Natural Selection: The Case of the Owl Butterfly

Biology Grades High School 13:29 Video
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Lesson Description

Explore the concept of natural selection using the owl butterfly as a case study. This lesson examines how intricate patterns, like the owl butterfly's eye-like markings, can arise through gradual, incremental changes over generations.

Video Resource

Natural Selection and the Owl Butterfly

Khan Academy

Duration: 13:29
Watch on YouTube

Key Concepts

  • Natural Selection
  • Genetic Variation
  • Adaptation
  • Evolution
  • Mutation

Learning Objectives

  • Students will be able to explain how natural selection can lead to the development of complex traits.
  • Students will be able to describe the role of genetic variation in the process of natural selection.
  • Students will be able to analyze the potential adaptive advantages of the owl butterfly's wing patterns.
  • Students will be able to define how small probabilistic changes over many generations can lead to significant evolutionary changes.

Educator Instructions

  • Introduction (5 mins)
    Begin by asking students what they know about natural selection and evolution. Show a picture of the owl butterfly and ask what they find remarkable about its appearance. Briefly introduce the video and its focus on explaining the origin of the butterfly's wing patterns.
  • Video Viewing (10 mins)
    Play the Khan Academy video "Natural Selection and the Owl Butterfly." Encourage students to take notes on the different theories presented regarding the purpose of the wing patterns and the explanation of how natural selection could have led to their development.
  • Discussion (15 mins)
    Lead a class discussion based on the discussion questions below. Focus on clarifying any misunderstandings about the concepts presented in the video and encouraging students to critically analyze the evidence and reasoning.
  • Interactive Exercise: Modeling Natural Selection (15 mins)
    Engage students in the interactive exercise described below, simulating the natural selection process with different wing patterns. This activity reinforces their understanding of how small advantages can accumulate over time.
  • Wrap-up and Assessment (5 mins)
    Summarize the key points of the lesson and assign the multiple-choice and fill-in-the-blank quizzes as a formative assessment of student understanding.

Interactive Exercises

  • Butterfly Wing Pattern Simulation
    Divide students into small groups. Provide each group with construction paper, scissors, and markers. Have them create several 'butterflies' with slightly different wing patterns (e.g., different sizes and positions of spots). Simulate a 'predator' (e.g., a student or the teacher) trying to 'capture' the butterflies. Give a slight advantage to butterflies with patterns that resemble eyespots, making them slightly harder to 'capture.' After several rounds, observe how the proportion of butterflies with eye-spot patterns changes over time.

Discussion Questions

  • What are the two competing theories presented in the video about the purpose of the owl butterfly's wing patterns?
  • How does genetic variation contribute to the process of natural selection?
  • Explain how a small survival advantage (e.g., 1% less likely to be eaten) can lead to significant changes in a population over time.
  • Can an individual organism intentionally evolve during its lifetime? Why or why not?
  • Why does the presenter state that the intricacy of bacterial structures and viral mechanisms might be more complex than the owl butterfly's wing patterns, even though the wing patterns are more relatable to humans?

Skills Developed

  • Critical Thinking
  • Scientific Reasoning
  • Data Analysis
  • Modeling

Multiple Choice Questions

Question 1:

What is the primary mechanism driving the evolution of the owl butterfly's wing patterns, according to the video?

Correct Answer: Natural selection acting on genetic variations

Question 2:

What role does genetic variation play in natural selection?

Correct Answer: It provides the raw material for selection to act upon.

Question 3:

According to the video, what is one hypothesis for why the owl butterfly has eye-like patterns on its wings?

Correct Answer: To scare away predators

Question 4:

The video mentions that even a small survival advantage can lead to significant changes over time. This is because:

Correct Answer: The advantage accumulates over many generations.

Question 5:

What is the source of the variations in the wing patterns of butterflies?

Correct Answer: Random mutations in DNA

Question 6:

Why is it inaccurate to say that an individual butterfly 'engineered' its way to have a better camouflage?

Correct Answer: Evolution works on populations over generations, not individuals in their lifetime.

Question 7:

The example of the peppered moth during the Industrial Revolution illustrates:

Correct Answer: How environmental changes can influence natural selection

Question 8:

What is the role of DNA in the development of the butterfly's wing patterns?

Correct Answer: DNA codes for the proteins that create the wing patterns.

Question 9:

Which of the following is most accurate about the speed of evolutionary change?

Correct Answer: Evolution can happen quickly or slowly depending on the circumstances.

Question 10:

What does it mean for a trait to be 'selected for'?

Correct Answer: The trait increases the organism's chances of survival and reproduction.

Fill in the Blank Questions

Question 1:

The process by which organisms with advantageous traits are more likely to survive and reproduce is called ______________ ______________.

Correct Answer: natural selection

Question 2:

Differences in traits among individuals within a population are known as ______________.

Correct Answer: variation

Question 3:

A trait that increases an organism's ability to survive and reproduce in its environment is called an ______________.

Correct Answer: adaptation

Question 4:

The owl butterfly's wing patterns are hypothesized to deter ______________.

Correct Answer: predators

Question 5:

Changes in the DNA sequence are called ______________.

Correct Answer: mutations

Question 6:

The peppered moth example shows how environmental changes can influence the ______________ of certain traits.

Correct Answer: frequency

Question 7:

DNA contains the instructions for building ______________ that carry out essential functions in cells.

Correct Answer: proteins

Question 8:

Evolution happens at the ______________ level, not at the individual level.

Correct Answer: population

Question 9:

Natural selection acts on existing ______________ within a population.

Correct Answer: variation

Question 10:

The eye-like patterns on the owl butterfly's wings may function as a ______________, diverting predators away from the butterfly's body.

Correct Answer: decoy

Educational Standards

B.LS4.2:Construct an explanation based on evidence that biological diversity is influenced by (1) the potential for a species to increase in number, (2) the heritable genetic variation of individuals in a species due to mutation and sexual reproduction, (3) competition for limited resources, and (4) the proliferation of those organisms that are better able to survive and reproduce in the environment. B.LS4.4:Construct an explanation based on evidence for how natural selection leads to adaptation of populations. B.LS3.2:Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

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