Bug Buddies- Balanced Isopods

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Objective

Students will use a diagram to record the difference between selected isopods.

Big Idea

What do the differences in isopods indicate about their function and environment?

Hook

5 minutes

In our next Science unit, we’re going to learn about something you see every day.”  I give them a hint, “First, I want you to lay down flat.  Next, as soon as you hear the bell, I want you to curl up really fast!  Ready..set..go!”  I give them about ten seconds to explore the feeling of laying down and quickly curling up before I ring the chime to get their attention.  I ask, “Anyone have an idea?  “Noooo”  So I announce…..“BugsBugs do thatWe’re going to exploreIsopods’.  Everyone ready?”.

Large Group Instruction

15 minutes

I begin by introducing the term,  “Isopod is a type of bug.  Let’s practice saying it..’i..so..pod’ ” I say slowly.  “Isopod”  “I wanted you to practice the word because it’s a specific kind of bug.  ‘Iso’ means equal and ‘pod’ refers to foot.  So ‘iso-pod’ means ‘equal-foot’, all their legs/feet are equal/same.  Pretty cool how we can break down words to figure things out, huh?”  Since this isn’t a Latin or Language lesson per se, I keep it simple.  I do though, like to quickly give what I like to call ‘stealth lessons’ to set a very basic foundation to future vocabulary.  You never know what will stick with this age! 

So today, we’re going to study the two most common types of isopods that we see around here- pill bugs and sow bugs.  They have several things in common, and some very important differences.  Let’s curl up again.”  This quick activity acts as valuable kinesthetic learning, along with a movement break.  I give them another ten seconds.  Any more and it could quickly get out of control (or maybe that’s just my class…).  After the time is complete, I ask them to sit again on their carpet squares.  As I begin to talk, I pass around a picture of a pill bug.  “The isopod we were just imitating was the pill bug.  It’s small and curls up, both to defend itself and conserve- that means ‘save’- moisture.”  While I aim to always use correct scientific terms, I translate them to give context. 

Now lay flat again.”  Again, I make it quick.  I pass around a picture of a sow bug.  “This flatter isopod is a sow bug.  It’s usually a tiny bit bigger than a pill bug but as you can see in the picture, much more flat in structure.  Let me share two other really cool things about isopods.  First, who remembers what is special about their legs?”  “They match!”  “Exactly, their legs are all the same and they synchronize- move at the same time- the movementThe other cool thing it they have gills, like a…”  “Fish!”  “Indeed they do.  And the function is exactly the same.  They use it to...”  “Breathe!”  Pictures speak louder than words, so I pass around a picture that shows the underside of a sow bug so they can really visualize the leg and gill structure. 

As it turned out, this was a nice way to review prior instruction, as well as connect it to the new subject matter.  Since they’ve been sitting for a long time during this long stretch of instruction, I felt it was time to get them back to their tables for a quick drawing activity.  

Individual Instruction

15 minutes

I ring the chime and said “We’re going to go back to our tables and create a scientific diagram of these two Iso….”  “Pods!”  "Naturalists like Charles Darwin did this to help remember what the observed. Head back to your tables now and we'll get started.”  I wait until they all sat down before I continue the directions.  “I want everyone to look at the ends of your fingers.  That’s about the size of a pill bug and sow bug.  So to get the shape right, the first thing you can do it carefully trace the end of your finger.  Next, draw their legs.  Each of these bugs has approximately ten to twelve legs, along with antennas near the head.”  Despite my research, there was no definitive answer of the number of legs so I felt- for the purposes of this lesson- approximation would be fine.  “The last thing is to give your isopod the accurate color.  A pill bug is usually dark grey, like in the picture.  A sow bug can be a variety of colors though the ones we usually see are a light grey or brown.  If you need some extra help, go ahead and look either at the pill bugs in the container on your desk or isopod pictures..or both.”  I post both pictures on the whiteboard at the front of the room, in full view of all the students as they work at their tables.  This lesson was later in the Fall and the weather had cooled down quickly, so there weren't as many isopods as expected.  Since living examples are valuable learning opportunities, we make good use of our small but mighty number, who happily help us learn.

I leave the students to their drawing activity, which will act as a formative assessment.  As I circulate, I ask questions to help them adjust their drawings, add any missing structures, and explain their reasoning.  After five minutes, I give them a three-minute warning with the chime.  Once they complete their drawing, they have another minute to have a brief discussion at their table and share ideas.  As that winds down, I again ring the chime.  I ask the students to bring their drawing when they return to their carpet squares to talk about our lesson and share their observations.

Wrap Up

5 minutes

I have the class share their ideas, “Who noticed something different between these isopods?”  “One was flat.”  “The color was different.”.  As each idea was shared, I added it to a quick list to be used in the next lesson.  After all ideas were recorded, we review the contributions before it was posted near the Science area so the students could refer to it during future Science lessons or drawing/writing activities.  I dismissed students by table group to put away their drawings and return to their carpet squares.