Nancy J. Schmitt
Before going into this activity, I would review percents and probabilities using a warm-up that gauges the students skill level.
Compare two ponds with the current number of frogs and the anticipated number of frogs after 2 years based on the following information.
The scouts are in the woods on their annual camping weekend. The scout leader has been taking an evolutionary biology class and has decided to put his knowledge to a test. He notices a pond that looks pristine. He decides to do a count of the number of frogs in the pond. Scout Chris finds 5 green frogs. Scout Kendra found 8 translucent frogs. Scout Harry found 15 yellow frogs.
1.
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Based on the amount of frogs they found and the fact they only canvassed 15% of the pond, how many frogs live in this pond?
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2.
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Although the pond looked pristine, danger was lurking beneath the surface, runoff from a nearby chemical company has put the levels of atrazine in the water at a level that it has impacted the amount of frogs able to reproduce. 20% of the male frogs are unable to reproduce. If the frogs in the pond are ½ females and each female pairs up with only one male for life and produces 100 eggs each spring. How many eggs are produced in the pond this spring?
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3.
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The probability that an egg becomes a tadpole, not having become a big blue fish's favorite lunch is 10%. How many tadpoles are there?
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4.
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The probability that each tadpole or young frog not becoming bird food and becomes a grownup frog is 20%. No grown up frogs have perished this year. How many frogs are now in the pond?
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5.
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Next year the same thing happens. How many frogs are in the pond?
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The second pond looks about the same but is far enough away from the chemical factory so that there is no atrazine in the pond. If the number of frogs found are the same as for the first pond. How many frogs will be in this pond after 2 years? Explain what the difference is and why. Defend your answer.