Volume 2, Issue 1 by Journal of FDR Science

JOURNA L OF FDR SCI ENCE

V OLUM E 2 I SSUE 1 December 2015 Page

WELCOM E! Welcome to this second volume of the Journal of FDR Science. The aim of this journal is to share and showcase some of the high quality student science that is occurring here at Colegio Roosevelt in Lima, Peru. I encourage you to note, as you read through the studies in this journal, that these studies represent authentic work that is original. Students devised their own question and created experiments to attempt to answer their questions. Work found here was conducted within our classes, for Personal Project as well as for Extended Essays. Special thanks must be given to our student editors who are starting to spearhead the continued development of this journal. Student Editors: - Carolina Sofia Gonzalez (Grade 11) - Savka Akester (Grade 11) - Pamela Paz (Grade 10)

This first edition of this journal would not be possible without the hard work of our teachers and lab assistants who spend time and energy coaching and advising our students. They help prepare materials, devise strategies and teach the scientific writing process. They inspire and provide opportunities for experiential learning, discovery and inquiry. They edit and encourage students through the cycle of improvement. Please join me in thanking our Science department teachers and laboratory assistants.

MS Team: Nikki Ellwood , Rae Marrigan, Rocio Malatesta and Diane Holloway HS Team: Grade 9: Amy Rebancos and Stuart Murray Grade 10: David Hoover, Leigh Petty, Amy Rebancos and Keith Herold IB Chemistry: Leigh Petty IB Biology: Gilles Buck, Stuart Murray and David Hoover IB Physics: Keith Herold IB ESS: Allana Rumble, Peter Martin and David Hoover Laboratory Assistants: Pati Moritani and Tabata Molina

Please join me in recognizing the efforts of our students whose work is showcased in this journal. They produced high quality work for their studies and then engaged in the cycle of editing and review that is necessary to have their work published. I would like to thank them for their effort and perseverance. Great job and congratulations.

Gilles Buck Editor-In-Chief Subject Area Leader Sciences IB Biology MYP Grade 10

Images used in this publication were taken by the authors of the study. Cover image and other images of Planaria were taken by senior student Gabriel Barret o.

I N THI S I SSUE Short Term Memory 04 UV Radiation & Lime Juice 11 Planarian Regeneration & UV Radiation 21 The Triple ?Tangarana?Mutualism 28 Cicada Nest Population & Man-Made Paths 34

SHORT TERM M EM ORY By: I sab el l a Fal ero, Sof i a Gumb i ner and V al eri a M uĂąi z

A BSTRA CT: Our group want ed t o find out how gender and age affect ed short t erm memory. The way we did t his was by t est ing t hree age groups, of bot h genders. To have a reliable conclusion we gat hered 10 people per group. We t est ed t hem on all five senses t o also have a view of which gender and age were st ronger in which sense. There were t en it ems for t he subject s t o smell, eat , t ouch, hear and see. Aft er each it em was given from a sensory cat egory t he subject s had 1 minut e t o writ e down all t he t hings t hey remembered in order. From t he t est result s we found out t hat overall women are st ronger in short t erm memory and t hat adult age of 30+ are overall st ronger in short t erm memory.

I NTRODUCTI ON: In t his science fair experiment we are t rying t o answer t he quest ion of how does t est ing gender and age affect short -t erm memory. We will t est t he subject s in all sensory t est s (t est of all t he 5 senses) t o see which one t hey are bet t er and worse at . Our group believes t hat women are bet t er and t hat t he youngest age group will be t he best at memory because t hey have a st ronger and fresher neural connect ion as t hey are learning and absorbing new t hings.

QUESTI ON: How does gender (different age groups) affect short -t erm memory?

BA CK GROUND I NFORM A TI ON: In this science fair experiment we are trying to answer the question of how does testing gender and age affect short-term memory. We will test the subjects in all sensory tests (test of all the 5 senses) to see which one they are better and worse at. Our group believes that women are better and that the youngest age group will be the best at memory because they have a stronger and fresher neural connection as they are learning and absorbing new things. What is memory? Memory gives us the chance to remember and learn about how we live and adapt in this world. To remember experiences and learn from facts of our past and to process the present. It gives us the power to have and build relationships , habits, impressions, and improve skills. It carries our experiences and activity by storing it in the mind with all the recognition in the activity and can be modified by behavior. It is the full knowledge that we remember.

Where is the memory stored in the brain and how? Memory is stored in the hippocampus. There are three kinds that we storage our memory. One of them is sensory memory (it gives us the ability to remember things after it happened and it's also the shortest term element of memory), there's also the short-term memory (it only last a few seconds and it gives you the capacity of to remember information for a short time), then there's also long term memory( its the memory that lasts the longest time, it can store information indefinitely). The more we use information it will most likely be part of the longest term memory.

What is short-term memory? Short-term memory also known as the post-it or scratch pad of the brain, it is the ability to remember and process a memory at the same time, it holds about 7 items or less at a time and can be remembered for 10 to 15 seconds or even up to a minute. A simple example that showcases short-term memory is math, when carrying a number in subtraction or addition your holding down to that number for a period of time. Sensory Memory: Sensory memory is the ability to keep impressions after the event has ended. It is one of the elements of the shortest-term memory. The five senses are sight,hearing, smell, taste and touch ,it involves your senses all your senses.

Does aging affect your memory? There is evidence that memory does get affected when you get older is yes, it does get affected. The reason why is because when you're younger you're cells are connecting with other cells as you begin to learn . And as you get older this connections start to fade, which affects how easily you can regain memories. This start when you get older, between your 20s or 50s. Some parts of your brain get affected more than others, one like the hippocampus, (7) According to How stuff works an article written by Richard C. Mohs, PhD every decade you lose 5 percent of the nerve cells and when you're up to your 80s you have lost a total of 20 percent. Your brain starts to shrink making it less efficient.

M A TERI A LS A ND M ETHODS for 2 seconds throughout each word 6. Tell the subjects to then write the words down in the order given, they will have 1 minute to complete this 7. Then move on to the touch test, under a cloche set 10 items, each with different textures (smooth, rough, fur, etc.) 8. Open the cloche and give the subjects 1 minute to study and touch each element, after times has passed close the cloche. 9. Tell the subjects to then write the words down in the order shown, they will have 1 minute to complete this. 10. Then comes the taste test, under a cloche give each subject 10 food items that are bitesize.

1. Print out 10 pictures of common items (house, dog, car etc.) 2. Sit the 6 subjects from one age group in a room sitting across in a row , before starting test ask if they have slept, well and what is their current mood (make sure they are all calm or happy) 3. Show each picture for a period of 5 seconds to the subjects then change the picture. Once you have shown all the pictures give them a paper and a pen and tell them to write in order the items they saw they need to complete this in 1 minute. (visual test) (Explain this process to the subjects before starting the test so they understand ?this applies to all tests?) 4. Prepare them for the hearing test. Write down a list of random words (the words should not be favorable to any gender) (avoid using words like lipstick, makeup or soccer and guns) use generic words like street, night etc. 5. Say the 10 words out loud to the subjects pausing 6

11. Give them 3 minutes to each eat food item, after they finish each food item give them a drink a water. Close the cloche. 12. Tell the subjects to then write down the food items in the order given, they will have 1 minute to complete this. 13. Then the smell test we will cover the subjects eyes and give them options of different kind of odours example a coffee, vanilla etc. 14. Give them the items to smell this will take one minute. 15. Then un-blindfold them and give them 1 minute to write down in order the various smells. 16. Then the tests are complete, collect the papers of the subjects and separate them by each person who was tested. Make sure their names and age are on the paper to organize them.

RESULTS

Our hypothesis was supported from one point and not supported by the other. With the research collected we were able to conclude that females have a slightly better use of short-term memory than men, however we found out that the age group of adults was the age that had better memory overall. The patterns that were shown in our data in genders was that gender does not really affect short-term memory as much, the numbers were really close, however it was age that showed extreme differences throughout the various sensory tests .

