Do students do better when they write exams faster (or slower)?

April 29, 2015 / Chris Buddle / 6 Comments

As I was grading my final exams last week, I wondered about ‘quantity’ of answers to written questions as opposed to ‘quality’ of the answer: in other words, some students write a lot of stuff for an answer, but could have received full points on a question without filling a page with tiny handwriting. Here’s what I tweeted about this.

The students that fill the page certainly take longer to complete an examination, and this reminded me of a little project I did many years ago* about the speed at which students write their exams relative to the grade they received on that exam. For one of my larger undergraduate classes the final exam is meant to be about a two hour exam, but some students finish in just over an hour, and some students wait until we take the exam from them at the end of the three hour exam period.

One year I tracked the order that students forwarded me their exams and after the course was over I plotted their grade on that exam relative to the time it took them to complete the exam**. I’ve always wondered whether or not students who finish quickly are the ones that really know the material, or whether the ones who take the longest are so careful to check and re-check everything that they tend to do better than their peers. Here are the results:

A grade on an exam relative to the order in which that exam was handed in.

Bottom line: there is NO relationship.

Some students write an exam quickly and do very, very well. Some students simply do not know the material, and write the exam quickly and hand it in early. Some students stay to the bitter end and do very well. For some students, staying to the end doesn’t help their grade. And, of course, a lot of students are in the middle.

This was a good little project to do, and actually helps me as an instructor. It helps me to NOT judge a student by the speed at which they write the exam. It provides a reminder that everyone works at their own speed, and will do poorly, or very well, even if they write quickly or slowly.

The other lesson this teaches me is that it’s important to have an exam length that aims for the middle ground. A three hour examination that takes the ‘fastest’ students three hours just isn’t fair. Every student is different and need different amounts of time to read, digest, think and answer questions. Assessments are always tricky business, but one overarching goal of assessments is to test about how well a student may be able to recall content, integrate that content, perhaps do calculations, and think about the material that was discussed in the classroom. Assessments shouldn’t be used as a means to weed-out poor students, especially when the ‘tool’ for this is the length and size of an examination.

Good students write exams quickly or slowly, and should be allowed the time to do so.

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*To preserve anonymity around this project, I will not comment on what class it was, or where I was working at the time, and the data are presented in relative terms (i.e., the actual scale is not presented)

**The order was tracked by writing a small number in the top corner of the front page of the exam as students handed in the exam: I did not look at or see this number when I graded the exam, to ensure I would not be biased or influenced by that number when I was grading. The scatter plot was done weeks after the final grades were submitted.

Beetles from the North

April 23, 2015 / Chris Buddle / 1 Comment

I’m super-excited to announce new research from the lab, published yesterday with lead author Dr. Crystal Ernst.

Crystal’s paper focused on taxonomic and functional diversity of beetles across 12 sites in northern Canada, ranging from Labrador to the Yukon Territory, and from the bottom of James Bay all the way up to the tip of Ellesmere Island. This work is result of the Northern Biodiversity Program: a multi-institutional collaborative project about the ecological structure of northern Arthropods.

Crystal Ernst, on the tundra.

The paper was titled “Drivers and Patterns of Ground-Dwelling Beetle Biodiversity across Northern Canada” and in this research Crystal sorted and identified over 9,000 beetles from 464 species, and she classified the species by their functional ecology to assess how functional diversity may vary across the large spatial scale of this project. Instead of re-writing a summary here, I thought to use this blog post as an opportunity to reflect on what I see as the critical findings from this work, and why this is a paper that I’m incredible proud to be a part of.

To me, one of the more interesting findings of this work was that the functional diversity of beetles varied by latitude: although beetles do many things (e.g., herbivore, decomposers, carnivores), it doesn’t seem like all these functions happen at all latitudes. For example, although we document an impressive number of carnivores at all the sites, they are relatively more common in the more northern locations. This is a bit peculiar, and suggests that food-webs involving arthropods vary in some important ways depending on the biome. We also document that temperature is a major explanatory variable when considering functional diversity, which raises the important question about potential effects due to climate change. Indeed, should temperatures change in the north, this may affect the functional ecology of beetles, which in turn could affect other parts of the system.

