Download Simulation 1: Big Claws vs. Small Claws The Crabolution activity

IC Lessons Crabolution
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A. Title of this lesson Simulation 1: Big Claws vs. Small Claws
B. Summary of this lesson
The Crabolution activity addresses the misconception that natural selection is
a completely random process and emphasizes that natural selection acts on
variation in a population in a non-random way by differential survival and
reproduction. The activity involves a series of simulations that demonstrate
how competition for resources (e.g., food) and other environmental factors
can drive natural selection in a population of crabs. Crabs compete to pick up
food with their claws. The amount of food that a crab captures will determine
how many of its offspring will go on to the next generation. Each round in the
simulation represents a generation. Crabs that are very successful will have
more offspring, and crabs that cannot get enough food will either die or have
few offspring. In each of the simulations, students will collect, analyze, and
graph their data to examine how variation within the population forms the
basis for natural selection. The students will then change no more than two
environmental variables to create their own extension of the original lesson.
In the new extension, the students will have to predict the outcome and
develop their own procedures for testing their prediction. After completing
the Crabolution activity, students should better understand the concept of
natural selection, how it acts on variation in populations, and the
environmental factors that affect it.
C. Objective(s)/Learning Goal(s)/ Key Student Learning(s) of this lesson
Students will know:
1. both genetic variation and environmental factors are causes of evolution
and diversity of organisms.
2. the reasoning used by Charles Darwin in reaching his conclusion that
natural selection is the mechanism of evolution
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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Scientific progress is made by asking meaningful questions and conducting
careful investigations. Students should develop their own questions and
perform investigations, and students will:
a. Select and use appropriate tools and technology (including calculators,
computers, balances, spring scales, microscopes, and binoculars) to
perform tests, collect data, and display data.
c. Communicate the logical connection among hypotheses, science
concepts, tests conducted, data collected, and conclusions drawn from the
scientific evidence.
D. Teacher Background Knowledge for this lesson
What can cause a population to change? The binder clips will simulate the crab
claw to capture the various food sources (i.e., rubber bands, split peas).
E. Prior knowledge that students need to understand this lesson - with an assessment to
determine what they already know (if appropriate).
Heredity, Inheritance of genes from parent to offspring, Population, Species,
Population Probe (attached).
F. Standards covered in this lesson
Current California Science Standards:
3. Biological evolution accounts for the diversity of species developed
through gradual processes over many generations. As a basis for
understanding this concept:
a. Students know both genetic variation and environmental factors
are causes of evolution and diversity of organisms.
b. Students know the reasoning used by Charles Darwin in reaching
his conclusion that natural selection is the mechanism of evolution.
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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NGSS:
MS-LS4-4. Construct an explanation based on evidence that describes how
genetic variations of traits in a population increase some individuals’
probability of surviving and reproducing in a specific environment.
MS-LS4-6. Use mathematical representations to support explanations of
how natural selection may lead to increases and decreases of specific traits
in populations over time.
CCSS that apply:
Reading:
RST.6-8.7 Integrate quantitative or technical information expressed
in words in a text with a version of that information expressed
visually (e.g., in a flowchart, diagram, model, graph, or table).
RST.6-8.9. Compare and contrast the information gained from
experiments, simulations, video, or multimedia sources with that
gained from reading a text on the same topic.
Writing:
WHST.6-8.2, WHST.6-8.9
Listening & Speaking:
SL.7.1
Math:
6.SP.5.b
G. Suggested time to complete this lesson
Two 50 minute class periods
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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H. Materials Used in this lesson typed in a bulleted list with quantities (e.g., 10 beakers; water –
2 liters)
medium binder clips, mini binder clips, rubber bands (bag), pinto beans (bag),
small cups, trays (or paper plates). (Other food sources of your choice – i.e.
popcorn seeds, lentils, split peas, rice)
I. Materials Prep for this lesson (should include number of copies needed (e.g. one probe per
student, one
set of directions per lab group)
Part 1:
In each group of 4:
- one small binder clip and one medium binder clip (claws).
- one tray per group (or paper plate) as defined space/area
(environment, neutral for part 1)
- 10 rubber bands, ½ cup of pinto beans (food sources)
- little cup (Dixie cup) as the stomach
Part 2:
- Open ended. Students choose type of binder clips (claw), different
food sources. Optional to change tray (environment).
J. Lesson Plan – detailed, numbered, step-by-step plans. This should be in enough detail for
another science teacher to teach the lesson.
CRABOLUTION ACTIVITY: Teacher Lesson Plan
Lesson: What can cause a population to change?
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
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Procedure:
PART 1 of 2
1. Administer the formative assessment probe "Is It A Population?" After
collecting responses, discuss the scientific definition of a population. A
population is defined as all members of one species in a particular area.
