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Adaptation

Investigation 1 – Lab

 

 

 

 

 

 

 

MINDSET

This Investigation is designed to:

  • illustrate to you that the variation in the individuals of a species is due to genetic variation,
  • allow you to conclude that genetic variation leads to adaptation to environmental change, and
  • allow you to investigate how genetic variation becomes a common trait of a species if it allows the survival of the members of a species.

BE PREPARED

Student Preparation for the Investigation includes gathering the following materials.

Note: The materials are listed in your SDR. They are also listed below for your reference.

  • (1) clear plastic container
  • (12) dark-colored gram cubes of the same color
  • (12) light-colored gram cubes of the same color
  • (2) 15 ml centrifuge tubes
  • (1) triple beam balance
  • (1) metric ruler
  • (40) toothpicks
  • (3) sticks of clay
  • (1) Light Meter
  • (1) flashlight
  • (1) marker pen
  • (1) calculator
  • (1) roll of masking tape

 

INVESTIGATE

  • Reflect on the PreLab video as you move through the procedural steps.
  • During the Experiment, every procedural step is important. If one step is skipped, data can become invalid. To help you keep on track, read each step thoroughly, complete the step, then check it off (Read it – Do it – Check it).
  • Complete all of the procedural steps in your SDR.

Note: The procedural steps are listed below for your reference.

Trial 1:

  1. In this Trial, you will model three individual cactus plants: one with no spines, one with few spines, and one with many spines.
  2. Use a stick of clay to create a model cactus with no spines.
  3. Place the stick of clay on the table so that the long end is pointing upwards.
  4. Prepare to use the Light Meter to take measurements for the experiment. Refer to the Procedure Light Meter Use and Operation for help.
  5. Measure the amount of light that would fall on a cactus if it had no spines. To do this, complete the following steps.

A. Place the Light Meter’s light sensor directly beneath one of the sides of the clay that has no spines, or toothpicks.

B. Place a flashlight 5 cm directly above the top of the cactus.

Adapt Inv. 1 Lab Figure 1

C. Shine the flashlight directly onto the light sensor so that the brightest part of the beam of light falls on the light sensor. Hold the flashlight steady for 5 seconds.

D. Find the number of light units (Lux) measured.

E. Record: How much light falls on the cactus when there are no spines? Record the amount of light in Table A.

6. Use a stick of clay to create a model cactus that has only a few spines.Adapt INv. 1 Lab Trial 1 A

A. On one of the long sides of the stick, place 8 toothpicks in a random pattern. These represent the spines of a cactus. Make sure there is still room at the bottom for the light meter.

 

7. Measure the amount of light that falls on a cactus that has only a few spines. To do this, complete the following steps.

A. Place the Light Meter’s light sensor directly beneath the side with 8 toothpicks. Remember, this side represents a cactus with only a few spines.

B. Hold the flashlight 5 cm directly above the side of the cactus with the 8 toothpicks.Adapt Inv. 1 Lab Trial 1 Figure 2

C. Shine the flashlight directly onto the light sensor so that the brightest part of the beam of light falls on the light sensor.

D. Hold the flashlight steady for 5 seconds.

E. Find the number of light units (Lux) measured.

F. Record: How much light falls on the cactus when there are few spines? Record the amount of light in Table A.

8. Use a stick of clay to create a model cactus that has many spines.Adapt Inv. 1 Lab Trial 1 B

A. On one of the long sides of the stick, place 30 toothpicks in a random pattern making sure there is still room at the bottom for the light meter. This represents a cactus with many spines.

9. Measure the amount of light that falls on a cactus that has many spines. To do this, complete the following steps.

A. Place the Light Meter’s light sensor directly beneath the side with 30 toothpicks. Remember, this side represents a cactus with many spines.

B. Hold the flashlight 5 cm directly above the side of the cactus with the 30 toothpicks.Adapt Inv. 1 Lab Trial 1 Figure 3

C. Shine the flashlight directly onto the light sensor so that the brightest part of the beam of light falls on the light sensor.

D. Hold the flashlight steady for 5 seconds.

E. Find the number of light units (Lux) measured.

F. Record: How much light falls on the cactus when there are more spines? Record the amount of light in Table A.

  1. Compare the two cacti with spines. Which received the most light? 
  1. Compare the two cacti with spines. Which was more shaded? 
  1. Were the two cacti with spines shaded from the Sun compared to the cactus with no spines? How do you know? 

Adapt Inv. 1 Lab Trial 1 Conclusion

  1. In the current climate, if a cactus receives more than 2500 Lux it will not survive. Would the cactus with no spines survive?
  1. Consider the two cacti with spines. How will the variation in the number of spines affect the survival of the two cacti? Can both cacti survive in the current climate? 
  1. If the temperature and intensity of the sun were to increase, would the variation in the number of spines give one type of cactus an advantage over the other cactus? Why? 

Trial 2:

  1. In this Trial, you will investigate variation in the trait of bone density in penguins.
  2. Create a model ocean. Fill a clear plastic container with water until the water is 3-4 cm from the top of the container.
  3. In this experiment, Falcon tubes will represent penguins with different bone densities.
  4. Use an empty centrifuge tube to represent one model penguin. Label the tube “Penguin A.”
  5. Use the other centrifuge tube to represent the second model penguin. Fill the tube with water until the water reaches the top line. Close the tube and label it “Penguin B.”
  6. Determine the density of each model penguin by completing the following steps.

