Fun Approach to Teaching DNA Structure

Teaching AP Biology students has many challenges, one of them being that by the time my typical student reaches me they are 3 years removed form freshman biology. As much as they may tell you that they already know something, or “We learned this freshman year”, that does not always translate to “we REMEMBER this from freshman year”. Finding new and fun ways to reintroduce concepts to these students is a challenge that I enjoy.

I have the luxury of having a class set of the 3-D Molecular Designs “DNA Discovery Kit” models. This allows me to have each lab group (4-5 students) use their own kit in this activity.

First, I give the groups each a kit and tell them…well, very little.

I say:

Each group gets one “puzzle” and your challenge is to be the first group to successfully put it together. You must use every piece, and it must be free standing on the provided stand.

Then they begin. Now, I don’t even tell them that it is a model of DNA. Most of them figure that out (especially since it says “DNA model” on the box the model comes in) but knowing that it is DNA does not always translate to being able to quickly assemble the model. Students quickly figure out that they do not know the structure of DNA as well as they thought they did since the “already learned this freshman year”.

Many groups start by just fidgeting with pieces to see how they fit, nitrogen bases get paired up pretty quickly and then we hit some snags and the real learning starts to happen as they begin to problem solve. At this point, many groups will attempt various strategies to get the pieces on the stand. this helps them start to figure out how the components of the nucleotides fit together.

The most successful groups will put together full layers first (two full complimentary nucleotides) and then assemble them on the model. At this point they start to make comments about how each side seems to be pointed in a different direction! The groups that figure it out will then start to push through and their models come together quickly.

I will make sure the first group knows that they “won the race” and sometimes have a prize. Then I will begin to give a few suggestions or tips to the struggling groups to get them rolling.

New thing I did this year:

After everyone is done, I had them all look at their model with a piece of paper and pencil and BY THEMSELVES write down 8 characteristics of DNA that their model shows. This gets challenging once they get to 6 or 7. Next, they work in their groups to create a master list of 10 characteristics. Third, I have them infer a purpose for each characteristic. Finally, I will have the group choose what they feel is the most important characteristic and then share that with the class. This is a good opportunity to have a more guided discussion with the class about the characteristics of DNA and the reasons or purposes for these characteristics.

In my experience, this is an activity that the students seem to enjoy AND students do tend to reference the model in subsequent class periods as they work further through our molecular genetics unit and evidence from student assessments supports that this at least has not discouraged student understanding.

This year, after the activity I had a student very excitedly ask if they could put ALL them models together into one BIG strand. YES, of course we can do that! It …sort of worked. (Pictured at the top)

Teaching Animal Locomotion

It may be coincidence that two Blue Valley North teachers have posted here this week.  …ok it’s not. Daniel just motivates me to be a better teacher…and post more on here… and I love that.

So, on to the point of my post.  Nothing too profound or Earth changing here, just a fun and interactive way to teach your students about animal locomotion.  I had an idea last school year to find a more interactive way to teach my zoology students about how various animals moved. It came late in the year so we had already made it through most of the animal kingdom and were working on reptiles.  I have silly ideas floating around in my head to try this with other inverts as well in order to help students make comparisons between animal groups but have not done so yet.

We study four basic types of snake locomotion in my class.  Rectilinear motion, Lateral undulation, Concertina motion, and Sidewinder motion. Looking at diagrams and hearing someone lecture about it can be a bit bland, and frankly difficult for students to make connections to the purpose of the various types for the animals. To help with this I have my class become the snake.  Standing in a line, hands on the shoulders of the person in front of you the class works together as one snake. Each person (aside from the head) acts as if the muscles in the snake might in order to propel the snake forward through the environment. Then the class (snake) follows a few basic rules for that type of locomotion and attempts to work their way through an obstacle course of desks I have set up the in the classroom.

I like to add a little friendly competition in the mix just because it always seems to help motivate many of my typically unmotivated students.  …and it’s fun.  I will time each group as they move thorough the classroom and then compare their times with the other classes.  This year the winning class earned some tasty baked goods (chocolate chip scones) that I baked the night before.  I have done this in small groups (6-8 students) and with the whole class(about 15 students). there were only 15 in my classes this year because seniors were already gone at this point.  I think any more than 15 might get a little unwieldy but might be fun to try. Some students get a bit more into it and there may be chanting, singing, motivational music…I believe the rocky theme song was played by one group as they competed last year.