2. Review natural selection concepts and vocabulary.
2. Divide students into groups of four and assign each group member one of
the following roles:
Student 1: player one, who represents an individual crab in a small
population of crabs
Student 2: player two, who represents an individual crab in a small
population of crabs
Student 3: timekeeper
Student 4: referee & “banker” of the offspring.
3. Distribute Crabolution worksheet & materials to each group.
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
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4. Read through the overview of the simulation & the ground rules with the
class:
Overviewof Crabolution simulation:
a) Each round lasts 20 sec. The timekeeper should keep track and call, “Go!”
to begin and “Stop!” to end.
b) Begin with beans & rubber bands in your tray.
c) Each of the two “crabs”/players should select one clip, one mini, and one
medium.
d) The person acting as the referee and “banker” should hold onto the extra
offspring for distribution after the round. As the referee, you need to make
sure the rules are followed.
Ground rules:
- You may only pick up ONE piece of food at a time.
- You may only use one hand to operate the claw. (You may not use another
hand or any other object to help you collect food.)
- For the food to be counted, it must be in your cup, which represents your
stomach.
- Wait until the time begins to collect food. Stop immediately when the time is
up.
- Only the food in your “stomach” (cup) will be counted.
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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Rules for offspring:
If you captured 0 – 4, then you did not eat enough to survive and have no
offspring. You do not play in the next round.
If you captured 5-9, then you survived, and have 1 offspring. You play in the
next round.
If you captured 10 or more, then you did very well, and have 2 offspring.
You play again.
e) After each round, the “banker” will give you a certain number of
offspring. Place them into the offspring “nursery” (the bowl!)
f) Record your data after each round in the “INDIVIDUAL CHART”.
g) Play the next round and repeat until all four rounds have been
completed.
h) Share your data with the class.
i) Graph the class data.
j) Draw a conclusion.
5. Have students record a hypothesis/prediction.
6. Begin the first round. Remind students to record their results in their data
tables.
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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Two sizes of claws within a population
Individual chart:
MINISIZED
# of foods
collected
MINISIZED
# of
offsprin
g
MEDIUMSIZED
MEDIUMSIZED
# of foods
collected
# of
offspring
Generation
1
Generation
2
Generation
3
Generation
4
7. After the class has completed the first round, it is recommended that the
teacher checks in with students to ensure that the procedure was correctly
followed.
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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8. Allow students to finish Generations 2 - 4.
9. Regroup as a class to fill in the class summary chart:
Class summary chart:
Total # of mini offspring
between all mini crab claw
members
Total # of medium
offspring between all
medium crab claw
members
Generation
1
Generation
2
Generation
3
Generation
4
10. Have students graph the class data on their worksheet.
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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11. Students should come up with a conclusion, which can be recorded on their
worksheet. Share with the class.
12. Tell the class that the next part of the lesson will be an activity where
students will have to choose the environmental factors (food source, claw
type/size) that will affect a population of crabs. Teachers can limit the changes
to the types of materials that are available at their sites.
Part 2 of 2 - EXTENSION
13. If part two is being done on a new day, begin by reviewing part one and the
rules for the scenario.
14. Explain to the class that they will design a new scenario and/or procedure
for today’s extension activity. These changes will show how some
environmental change can affect this population of crabs.
15. Have students discuss and answer the following questions in their lab
groups:
1. What kind of environmental change might explain your new scenario?
(natural disaster, invasive species, etc.?)
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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2. What changes will you make to the scenario? (No more than two
changes.)
(Will a new food be added, will other foods be removed, will this be your
only food source, limited number of foods,etc?)
16. Students should record their hypothesis/predictions.
17. Have students write down the directions for their new procedure and
design their own data chart for data collection.
18. The students should carry out their procedure and record their data.
19. Direct students to create a graph that reflects their data and write a
conclusion.
20. As a class, have students share their findings and review what lessons were
learned about population changes. The teacher may want to stress the
following ideas:
a) Evolutionary change in a species does not happen during a lifetime.
b) Natural selection is a completely random process.
c) Natural selection acts on variation in a population in a non-random way by
differential survival and reproduction.
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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d) Certain traits/phenotypes may be advantageous in one environment, but
may not be as advantageous under different environmental conditions.
K. Vocabulary words – key vocabulary words that are targeted or taught as part of the lesson.
(Understanding these words is essential for students to understand the key concepts of this
lesson.)
Evolution, Natural Selection, Population, Genetic Variation, Adaptation,
Generation, Offspring, Environmental Factors, Competition, Fitness, Predator,
Extinction.
L. Potential Pitfalls for:
a. student understanding:
- Having a misconception of what is a population.