Figure 1 from the paper: Fig 1. Map of the 12 study locations (North Pole Azimuthal projection), showing the spatial distribution of functional groups. These were pooled into trophic groups, and the pie charts show the proportion of the total site biomass represented by each trophic group

Figure 1 from the paper: Fig 1. Map of the 12 study locations, showing the spatial distribution of functional groups. These were pooled into trophic groups, and the pie charts show the proportion of the total site biomass represented by each trophic group

The research generally supported the well-known pattern in biogeography about how species richness decreases at more northern latitudes. When looking at which environmental variable may explain this pattern, temperature again came out on top. In other words, what beetles are found where is in part due to the temperatures in that region. Climate change scenarios therefore have significant potential effects on beetles in the north: beetles, like most other arthropods, are tightly linked to temperature. Even small changes in temperatures in the north may have big consequences for beetles.
One of the other big findings, to me, was the fundamental value of species-level data for an important taxa, across vast areas of Canada. Crystal recorded new Territorial and Provincial records for 15 beetle species, increasing knowledge about northern biodiversity. I’m also pleased that the data are fully available on-line, via Canadensys, so other researchers can access the information, re-analyze data, and benefit from and build upon this work.
The Arctic is special: it is a vast, cold, treeless landscape, with blankets of tundra, and permafrost underfoot. But it’s also special for beetles. After Crystal analyzed the community-level beetle data, using ordination methods, it became apparent that assemblages from the Arctic Islands of Canada were distinct from the sub-Arctic and north-Boreal sites. From a conservation perspective this is quite important. To some, the Arctic may come across as a big, ‘life-less’ region, with the odd polar bear roaming about, but in reality it hosts thousands of species, including hundreds of beetle species, and that beetle community is very different from what we find in other parts of North America. Special things deserve recognition and protection.
Every journalist I talked to has asked “Why beetles?” This is an easy one to answer: they fill virtually all roles in ecosystems, they are diverse, they are of interest to many people, and they are beautiful. The latter point is an important one, as it is important to capture curiosity and fascination about arthropods.

A northern beetle: Carabus vietinghoffi. Photo by Henri Goulet.

In sum, this was a terrific project to be involved with, and our lab (and our collaborators) are thrilled that the efforts from the Northern Biodiversity program are showing up in the literature (for more examples, check out this, or this).

And rest assured, there’s more to come…

Earthworms at the Morgan Arboretum

April 17, 2015 / Chris Buddle / Leave a comment

This is a post written by undergraduate student Jessica Turgeon - she’s finishing up a project about earthworms.

When I was a child, you could always find me either in a tree or in the dirt. I liked to follow the ants up into the trees and back down again, where I would switch over to digging for earthworms. I loved the feeling of soil between my hands and thinking to myself that these little worms were responsible for making the soil the way it is. I now know that the process is a bit more complex than this but overall, five year old me was almost right.

I spent my whole life loving nature, especially those living in it. By high school I became a strong advocate for environmental protection, even helping a teacher create a bylaw in my municipality to stop parents from idling in front of elementary schools. This experience truly opened my eyes to the will power and determination this generation has when it comes to changing old mentalities about the environment.

When choosing a university to go to, there was no doubt in my mind whether I should apply to Environmental Biology at the Macdonald campus of McGill or not. This program combines both of my passions: nature and its diversity and environmental management. I’ve since embarked on an amazing journey that has shaped me as a person.

Being around so many naturalists rekindled my love for earthworms, so much so that I decided that I wanted to conduct a research project about them. With the help of Chris Buddle (McGill) and NSERC USRA, I decided to take on a project detailing their biodiversity at the Morgan Arboretum, a nearby forest.