A. Record: Using the triple beam balance, determine the mass of the empty centrifuge tube. Record the mass in Table B.

B. Record: Using the triple beam balance, determine the mass of the filled centrifuge tube. Record the mass in Table B.

C. The volume of the tube is 15 ml.

D. Calculate: Determine the density of each tube using the formula for density: Density = Mass ÷Volume

E. Record: Write the density of each penguin in Table B.

 

  1. Which tube is denser? Which penguin has denser bones? 

Adapt Inv. 2 Lab Trial 2 Prediction

  1. Make a prediction. Which model penguin do you think will be able to dive deeper into the ocean where there is more food? Why? 
  1. To model how Penguin A dives, use the following steps.

A. Hold Penguin A (the empty tube) so that the cap end Adapt Inv. 2 Lab Trial 2 Arests on the top edge of the container. One student should hold the tube on the edge of the container.

B. Another student should sit or crouch beside the container so that they are able to watch the penguin through the side of the plastic container.

C. Allow Penguin A, the empty falcon tube, to fall into the water.

10. To model how Penguin B dives, use the following steps.

A. Hold Penguin B (the tube filled with water) so that the cap end rests on the top edge of the container. One student should hold the tube on the edge of the container.

B. Another student should sit or crouch beside the container so that they are able to watch the penguin through the side of the plastic container.

C. Allow Penguin B, the falcon tube filled with water, to fall into the water.

 

11. Remove the tubes from the water and dry them with a paper towel.

12. Which penguin floated lower in the water? 

Adapt Inv. 1 Lab Trial 2 Rules

  1. How does bone density relate to the depth of dive? 

Adapt. Inv 1 Lab Check Understanding

  1. In the current environment, there is food at all levels of the water and on land. How does the variation in the density of bones affect the survival of both penguins? Can both penguins survive in the current environment? 

15. If there was little food at the surface of the water and on the land, but plenty of food at lower depths of the ocean, would the variation in the density of bones of one penguin provide it with an advantage over the other penguin? Why?

16. How do the traits or adaptations that animals and plants have help them survive in their environments?

17. Are all members of a species exactly alike?

18. Can individuals of a species with different variations of a trait survive in a particular environment? 

Trial 3:

  1. In this Trial, you will analyze the genetics of bone density.
  2. Separate the gram cubes into one pile of dark color and one pile of light-colored cubes.
  3. Place the dark-colored cubes beside Penguin A, the empty centrifuge tube. Each dark-colored gram cube represents the allele that determines less-dense bones. This is the dominant allele.
  4. Place the light-colored gram cubes beside Penguin B,Adapt Inv. 1 Lab Trial 3 A the centrifuge tube filled with water. Each light-colored gram cube represents the allele that determines more dense bones. This is the recessive allele.
  5. Refer to the key in Table C.

Note: Be sure that you understand the key in Table C. You should work collaboratively to complete Trial 3 questions 6A to 6F.

  1. Create genotypes for penguins with different variations of the bone trait by combining two alleles.

A. Connect two dark-colored gram cubes.

B. Use the key to answer the following question. Will the penguin you just created have the phenotype of more dense or less dense bones? 

C. Connect two light-colored gram cubes.

D. Will this penguin have the phenotype of more dense or less dense bones? 

E. Connect a dark-colored gram cube and a light-colored gram cube.

F. Will this penguin have the phenotype of more dense or less dense bones? 

 

7. Use the Punnett square in Table D to help find the possible combinations of alleles if two penguins mate.

A. Locate the penguin that was made with two dominant alleles (dark-colored gram cubes). This is a penguin with less dense bones.

B. Disconnect the cubes and place each cube over a dark square in the left column of the Punnett square.

C. Find the penguin that was made with two recessive alleles (light-colored gram cubes). This is a penguin with more dense bones.

D. Disconnect the cubes and place each cube over a light square in the top row of the Punnett square.

E. Locate the extra gram cubes. The alleles from the left will combine with the alleles from the top. As an example, in Box 1, you would connect one dominant allele with one recessive allele. Box 2 has been filled in as an example.

F. Connect pairs of cubes in the correct combinations and place them in the correct boxes in the Punnett square to represent the remaining two genotypes.

 

 

  1. Notice that all the possible combinations included one dominant allele and one recessive allele. Based on the key in Table C, will these penguins have the phenotype of more dense bones or light bones?
  1. Use the Punnett square in Table E to help find the possible combinations of alleles if two heterozygous penguins mate. Use the key in Table C for help.

A. Create a penguin that has one dominant allele and one recessive allele. This is a penguin with less dense bones.

B. Place the alleles on the dark and light squares to the left of Table E.

C. Create another penguin that has one dominant allele and one recessive allele.

D. Place the alleles on the dark and light squares above Table E.

E. Locate the extra gram cubes. Connect pairs of cubes in the correct combinations and place them in the correct boxes in the Punnett square to represent the four genotypes.

 

  1. What are the possible genotypes (combinations of alleles)? 
  1. Which phenotypes of the bone density trait do the different genotype combinations represent?
  1. Use the Punnett square in Table F below to help find the possible combinations of alleles if a penguin with two dominant alleles and a penguin with one dominant and one recessive allele mated. Use the key in Table C for help.

A. Create a penguin that has two dominant alleles. This is a penguin with less dense bones.

B. Place the alleles on the dark squares on the left of Table F.

C. Create another penguin that has one dominant allele and one recessive allele.

D. Place the alleles on the dark and light squares on the top of Table F.

  1. What are the possible genotype combinations if a penguin with two dominant alleles and a penguin with one dominant and one recessive allele mated? 

 

CLEAN UP

Be sure that you clean up your lab bench after completing your experiments.