- Understanding how genetics and environmental factors affect
populations through natural
selection.
b. laboratory mishaps and common procedural errors:
- Generation 1 dies if clip not manipulated correctly for them to
gather enough food.
c. academic vocabulary issues, etc.
- Variation is from the phenotypic/genotypic differences of a population.
- Evolutionary “fitness” is different from common usage of “fitness”.
M.Differentiation: Modifications for English Learners, advanced learners, struggling learners, etc.
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
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*Grouping modifications – group ELL students/struggling learners with
advanced learners.
*Scaffold vocabulary before lesson (visuals, concept maps, word walls)
*Model the lesson/procedure with a student volunteer.
N. Please list all worksheets used in this lesson.
-Part 1 & Part 2 of Crabolution Student Worksheet. (See attached)
O. Please list all assessments that require a separate sheet.
- Population Probe
P. Photos/Illustrations
- Graph in the worksheet.
- Optional real-world Crab population slideshow (showing variation).
Q. Other Resources
N/A
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
This is lesson __1_ of __1_in this IC
NAME: __________________________________ DATE: _________________ PERIOD: ____
CRABOLUTION ACTIVITY
Question: What can cause a population to change?
Today, we will simulate how crab populations can change over time in order to find the answer to
this question. In our lab groups of four, two of you will each be an individual crab in a small
population of crabs, one will be the timekeeper, and one will be the referee & “banker” of the
offspring. We will be using binder clips to represent crab claws, and we will use our claws to
capture food. Compete over the available food, then at the end of four generations, your entire
lab group should compile their data to complete the summary chart.
General procedure:
1) Each round lasts 20 sec. The timekeeper should keep track and call, “Go!” to begin and “Stop!”
to end.
2) Begin with beans & rubber bands in your tray.
3) Each of the two “crabs”/players should select one clip, one mini, and one medium.
4) The person acting as the referee and “banker” should hold onto the extra offspring for
distribution after the round. As the referee, you need to make sure the rules are followed.
Ground rules:
- You may only pick up ONE piece of food at a time.
- You may only use one hand to operate the claw. (You may not use another hand
or any other object to help you collect food.)
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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- For the food to be counted, it must be in your cup, which represents your stomach.
- Wait until the time begins to collect food. Stop immediately when the time is up.
- Only the food in your “stomach” (cup) will be counted.
Rules for offspring:
If you captured 0 – 4, then you did not eat enough to survive and have no offspring. You do
not play in the next round.
If you captured 5-9, then you survived, and have 1 offspring. You play in the next round.
If you captured 10 or more, then you did very well, and have 2 offspring. You play again.
5) After each round, the “banker” will give you a certain number of offspring. Place them into the
offspring “nursery” (the bowl!)
6) Record your data after each round in the “INDIVIDUAL CHART”.
7) Play the next round and repeat until all four rounds have been completed.
8) Share your data with the class.
9) Graph the class data.
10) Draw a conclusion.
HYPOTHESIS/PREDICTION:
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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Two sizes of claws within a population
Individual chart:
MINI-SIZED
MINI-SIZED
MEDIUM-SIZED
MEDIUM-SIZED
# of foods
collected
# of offspring
# of foods
collected
# of offspring
Generation 1
Generation 2
Generation 3
Generation 4
Class summary chart:
Total # of mini offspring
between all mini crab claw
members
Total # of medium offspring
between all medium crab
claw members
Generation 1
Generation 2
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
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Generation 3
Generation 4
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
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GRAPH:
**Remember, all graphs should have a title, labels on the x & y axes, a key if necessary, and
equal increments along the axes. What kind of graph would work best to represent your data?
Title:
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
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CONCLUSION:
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
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NAME: __________________________________ DATE: _________________ PERIOD: ____
CRABOLUTION ACTIVITY - Part 2
EXTENSION: It’s your turn to design your crabs’ “environment”.
You will have access to a new “food” material. In your group, design a new scenario & procedure
that will show how some environmental change can affect this population of crabs.
1. What kind of environmental change might explain your new scenario?
(natural disaster, invasive species, etc.?)
2. What changes will you make to the scenario? (No more than two changes.)
(Will a new food be added, will other foods be removed, will this be your only food source, limited
number of foods,etc?)
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
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3. Make a prediction/hypothesis for each variable.
4. Briefly describe your new procedure:
Create your own DATA CHART:
Generation 1
Generation 2
Generation 3
Generation 4
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
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Create your own GRAPH (use a ruler!)
TITLE:
CONCLUSION:
Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012
IC Lessons Crabolution
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Created by Angelica Gallegos (Hayward USD), Pat Ivester (San Mateo-Foster City USD), Corinna Low (South
San Francisco USD), and Gerald Willkom (Hayward USD); 2012