Earthworms can greatly affect Southern Quebec soils because all of the species found here are invasive¹. Forests have evolved without the help of earthworms, meaning that earthworm burrowing action is somewhat of a new experience for the trees¹. The worms break up and mix the soil when they crawl, leaving the soil readily susceptible to erosion². While earthworms are prized by gardeners as natural tillers, this can have drastic effects on hardwood forests².

It was important to me to find out where certain earthworms were in the Morgan Arboretum and why they were there. Soils vary in their composition and properties, meaning that some are more suitable for earthworms than others. The goal of my project was to analyze three different soil types (sandy, clay, loam) with regard to earthworm species. I did so by sampling in the three soils and by collecting and analysing the soil using basic soil analyses.

I found no earthworms in the sandy soil over the course of the sampling period, strongly suggesting that no earthworms inhabit sandy soils. Sandy soils are too rough and painful for earthworms to crawl through, therefore they are actively avoided. The clay and loam soils had much higher numbers of individuals, with 9 species each. After statistical testing, it was concluded that there is no significant difference between the two soils and it could be said that they are similar in biodiversity. In addition, a strong correlation between particle density (how dense the soil is) and earthworm abundance was found. As particle density increases, to a certain extent, so does abundance.

To conclude, my data suggests that the clay and loam soils in the Morgan Arboretum are similar in biodiversity, both supporting an equally diverse number of earthworm species. However, the sandy soil does not contain any earthworms, suggesting that this type of soil is incapable of supporting earthworm activities. This is interesting information for soil management, since, in terms of earthworm abundance and biodiversity, clay and loam soils are similar.

Earthworms are essential ecosystem engineers that change the soil to better suit their lifestyle and this is why they are often studied. Hopefully my story has encouraged readers to respect earthworms a bit more; after all, they do much more than be an excellent fish bait!

[1] Cameron, E. K., Zabrodski, M. W., Karst, J., & Bayne, E. M. (2012). Non-native earthworm influences on ectomycorrhizal colonization and growth of white spruce. Ecoscience, 19(1), 29-37.

[2] Jouquet, P., Dauber, J., Lagerlöf, J., Lavelle, P., & Lepage, M. (2006). Soil invertebrates as ecosystem engineers: intended and accidental effects on soil and feedback loops. Applied Soil Ecology, 32(2), 153-164.

The effects of Twitter on student engagement and learning

April 14, 2015 / Chris Buddle / 2 Comments

There are lots of ‘feel good’ stories about using Twitter in teaching, and I’ve long been a supporting of using social media in undergraduate classes. But does it work…? What effects does Twitter have on learning?

An example of a student Tweet, used to promote their blog post.

This was a question we decided to tackle in my field biology class, and recently, in a collaboration with Lauren Soluk (as part of her graduate work), we surveyed students about using Twitter in the classroom*. Here are the take-home messages from the work:

Students Tweeted over 200% more than what was required as part of the course work
Students used Twitter in many different ways, from informal communication, to promoting their own blogs, to asking questions of each other or of the course instructors and TA.
Students used Twitter to communicate with their instructor or TA 56% of the time, with their peers 27% of the time, and with people external to the course 17% of the time.
94% of students felt that among-group communication was beneficial (i.e., either ‘yes” or ‘somewhat’) to their learning, and 78% of students surveyed felt Twitter increased this among-group communication.
When asked whether Twitter had an impact on how they engaged with the course content, 67% of the students answered ‘yes’ or ‘somewhat’.
When asked whether Twitter is a good tool to help student learn in the classroom, 78% of the students answered ‘yes’ or ‘somewhat’.

A learning community: One student group Tweeting at another student group, to ask them a question.

Interesting, most students surveyed said they wouldn’t continue to use Twitter after the class was over. They certainly preferred other tools (e.g., Facebook) to Twitter. Despite this, the students felt Twitter useful in the context of the field biology class, and could see its value independent of their own personal views.