DI SCUSSI ON Our hypothesis was supported from one point and not supported by the other. With the research collected we were able to conclude that females have a slightly better use of short-term memory than men, however we found out that the age group of adults was the age that had better memory overall. The patterns that were shown in our data in genders was that gender does not really affect short-term memory as much, the numbers were really close, however it was age that showed extreme differences throughout the various sensory tests. Concerning the gender aspect of the memory tests women showed to be the stronger gender in memory although it was a close run between them. Women got an average of 18.7 out of 50 questions and men got an average of 17 out of 50 questions making the difference 1.7. In the graphs shown it is seen that in the visual and hearing test men were better than women. In the visual and hearing test men were better than women by .2 points however in the rest females were stronger in the other tests. In the taste test women surpassed the men by 0.9 points. In the texture test women again beat the men by .2 points and in the in the smell test women got .1 more points than the men. An uncommon observation we saw was that many of the differences between each test was by .2 points and in the taste test the amount of difference it had (0.9) was unbelievably larger than the rest of the numbers. In the age sector of the memory tests, the adults were the ones that had the overall highest scores in the tests. In the taste, texture and smell test the adults scored the highest score. The 12-13 year olds did better in the visual and hearing tests and overall the 8-9 year olds had really low scores and paid no attention, to the test, which reflected on their scores. The difference between the visual from the 12-13 year olds and the adults was 0.9. We believe this happened firstly for gender because the women?s hippocampus is larger than men's

making their short-term memory span larger. For the age sector we believe that the adults were better not because the adults are better in memory but we also feel that the level of attentions spans that the 8-9 and the 12-13 year olds had was short. They did not really concentrate on the tests and were focused on other things causing them to not really put their full focus on the test. This affected their test scores unlike the adults who were more concentrated and calmer and easier to control. Another aspect that affected our test was the experience. The 8-9 and 12-13 year olds have not had as much life experience in all the sensory tests, they do not have a job and have not lived as long as the adults. The final answer to our research question is that gender and age do affect short-term memory. Women are better in short-term memory and the adults are the better age in memory. Unfortunately, we were not able to control many variables due to the fact that we were testing people, not objects. We could not have a ?type? of person, because everyone is different making the test more difficult. Firstly, the original plan was to have 16 year olds also do our test, sadly they did not want to participate when the email was sent, making us only have three age groups. This would have added a different path to our test and could have changed all the results, as well as having a close age group instead of jumping from young adults to adults however this was not feasible forcing us to adapt to something else. Another variable we could not control was the actual subjects/people that were tested. It was impossible to have everyone in the exact same mood and we did not know if some of the picture or objects shown had an emotional or important connection to their life making them remember it better. As well as we do not know if the genetics of that family line are good at memory or they are just naturally have above average memory or have done a program for memory improvement as a kid. Although our group made an attempt to try

making the locations of the test in the same place, but it was too difficult for the adults to come all the way to school when we had already interrupted their working time, so we could not control the variable of the ?same? location. Also all of the students we tested did the test in lunch and sometimes we could not finish the test so we had to move it to another day, this could have created an effect in our data because the lighting that day might have been different and their mood might have changed from one day to another causing them to do the test differently. Having people as our testers especially for a long test of all the senses really was difficult and made us struggle with controlling all the variables. Apart from our written control variables we also realized that another factor that might have affected our data, was the nationalities of everyone. For example in the hearing test for the teens the words were said in English, but for the adults the words were said in Spanish. However, some people of that group were not native Spanish/English speakers that might have caused difficulty when remembering because it is not their first language. These various variables that we could not control at least were tried to control. They were some that could have been possible but the time we had to collect all the data was to short. We wish we could have added more experiments for each test, to make our data table bigger. We would control the variable by using the same equipment for each person that we tested. Our group used blindfolds, or a quiet environment, and the same test sheet. But things didn?t always go as planned. Some of our tests were different from the others, meaning that the food, the smells, the touch experiment and the noise level differed. For example, for the smells, we had to change them daily since we didn?t want them to rot and some of these smells when we got back home we didn?t have. The same situation was with the taste test. I believe that if we would have organized ourselves better, this problem wouldn't of been created. We believe that we did not collect sufficient data in 9

our science fair project to answer the research question because of the lack of 16 year olds we believe that, that could have changed so much in our data collection, especially because it is the age between a young adult and an adult. Naturally, the more people that take our test the more precise and narrow your results get. We were really disappointed as a group when we could not do the 16 year old age group because although it would be the most embarrassing we knew would be really the age that made out data have more differences due to the fact that they are more mature than the ages so we would have two not as mature ages and two fully matured ages. We think that was the major setback in our test that made us believe that we do not have sufficient data. The main challenge we faced during the process of this science fair project was getting the people to do our test especially the smallest kids. The adults had no complications to them, due to the fact that they were already adults. Overall sometimes the 13-14 couldn?t come to do the test because they needed to finish an assignment or they just forgot about it. The way we overcame this was by sending an email to them and telling them to please come on a specific date at a specific time and in the end they did show up and we were able to finish that age category. The most challenging part was controlling the kids ages 8 and 9 they were loud, annoying, did not respect us and were overall a real struggle to work with. They would say the answers out loud and copy from each others papers and do things that affected our data. The way we overcame this issue was basically acting like a very strict and mean teacher, we told them to be quiet then we repeated things over and over again. However, after all the frustration and screaming and annoyance we finished the test. Overall the lesson we learned is that there always is a solution to every problem even though the solution may not be the most exciting.

Ref erences "The Human Memory." The Human Memory. Luke Mastin, n.d. Web. 28 May 2015. <http://www.human-memory.net/>. "Long-Term memory." The Human Memory. Luke Mastin, n.d. Web. 28 May 2015. <http://www.human-memory.net/types_long.html>. "Short Term (working) memory." The human memory. Luke Mastin, 2010. Web. 28 May 2015. <http://www.human-memory.net/types_short.html>. "Stages of Memory - Encoding Storage and Retrieval." Simply Psychology. Saul McLeod, 2007. Web. 28 May 2015. <http://www.simplypsychology.org/memory.html>. "Who have better memories: men or women?" Encyclopedia Britannica Blog. Kara Rogers, 27 Feb. 2008. Web. 28 May 2015. <http://blogs.britannica.com/2008/02/who-has-a-better-memory-man-or-woman/>. "Men and Women's Brains Are 'wired Differently' - BBC News." BBC News. N.p., 3 Dec. 2013. Web. 15 June 2015. <http://www.bbc.com/news/health-25198063 > Mohs, PhD Richard C. HowStuffWorks. HowStuffWorks.com, n.d. Web. 15 June 2015. <http://science.howstuffworks.com/life/inside-the-mind/human-brain/ human-memory4.htm> "Gender & the Brain: Differences between Women & Men." Fit Brains Blog. N.p., 18 Feb. 2014. Web. 15 June 2015. <http://www.fitbrains.com/blog/women-men-brains/> Bailey, Regina. "Hippocampus." About Education. N.p., n.d. Web. 15 June 2015. <http://biology.about.com/od/anatomy/p/hippocampus.htm> "Memory, Learning, and Emotion: The Hippocampus | PsychEducation." PsychEducation. Word Press, n.d. Web. 15 June 2015. <http://psycheducation.org/brain-tours/memory-learning-and-emotion-the-hippocampus/> "Memory Storage - Memory Processes - The Human Memory." Memory Storage Memory Processes - The Human Memory. N.p., n.d. Web. 15 June 2015. <http://www.human-memory.net/processes_storage.html>

UV -RA DI A TI ON A ND LI M E JUI CE

BY: M I K HA I L LUJA N

A BSTRA CT The effects of using lime juice and UV Radiation as means of water purification. This was tested by exposing all 4 trials to a different set of stimuli to help answer my research question. I found out that a combination of lime juice and UV Radiation was the most effective method of water purification from my experiment.

