What have we been up to this year? Lizards (and an innovative way to teach kids to think and act like scientists)! A recap of The Lizard Project.



This year we tried to do something that is rarely done in high school science classrooms. We did science! With the help of the National Science Foundation and our friends Dr. Fred Janzen and Dr. Dan Warner at Iowa State University, we conducted research in ecology and evolution at the level of rigor practiced by professional scientists. Our research aimed to answer the basic questions of: "For animals that lay eggs, how do mothers choose nesting sites?" and "What effect does that choice have on the physical traits of her offspring?". We used 80 brown anole lizards in 20 different enclosures (although our project grew as babies hatched!) for our experiments and throughout the project we emphasized that our questions are questions to which no one (not even an expert evolutionary biologist) has the answers to for our study species. These are the kinds of questions which working scientists work to answer.

We used the entire experiment as the framework for learning the scientific method. Students identified a hypothesis and variables in the experiment. In our first experiment, we presented the female lizards (who were housed with males to ensure eggs) with choices in the types of locations available to lay their eggs. We presented the moms-to-be with five carefully measured levels of soil moisture, both with and without plants.
Then once a week, the students in my five classes carefully sifted through all of the soil to search for jelly bean sized eggs and record the choices that the females had made as well as the mass of each egg.

For our second experiment, each egg that was found was assigned to soil with a randomly chosen moisture content. The moisture content for the soils in the incubator were the same as the five moisture choices the females had in their cages. This allowed us to collect data on how the choices the mother made (and didn't make) could have affected her offspring. Once the lizards were hatched (they are about thumbnail sized and cute as can be) we measured their size and growth carefully to see if its incubation conditions had an effect on its physical attributes.

This was a powerful learning experience for me and my students. My students and I produced products at different levels to show our learning and communicate our findings. My sophomore biology students produced lab reports, my senior zoology students produced papers in the format of a peer reviewed scientific journal and I am currently working on a paper for publication in a peer reviewed journal.

We are looking forward to producing a movie for classroom use with footage from the the lizards' wild habitat and in the classroom to share our experiences and give teachers and students exciting material to teach and learn the scientific method and data analysis. Stay tuned for more!

Keep reading to learn about The Lizard Project in the field in the estuary ecosystems of central Florida.


What science did you do down there? (Click on the photo below for a slideshow of the field work.)


Click on the picture in this post to see a slideshow of more pictures from the field.

So as you know we had 3 different hypothesis that we were testing during our time in the field down in Florida. I want to review each of those hypothesis and let you know what we did to collect data to test each one.

#1) The Brown Anole population faces different relative selection pressures in different parts of the environment.
To test this one we put out 50 clay models in 5 locations that were carefully chosen (forest, park, residential area, beach and island) and recorded all bites in the models from predators and lizards. We only got one lizard bite but we got many predator bites. We tried putting out models with and without paper dewlaps. After the first week we moved the models to new but similar locations. We also took careful photos of the shade cover where each model was placed. A computer will analyze these photos and we will check to see if the amount of cover above a model affected how often it was attacked by predators.

#2) Morphological (physical) differences exist in the lizards in different parts of the habitat.
To test this one we planned to measure hundreds of lizards (we measured more than 800) and record careful data about the locations they were spotted in. Unfortunately this part of the project suffered a bit from our high work load. We did not have time to measure carefully the locations of each captured lizard. However, we do have careful measurements for each lizard in our island experiment so when we go back to collect lizards again we will be able to see if physical differences begin to exist on the different experimental islands.

#3 Biased Operational sex ratios will affect population growth and natural selection (evolution).
To test this hypothesis we released 835 lizards on 9 different islands. The islands were not all the same size so we released them in numbers that kept population densities (lizards per square meter) the same. On 4 of the islands we released 66.6% males and 33.3% females. On 5 other islands we did the opposite. We will be going back at the end of the summer to catch babies and record population sizes. We will take DNA samples of all the new hatchlings and compare them to the DNA of the founding populations to see which males and females are having the most reproductive success.



Fine looking female and a handsome dude.




One of the questions that you guys asked was- "How do we tell the differences between male and female lizards?"

Many of you already know if you were part of our class in the first semester because we handled so many lizards in our experiment. However, if you don't know or even if you do know and just like seeing pictures of lizards, here are two photos showing fine looking examples of both a female and a male. The female is the one with the diamond pattern on her back and the male is the larger one with the little yellow spots on his side.

Thanks for all of your interest and support.


Thanks for following along with us as we worked.
Dr. Warner and I had so much fun communicating with all of you and answering your questions as we worked. We are now back home and in need of some much deserved rest. We worked extremely hard and slept very little! However, we love what we do and feel like we really did some great experiments that will give us tons of good data to evaluate our hypothesis and write conclusions to share with the scientific community.

I will continue to answer your questions and post on the blog as long as you guys are still following. This weekend I will get caught up and answer the most popular questions. If you email me a question directly at aaronmreedy@gmail.com I will make sure that I answer it. Also look for a slide show with 20-30 pictures of lizards, other animals and our work sites. I will have it all posted by Monday so you won't be bored while you are on spring break. Check back with Wide World Science soon.

Thanks again. Your posts and questions were great. You are the best.

The island experiment is fully up and running.

Today was our last day in Florida and our busiest yet. We collected all of our clay models and took careful data about their placements. We also released the final 135 lizards on 3 islands in Tomoka State Park. This brings our experiment up to 835 lizards on 9 different islands. That is a truly large scale and should give us great data on how the sex ratio effects the ecology and evolution of populations.

Moving in to a new world.

This brown anole was just released into his new home on island H. How will he do? Will he succeed in this habitat? Will he mate and father many offspring? Will his dewlap tattoo give him an advantage? These are the questions we will try to answer when we return to Florida in the summer and fall. We are not quite done yet. We still have to release lizards on 3 more islands. Stay tuned for more updates.

698 lizards now have new homes.

The lizard release was a success. We took the boat out at 7:30 this morning filled with 698 lizards. We dropped them of at our six experimental islands in the Matanzas River. Now for our 4 islands back at Tomoka State Park.