Overall, the results are impressive, and suggests there are good reasons to consider using social media tools such as Twitter, in a University class. It’s certainly not a tool for everyone (and there are important guidelines to consider), nor would it be useful in all contexts, but it clearly serves an important role in my field biology class. Twitter allows students to engage with different audiences, and helps create a rather novel learning community: a community that can include experts from around the world.

A question asked by students, over Twitter

The answer… from an expert from a different country.

Reference:

*Soluk, L & CM Buddle Tweets from the forest: using Twitter to increase student engagement in an undergraduate field biology course [v1; ref status: awaiting peer review]

Note: this paper is currently awaiting peer review - please consider reading the full paper and providing a review!

What to do with a spider in your fruit

April 9, 2015 / Chris Buddle / 4 Comments

Earlier this week, Liz Langley posted a great piece about finding spiders hiding in your fruit. My interview with her was a little longer than what was posted, so I decided to post the full text here…

OMG THERE’s A GIANT VENOMOUS SPIDERS IN MY BANNANAS WHAT DO I DO?????

Imagine you spot a spider, or spiders, or hundreds of baby spiders tucked in with the bananas you recently brought home from the grocery store, or perhaps a black widow in some grapes. The media reports on this phenomena all the time, and the headlines dazzle us with images of dangerous spider lurking amongst our fruits and veggies. And some stories are downright ridiculous.

This is largely an exaggeration: although it’s true that spiders sometimes get shipped around the globe with our produce, it’s relatively rare. Just think of the hundreds of times you bought spider-less bananas! Spiders do live in crops around the world, and generally do good things when they are living in proximity to the foods we like to eat, as they are often important predators of economically important pests occurring in agro-ecosystems. However, they are good at hiding, and sometimes end up being carried along with our bananas or grapes and in this way they hitchhike around the globe.

A wandering spider that is sometimes found in fruit (photo by Sean McCann, reproduced here with permission)

So… if you do find a spider alongside your fruit… here are some Do’s and Don’ts:

Don’t panic. The vast majority of spiders occurring in with our fruits are not dangerous, as a recent scientific study has shown.
Don’t call the authorities or the media: There are bigger and more important things in the world than hitchhiking spiders. Spiders are our friends, doing good things in the world. They are not important enough to warrant notifying the authorities, or your local TV station. It’s easy to get carried away, especially if you see a spider with an egg sac, and perhaps the baby spiders all crowding around. But avoid the compulsion to feed the fires of arachnophobia. Stay calm, carry on. You may wish to call your grocery store, not to get angry, but rather to inform them that you found a spider with your fruits or vegetables. This will allow them to check for other critters in their produce section.
Do isolate your fruit: take a step back, relax, and assess the situation. Ideally, grab a plastic bag or plastic container, place it over your fruit and spider, and gently place your fruit in an isolated area. Do this gently as to avoid crushing the spiders or the bananas. If you stick this package in your fridge, this will ‘slow down’ the spiders (they are cold-blooded critters, and thus are less active when cooled down). You will want your critter to slow down before you get to step #4.
Do collect your spider: this may be beyond the comfort zone of many people, but it’s not that tricky to do, and it’s important. If the spider can be collected and/or photographed, it may be possible to get it identified properly. After your fruit has been cooled off in the fridge for a while, and the spider has been slowed down, you can collect the spider by ‘brushing’ it into a smaller container, perhaps a pill bottle or mason jar. Do this carefully, quickly and with confidence. You can also gently grab it with a smaller zip-lock bag (much like you would pick up dog feces). If you are very nervous, wear a pair of rubber gloves. If you are just too uncomfortable with ANY of this, you may just have to say goodbye to your bananas and stick them in the freezer along with their spider, and in that way you will kill the spider too.
Do document your adventure: One your spider is in a container or zip-lock bag, it may be possible to photograph the spider, or at least compare it to images on a reputable website, such as Rick Vetter’s excellent website. However, be very, very cautious jumping to the conclusion that the spider is venomous. It’s tricky to identify spiders, and even arachnologists can struggle with the suite of species found in fruits. That being said, you could also contact your local museum, college or University and ask about whether someone there is willing to help you with your spider. There are also excellent resources through the American Arachnological Society:
Don’t release your travelling spider into the wild: most likely you are dealing with a tropical species that just won’t live in the climates outside your house. It’s also risky to release spiders into a new environment as you don’t want to potential introduce something that doesn’t occur naturally in your backyard. And although it pains me to say this (as an arachnologist), the best course of action is to probably to kill the eight-legged cargo, and freezing it is probably the best strategy. Again, your local museum, college or university may want to see the specimens after the fact.
Do enjoy your fruit: The spiders have not laid eggs in the fruit and provided you did a good look, everything is fine: wash your fruit, as normal, and enjoy. The spider is gone.