I NTRODUCTI ON I selected this topic because water scarcity and the pollution of clean water sources has been a major international issue, especially in Lima, Peru where I live. I was researching into ways that people in impoverished areas filtered their water when I came upon an article from the WHO (World Health Organization) about using UV Radiation to purify water. Delving deeper into this specific method of water purification, I read another study on how lime juice contains a protein that inhibits biological reactions to occur. I believed that if I were to add lime juice to polluted and or contaminated water, it would stop the biological reactions (the splitting) of multiple bacteria which would then speed up the process of UV Radiation. With few experiments into this area of water purification, I decided that this would be an exciting, challenging, and worthwhile experiment. By the end of this project, I hope that I can find meaningful data that could have a major impact on the water quality of Lima and other poor areas around the world. Solar dis-infection is a method used by many poor and rural communities around the world to purify water. Solar dis-infection (or SODIS as it is more widely known as) is extremely effective in sterilizing water and has been shown to remove up to 86% of Cholera from previously contaminated water. ?This method is reported to substantially reduce the number of children falling ill to diarrheal diseases (some studies suggesting by up to 70%) and cholera (by approximately 86%)? (Burton, Adrian, 2015). It is currently being used in 24 countries around the Globe by approximately 5 million people. In addition to being a useful method for purification, SODIS leaves no residual after

purification (i.e. harmful chemicals). However, without a residual there is nothing remaining to keep bacteria numbers from multiplying and contaminating the purified water. There is recent controversy surrounding the safety of SODIS as a sole basis for water purification, as it can result in coliform proliferation. Coliform is a broad group of bacteria that fit specific parameters (i.e. rod-shaped Gram-negative non-spore forming and motile or non-motile bacteria). This occurs when small amounts of coliform multiply and become extremely numerous. An easy solution to this problem would be a second step of purification using chemicals as a safeguard to coliform proliferation yet; this would also result in the exponential growth in the cost of purification. ?As with any disinfectant, UV has its limitations. For example, because it is a physical rather than a chemical disinfectant, it does not provide a residual to control? ("Ultraviolet Radiation." 2015). This cause and effect is a major issue for any study in low-cost purification methods

as safety is an obvious key factor of the said experiment. But for the sake of simplicity, the SODIS method should be efficient in purifying most, if not all of my samples. I say this as coliform proliferation is only a major problem when sending said water into a distribution system where, if time permits, the bacteria will be able to multiply. These reasons above are why lime juice is such an important factor within this experiment. Limes contain a large quantity of molecules known as psoralens which have the ability to form covalent crosslinks between strands of DNA, therefore preventing DNA Replication for a period of time. This has been shown to drastically improve the speed of the SODIS method (on a sunny day the SODIS method takes an 13

average of 6 hours to dis-infect the water to a sufficient degree, adding lime juice to this method speeds up the process to only 4 hours before the water is dis-infected). For 2 liters of water, researchers added 30 ml of plain lime juice and let these bottles remain in direct sunlight for 6 hours ?Both lime slurry and plain lime juice, combined with SODIS, reduced E. Coli by roughly 1 million times in just 30 minutes, whereas SODIS on its own was about one-quarter as effective.? (Burton, Adrian, 2015). SODIS on its own was about one-quarter as effective. Reductions in MS2 were measured over a 2.5-hour solar exposure, with viable virus particles reduced by about 10,000 and 100 times with the lime slurry and lime juice, respectively, compared with a 25-times

reduction by SODIS alone. The MNV virus was only modestly affected by any combination of methods.?(Burton, Adrian, 2015). The only major differences between Schwab?s study and mine is the difference of times to UV exposure (my trials were left out for 4 hours while his were left out for 6) and his use of both lime juice and centrifuged lime slurry. The only similarity between our experiments was the use of E. Coli within the experiment. Given these differences we still reached a similar conclusion that the addition of lime to SODIS is very effective. Coliform Proliferation was another major area within my experiment. I did not understand the concept well t first but after some research, I began to see how large of an issue it could be. I never considered it as an issue during the experiment as it couldn?t affect my results. The only foreseeable issue would be if the water was later added to a distribution system, how could I counter Coliform Proliferation?I decided that if I were to continue this project, this would be a good area of research. It would be helpful as th ewater would usually require a chemical cleansing as a secondary step. If there is a more cost efficient method to stop Coliform Proliferation, it would make the

SODIS method safer and cheaper to people in poor areas. It would also make it a realistic method of purification for large areas that require distribution systems to transport water. That is why this would be a worthwhile continuation to my project. My data was reliable because of its similarity to other researches done on this topic. While there were a few samples that I believed had been contaminated, there was a clear result from the experiment. The result was also backed up by other major studies done on the topic and can therefore be counted as reliable. Because I added a large amount of bacteria compared to what would be found naturally, it was expected that there would be many TMC?s. That is why this data is both relevant and reliable to the real world context that I created this experiment for. There were mistakes within my experimental design that led to errors, such as the lack of professional tools such as an alcohol spreader that could have left to small errors within the data. It was also an impossibility to fully sterilize all of my equipment in the experiment which could have created more error. If the experiment were to be improved it would require all proper equipment and the full sterilization of all tools that I used in the process.

QUESTI ON What is the effect of the addition of lime juice to contaminated water (300.0ml of water) with no variations in the amount of lime juice (3.0 ml of lime juice, plus or minus 0.05ml of lime juice) on the amount E. Coli left within the multiple trials measured by the number of colonies of E. Coli that are left within 100ul of water of the mixture extracted from the experiment (plus or minus 0.5ml) in the petri dishes when the amount of water (300.0ml, plus or minus 0.5ml per bottle), the type of water (clean water with a controlled amount of E. Coli added), the amount of sunlight (UV radiation) subjected to the water, the amount of lime juice (starting from 0.0ml with an increment of 0.5ml per group, plus or minus 0.5ml of lime juice), and the number of E. Coli added to the water (1ml of water containing microbes, plus or minus 0.5ml water) are kept constant?

M A TERI A LS A ND M ETHODS 1. Using a Bunsen Burner, sterilize occultation loop 2. Take a single colony of DH5 Alpha strain of E Coli. 3. Place strain in sterile broth 4. Let the bacteria grow overnight (at 37 degrees Celsius) 5. Return next morning and prepare bacteria for experimentation The occultation loop was sterilised using a Bunsen Burner. A single colony of DH5 Alpha strain of E Coli was placed in the sterile broth. The bacteria was let to grow overnight at 37 degrees Celsius. The bacteria for experimentation was prepared the next morning.

300ml of distilled water were poured into sterilized bottles (5 bottles per trial, out of 4 trials). 1ml of broth/bacteria solution was then added to the bottles.

Repeat Trials 1 and 2 from General Requirements section of procedure 1. Add 3ml of lime juice to all bottles in this trial 2. Place bottles in darkness to minimize the amount of UV Radiation to the bottles

4. Place water in petri-dishes 5. Streak water across the petri-dishes as evenly as possible 6. Place petri-dishes in the ?oven? for one night (at 37 degrees Celsius)

(Experiment-Control Trial) General

2. Place bottles in darkness to minimize the amount of UV radiation reaching the bottles 3. After 4 hours, remove 100ul of water from bottles

7. After one night place petri-dishes in the fridge to minimize bacterial growth (Experiment-UV Trial) 1. Repeat Trials 1 and 2 from Requirements section of procedure

General

4. Place water in petri-dishes

2. Place bottles in direct sunlight to maximize the amount of UV Radiation

5. Streak water across the petri-dishes as evenly as possible

3. After 4 hours, remove 100ul of water from bottles

6. Place petri-dishes in the ?oven? for one night (at 37 degrees Celsius)

4. Place water in petri-dishes

7. After one night place petri-dishes in the fridge to minimize bacterial growth

(Experiment-Lime Trial)

3. After 4 hours, remove 100ul of water from bottles

General Requirements-

1. Repeat trials 1 and 2 from Requirements section of procedure

Trials 1 and 2 from the General Requirements section of the procedure were repeated. The bottles were placed in darkness to minimise the amount of UV radiation reaching them.100ul of water were removed from the bottles after four hours. 4-

5. Streak water across the petri-dishes as evenly as possible 6. Place petri-dishes in the ?oven? for one night (at

37 degrees Celsius) 7. After one night place petri-dishes in the fridge to minimize bacterial growth (Experiment-Lime/UV Trail) 1. Repeat Trials 1 and 2 from Requirements section of procedure

General

2. Add 3ml of lime juice to all bottles in this trial 3. Place bottles in direct sunlight to maximize the amount of UV Radiation 4. After 4 hours, remove 100ul of water from bottles 5. Place water in petri-dishes 6. Streak water across the petri-dishes as evenly as possible Place petri-dishes in the ?oven?for one night (at 37 degrees Celsius) After one night place petri-dishes in the fridge to minimize bacterial growth (Analyzing Results-All Trails)

Remove petri-dishes from the fridge Place 32 Square-Grid Bacteria Counter over petri-dish Count the number of bacterial colonies remaining (if possible) Note: If the bacterial count went past 3000 colonies, the sample was marked as TMC (Too Many to Count). On the upcoming graphs and charts all TMC?s will be treated as 3000 bacterial colonies to make graphing the data easier and more understandable for the reader.