Finally, here is how I do it.

  1. I have student front load with the more technical information by completing a simple reading assignment and then answering some analysis questions about the types of movement.   (We use Integrated Principles of Zoology; 16th edition)                               _Type of Snake locomotion
  2. After completing the reading assignment, we discuss and then I give instructions for the activity. I will already have set up my classroom by moving desks around to create a pathway (usually a figure 8).  It is important that students are able to reach an object with their hands (desk, wall, chair) from any point in the classroom for this to work. (you can see in the videos why).
  3. I use the “student snake locomotion” document on the projector to walk them through the various types of locomotion, one at a time.  We review type one, then line up and try it out.  Once students are comfortable with the rules than we run through the timed round.  It’s important to make sure they know you are watching for rule breakers and that breaking a rule would disqualify them from the competition.                                                                                                                          student snake locomotion
  4. After each locomotion type we record the times and then introduce the next type.                                                                                                                             ** Not sure how to add the mov files as embedded images so I hope the links will suffice.**

rectilinear

lateral undulation

concertina

sidewinder

Well, that’s it.  Just a fun way to teach about animal locomotion.  I am sure there are plenty of ways to modify this for other animal types so have at it.  Also, I am sure my documents could use a little friendly editing so have at it.  Use them as you wish. Also would probably be good to add some additional reflection piece at the end (after completing the activity) to reinforce the concepts.

Hominid Skull Analysis

hominid1

This year, inspired by previous conversations in this group about using hominid skulls in the classroom, my colleagues and I worked to develop a lab analyzing variation in hominid skulls.  The original scaffolding for the lab came from an internet find created by ENSI (my typical process usually involves taking ideas from what others have done and mushing it all together until it resembles some sort of coherent learning experience.  Sometimes it works).

The basic idea was that students would look at a variety of hominid and primate skulls, take measurements of some key adaptive features, and attempt to interpret the evolutionary significance of said adaptations/changes. The original lab seems to be directed towards students with a more complete background in anatomy.  Since we were working with freshman biology students (and our goal was not to teach expertise in anatomy) we refocused on a few key features and walked the students through each of those measurements in the lab.  Our main focus(hope), after the measurements were complete, was to have the students really think about why each of the species had the characteristics that they did and how we got to where we are today.

I began with a discussion on what a hominid was and a short discussion on human evolution.  I then showed them “Dawn of Humanity” which is an amazing NOVA special on the discovery of Homo naledi.  It’s 2 hours long so I only showed the second half that focuses on the discovery of this new species.  It is really an amazing video that shows what all goes into the discovery of a hominid.

Next, I introduced the lab and discussed the expectahominid3tions and demonstrated a few key measurements and how to use the calipers.  Then I set them free.  I had one hominid(or primate) on each lab station and had each group take all the measurements on their specimen (about 15 minutes for the first one) and then rotate to a new lab bench and start over with the new specimen.  They get quicker each time (about 8-10 minutes on average per specimen) 7 specimen in total.  You could either hominid2print out the instructions for measurements (in color would be best), or I just had them as a pdf and had the students access them with ipads.

After measurements are complete there is a 1 paragraph description of the specimen (provided by “Skulls Unlimited”) that does a nice job describing the organism.  This information, paired with the measurements are what the students use to answer the analysis questions.  I also have the students choose 1-3 key measurements that they feel early illustrate transitional adaptations to graph. (shown above)

I was a little hesitant to dig into this (get it?) at first because I am certainly no expert on hominid skull anatomy (hopefully we didn’t make any big errors in our set up but feel free to let us know if we did). However, once we got started and I saw the results I was very pleased.  As long as the students took the time to read the species descriptions and took careful measurements, they did a good job and demonstrated a good understanding of the material.  So, here you go.  From our classrooms to yours.

I hope I attached the documents correctly…

_Homonid cranium measurements STUDENT

_Hominid Bone Clone Descriptions