Student for a day (Part 3): operation dissection

April 2, 2015 / Chris Buddle / 1 Comment

This is the third and final post about going back to the classroom: you can find the first post here and the second one here.

We rushed from the lecture hall to the basement of the main teaching complex on campus. I walked down the hall towards the lab, that old familiar smell was in the air: it was the “face-muscle dissection day” in Comparative Anatomy. This took me immediately back to my undergraduate days at the University of Guelph. There were just over a dozen students in the lab, and the ‘specimens’ (I shall NOT mention what they were!) were sitting on stainless steel lab tables, with the dissection gear at the ready. Scalpel? CHECK. Forceps? CHECK. Scissors? CHECK. It was operation: dissection. I was nervous…. then I was handed rubber gloves and a labcoat. I was WAY out of my element…

The instructor started with an extremely detailed 45 minute lecture, providing an excellent overview of the game-plan for the dissections: the expectations of the students was exceedingly clear, and the instructor’s own deep expertise was obvious.

Checking the notes before the dissection commences…

And then the music went on (yes, music! One of the TAs always picks a lovely selection to work to) and the clang of forceps, scalpels scissors started: the students were off, peeling skin and searching for ever-elusive face muscles. It was hard and tedious work: after 30+ minutes our team had only just begun to expose the first layer of muscles. The students expressed how tough the class was, and how it took an incredible amount of time to study their notes after labs. In addition to their own notes, the textbook, and the laboratory notes, my team was taking photos with their smartphones, and taking some videos to use as future study aids. They have a test coming up soon, and were working hard to remember the content and link the ‘thing’ to the ‘name’. I asked the students why they were taking such a challenging course… surely it was required for their program? It turns out that the course wasn’t required, and the students were taking it because they wanted to. It was one of their favourite classes because it involved ‘doing’ things and involved experiential learning on a topic they were deeply interested in (animal biology). The act of dissecting was how they were learning, and the act of dissecting allowed them to really understand how animals work: from the shape and size of salivary glands, to why certain muscles were more developed than others, or how whiskers are embedded deep under the skin surface.

At one point I looked at the clock and was amazed that a full hour had already passed. I looked up from our specimen (and yes, my lab partners had given it a name…) and did a scan of the laboratory: everyone was hunched over, smiling, and now and then you heard ‘COOL’ and ‘WOW’. They were learning together, learning by doing, and loving it. They loved the challenge of the class and they weren’t watching the clock.

I had to leave and get back to my office, and the instructor came up afterwards to say thanks. I was told that never before had another instructor or Prof stepped into the classroom to see what they were doing. That’s a shame.

With my lab partners.