RESULTS

DI SCUSSI ON The results of my project answered my research question, showing that both lime juice and UV Radiation had an effect on the amount of E. Coli left in water after purification. While many of my samples were TMC (this has been set at 5000 or above), the Lime and UV combination had obvious results. Lim and UV on their own had similarly beneficial results but were not as effective as Lime and UV. Lime?s lowest count of bacterial colonies was 2144 colonies. UV?s lowest count was 79 colonies. Finally UV and Lime had its lowest bacterial count at 0, without a single example going above 35 colonies (the two TMC?s were obviously contaminated). These huge differences in numbers show how effective the lime and UV method of purification is compared to my other trials. Compared to other studies, my conclusion follows their findings exactly. The UV and lime method was shown to be most effective in all of the studies and research that I looked at. In one study done by Kellogg J. Schwab, the director of JHU Water Institute and the JHU Global Water Program, Schwab noted that the lime and UV combination was extremely effective. ?Both lime slurry and plain lime juice, combined with SODIS, reduced E. coli by roughly 1 million times in just 30 minutes, whereas SODIS on its own was about one-quarter as effective. Reductions in MS2 were measured over a 2.5-hour solar exposure, with viable virus particles reduced by about 10,000 and 100 times with the lime slurry and lime juice, respectively, compared with a 25-times reduction by SODIS alone. The MNV virus was only modestly affected by any combination of methods.?(Burton, Adrian, 2015). The only major differences between Schwab?s study and mine is the difference of times to UV exposure (my trials were left out for 4 hours while his 18

were left out for 6) and his use of both lime juice and centrifuged lime slurry. The only similarity between our experiments was the use of E. Coli within the experiment. Given these differences we still reached a similar conclusion that the addition of lime to SODIS is very effective. Coliform Proliferation was another major area within my experiment. I did not understand the concept well t first but after some research, I began to see how large of an issue it could be. I never considered it as an issue during the experiment as it couldn?t affect my results. The only foreseeable issue would be if the water was later added to a distribution system, how could I counter Coliform Proliferation? I decided that if I were to continue this project, this would be a good area of research. It would be helpful as the water would usually require a chemical cleansing as a secondary step. If there is a more cost efficient method to stop Coliform Proliferation, it would make the SODIS method safer and cheaper to people in poor areas. It would also make it a realistic method of purification for large areas that require distribution systems to transport water. That is why this would be a worthwhile continuation to my project. My data was reliable because of its similarity to other researches done on this topic. While there were a few samples that I believed had been contaminated, there was a clear result from the experiment. The result was also backed up by other major studies done on the topic and can therefore be counted as reliable. Because I added a large amount of bacteria compared to what would be found naturally, it was expected that there would be many TMC?s. That is why this data is both relevant and reliable to the real world context that I created this experiment for. There were mistakes

within my experimental design that led to errors, such as the lack of professional tools such as an alcohol spreader that could have left to small errors within the data. It was also an impossibility to fully sterilize all of my equipment in the experiment which could have created more error. If the experiment were to be improved it would require all proper equipment and the full sterilization of all tools that I used in the process. I did not have an alcohol spreader and was forced to use disposable pipets to streak my petri-dishes. This could have negatively affected my data because it was not the right tool for the job and it could have led to some of the contamination that I noticed. An improvement to this section of the procedure would be to order an alcohol spreader beforehand, so that I could have more accurate results in my data. The bottles that I used were sterilized but could have easily become re-contaminated. This could lead to small amounts of bacteria other than E. Coli that could slightly affect my results. In order to prevent this error, I could carry out the project in a more sterile environment with better control over the stimuli that affect my trials. I had to open the petri-dishes for a short amount of time to steak the water. This could introduce unwanted bacteria to the plates therefore corrupting my samples. A way to avoid

this would be to carry out the project in a more sterile environment. A final experimental error I encountered was that condensation from the lids of the petri-dishes would drip and build up on my samples. The condensation could introduce contaminants to my samples, making them less reliable. An improvement to the design of my experiment would be to periodically remove the condensation form the lids without exposing the petri-dishes to contamination.

Ref erences Burt on, Adrian. "Purifying Drinking Wat er wit h Sun, Salt , and Limes." Environment al Healt h Perspect ives. Nat ional Inst it ut e of Environment al Healt h Sciences. Web. 14 Apr. 2015. "Cent er for Global Healt h." Kellogg J. Schwab, PhD MSPH. Web. 14 Apr. 2015. ht t p:// www.hopkinsglobalhealt h.org/facult y-research/facult y -direct ory/ kellogg-j.-schwab Characklis, W illiam. "Bact erial Regrowt h in Dist ribut ion Syst ems." Google Books. Web. 14 Apr. 2015. ht t ps:// books.google.com.pe/ books?id=hS94LSDpm UYC&pg=PA73&lpg=PA73&dq=coliform+proliferat ion&sourc e=bl&ot s=ibj48GzIIq&s ig=Bc6CTY7XBcIS7li_fEt o6s6D3hs&hl=en&sa=X&ei=ZkIwVZHu "General Informat ion." Cent ers for Disease Cont rol and Prevent ion. Cent ers for Disease Cont rol and Prevent ion, 1 Dec. 2014. Web. 14 Apr. 2015. "Ult raviolet Radiat ion." Wat er.epa.go. Epa. Web. 14 Apr. 2015. "Wat er Purificat ion." ScienceDaily. ScienceDaily. Web. 14 Apr. 2015. ht t p:// www.sciencedaily.com/art icles/ w/ wat er_purificat ion.ht m "Limes" https://upload.wikimedia.org/wikipedia/commons/f/f2/Limes.jpg

PLA NA RI A N REGENERA TI ON A ND UV RA DI A TI ON

BY SOFI A GONZ A LEZ

A BSTRA CT

I NTRODUCTI ON

This experiment investigated the effect of different UVA levels (0, 1, 3, 5 min) on the regeneration rate of planaria. The results were gathered by first separating the planaria into 4 groups of 2. Then each group was exposed to either 0, 1, 3 or 5 minutes of UVA radiation from a black light. The length of each planaria was recorded for a period of one week. The data collected showed that the planaria exposed to 3 minutes of UVA had a greater regeneration rate while the planaria exposed to 5 minutes, though smaller, of UVA regenerated its head faster, meaning that UVA exposure makes planaria regenerate faster, but be smaller than before.

This experiment will be looking at the effect of different levels of UV exposure on the regeneration rate of planarians, measured by the time it takes the planarians to regenerate in days. Planarians are non-parasitic flatworms (Phylum Platyhelminthes) that live in freshwater or saltwater environments (freshwater for this experiment), and feed off of dead animals. On average, they range from 3mm to 12mm in length and they have two eyespots in their head to use to detect light. Planarians avoid light because it is a possible heat source that can dehydrate them (Sace). Planarians have an outstanding ability to regenerate: they are able to regenerate any body part that is lost or damaged, including its head (Massachusetts Institute of Technology 1). If you cut a flatworm in half, the tail half will grow another head and the head will grow a tail.

