SBI 3UPage 1

AGENTS OF EVOLUTIONARY CHANGE

Inquiry Major Lab Weight 2: Total 45 Marks

The ability of an organism to survive and reproduce will depend on the organism’s genetic make-up and how well it can cope with various environmental factors. This is the name of the game… SURVIVE AND REPRODUCE!

QUESTION: How do evolutionary agents, such as natural selection, artificial selection, genetic drift, and gene flow, and predator-prey relationships affect the genetic frequencies within a population?

Pre-Lab Questions (In Lab Book)

1. What will be evident in a population of rabbits if microevolution is taking place? [K 1]

2. What are the similarities and differences between artificial selection and natural selection? [A 2]

3. What are the similarities and differences between natural selection and genetic drift? [A 2]

4. Give an example of directional, stabilizing, and disruptive selection. [A 3]

5. Prepare your lab notebook for class by completing your predictions, making your data tables, and including your rough notes for your simulation in Part B. Think about how you will graph your data. [T 1]

MATERIALS:

  1. Designed wrapping paper (habitat)
  2. 30 blue paper chips
  3. 30 orange paper chips
  4. 30 yellow paper chips

PROCEDURE PART A: NATURAL SELECTION

  1. In groups of three, assign a role to each member for the first trial. You need a timer, a predator, and an assistant.
  2. Turn off the lights.
  3. The predator turns away while the assistant sets up the habitat. The assistant will place 7 of each coloured paper chip across the habitat.
  4. The timer will then yell out “hunt” and the predator can turn around and “hunt” for its prey (the paper chips). The predator has four seconds and then the timer will yell out “stop”. The prey must be removed one at a time.
  5. The assistant will collect the remaining organisms (chips).
  6. To simulate reproduction, each surviving chip will replicate once. The offspring are the same colour as the parents. Record in your table how many chips of each colour are at the start of the hunt for round 2.
  7. Switch roles and repeat the procedure three more times and record your results each time.
  8. Construct a graph for each generation showing the different phenotypic types and their frequencies(not numbers obtained) in the population.

PROCEDURE PART B: ALTERNATE EVOLUTIONARY AGENT

In Part A you investigated the role of natural selection on a population of chips. Natural selection is just one factor that can drive microevolution. Other factors can also affect the phenotypic frequencies of a population such as:

artificial selectiongenetic drift gene flow

9. Design a procedure to simulate one of the above processes over at least three generations.

Here are some guiding questions to help with your design:

-What controls will you have in place to ensure you are investigating the chosen selective pressure only?

- What kind of data will you be collecting?

10. Predict what you expect to happen after your simulation.

11. Record your observations in a data table and graph the results.

EVALUATION:

Reminder: The entire lab should be written in third person past passive tense.

You may choose to submit your experimental write-up in one of the following forms:

a. A formal written lab report in your lab book.

b. A power-point presentation including a 3-4 minute presentation of your findings.

Both methods should include the following:

Purpose: [1 mark]

Prediction: [2 marks]

PART A: Predict the outcome of the investigation and give reasons behind your prediction.

PART B: Predict the outcome of your evolutionary agent and give reasons behind your prediction.

Procedure:

  • Summarize the procedure in paragraph form in past passive tense for Part A. [2]
  • Write a detailed description of your experiment for Part B in paragraph form past passive tense and how results were recorded. [4]

Observations:

Part A:

  • Data Table (Record the population size at the start of each round after replication) [2]
  • Properly labelled graph (s)(computer generated or hand-drawn on graph paper). There are many ways to graph these results. You choose which method you prefer to demonstrate the type of selection that is occurring. For the purposes of graphing assumeblue is homozygous dominant, yellow is heterozygous dominant, and orange is homozygous recessive. [4]

Part B:

  • Data Table and Graph as above [6]

Explanation: [15 marks]

In paragraph form, analyze the results of your experiments. Some things you should include are:

  • Analysis of data and graphs
  • Reflect on predictions and see whether or not data/graphs support them
  • Reasons for results
  • Type of selection occurring (directional, stabilizing, disruptive) in each experiment
  • Other factors that might influence frequencies in your simulations
  • Analysis of experimental designs: Discuss errors and ways to improve designs
  • Significance of experiment and real-life applications to the “real world”. Be specific by giving practical applications found in nature.
  • Final concluding statement