Flatworm sex

Sex.  It's how babies are made.  Whenever a student asks about sex in class I always begin my answer the same way:  "When two people/lions/jellyfish/etc. love each other very much, the engage in a special hug...(pause)...and then babies come out!"  But the truth is that not only is love not always a part of it, other individuals are not always involved.  Critters can reproduce many different ways, and students are often surprised to find that the world of animal reproduction is incredibly diverse.  

Below is an excerpt from the Zoology/Evolution text that I wrote.  It deals with one of the many methods of reproduction and it involves flatworms, or to use their correct phylum name, Platyhelminthes.  The students have already read the previous section of the chapter dealing with the flatworm's incomplete digestive system and a few other physiological tidbits, but this is the bit that I normally get the biggest response from.
  

 Flatworms can typically reproduce sexually, but they are mostly hermaphrodites which means both types of sex organs are present in each organism.  This is a great adaptation and makes reproduction so much easier.  Let me explain.  Imagine that you are a male worm and in the mood for a little reproduction.  You cruise out into your little part of the puddle in the hopes that you might meet the female worm of your dreams.  You know the kind - all flat and sexy.  Anyway, your little auricles tell you that there is another flatworm a few centimeters to your left and you begin your long crawl over to her.  On the way over you are working on your lines, fixing your pharynx so it is not dirty from your latest dinner/poop, and, in general, getting ready to mate.  When you get over to her you begin the courtship process and are immediately pushed off because the love of your life happens to be rather more male than you had expected.  You might find that you enjoy this other male's company and that you even support the same wormy soccer team, but alas, tonight is about reproduction and another male simply will not help in this matter. 

So you move on to the next worm in the pond who also happens to be male.  The same is true of the next 3 worms you try your little wormy pick-up lines on ("Hey there - I couldn't help but notice the cleanliness of your mouth/anus and I was wondering...").  Hopefully you are starting to see that it can be a bit of a problem to find a mate if the population is split into males and females.  With hermaphrodites you don't have to find a female worm or a male worm, you simply have to find another worm.  All worms are potential mates.  Not that they will all be willing to mate with you, but the possibility is there.  This is especially helpful if you happen to be a parasite and are literally stuck to a space on the intestinal wall. 

It is a little shameless self promotion, but if you like this sort of thing and are looking for something that is entertaining and informative, check out the rest of the text that I wrote for my Zoology/Evolution class at my store on Teachers Pay Teachers.  Available here.    

  

Correlation and causation

Often things appear to be connected but aren't really. For example, the sun rose after I got up this morning, so clearly I cause the sun to rise.  Just because two variables change with each other doesn't mean that one is causing the other.  This correlation-causation mixup happens all the time and the most obvious current example is the controversy surrounding vaccines and autism. For the record, there is no connection between the two, but many people are concerned of the alleged causal relatonship and have stopped vaccinating their children. 

Here are two tongue- in-cheek examples of correlations that you could use to help students understand this concept. 

1:1 Computing - Data Analysis and Climate Change

I love this comic.  In the past few weeks I have heard at least 3 impromptu lectures, normally at top volume, on the general theme of "WOW IT'S COLD OUT!  SEE?  CLIMATE CHANGE TOTALLY ISN'T REAL!  STUPID SCIENTISTS!  HAHAHAHAHAHA!"  This comic does a great job of explaining why that sort of statement doesn't make much sense.

People, by their nature, are not normally very good at looking at long range problems.  If it isn't something happening right now then it probably isn't going to get much attention.  Because of this, humans are always going to struggle with concepts like Climate Change and Evolution because neither of them are happening right now.  Well, technically they are but the results aren't immediately visible.

Students, being people, also have this problem.  Students, being teenagers, also have additional problems like acne, the girl that sits in front of them in Algebra, soccer practice, prom dates, what to do on the weekend, who they hate this week and, of course, their parents.  With all of these additional problems it makes it incredibly unlikely that they will pay attention if you are telling them things unless those things will immediately impact them.  All teachers have experience with this to some extent.  "There is a test on Friday," isn't nearly as likely to drive the students to study as "There is a test tomorrow." Additionally, "There is a test in 6 minutes," is where you will see the most studying, mostly by students who ignored the first two statements.