Planarians owe this impressive regenerative ability to the presence of neoblasts. Neoblasts are adult stem cells that are very similar to embryonic stem cells, meaning that they are capable of creating any type of cell. They make up about 30% of the planarians? body. Planaria have neoblasts all over their body, except in their eyespots and their pharynx (Wenemoser and Reddien). So how does the process of regeneration work? First, the wound is closed through muscular contractions of the body wall and then the epithelium heals over the wound. Now that the wound is healed, a blastema ?a buildup of neoblasts that will form the missing body part? is formed. The rate of this process depends on the temperature, but at about 22-24°C the blastema forms in 1 to 2 days, in 4 to 6 days the differentiated structures are regenerated, and in 2-3 weeks the regeneration process should be complete. This regeneration process, in which the lost parts are rebuilt from a group of undifferentiated cells, is called epimorphosis, which planaria undergo during regeneration (University of Minnesota 5). Because of this impressive regenerative ability, planaria are often used in regeneration experiments to study human regeneration, specifically the regeneration of human skin and liver cells (Sace). UV radiation is one type of light that reaches the earth from the sun. In the electromagnetic spectrum, it is between visible light and x-rays, with a wavelength between 100 & 400 nm. There are 3 types of UV light: UVA (320-400nm), UVB (290-320nm), and UVC (200-290nm) (Horton, 1977; Diffy, 1991). UVA rays make up around 95% of UV radiation that reaches earth?s surface; therefore most of us are exposed to large amounts throughout our lifetime. UVA light penetrates more deeply, and it has been proven to damage skin cells in the basal layer of the epidermis ?where skin cancer occurs?, meaning that UVA not only contributes but may initiate skin cancer ("Understanding UVA and UVB"). Though UVA rays help our body produce vitamin D, they also play an important role in protein oxidation, preventing the DNA from repairing itself, which then leads to mutations and genomic instability (Girard et al. 8). This is relevant to this experiment because this DNA damage would affect the stem cells in the planaria, affecting its regeneration. A study on the effect of UVC on planarian regeneration was conducted by Amy Gavlik and Rebecca K. Szymczak, and their results were that at all the planaria exposed for over 5 minutes to UVC died, and the flatworms exposed to UV regenerated slower than the controls (Gavlik and Szymczak 120-121). Another project, conducted by Natasha Kohli and Kosha Patel for the California State science fair also tested the effect of UVC, and their results were that UVC caused the planaria to grow back their heads and tails faster, but they grew smaller than the control (Kohli and Patel 1). Even though these experiments tested with UVC, they apply to this experiment because UVA is just a weaker form of UV life, meaning that it will produce similar effects on the planaria. 22

QUESTI ON What is the effect of different levels of UVA exposure with variations of 0, 1, 3, and 5 minutes, with an uncertainty of ± 5 seconds, on the regeneration rate of planaria, measured by the length each planarian grows per day in millimeters with an uncertainty of ± 1 mm when planarian species (genus Planaria), type of cut (transverse cut), type of water used (bottled water), temperature (27°C ± 5°C), environment (Light Exposure in cabinet: 0.9 lux ± 0.5 lux, pH of water: 6.9 ± 0.5, humidity: 65% ± 5%, pressure: 98.78 kPa ± 1 kPA), and UV light intensity (52.5 lux ± 5 lux) are kept constant?

M ETHODS 1. Prepare 8 petri dishes by adding 20 mL of bottled water and labeling them for "0", "1", "3" and "5". 2. Separate planaria into 4 groups (at least 2 planaria per group). Group 1 won't be exposed to UV radiation, group 2 will be exposed for 1 minute, group 3 for 3 minutes, and group 4 will be exposed for 5 minutes. 3. Place each planarian in its corresponding petri dish (1 per dish). 4. Measure the initial length of each planaria. Record in data table. 5. Place petri dish 45cm away from the UV light source, that has an intensity of 52.5 lux ± 5 lux, in a dark place. 6. Expose the planaria in group 2 to UV light for 1 minute, group 3 for 3 minutes, and group 4 for 5 minutes. 7. Bisect each planarian across the midsection by cutting them with the razor blade under a microscope. 8. Cut it in half with a scalpel or single-edged razor blade. Make the cut midway between the anterior (head) and posterior (tail) ends of the animal. 9. Measure head and tail piece of each planaria. 10. Cover the petri dishes with other plates to avoid water evaporation. 11. Environment was kept constant by placing planaria in an environment with a constant temperature of 27°C ± 5°C, a light exposure in the cabinet of 0.9 lux ± 0.5 lux, the pH of water at 6.9 ± 0.5, a humidity of 65% ± 5%, and a pressure of 98.78 kPa ± 1 kPA. 12. Do not feed planaria during the regeneration period, as they are unlikely to feed during this time. 13. Do a 10% water change every few days. (If the water looks cloudy, change more often and/or change a larger fraction of the water.) 14. Measure each planarian segment (head and tail) daily using the microscope for 1 week. Record data. 15. After 1 week, summarize your results. There should be 128 pieces of data (8 measurements per day). 23

RESULTS

QUA LI TA TI V E DA TA

Figure 1: tail segment of planarian not exposed to UVA after seven days, with no clear head growth (no eyespots).

Figure 2: tail segment of planarian exposed to UVA for one minute after seven days, showing the start of the head regeneration (can see eyespots, but rest of head is small).

Figure 3: tail segment of planarian exposed to UVA for three minutes after seven days, with head partially grown back (can see eyespots and some more growth).

Figure 4: tail segment of planarian exposed to UVA for five minutes after seven days, with head fully grown back (can see eyespots, and head has considerable growth).

DI SCUSSI ON According to the data collected, my research question was answered. When exposed to 0 minutes of UVA exposure, the both planarian segments grew an average of 0.143mm per day, while when exposed to 3 minutes of UVA the head segments grew an average of 0.2145mm per day, and the tail segment grew an average of 0.268mm per day. Even though this implies a correlation between UVA exposure and regeneration rate, the planaria exposed to 5 minutes of UVA had a growth of 0.143mm per day for the head segment (same as the control), and the tail segment had a growth of 0.0715mm per day (less than the control). However, the planaria exposed to 5 minutes of UVA exposure regenerated their head before all the others, with the planaria exposed for 3 minutes coming in a close second, then the ones exposed for 1 minutes, and the ones exposed for 0 minutes showed no evidence of head growth. This suggests that if you expose planaria to UVA they will grow back faster but smaller in length, answering my research question. The scientific reasoning behind this data is that though UVA does cause harm to organism, it only causes damage when the organism is exposed for extended periods of time. Prior scientific research found that exposure to UVC causes planarian regeneration to slow down, since it causes a DNA to form pyrimidine dimers, which slows done DNA replication, which in turn would slow down the division of the neoblasts. The presence of pyrimidine dimers also affect transcription, preventing RNA polymerase from initiating transcription, or leading to the cutting off mRNA transcripts (Gavlik and Szymczak 120-121). My data partially supports this theory because the though the ones exposed for 1 and 3 minutes regenerated faster than the planaria exposed for 5 minutes, but the one exposed for 0 minutes regenerated at the same rate as the planaria exposed for 5 minutes. However, since I used UVA instead of UVC, there is a different effect on the planaria. UVA is the most common yet least harmful form of radiation, while UVC is the most harmful yet least common because it?s mostly blocked by the ozone layer (?Ultraviolet Radiation?). This means that the effect caused by UVA wouldn?t be as extreme as the effect of UVC. According to another experiment testing the effect of UVC on planaria, UVC caused the planaria to become fully-grown faster but smaller than before. These findings partially support my data because though the planaria exposed to UVA regenerated their heads and tails back faster, data didn?t seem to be following a particular pattern or trend. The reason I had little correlation with the past experiments and no discernible pattern in my data is because there was a lack of data. For this lab I only had 2 trials, which makes it difficult to come to a conclusion since there are many variables influencing the experiment, like the fact that not all planaria have the same regeneration rate to begin with, since all planaria are not made equal. As you can tell from the large error bars in the graph, the lack of data makes it impossible to draw a conclusion on the growth in the planaria. Having only 2 trails means that the data varies depending on ththis error. Also, in this experiment some planaria died, meaning that I only had data for one planaria for that value (1 min and 0 min) which completely threw off the data, since it?s not an accurate portrayal of the regeneration for planaria in that group.

