Vestigial Structures - Evidence for Evolution
Lesson 8 of 15
Objective: SWBAT apply scientific ideas to construct an explanation for how vestigial structures are a source of evidence for evolution.
I open by showing students this video titled Why Some Humans Are Born with Tails. It is an attention grabber, discussing one of the most common known human vestigial structures, the human tail bone.
As students watch the video, they answer the following questions:
1. According to the video, one out of thirteen people can do what just like chimps?
2. What does vestigial mean?
3. List four examples of vestigial structures.
4. What is lanugo, why is it considered a vestigial structure/behavior?
5. What was the purpose of having a third eyelid?
Teacher Note: Students will explore the vestigial structures introduced in this video during the explore section of lesson.
Now students explore 10 vestigial traits by completing an Inside-Outside Circle. (SL.8.1 - Engage effectively in a range of collaborative discussions (one-on-one, in groups, teacher-led) with diverse partners on grade 6 topics, texts, and issues, building on others’ ideas and expressing their own clearly.)
Directions: (These directions are for a class of 20 students, it might be modified by adding more vestigial traits cards to list).
1. 10 students receive 1 Vestigial Structures card.
2. Students becomes experts of their individual card.
3. Students will be outside circle for the following activity.
More detail on the Inside-Outside Circle strategy can be found in my reflection. I set it up so that the Outside Circle students explain to their inside partner what their Vestigial Structures card is about.
In this section of lesson I show students the Vestigial Structures video to give students an explanation on what vestigial structures are. (MS-LS4-2. Apply scientific ideas to construct an explanation for the anatomical similarities and differences among modern organisms and between modern and fossil organisms to infer evolutionary relationships.)
As students watch video they answer the following questions:
1. According to video what is the reason that vestigial structures came to be? In other words what changed that made theses structures of no use. (CCC - Patterns - Patterns can be used to identify cause and effect relationships.)
2. List some examples of vestigial structures.
3. What kind of information can we get from vestigial structures?
4. According to video our tail bones are not completely useless, what is one of its minor functions?
5. According to video why don't humans have a need for wisdom teeth anymore?
After showings students video I have students read an article from cK-12 titled Structural Evidence for Evolution.
Once students have completed readings students are required to answer the following questions:
1. What is a vestigial structure? Give an example.
2. How does embryology provide evidence for evolution?
3. Given an example of a structure that is present in human embryos, but has disappeared by birth?
In this section of lesson students elaborate on what they have learned by reading an article titled Scientists may have found appendix's purpose from NBC news.
To access the informational text, students use the Writing in the Margins strategy.
Writing in the margins engages readers in the reading task and allows them to document their thinking while reading. Both writing in the margins and drawing in the margins engages students in actively thinking about the texts they read. The power of this strategy is not the actual act of writing and drawing in the margins; instead, it is the thinking processes that students must undergo in order to produce such ideas.
For the purpose of this text, students focus this by using the Clarify strategy.
Clarify complex ideas presented in the text. Readers clarify ideas through a process of analysis, synthesis and evaluation. Pausing to clarify ideas will increase your understanding of the ideas in the text.
In order to clarify information you might...
Define key terms.
Reread sections of the text.
Analyze or connect ideas in the text.
Paraphrase or summarize ideas.
To close, students complete an Exit Slip where they are required to construct a scientific explanation. Students are required to explain what vestigial structures are and how they represent evidence for evolution. (RST.6-8.1 Cite specific textual evidence to support analysis of science and technical texts, attending to the precise details of explanations or descriptions./SP6 - Constructing a scientific explanation.)