It is for this reason that I have taken to not telling them about climate change.  Oh, it isn't as if the

subject isn't in my curriculum - it totally is and it takes up about 2 weeks of our time - but I don't normally lecture on it until the end of the unit.  It has been much more effective to have them look at the data for themselves and come to their own conclusions.

The activity I use takes one of two forms.  Before each student had a chromebook I would give the students printouts of actual data sets from NOAA, The Hadley Centre, the World Bank, and others and ask the students to make several different graphs of the data.  For example, one of the graphs would be from the Hadley Centre data on temperature anomalies of the past century while another graph was from the World Bank data on oil consumption since the 1960's.  The students make graphs, compare the data, and determine if there is a relationship between the two data sets.  This is repeated for the Hadley Centre data and the atmospheric carbon dioxide levels from NOAA and for all of the other data sets.  I would then ask them to write up their conclusions on how the variables are related to each other.

Now that each student has a chromebook I share the data sets with them using Google Drive and ask them to make the graphs using Google Sheets.  They then transfer these graphs to Google Docs and then do their variable analysis there.  So much simpler!  Also,since I totally love using these computers in my classroom, I have modified this activity for my Advanced students so that after they have made the graphs from the available data sets they must then go find alternative sources to determine if multiple data sets match up.  This requires quite a bit more time and a lot more work from the students (and me!) but it is worth it.

Whichever method you use, it gives the students practice making and analyzing graphs which is a big part of the Next Generation Science Standards, and it helps them become familiar with real world data sets.  Also, hopefully the next time someone starts in on a grocery store checkout line lecture about cold weather and climate change, the students will have enough experience with the vast amount of data supporting the facts of climate change to know enough not to listen.     

1:1 Computing. The Two Column Notes Sheet

In the second part of this series, I figured I’d just jump right in with an example of something that I use in my classes.  It is simple to use and incorporates the Chromebooks or Laptops into your classroom in a way that avoids the whole “my principal told me I have to use these things so I am gonna do it whether it makes sense or not” feeling of some other activities.

In my zoology class, students spend quite a bit of time watching videos from the series “Inside Nature’s Giants”, many of which can be found on YouTube.  I have them watch these videos for three main reasons.  First, it is a great way to show dissections performed by top notch scientists and to expose the students to real dissections of large animals we could never fit into a high school science lab.  The camera work is amazing and, if you can get past a bit of blood and guts, you get to see things like the entire digestive system of an elephant laid out on the floor.  

Second, and this is a big one for a group of students who have never really studied evolutionary biology, they are not shy at all about discussing the evolutionary history and adaptations of these organisms.  Each episode normally features a few minutes on the ancestry and environmental changes that led to the critter we see today.  They also do an amazing job of showing things like the 15 foot long Laryngeal Nerve in a giraffe or the evolution of shark teeth from scales in the episode on the Great White.  

Third, in at least two episodes one of the main anatomists on the show, Joy Reidenberg, climbs in a freaking whale.  You read that correctly.  She climbs in a whale.  In.  A.  Whale.  

Totally cool.

Anyway, I have them watch these as a primer for the animal they are going to dissect the next day.  For example, we watch the episode on the Giant Squid before we dissect a squid, and I show them the episode on the Great White shark before we dissect the dogfish shark.  This gives them an opportunity to compare and contrast the large animal on the video with the one on their dissecting tray.  This comparison is, in fact, the primary thing I look for in their dissection write-up.  

Watching the videos also gives them a chance to work on picking out relevant details.  Sometimes I  just have them watch and take notes about what is interesting. (Holy cow!  That lady just climbed in the whale!)  Other times I have a more specific reason for watching like “pick out adaptations and evolutionary trends that allow the alligator to live both in the water and on land”.    

While watching the video I have them work on a document called the Two Column Note Sheet.  This note sheet, pictured below, has two columns:  a column designated for notes and a column designated for other things.  In the first column the students will type out anything that seems interesting or relevant to the main point of the video.  They fill this part out while watching the video.  