Ref erences Gavlik, Amy, and Rebecca K. Szymczak. "Retardation of Planaria Regeneration by Ultraviolet Radiation." Bios 74.4 (2003): 118-23. Print. Kohli, Natasha, and Kosha Patel. "How Will the Regeneration Process of Planarians Be Affected by Exposure to Microwave and Ultraviolet Radiation?" 2013. PDF file. Girard, P. M., et al. "UVA-Induced Damage to DNA and Proteins: Direct versus Indirect Photochemical Processes." Journal of Physics: Conf. Series 261 261st ser.: n. pag. Print. Massachusetts Institute of Technology. "Regeneration: Animal Growth and Development." N.d. PDF file. Sace, J. "Fun Biology Experiment: Planaria Regeneration." Ed. Donna Cosmato. Bright Hub Education. N.p., 1 May 2012. Web. 14 May 2015. <http://www.brighthubeducation.com/ science-lessons-grades-9-12/36527-planaria-regeneration-experiment/>. "Understanding UVA and UVB." Skin Cancer Foundation. N.p., n.d. Web. 28 May 2015. <http://www.skincancer.org/prevention/uva-and-uvb/understanding-uva-and-uvb>. University of Minnesota, ed. "Chapter 13: Planarian Regeneration." N.d. PDF file. Wenemoser, Danielle, and Peter W. Reddien. "Planarian Regeneration Involves Distinct Stem Cell Responses to Wounds and Tissue Absence." Developmental Biology 344.2 (2010): 979-91. Science Direct. Web. 25 May 2015. <http://www.sciencedirect.com/science/article/pii/ S0012160610008377?np=y>. "Ultraviolet Radiation." NSF Polar Programs UV Monitoring Network. N.p., n.d. Web. 11 June 2015. <http://uv.biospherical.com/student/ page9.html#UVradiation>.

A ck now l edgements I would like to thank Mr. Bourke and Mr. Buck for their unwavering support and encouragement throughout my project. Thanks to Ms. Patty for not only getting me the necessary materials but for also helping me conduct my experiment. I would also like to thank Savka Akester for helping me carry out my lab without any obligation whatsoever. Finally, I would like to thank Maria Eugenia Barrios and Carolina Zapata for helping me obtain the planarians in the first place.

THE TRI PLE ?TA NGA RA NA ? M UTUA LI SM : PSEUDOM YRM EX TRI PLA RI NA A NT CONCENTRA TI ON A CCORDI NG TO TRI PLA RI S A M ERI CA NA TREE CI RCUM FERENCE I N FLOODPLA I N A ND TERRE-FI RM E ECOSYSTEM S OF TROPI CA L RA I NFOREST I N THE M A DRE DE DI OS REGI ON OF PERU

BY M A RTI N PEREZ

A BSTRA CT This experiment was focused on exploring the relationship between Triplaris americana circumference and Pseudomyrmex triplarina ant attack activity, as the ants and tree exist in a mutualistic symbiosis, with ants using the mainly hollow insides of the tree as their spatial niche, but protecting the outsides of the tree in return. The investigation was done in two different sites of the Madre de Dios Tropical 28

Rainforest (Floodplain & Terre-firme) by placing a Post It note in the tree trunk and recording the amount of ants that approached/attacked it during one minute. Results show a slight positive, directly proportional correlation (r factor of 0.273) between T. americana circumference and P. triplarina response.

I NTRODUCTI ON As I explored the Tropical Rainforests of Madre de Dios, the odd adaptations of species such as the Walking Palm Tree (Socratea exhorrhyza) made it clear that organisms developed in a state of perpetual rivalry. I could observe nearly relentless interspecific competition everywhere: in secondary succession sites, in Howler Monkey-dominated treetops, and in the dense foliage of the shrub layer. This kept me wondering: was there any mutual benefit relationship, or was it all just competition? A chat with seasoned guides led me to meet the ?Tangarana? tree, an icon of the jungle, a vine-like species that hosted small, protective ants that peppered the outside trunk and seemed to be willing to protect it great cost. Even at first sight, this was a most distinct mutual benefit coexistence, one of the very few in the jungle. I was interested in the relationship (if any) between the size of the Tangarana tree? as determined by circumference? and the level of activity of the ants that protected the outside. I thought I could place a quadrat on the tree, and count the amount of ants that would attack or approach the area during a determined period of time, but the dimensions of the quadrat were too large for the task. Moreover, since this was a product of serendipity, I did not pack equipment beforehand; thus, I was limited in terms of apparatus availability. Given the size of ants, the most suitable quadrat-like measuring instrument available was a Post It© note that would be adhered to the tree, and a stopwatch (my iPhone 4), which could be used to take time. Both would provide data necessary for the goal of the study. 29

Madre de Dios is the eastern Peruvian Amazon basin, and is a ?departamento? with two dominant biomes: Tropical Rainforest and Tropical Grassland (GCF, 2012). Bahuaja-Sonene National park, a 1?091,416 hectare piece of land, inaccessible to tourists and non-investigators, hosts one of the highest biodiversities anywhere in the world (SENARP, 2015). About 54% of Madre de Dios 85,184 km2 is under legal protection, leading to vast, pristine rainforest territories with little economic exploitation or human presence (GCF, 2012). The Tambopata Research Center, one of the locations of study, is across the Bahuaja-Sonene Park within the Tambopata National Reserve (floodplain forest); the Refugio Amazonas (terra firme forest) is within a concession for ecotourism. Bahuaja-Sonene shares much of the National Park?s biodiversity, even if this is reduced in the Refugio Amazonas. Symbiosis is the coexistence of two species, and exerts neither positive nor negative influence upon the organisms at hand, while mutualism is a type of symbiosis that affects a positive influence on the participants, leading to mutual benefit coexistence between participants (Pringle Lab, Harvard U, 2012). The ?tangarana? is a type of mutualism between ant and tree. Tangarana Ants (Pseudomyrmex triplarinus) are characterized by being generally reddish, although with black abdomens and dark heads, and are typically found in Triplaris americana trees, hence their species name (RF Expeditions, 2012). Plants such as the Triplaris Americana are considered ?myrmecophilous?, meaning that they have reached a degree of specialization in which

they can host a population of ants; their properties are characterized by ?domatia?, hollow cavities that allow the traffic of insects (Gómez-Acevedo et al., 2010). Hollow or near-hollow insides make room for larvae of the genus Homoptera, which secrete a ?syrup? useful as nutrition for the P. Triplarinus ants (Fuller, 1921).

QUESTI ON: What is the effect of Triplaris Americana tree circumference (cm) with variations of 6 naturally occurring sizes (8.3, 8.6, 9.0, 12.5, 21.2, 24.2 cm ± 0.05) on the effect of the response of Pseudomyrmex triplarina protective ants to an invading 9cm2 Post It note during one minute measured in terms of ants/minute, when the T. Americana tree exceeds two meters in height and 5cm in circumference and is in either Terra Firme or Floodplain ecosystems of the Tropical Rainforest of the Madre de Dios region in Peru?

M A TERI A LS A ND M ETHODS

Experimental Setup

1. Using a TI-84 calculator, a list of 5 random numbers was produced, all ranging between 1 and 200. These were the heights, in centimeters, at which the Post It note was to be placed. 2. In a Floodplain forest of the Tambopata Research Center, Tangarana (Triplaris) trees were located, using expertise of local guides. Using the measuring tape, the circumferences of three trees in the immediate/nearby area were recorded. 3. Using a double layer of protective latex gloves, a Post It note was placed on the surface of the tree. The height at which the Post It note was to be placed, determined randomly by the Calculator as described in Step 1, was ensured by the measuring tape. The tape was stretched to the desired distance, placed next to the tree, and the Post It note was glued at the correct height. 4. The number of ants that approached/attacked the Post It note was visually counted for one minute. A stopwatch regulated this timespan. 5. Steps 1-4 were repeated in a Terra-Firme Forest of the Refugio Amazonas area, totaling six times in the entire study.

