It has them try to determine the factors that lead to the formation of different species (Natural selection as a driving force of evolution). By analyzing different beak shapes and watching a PBS video on salamander evolution, students develop an appreciation for the true meaning of "Survival of the Fittest". Fit relating to best adaptations for surviving in a certain region, not necessarily the strongest individual.
DO NOW: Start by projecting (Beak picture 1) and have students determine which Finch would most likely eat small seeds, nuts, nectar from flowers and larger seeds. Students will use their observation and inference skills to develop an argument. Have students then jot down the factors that they feel determine how organisms look. You can then have students share with each other or in a larger group discussion setting.
Introduce Darwin: naturalist who traveled around the world collecting data on organisms in different areas of the world. Talk briefly about Galapagos islands and Finch beaks., etc.
Model natural selection with beak activity. Have different people in each group have beaks made of spoons, forks, fork and spoon combination, etc. They will then be competing for food. You can then model how some organisms won't have enough food to survive, not reproduce and therefore not pass on their genes. This results in the organisms exhibiting the traits inherited by their parents. Note: I don't get too far into genetic variation or punnett squares--they receive more indepth understanding in upper grades.
Show PBS video on salamander evolution and then have kids answer questions on Salamander Worksheet--review. The primarily goal of this activity is for them to be able to explain why each salamander population has different coloration, yet are the same species. This video helps them visualize evolution by way of natural selection, especially how it applies to camouflage and mimicry.
Have students reflect on how they now think speciation occurs--these answers should be more on target than their original thinkings. You should follow-up with checking for understanding (Check for understanding Powerpoint).
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