Natural Selection ( Jacki Fonseca)
Title: Natural Selection ( Predation )
Principle(s) Investigated:
How natural selection causes populations to change.
How predation selects for traits in populations.
Standards:
PE-HS-LS4-3: Apply concepts of statistics and probability to support explanations that organisms with an advantageous heritable trait tend to increase in proportion to organisms lacking this trait.
DCI-LS4.B Natural Selection & LS4.C Adaptation
Materials:
White sheet of paper ( Michaels or office depot)
News paper ( Starbucks:) )
Hole punch ( Target)
Cups ( Or anything to fill in as a "nest" to hold hole punched paper) ( 99c store)
Tweezers ( 99c )
Computer access/ Wifi ( Hopefully provided)
Procedure: ( Students)
Warm-up: Can the color of an animal determine whether they live or die? Why or why not?
Natural Selection Activity
Introduction:
Within a population, organisms will vary. Charles Darwin stated that in the struggle for existence, those variant organisms that have favorable variations are "better adapted" to their environment and will survive and reproduce in greater numbers. Favorable variations may mean that they are faster, or stronger, or able to eat different types of food, or better camouflaged to avoid predators. In this lab you will simulate the effect of predation by a hawk on a large population of assorted mice. Your population of mice will consist of black, white, and speckled mice. You will represent the hawk.
Big Question: How do organisms change over time in response to changes in the environment?
Objectives:
–to simulate the effect of hawk predation on the appearance of mice
-to simulate the natural selection of traits
Materials:
1 large sheet of newspaper 2 hawks (students)
1 Container (to hold paper circles) 30 white mice (paper circles)
30 speckled mice (paper circles) 1 pair of tweezers
Prediction:
Procedure:
1.Place your sheet of newspaper/ white sheet of paper on the lab table. This will serve as the environment for your mice.
2.Place the container on the other side of the lab table. This will be the nest.
3.Select one person from your group to act as a hawk. This person should stand by the nest.
4.Spread the mice on their environment evenly.
5.The hawk now swoops over and has 1 minute to pick up as many mice as possible. The hawk may only pick up one mouse at a time and must place it in their nest (Container) before flying back to pick up another. The goal is to pick up as many mice as possible in the given time period.
6.When the time is up record the number of mice left in the environment in the data table below. Multiply that number by 2 to get the starting population of your next generation.
7.Repeat this procedure for each generation in the lab group.
8.After all data is collected, Move on to the Analysis section.
Data:
Student prior knowledge: What prior concepts do students need to understand this activity?
Prior knowledge: Students need to know that natural selection happens at the level of individuals.
Students need to know the relationship between predator and prey.
Students need to understand Camouflage as a mechanism for survival.
Skills: Students will need to know how to gather and analyze data.
Students will need to know how to operate the simulation
Explanation: Give a thorough explanation of the experiment or demonstration. Your explanation should be written to give your fellow teachers a solid understanding and include greater detail than what you might provide for your secondary students. Make certain to include equations whenever pertinent.
Procedure: (Teacher) Give a detailed explanation of the procedure and include diagrams if possible.
Student Grouping: Students will be seating at a table in pairs
Teacher actions:
Students will be given pre-prepared Data Sheets and handouts for the simulation
Teacher will say: Evolution is the result of many random processes selecting for the survival and reproduction of a population.
Class will discuss idea of evolution briefly
Students will answer this question. (Can the color of the animal determine whether they live or die? Why or why not?)
Select students will read their partners answer out loud.
Teacher will say: Now that we have reviewed the basic idea lets see if we can corroborate
that populations can change over time
Students will then be instructed to lay out a newspaper/ white sheet of on their desk.
Inside their envelope they have 2 different colored specks and a procedure/ data sheet.
Teacher will have students take 30 seconds to read the procedure and will call on student to repeat what their task is.
Once we have an understanding of the assignment students will begin simulation.
( During the simulation students are to act as predators ( hawks) trying to catch Prey( mice/small white or newspapered specks)
Students are to document every remaining generation on table provided.
After 1 minute the students will switch roles
After that minute the students will stop and graph their data on sheet of paper.
Students will then input data into collaborative spread sheet.
and we will determine if their graphs match up and find patterns between everyone's graphs.
Questions & Answers: Give three thought-provoking questions and provide detailed answers.
Analysis:
1. Describe how the population of moths changed in each generation for both the newspaper and the white moths.
2. What moth coloration is the best adaptation for a dark (newspaper) background? How do you know?
3. How does the simulation model natural selection?
4. Over the long term, what trait (ability) could be strongly selected for in the predator population in the situation of similar color variants proposed above ?
Extension:
5. Examine the table and construct a graph. Plot the years of the study on the X-axis, and the number of moths captured on the Y axis. You should have 2 lines on your graph - one for light moths, and one for dark moths.
6. Explain in your own words what the graph shows. What type of environment do you think these moths live in?
Applications to Everyday Life: Explain (don't just list) three instances where this principle can be used to explain other phenomenon.
1. Antibiotic Resistant Bacteria - Once the environment has been over saturated with antibiotics, bacteria that survives an antibiotic treatment becomes resistant to the medication and reproduces.
2. Lactose intolerance- Humans in areas where cattle are raised have developed the enzyme that allows them to break down cows mile, where-as humans in non -cattle raised areas are lacking in that enzyme and are lactose intolerant.
Photographs: Include photos and diagrams that illustrate the how the investigation is performed.
IMPORTANT NOTE:
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Videos: Include a video of your investigation
IMPORTANT NOTE: Embed a Youtube Video that illustrates the procedure and results. This video should reside in your YouTube account and should be viewable by all. You may use a video in another persons YouTube channel if the video is better quality than what you can make.