Natural Selection: Pre-Requisite

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Objective

Students will be able to learn the basic concepts and vocabulary of natural selection.

Big Idea

Stories are fun...but they aren't science!

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Purpose of Lesson:

The purpose of this lesson is to introduce some of the major ideas around natural selection and have some fun with some myths and stories.  I like to use stories to introduce ideas that aren't science because it helps kids talk about evidence with a topic that isn't religion.  

 

Major Strategies to Watch for:

  1. Multimedia options for stories - Check out the hook for different options for introducing the story of the Elephant child.
  2. Vocabulary Activity - This collaborative activity uses pictures, definitions, and sentences to help introduce students to important science terms.
  3. Picture notes - Picture notes are a great way to make note taking individual and approachable.

Ready. Set. Engage!

5 minutes

Learning Goal: Understand Important basic concepts about natural selection.

Opening Question: What do you already know about the terms "evolution" and "natural selection" ?

Students record their opening question on their learning goal sheet and are ready to start class 3 min after the bell has rung.  I reward students who get started early with ROCK STAR SCIENTIST tickets.  

Today, I asked students to share out loud information that they already know about evolution.  I use the information to make a word splash that I can display in the room for the entire unit and connect students to.

Follow the links to learn more about the beginning of class strategies and ROCK STAR scientist tickets

Hook

15 minutes

Today's hook is longer than I like. Generally, I like the hook to be only a few minutes. There are three different options for this hook that you can choose from depending on what you feel your students would enjoy better. They are all adaptations of Just So Stories by Rudyard Kipling.

  1. The first option is The Elephant's Child video. I like it because it is kind of old fashioned and hokey.  That matches up well with the content because we are trying to show that the ideas are old fashioned and don't have much evidence behind them. I start by asking students if they've ever heard about how the elephant got its trunk.  In my school, almost none of the students have heard this story! I ask them to look carefully for the evidence presented in the story. (There is no evidence presented.) We watch the video and then at the end of the video I talk about whether they think this story is true or not. Most importantly, I ask the students, "How do you know whether to believe a story or not?"

2. The second option is Reader's Theater, How the Elephant Got Its Trunk!  I find that students in middle school still get excited about reading plays and getting to pretend. You can easily ask some volunteers to act this out in front of the class or simply do a reading at desks. Again, at the end of the play, I ask the students whether they believe the story, what evidence they heard, and how they decide what to believe.  

3. The third option is a The Elephant's Child story. This is a great option if you have a substitute for the day or are looking for another way to put literacy into the class. Again, at the end of the story, I ask the students whether they believe the story, what evidence they heard, and how they decide what to believe.  

Vocabulary Activity

15 minutes

Now that students are excited to learn about evolution and change, it is a perfect time to introduce some vocabulary words.  I use a multimodality strategy to introduce only about five to seven words, and do this in collaborative groups of four with each person having an assigned job.  

1- Word person- states what they already know about the word or what the word means to them.

2- Image person- States what they think about the picture and what it means to them.  

3- Definition person- Reads the definition and states what it means to them.

4- Sentence Person- Reads the sentence and states what it means to them.  

I project the presentation on the board or put individual copies at the desks.  

I use a timer and a bell.  Each person gets 15 sec for their role.  In the beginning of the activity the students need to be trained on what to do and it helps to give them some sentence starters, like "This means..."  "When I hear this I think..."

After each person has rotated through their roles for the first word, I give the students 1-2 min of independent time to make their TIP charts (Term, Information, Picture) for that term. Then we move on as a class to the next term.  Later in the year, when students are familiar with the process this can be released to them to manage their time.  But in the beginning I manage the time to keep the class on track.

This work has meaning and purpose. Students keep these homemade glossaries in their folders and can use them on all the work we do in class including tests and quizzes.  This is a great resource for them to use the rest of the year!

Below is a picture of the slide for NATURAL SELECTION and a video of the student discussion.

Sexual and Asexual Reproduction

10 minutes

The purpose of this section is to help students understand the differences between sexual and asexual reproduction.

This is a very simple mini-lecture I do using a document camera and a blank piece of paper.  The students take notes in their notebooks for easy access at later points.

Instead of getting into chromosomes, mitosis, meiosis, and other complex content, I keep it very simple using shapes for the chromosomes.  This might not fit your state standards.  We used to be responsible for teaching the difference between mitosis and meiosis in Colorado, but now our standard is simply to teach the difference between sexual and asexual reproduction.  Be sure to read the state standards where you are teaching so that you will be able to adjust to the level of complexity necessary.  

During the lesson I stop and ask students questions asking that they can summarize information I have given them or predict what will happen.  A video of the lesson is below.

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Closure

2 minutes

Closing Statement:  Today we talked about stories and evidence and learned some of the basic vocabulary we will use this unit.

Closing Question: Look around the room, what variations do you see between different people in the room?

Closure depends greatly on timing and is not as easy to plan in advance as opening.  You can find more information about how I manage closure here.