Data Analysis in a Natural Selection Simulation

+/-1 SEM bars added

I really like the HHMI Biointeractive activity “Battling Beetles”. I have used it, in some iteration (see below), for the last 6 years to model certain aspects of natural selection. There is an extension where you can explore genetic drift and Hardy-Weinberg equilibrium calculations, though I have never done that with my 9th graders. If you stop at that point, the lab is lacking a bit in quantitative analysis. Students calculate phenotypic frequencies, but there is so much more you can do.  I used the lab to introduce the idea of a null hypothesis and standard error to my students this year, and I may never go back!

 

We set up our lab notebooks with a title, purpose/objective statements, and a data table. I provided students with an initial hypothesis (the null hypothesis), and ask them to generate an alternate hypothesis to mine (alternative hypothesis). I didn’t initially use the terms ‘null’ and ‘alternative’ for the hypotheses because, honestly, it wouldn’t have an impact on their success, and those are vocabulary words we can visit after demonstrating the main focus of the lesson. When you’re 14, and you’re trying to remember information from 6 other classes, even simple jargon can bog things down.  I had students take a random sample of 10 “male beetles” of each shell color, we smashed them together according the HHMI procedure, and students reported the surviving frequencies to me.

Once I had the sample frequencies, I used a Google Sheet to find averages and standard error, and reported those to my students. Having earlier emphasized “good” science as falsifiable, tentative and fallible, we began to talk about “confidence” and “significance” in research. What really seemed to work was this analogy: if your parents give you a curfew of 10:30 and you get home at 10:31, were you home on time? It isn’t a perfect comparison, and it is definitely something I’ll regret when my daughter is a few years older, but that seemed to click for most students. 10:31 isn’t 10:30, but if we’re being honest with each other, there isn’t a real difference between the two. After all, most people would unconsciously round 10:31 down to 10:30 without thinking. We calculated the average frequency changed from 0.5 for blue M&M’s to 0.53, and orange conversely moved from 0.5 to 0.47. So I asked them again: Does blue have an advantage? Is our result significant?

Error bars represent 95% C.I. (+/- 0.044) for our data.

Short story, no; we failed to reject the null hypothesis. Unless you are using a 70% confidence interval, our result is not significantly different based on 36 samples. But it was neat to see the interval shrink during the day. After each class period, we added a few more samples, and the standard error measurement moved from 0.05 to 0.03 to 0.02. It was a really powerful way to emphasize the importance of sample size in scientific endeavors. 

Should the pattern (cross-cutting concept!) hold across 20 more samples, the intervals would no longer overlap, and we could start to see something interesting. So if anyone has a giant bag of M&M’s lying around and you want to contribute to our data set, copy this sheet, add your results, and share it back my way. Hope we can collaborate!

Email results, comments, questions to Drew Ising at aising@usd348.com or drewising@gmail.com

–Versions of Battling Beetles Lab I’ve Tried–

HHMI Original

My “Student Worksheet” Edit

Lab Instructions Google Doc

Lab Notebook Intro. from 2017-18

Lab Notebook Data from 2017-18

How Evolution Gave Us The Human Edge

Click on the image above to access this unique NPR Resources containing

  • 4 Interactives on Brewing a Human, An Upright Primer, Lost Cousins and Fossil Forensics (the last two are a small portion of the Smithsonian Human Origins Initiative)
  • A collection of 20 NPR audio stories previously broadcast on Morning Edition or All Things Considered that provide an eclectic and pretty comprehensive prespective on human evolution.  Topics include, skin color, walking and running, tools and weapons, diet, brain development, talking and language, culuture and belief systems.

I have not used this resource in class having just noticed it while preparing my previous post on the NPR Science site.  If you have used it before and have particular suggestions on its integration please share your experiences with a comment.

Energizing Evolution

it, as well as our understanding of it, just keeps going and growing and going…

During the holiday break, I have come across a number of valuable resources (video, audio, and paper) for demonstrating to students that the processes of natural selection and speciation, that Darwin made us aware of 150 years ago this past year, are actually occuring before our very eyes.  