Safety-wise, the study had great challenges. A population of ants capable of biting and injecting Formic or Methanoic acid (HCOOH) represented a hazard in the collection of data. This danger was overcome by using two latex gloves in one hand as a measure of protecting skin. A double-layered gloving was a barrier thick enough to prevent the ants from reaching the surface. Additionally, the data collector only used long-sleeved cotton t-shirts in order to minimize the amount of bare skin exposed, lowering the risk of ant bite(s); this long-sleeve t-shirt was placed under the gloves, further minimizing the possibility of an ant reaching bare skin. Moreover, the presence of a guide during the study decreased risk of other environment-related dangers. Environmentally, the trees were treated with delicacy and attention. Because they represent a component in the larger ecosystem, they were not mistreated or destroyed. There was also a risk of having ants fall from taller leaves, thus, the stem of the tree purposefully received very minimal or no agitation. Moreover, no tree was lost to the study. Only a very minimal number of ants may have died by accidental causes? falling into small ponds due to agitation, or otherwise. No toxic substances were involved in the experiment, and all Post It notes were collected and returned to the lodge after the study concluded. Ethically, the ants? who were willing to give up their lives in protection of the tree? had to be treated properly. None of them were purposefully harmed, and in any case, they were returned to their tree.

RESULTS

DI SCUSSI ON T. americana trees of larger circumference seem to have greater ant activity. With an correlation coefficient (R) value of .27, there seems to be a positive directly proportional correlation between the tree circumference and the level of ant activity. Because this R factor is 0<R<1, there is a positive correlation but because it is <5, the correlation is not too strong. This may imply that circumference variations are not statistically significant in P. triplarina activity. Large variation within data is also an indicator that there is no sharp and ongoing universal trend as to how tree circumference plays a role in ant activity. As shown in Graph 1, when the tree had a circumference of 8.3 cm average ant activity was of 56 ant/min, while when the tree had a circumference of 24.3cm, average ant activity was of 63 ant/min, only a 7 ant difference, much less variation than when circumference was 8.6 cm and average activity was of 34 ant/min, a much larger decrease even if there was a small increase in circumference. This positive correlation may perhaps be attributed to domatia inside of the tree, meaning that a larger tree maybe capable of holding more ants because of broader living spaces. However, non-controllable factors, such as terrain, weather, and location may have skewed the results, making the weak correlation all the more inconclusive. Thus, more research is needed, especially more focused on a single ecosystem. Large Standard Deviations as shown in Graph 1 also make the data more unreliable; in the worst of cases there may be either no correlation or a negative correlation. Conclusions are not supported by third party data, as the activity of ants is not a major point of focus in research given that most ecologists are keen on investigating the mutualistic relationship on an evolutionary level and not on a more direct plane. Most of the research is focused on the origins? not on the nature? of the coexistence. This leads to uncertainty in the interpretation of the results, as the correlation found may or may not be significant. Future improvements may be to study P. triplarina ant activity according to height of the tree, or comparing activity with abiotic factors. Repeating this study in waterlogged and non-waterlogged soils would be helpful in developing knowledge of ant?s behavior as proximity to the ground increases. Further studies like this may appreciate differences in ant behavior according to a variety of factors, which can shed light in the evolutionary process from which the mutualism developed. One of the errors in the lab counting method. Ants are very mobile organisms. Counting them visually is a challenge, especially when they are in large numbers and work by attacking together. Instead of using a Post It note, it may be more helpful to capture ants for a lapse of time, record their quantities, and then return them back to the tree. Another error was the measuring of the circumference. Due to equipment constraints, 30m measuring tape had to be used to measure the circumference of the tree. The tape was too long, and thus, inappropriate, for the measurement. Using a smaller measuring tape (<10m) may increase accuracy of measurements. 32

Ref erences Fuller, Geo D. Myrmecophilous Plants. Technical rept. no. 6. Chicago: UChicago, 1921. Print. Gomez-Acevedo, Sandra, et al. Neotropical Mutualism Between Acacia And Pseudomyrmex: Phylogeny And Divergence Times. Molecular Phylogenetics and Evolution, 2010. PDF file. Huisa, Cesar. Madre De Dios. Puerto Maldonado: Madre De Dios Regional Government, 2012. PDF file. Ministerio del Ambiente, and Servicio Nacional de Areas Naturales Protegidas Por El Estado (SENARP). "Parque Nacional Bahuaja-Sonene." SENARP. Gobierno del PerĂş, 2015. Web. 10 June 2015. <http://www.sernanp.gob.pe/sernanp/zonaturismoi.jsp?ID=12>. Pringle Laboratory. "Mutualism: Cooperation and Interactions." Pringle Laboratory: Ecology & Evolution Of The Fungi. Harvard University, 2012. Web. 10 June 2015. <http://www.oeb.harvard.edu/faculty/pringle/>. Rainforest Expeditions. "Tangarana Ants." Amazon Wiki. Rainforest Expeditions, Dec. 2012. Web. 10 June 2015. <http://amazonwiki.org/index.php?title=Tangarana_Ants>

A ck now l edgements Thanks to Mr. Gilles Buck and Ms. Leigh Petty for an extremely enriching trip to the depths of the Amazon Jungle, as well as for their scientific advising and explanations of phenomena. Cheers to Lucas Arnovitz who, without any obligation whatsoever, committed to helping me in the pesky and painful task of measuring the circumference of trees in the field (but at least got to flavor what methanoic acid tastes? or feels? like). Lastly, to the Amazon Expeditions Team, for leading me to the trees used in this study, going the length to find some boots my size, and for letting me stare at the insides of the jungle.

CORRELA TI ON BETWEEN CI CA DA (FI DI CI NA CHLOROGENA ) NEST POPULA TI ON A ND M A N M A DE PA THS I N THE M A DRE DE DI OS RA I NFOREST, PERU. BY STEV E LI U A BSTRA CT The goal of this lab was to figure out if there was a correlation between cicada (fidicina chlorogena) nest population and the man made paths in Tambopata by using quadrats to accurately count the exact population of cicada nests in a 25x25 meter area as sampling in terra-firme jungle. We found out that there was strong statistical significance between the cicada clay towers and the paths, although bias and insufficient data might make it an inconclusive study.

I NTRODUCTI ON Cicadas (Fidicina Chlorogena) are members of the cicadoidea family of insects (itis.gov). Cicadas are the only animals in the jungle that builds nests in the shape of small clay towers that protect them from predators as well as floods. There are many factors that might affect the placement of these towers as well. My assumption is that a possible factor might be that access to clay to build these towers might make them more common around terra-firme since it is dryer and contains more clay than the other jungle types. Other jungle types such as

the flood planes, flood, which means that the cicadas would still drown even if they built their towers. The fundamental niche of cicadas should allow them to build their nests in more than one type of jungle, since they?ve adapted to create claw tower for protection form predators and abiotic factors such as floods, but the realized niche, affected by limiting factors such as moisture, flooding or type of soil/clay affect this decision as they ultimately choose terra firme over other jungle types out of convenience. It is a possibility that cicadas build more nests near human made paths, likely due to the top layer of dead organic matter of the jungle being removed to build these paths. Constant use of the trails as well as rain run off increase this effect, not allowing a top layer to grow back as dramatically. All this together could increase the number of clay near and around the paths. This is an example of a commensalist relationship between humans and cicadas. Cicadas benefit from humans digging paths into the ground since it exposes more clay, which makes it easier for them to dig their nests and build the small towers; on the other hand, humans are not affected or harmed (cicadamania.com) . Using a ?Node?Sensor, the weather for the day that the experiment was conducted was recorded, although it has no impact on the lab whatsoever. The temperature was around an average of 27.5 degrees Celsius, with a relative humidity of 8.5%. This data was gathered just to make sure no variables were left out just in case, even if it didn?t have an impact on the lab.

The method used to gather data was with 5x5 meter quadrats in a 25x25 meter area. I used two 25 meter long measuring tapes 5 meters apart from each other to measure out the length of the area and then walked through the two tapes in 5 meter intervals, these represented the quadrats and allowed us to accurately count the total number of cicada nests per quadrat and in the 25x25 area. I then placed the first measuring tape and put it behind the second one, 5 meters apart from it and walked through in 5-meter intervals again. We repeated this process until the whole 25x25 area was covered. This was the fastest and most efficient way with our limited time, 35

Figure 1 shows how the procedure was done. The area was 25x25 and each small square represents a single quadrat. Each small arrow indicates how I walked from quadrat to quadrat between two measuring tapes to make sure the size of the quadrats was as accurate as possible. After the first line was done, the first measuring tape moved 5m above the second one and the same process was done. It was a fast and efficient process.

and it was also not a substantial difference to affect the data. When put in practice, the chances of miscounting the nests and confusing them between one quadrat to the other were very low. During all of my trials I had a group of 2-3 people help me do the lab, I was the only data collector though.

