Unveiling Evolution: Evidence from Structure, Microbiology, and Direct Observation

Biology Grades High School 12:58 Video
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Lesson Description

Explore the compelling evidence supporting the theory of evolution, examining structural similarities, microbiological insights, and real-time observations of evolutionary processes.

Video Resource

Evidence for evolution | Common ancestry and phylogeny | High school biology | Khan Academy

Khan Academy

Duration: 12:58
Watch on YouTube

Key Concepts

  • Homologous Structures
  • Fossil Record
  • Microbiological Evidence (DNA similarities)
  • Direct Observation of Evolution (Antibiotic Resistance)

Learning Objectives

  • Students will be able to identify and describe different types of evidence that support the theory of evolution.
  • Students will be able to explain how homologous structures and the fossil record provide evidence for common ancestry.
  • Students will be able to describe how microbiological evidence, such as DNA similarities, supports the theory of evolution.
  • Students will be able to explain how direct observation of evolution, such as antibiotic resistance in bacteria, demonstrates evolution in action.

Educator Instructions

  • Introduction (5 mins)
    Begin by showing the Khan Academy video 'Evidence for Evolution'. Briefly introduce Theodus Dobzhansky's quote and its significance in understanding biology through the lens of evolution.
  • Structural Evidence: Homologous Structures (15 mins)
    Discuss homologous structures using the examples provided in the video (human forearm, dog leg, bird wing, whale fin). Emphasize the similarities in bone structure despite differences in function. Ask students to brainstorm other examples of homologous structures. Explain how these similarities suggest common ancestry.
  • Structural Evidence: Fossil Record (15 mins)
    Explain how the fossil record provides a timeline of evolutionary changes. Use the horse evolution example from the video to illustrate how fossils show gradual changes in species over millions of years. Discuss the techniques used to date rock strata and fossils.
  • Microbiological Evidence (15 mins)
    Discuss DNA similarities and shared processes (DNA replication, transcription, translation) across different species. Present the data on genetic similarity between humans and other organisms (chimpanzees, mice, yeast). Explain how this evidence supports the idea of a common ancestor and evolutionary relationships.
  • Direct Observation of Evolution (15 mins)
    Explain how antibiotic resistance in bacteria is an example of evolution happening in real-time. Discuss the process of natural selection leading to the proliferation of resistant bacteria. Relate this to the flu virus and the need for new vaccines each year.
  • Conclusion (5 mins)
    Summarize the three types of evidence discussed and reiterate the importance of understanding evolution in the field of biology. Encourage students to further research specific examples of evolutionary evidence.

Interactive Exercises

  • Homologous Structures Matching Game
    Provide students with images of different animal limbs or structures and ask them to match homologous structures based on their underlying bone structure, demonstrating the structural similarities despite functional differences.
  • Fossil Timeline Creation
    Have students create a timeline showcasing the evolution of a specific organism (e.g., horse, whale) using information from the fossil record. They should include key fossils and the approximate time periods they lived in.

Discussion Questions

  • How does the concept of homologous structures support the theory of evolution?
  • Why is the fossil record considered a strong piece of evidence for evolution?
  • How do DNA similarities between different species provide evidence for common ancestry?
  • Explain how the development of antibiotic resistance in bacteria demonstrates evolution in action.

Skills Developed

  • Critical Thinking
  • Data Analysis
  • Scientific Reasoning
  • Evidence-Based Argumentation

Multiple Choice Questions

Question 1:

Which of the following best describes homologous structures?

Correct Answer: Structures with similar ancestry but not necessarily the same function.

Question 2:

The fossil record provides evidence for evolution by showing:

Correct Answer: Gradual changes in species over time.

Question 3:

What type of evidence for evolution is provided by comparing the DNA sequences of different organisms?

Correct Answer: Microbiological evidence

Question 4:

Antibiotic resistance in bacteria is an example of:

Correct Answer: Direct observation of evolution.

Question 5:

Which scientist's quote emphasizes the importance of evolution in understanding biology?

Correct Answer: Theodosius Dobzhansky

Question 6:

What does the term 'ontogeny recapitulates phylogeny' refer to?

Correct Answer: The evolutionary path of an organism is traced in its embryonic development

Question 7:

According to the video, what percentage of genes do humans share with yeast?

Correct Answer: 26%

Question 8:

Why must the flu vaccine be updated every year?

Correct Answer: The flu virus constantly evolves.

Question 9:

What does the term 'homologous' refer to in the context of biology?

Correct Answer: Structures that have similar structure, position, and ancestry but not necessarily the exact same function.

Question 10:

Which of the following is an example of structural evidence for evolution?

Correct Answer: Homologous structure

Fill in the Blank Questions

Question 1:

According to Theodus Dobzhansky, 'Nothing in _________ makes sense except in the light of evolution.'

Correct Answer: biology

Question 2:

Structures that have similar structure, similar position, similar ancestry but not necessarily the exact same function are called _________ _________.

Correct Answer: homologous structures

Question 3:

The _________ _________ provides a timeline of evolutionary changes.

Correct Answer: fossil record

Question 4:

Humans share approximately 26% of their genes with _________.

Correct Answer: yeast

Question 5:

_________ _________ in bacteria is a direct observation of evolution in action.

Correct Answer: Antibiotic resistance

Question 6:

The study of microorganisms, is known as _________.

Correct Answer: microbiology

Question 7:

The process by which the environment selects for advantageous traits is called _________ _________.

Correct Answer: natural selection

Question 8:

Scientist Ernst Haeckel famously claimed _________ recapitulates phylogeny

Correct Answer: ontogeny

Question 9:

Evolution is defined as a heritable change of _________ over time.

Correct Answer: traits

Question 10:

_________ is the molecule that contains the instructions for all known forms of life.

Correct Answer: DNA

Educational Standards

B.LS4.1:Communicate scientific information that common ancestry and biological evolution are supported by multiple lines of empirical evidence. B.LS4.4:Construct an explanation based on evidence for how natural selection leads to adaptation of populations. B.LS1.1:Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells.

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