Download Evolution Worksheet

Evolution Worksheet
Part 1: Take approximately five minutes for each student to read the scenario below and then write a good explanation
of evolution by natural selection. After all group members are done, switch papers within your group and critique each
explanation.
Effect of Penicillin on Bacteria in a Petri Dish
# of Bacteria
6000
5000
4000
3000
2000
1000
0
Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day
10
Time
Note: On Day 6 & 7, some bacteria were detected, but the levels were too low to show up on the graph.
You are an instructor of a high school biology class. Your students did a lab where they added penicillin to a petri
dish full of bacteria. Penicillin kills bacteria by binding to DD-transpeptidase, (an enzyme which is critical to
bacterial cell wall structure) and preventing the bacteria from building/repairing its cell wall. The penicillin was
added to the petri dish on Day 1 after the initial population of bacteria was counted. Use the data above to clearly
explain to your students about how natural selection works (remember the 4 postulates/criteria!). Be sure to specify
what the adaptation is in this scenario.
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Part 2: Take five minutes for each student to complete their own answers to these questions. Then discuss your
answers with your group.
In the early 1800’s a ship’s crew captured 30 small squirrel monkeys (Saimiri boliviensis) on the coast of Brazil to
use as a food source on their long journey home. Sadly the ship was wrecked near an unpopulated island several
hundred miles away and only the monkeys survived. The island contained no other monkeys and had a very
different environment from the shipwrecked monkey’s former habitat in Brazil. In 1970 researchers went to the
island for the first time and discovered what they thought was a new species of monkey based on morphological
differences between it and other species found nearby in Brazil.
a. Define evolution (measurable definition)
b. Which mechanism for evolution (circle one: natural selection, genetic drift, mutation or gene flow) cannot be
involved in this scenario? Explain why.
c. Which mechanism for evolution (natural selection, genetic drift, mutation or gene flow) would best explain the
differences seen in this population? Support your answer by including a definition/description of the mechanism
(natural selection, genetic drift, mutation or gene flow) and connecting to this scenario.
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