The second column is for images, video links, or any other information that might be useful in helping them understand their notes.  I encourage them to go wild in this section because it is digital they are not wasting any paper or printer ink.  This not only encourages the students to engage with the material on a deeper level than had they simply taken the notes, it also allows me to see what sort of connections the students are making.  It is sort of a quick check to see if they are thinking about the material of just finding pictures.  For example, one student wrote about shark tooth evolution in column 1 and then just had a picture of a sharks tooth in column 2.  A second student had the same note about tooth evolution  but had several pictures of teeth ranging from sharks, crocodiles, dinosaurs and humans.  This second student had also written “...all from the same ancestor?” in the area below the picture.  The first student didn’t think much about the concept beyond the obvious, while the second student was clearly looking to the larger pattern.

The last part of the two column notes sheet is the summary box.  In this box I ask them to write a few sentences to tie together their notes from column 1 and the pictures and links from column 2.  I’m not looking for anything fancy here, just a few complete sentences that show me that they are thinking about what they just watched.

There are many other benefits to using Chromebooks and laptops in the classroom and I will expand on a few other activities in the next part of this series.  

To get your very own copy of the two column notes sheet, click the link below and make a copy of it.

Link to Google Doc version of Two Column Notes Sheet.   

1:1 Computing - It's Kind of a Big Deal

Technology is amazing.  My son, who shall remain nameless until I forget that he is supposed to remain nameless, is fascinated by Egypt.  He is currently reading a series of books called the Kane Chronicles (I think) which centers around a few kids (Calvin and Sadie?) who are descended from pharaohs (I think) who battle the old Egyptian gods (maybe?) in order to save the world.  The abundance of Egyptian references in the books has made him curious about that part of history and now he is always asking me questions I can't answer.

"Siri," he says after grabbing my iPhone.  "Show me a picture of Anubis because my dad has no idea what he is talking about."  I may or may not have deserved that little dig, but due to the fact that in the previous 5 minutes I had told him Anubis was part shark and part octopus, and that there was a movie based on the legend of when Anubis ate a helicopter while it was flying over the ocean, I probably did.  I like to keep my kids on their toes.     

Anyway, Siri completed the search and came back with pictures and information about Anubis which immediately called into question my version of things.  So now my kid doesn’t trust me anymore.  Not that he should, what with all the stuff I make up, but it still hurts.  

The point I am trying to make is that this child of mine, who until 2 years ago still occasionally put his underpants on backwards, is now able to lecture me about Egyptian gods.  And I am totally OK with that.  It makes life more interesting, certainly, but it also means that he is becoming well prepared for this time in which information is always at our fingertips.  He knows he doesn’t have to believe everything he hears because he can always check for himself.  

Technology makes this sort of thing - the quick, real-time research to find something out - significantly easier than it used to be.  This is the sort of world in which our kids and our students are growing up.  The age of memorizing the periodic table or the steps in the Calvin Cycle is over because, as the old iPhone ads used to say, there is an app for that.  When you pull out the tiny rectangle from your pocket that is typically always connected to the internet, you have no excuse for not knowing the atomic mass of Xenon or when Lincoln was president.   

This is a frightening time for some teachers because it means the old way of doing things is on its

way out, even before we really have a new way of doing things.  Teachers are no longer the ones who dispense knowledge to help fill the little sponges that sit in their desks.  Technology, like cell phones and laptops in the classroom, present a significant adaptive challenge because they change the rules of the game.  Those sponges don’t need us to fill them with facts anymore because they have access to the collective knowledge of the entire human race.

What makes things a bit more interesting is that many schools are embracing this new paradigm and are issuing laptops to each and every student.  No longer are the students stuck using a 3G network to correct their teachers, they can now do it using the school’s WiFi network.   My school has been running a Chromebook pilot program (full implementation in 2014-2015 school year) and I have been lucky enough to be a part of it.  In the past year I have used the Chromebooks in my classes and there have been a few times when they have been a bit of a nuisance.  The vast majority of the time, however, I have found them to be a valuable tool in teaching my students.  

What is a teacher to do when the kids can access all of the facts without us?  Is technology in the classroom something to be worried about or embraced?  In this series of posts I’ll give my opinions on these and other questions, as well as offer (hopefully) helpful suggestions as to how you can use the little machines in your classroom.

If you have any comments or questions, feel free to share them.