I come away from my “student for a day” experience with some vivid memories, new perspectives, and the following take-home messages:

There’s a lot of material! Wow, there was a lot of material! The students are learning a very high volume of content, and this happens day after day after day. No wonder they are sometimes stressed and fall behind. As Profs, we need to perhaps better recognize and respect work loads.
Different teaching styles are valuable: from lectures to discussions to hands-on laboratories, the variation was much appreciated. It would be tough sitting through six straight hours of lecture, but varying it between different formats works very well. Education is not, and should not *ever* be uniform. One shoe doesn’t fit all, and there is incredible value to ensuring our students get the variation in educational styles.
Spaces are important, perhaps more so than I appreciated before: the physical space itself had a great influence on my time as a student, from the angle of the screen to the placement of the door. The little things matter and the space is a key partner in learning. Variation in available spaces must match variation in different types of courses and instructors. We need big and small lecture halls, well-equipped laboratories, and collaborative learning spaces.
Students are bright, motivated, serious, and have high expectations: this is good to recognize. I already felt this about students on my campus, but seeing this first hand in three different classes confirmed my suspicions. We should maintain rigor and approach each course with an expectation that the audience is ready to learn and ready to be engaged.
Instructors always rush around from class to class and meeting to meeting, but we sometimes forget that students need to rush around too! There isn’t always time in their schedule to eat, line up for the washroom, or physically get from one classroom to another. This is a reminder for me to end class when it’s supposed to end, and be a little more forgiving when students come in a little bit late.

In sum, I will do this again, and would urge my colleagues to do the same. It’s important to see what students see, learn about different approaches to the classroom, and be sensitive to a full timetable and to the high workload that students experience.

A very special thanks to the students who allowed me to tag along: you were patient, kind, and made the experience extra-special.

Student for a day (Part 2): the lecture hall

April 1, 2015 / Chris Buddle / 5 Comments

This is the second of a three-part series on going back to the classroom: check out the first part here.

So far I was enjoying shadowing students for a day: I was excited after my exposure to the research project course, and was fuelled up on coffee as I checked the schedule, wolfed down my lunch and met my next chaperone. We walked together to a different building and to a more traditional setting: a lecture hall. The class was about animal health, and the content was about a retained placenta in cows, and how this affects bovine health and how the retained placenta might lead to other uterine diseases. The instructor, after setting up the Powerpoint, first took 5-10 minutes to ask the class questions from the last lecture. It was clear that this was a normal start to each lecture as the students had dutifully prepared questions for the instructor, and time and care was taken to address each student. This is a great approach, and although I sometimes do this with my own lectures, I don’t do this consistently at the start of each class. I think the students really appreciated devoting this time to discussion at the start of each of their lectures.

The instructor had carefully prepared slides, and had a very nice pace for the entire 90 minutes lecture. I learned a great deal, from Freemartins, to how to treat a cow with a suspected uterine infection. I was deeply impressed by the depth of knowledge of the instructor: research from peer-reviewed papers was used throughout the lecture, and many anecdotes were used to ground the content. There was a lot of content, and it was also clear that the instructor has high expectations of the students. The instructor was also passionate about the material, and this helped keep my interest.

The view from my seat in the lecture hall.

One of the most interesting experiences for me was being able to view the students’ computer screens from the vantage point of a student! I could see about 6-7 screens, and I had some expectation that Facebook or cruising on web-browsers would occur. To my surprise and delight, students were using their computers largely to take notes: some students had the lecture slides (provided by the instructor before class started) on half their screens and a word processer on another part of their screen and they were moving with ease between the two. This was the definition of effective multitasking. My chaperone had a different approach, and was writing in a spiral-bound notebook. She told me that later on she looks at the lecture slides and cross-references with her hand-written notes as an effective way to study. I was impressed: these students are serious, and have given a lot of thought to the best way to take lecture notes and study. I have previously offered some rather strong opinions about instructors posting Powerpoint slides on-line, but what I was seeing in the classroom was certainly causing me to reflect and reconsider my opinions.

There were three important take-home message for me during this lecture:

start each class with questions and answers from the previous lecture
bring examples from peer-reviewed literature into lectures
recognize that students with laptops in class are using these laptops for class.

After lecture we had to rush (10 minutes between classes is not much time!) through melting snow and mud-puddles to get to the basement of another building for the final adventure for the day…

Arthropod Ecology

Writings about arthropod ecology, arachnids & academia at McGill University

Month: April 2015