The method to test for a relationship between cicadas and human made path will be through a t-test, which tests for statistically significant difference on the mean of two sets of data. Data is plugged in into an excel sheet with two separate sets of data. One is the set of data that was parallel to a path, and the other is the set of data that was not parallel to a path. Both sets were plugged in into the t-test, then two distribution tails were specified and finally the third type of t-test was performed.

M A TERI A LS A ND M ETHODS I decided to use quadrats as my data collection method since I wanted to count out the exact number of cicada towers in a certain area. I started off using belt transects first, but the areas were too big and I would get lost trying to count everything. The quadrats narrowed everything down into a small enough space to count everything exactly, and also be representative of what I was trying to figure out. The size of each quadrat, 25m^ 2, were big enough to show a difference between the areas closer to the path as well as also the ones farther from it in their respective 625m2 areas, but also small enough so that it could remain as accurate as possible (reducing variation) as well as plausible in the amount of time I had.

M eth od: 1. I found an area with cicada nests parallel to a path (it?s better if the area is parallel to a path in more than two sides) 2. I used one of the measuring tapes and measured out 25 meters parallel to the path 3. Starting at zero on the measuring tape, I measured 5 meters into the vegetation/ deeper into the jungle and used a meter stick or flag to mark the location. 4. I took the other 25-meter measuring tape, used the flag as a starting point and measured out 5 meters parallel to the other measuring tape. It looked like a type of belt transect that was 25 meters long and 5 meters wide. 5. I went back to the 0 mark on both measuring tapes and walk 5 meter in, between both of the tapes, marked it and counted all of the cicada nests. 6. Walked another 5 meters in, marked it, and counted all of the cicada nests again. 7. I repeated step 6 until I reached the 25-meter mark. 8. I measured out 5 meters parallel from the second measuring tape, facing into the jungle and then marked the spot 9. I repeated steps 3-7, until the whole area was checked

Figure 2: Cicada nest s

Saf ety, Env i ronmental and Eth i cal Consi derati ons: The only considerations might have been that some plants might have been stepped on while walking through the jungle as well as small critters such as insects. The jungle is able to fix itself really fast, which means that after a few days, all signs of us being there will have disappeared. Like most labs that are done near wild life, we also had to be careful for any poisonous spiders or insects while walking through, but just being careful of where you step solves the problem. A professional accompanied me at all times to ensure all safety protocols were followed. I made sure that we properly cleaned up after ourselves after experimenting, trying to reduce the impact of us being there. There were no other safety, environmental or ethical problems when conducting this lab.

RESULTS Tab l e 1: Processed Data

Graph 1: Th e error b ars represent 1 standard dev i ati on

Graph 2: Densi ty Di agram

The above diagram shows the density of cicada nest population by quadrat. The lighter hues indicate a lighter population density, while the darker colors indicate a heavier population density. A white box indicates a population density of zero. 37

DI SCUSSI ON Upon evaluation cicada nests were found to be more common near paths. After completing the t-test, I figured out that the t value results showed that there is a statistically significant difference. After graphing all the data points, it turns out that although the mean cicada nests near paths is higher than that of the quadrats that were not next to a path (4 against 1 respectively) the standard deviations of both data sets were at 2 and 4, meaning that there is a large variation in this lab. Upon further inspection, we can see in the population density diagram (figure 4) that, although not necessarily next to a path, cicadas did seem to prefer nesting closer to the paths. Although they might not necessarily only build near the paths, they did seem to prefer building near them. Testing more areas and having more data points could?ve solved these problems. In conclusion, we can see that the data from the t test (calculations) showed strong statistical significance between the path and a higher density of cicada nests, meaning that there was very little chance that the averages were by chance, but it could be said that the results were due to bias and that I chose the areas to test. Although the first area tested was chosen (for the sake of time) meaning that there was bias, the second area which was next to the first one (split by a path) was not, meaning that a large part of the data is still unbiased. A large part of this lab was constrained by time, so it is a factor to consider. Cicadas and humans have had interactions for many years already. The interaction has gone for long enough that some even labels them as locusts, the commonly known pest that destroys crops and farmlands (TheWire.com). This means that cicadas might be used to human interaction, which might explain the nesting near man, made paths. Although this is a different type of cicada found in America (Magicicada) and the human exposure is different (more limited), a similar hypothesis could be pulled from its North American counterpart. No other scientific theories regarding the correlation between cicada nest populations in Tambopata and human made paths has been done before (as of now), so there are no other tangible ways of comparing this lab to accepted scientific theories. Not enough testing was done to really have concrete data to perfectly answer my research question. There were not enough data points (only 50 total) so I?m not one hundred percent confident about the reliability of my data. Although the t-test did show a strong correlation, I would?ve liked to do the lab a few more times to really have a concrete answer. I 38

There were a few weaknesses in this lab. The first one was in the testing method; I wasn?t able to accurately measure every quadrat, but it wasn?t significant enough to change the outcome of the data. It also took a very long time to finish testing the 625m2 area every single time which meant that I could only do it a few times resulting in a rather small data sample of only 50 maximum points. This means that there is not enough data to concretely justify my research question; we could see this in the standard deviation of both data sets. There could?ve also been some bias while choosing the areas to be tested which could have had an effect on the data, randomly choosing areas could?ve fixed this. The strengths in the lab include the method of testing used. Although it took a long time to test every time, it was still a very efficient method and was definitively faster than drawing out all the quadrats and then counting. It might not be as accurate, but when testing cicada nests, it is not statistically significant to affect the data in any major way. This lab allowed me to use novel ways of comparing data such as a t-test or using population density diagrams over conventional graphs, it allowed me to expand my repertoire of skills. Other factors such as temperature, humidity, rain don?t affect my lab as much as it affects other, meaning that my lab can still be accurate even with these abiotic factors. One error in my lab was the method of testing because although it had almost no effect on my data, it is still a factor to consider. To improve my design I would actually use quadrats to be 100% sure the count of nests is accurate. If I get enough time, a good method to count these nests would be by first measuring and then drawing the quadrats out with rope, this would ensure that there is no variation between quadrats and that the counts are more accurate. It might not be necessary since there were not enough nests to miss count, but in an area with a higher density of nests it might be a good option. Another error was the lack of data, which was inconclusive and had a very large standard deviation. To improve this error I would have to manage my time better to be able to test more in a limited schedule. I wasn?t able to properly manage my time to have enough data, a good improvement would be to plan better before hand so that I can test as many times as possible. Finally, there was a possible bias in my result, which may have affected the outcome. To improve my design I would randomly choose areas to test by using numbered marks and randomly generating numbers to pick areas to test. This would allow bias to be removed from the lab making the results as accurate as possible, and removing some of the doubt of the lab.

Ref erences 1: "ITIS Standard Report Page: Fidicina Chlorogena." ITIS Standard Report Page: Fidicina Chlorogena. N.p., n.d. Web. 29 May 2015. <http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic= TSN&search_value=847254>. 2: "What's New on Cicada Mania." Cicada Mania: Cicada Insects, Life Cycle, 17 & 13 Year Cicadas. N.p., n.d. Web. 02 June 2015. <http://www.cicadamania.com/>. 3: "Calculators :: Statistics Calculators :: T-Test Calculator." T-Test Calculator. N.p., n.d. Web. 29 May 2015. <http://www.mathportal.org/calculators/statistics-calculator/ t-test-calculator.php>. 4: Greenfield, Rebecca. "Everything You Need to Know About the Impending Cicada Sex Invasion." The Wire. N.p., n.d. Web. 29 May 2015. <http://www.thewire.com/technology/2013/04/cicada-2013/64086/>.