Instead of hypothetical just-so-stories, these resources are user friendly and thought provoking real world examples with organisms and adaptations that students can relate to.  These examples also highlight the work of the people, and the personalities, behind the acquisition of new scientific knowledge.  I commend these scientists and numerous others who understand the importance of communicating science to a sometimes skeptical public and whose efforts have provided us with these wonderful resources and springboards for learning.

 Lizards

Read on to find out about these 7 resources…

Continue reading “Energizing Evolution”

Avida-Ed: Exploring Evolution in Silico

At the NABT Conference in Atlanta in the fall of 2007, Brad Williamson talked me and a few others who were loitering around to come to a workshop presentation on Avida-Ed software as a means of fostering inquiry of evolutionary processes.  After the presentation, Brad suggested that I write a post about the experience.  At the time, I didn’t have much to say.

Having had time to play around with Avid-Ed and to make my way through most of the unedited model lessons downloadable from the Avida-Ed website, I have decided to make the post.  The best place to start is to download the software developed by Robert T. Pennock from the Avida-Ed website at Michigan State University, and to read the Discover magazine article written by Carl Zimmer highlighting Robert Pennock’s development and use of the research version of the software to study the process of evolution (The first activity below has pre-activity questions that require students to read this article).  The links below will get you that far.

  1. Avida-Ed Website
  2. Testing Darwin by Carl Zimmer in February 2005 edition of Discover magazine.

If you are a self learner, after downloading the Avida-Ed, open it, drag the @ancestor into the black area of the Petri Dish window to the right, select the play button, and have fun.  Otherwise, keep reading…

Well, as I said, I have had the time to make my way through the unedited model lessons posted on the Avida-Ed website.  In effort to prepare to introduce my freshman honors biology and AP Biology student for the software, I have cut and pasted, edited, and created (in some cases) more detailed step-by-step instructions for the activities presented in their models lesson.  In a few cases, I have even collected and attached data in a teachers section at the end of the student friendly documents that help you understand what the students will be doing prior to your own exploration of the software.

Explorations in Evolution Series

  1. I – Introduction to Avida-Ed
  2. II – Observing an Instance of Evolution in Avida-Ed
  3. III – How do Resource Availability & Mutation Rate influence Avidian Fitness?
  4. IV – Observing Mutations in the Genomes of Evolving Avidians
  5. V – Common Misconceptions of Evolution

I look forward to your comments and criticism of the activities but realize that I am just beginning to use these activities in my class for a second time.

As a justification for activities such as these, if you take the time to read the Bio2010 published by the National Academies as well as the most recent bulletin from HHMI (read Thinking like an Engineer and Add 56), you will quickly learn that we should be doing more to motivate our keen biology students to appreciate the importance of other scientific perspectives (mathematics, computer science, physic and engineering).  Similarly, we should be reaching out equally to those that are already bent toward study in these other fields and show them that they can fulfill there interests while helping to make new discoveries in the biological sciences.

Download the non-education version of Avida.

Enjoy!

Nature’s Evolutionary Gems

A pdf Resource for Teachers wishing to spread Awareness of Evolution by Natural Selection

darwinnatureimage1
www.nature.com/evolutiongems

In this celebratory year of the Birth of Charles Darwin and the publication of his On the Origin of Species, it is fitting that the January 1 issue of the journal Nature announces a document “for teachers and others wishing to spread awareness of evolution by natural selection.”  The document is accessible at the link above, which forwards one to a seventeen page pdf file

The document includes student-friendly “editorial introductions” to 15 papers that have been published in Nature during the past decade.  These papers were selected “to illustrate the breadth, depth and power of evolutionary thinking”, and cover natural selection from the perspectives of the Fossil Record, Habitats, and Molecular Processes.  The specific titles are given by clicking the more link at the end of this post. 

Each abstract is formatted to a single page, and is followed by a link to the orginal paper, links to additional resources (which may not be accessible), and a link to the website(s) of the author(s).  For those that don’t have a subscription to the journal, many of the links to abstracts of the original research papers provide access to the full text and a freely downloadable pdf .  Happy readings!

Nature, thanks for compiling this fitting and freely available educational resource!  It is a wonderful New Years Gift!

Continue reading “Nature’s Evolutionary Gems”