Saturday, March 19, 2016

Spring Phenology

Note: This program first aired on March 19, 2016.

Years ago when I was in college a friend commented on the phenomenon of March break. He said that you leave for break and it is winter, and when you come back to school, it is spring. That was certainly the case this year, I went away for a week and when I returned I found the seeds germinating in the green house, wood cocks calling in the evening and elderberries in my yard breaking bud. The next day out walking in the spring like sunshine I came upon alders shedding pollen from their male catkins, another of my favorite early signs that spring. It may get cold again, and snow, but the mechanisms of spring are now underway, there is no turning back. I’ve been paying attention for enough time now that I know soon I’ll hear wood frogs on sunny afternoons with no wind, and after that will come the spring peepers. After the alders will come the blooms of beaked hazelnut, and after that red maple. The birds will return, one day I’ll look up to see turkey vultures and broad winged hawks, hear phoebes in the morning, and hermit thrushes in the evening.

Keeping track of the dates of all of these spring occurrences is a hobby I came to on my own. Do it for a few years and you have a living record of the seasons in your home ground, it becomes addictive. I can look back and see that last year I didn’t hear a wood cock at my house until April 1, this year I heard them on March 12, about the same time I heard them in 2013. Last year the alders started shedding pollen on April 14, this year they started a full month earlier, on March 13. I can make notes on the winter weather, but there is nothing as telling as seeing how early or late the first signs of spring arrive. Little did I know when I started that I was participating the time honored naturalist tradition of observing and documenting the timing of seasonal events in personal journals. It even has a name—phenology: the study of the timing of recurring natural events.

The neat thing is, phenology has made the big time. No longer is it just the pet of introverted nature nerds (like myself) everywhere, quietly rejoicing in the first bloom of shadbush, noting the emergence of the coltsfoot or watching for amphibian egg masses in local vernal pools. No, phenology is now big science. Climate scientists have discovered that naturalists’ records are a treasure trove of data related to how ecosystems are adapting and changing as climate warms. Just as arctic researchers are pouring over the journals of arctic explorers and sailors to document the changes in sea ice over the past two centuries, climate focused biologists and ecologists are reading the journals of 18th and 19th century naturalists to establish how the timing of natural events has changed in the industrial era. Looking at a large number of records, over a long period of time is best. If we just had to go on my ten years of data, what would we make of hearing the wood cocks in early March this year, not till April last year, and in mid March the year before that? We really couldn’t make much of these data, other than to broadly state that woodcocks call in the early spring, which we already know. Reading and compiling naturalists’ seasonal observations is one way scientists are finding data, another is the growing citizen science movement. Now you don’t have to simply keep a meticulous nature journal that you hope someone will find useful after you die, you can participate in a state or national phenological programs and start sending useful data to scientists immediately. The Signs of the Seasons program is based at the University of Maine and has New England as its focus area. The USA National Phenology Network collects similar information at a national level. Both have well developed online presences and I encourage you to check them out and consider volunteering.

Here in the 21rst century, I’ve inadvertently discovered another way of keeping records of spring phenological events. Looking back through Facebook posts I see that I have excitedly posted every year the day I first heard woodcocks peenting in the marsh beyond my house. Ditto for wood frogs. And nature oriented friends are doing the same. This past winter wasn’t long or particularly hard, but it was weird, and people are ready for the predictability of the signs of spring. It is refreshing that so many people find something as simple as hearing a woodcock so exciting. I think we’ve finally found what Facebook is good for.

Read all about UMaine’s Signs of the Seasons Citizen Science New England Phenology program, find out about training sessions and sign up to participate!

The USA National Phenology Network collects citizen science data at a national level

Using Thoreau’s journals to track climate change:

A more science oriented article about Thoreau’s journals, including a researcher from Acadia National Park

Saturday, March 5, 2016

Biology Midterm:What we learn from teaching

Note: This program first aired on March 5, 2016.

This semester has been a busy one, as I am teaching the freshman biology class for our Ocean Studies majors, and find myself relearning topics I haven’t thought about in a long time. This week we reached the midway point of the semester, and in the time honored tradition of academic institutions everywhere, we are having a midterm exam. I don’t give a lot of tests in my classes, but I do feel that it is prudent to stop every once in a while and take stock of where we’ve been and what we’ve learned. Just as the students review their notes and try to prioritize the content of the last seven weeks, so do I. I want to craft an exam that emphasizes the most important ideas and provides an opportunity for students to actually apply those ideas, rather than simply parrot them back at me.

In reviewing my notes from the first several weeks it became clear we had covered some serious ground. It took a few days to distill out the big ideas, but eventually they floated to the top. We started by thinking about the biggest idea you can in a biology class—what is life? How do we determine when something is alive or not? In many ways this is clear cut, things that are alive are made of cells, use energy, have genetic information, have a means of reproducing them selves and evolve over time. The longer you spend in biology though the more amazing and wonderous life gets, and I hope that my students will spend their careers parsing its beautiful nuances, rather than resting on these five broad criteria. A central tenant of modern biology is Cell Theory: all living things are made of cells and all cells arise from other cells. When you think of the implications of that in your own body, all of your cells, the trillions of cells in your body, came from one original cell, the fertilized egg in your mother’s womb. And all of us as leaves on the tree of life, came from one original cell, a mash up of phospholipids and primitive RNA in a hydrothermal vent or mud volcano nearly 4 billion years ago.

We are doing the cellular biology part of freshman biology this semester, trying to understand how those fundamental units of life work. To do that we cover the basic classes of biological molecules: proteins, nucleic acids, carbohydrates and lipids. Each of these classes plays a critical role in cell function, and therefore life. Proteins have the highest diversity, because they have over 20 different subunits (called amino acids) that can be arranged like beads on a string in a nearly infinite number of different combinations. Carbohydrates also have relatively high diversity, based not on having lots of different kinds of sub units—because carbohydrate subunits are very similar and there aren’t that many of them—instead carbohydrate subunits have many many different ways they can get hooked together. If proteins and carbohydrates were Lego sets, proteins would be a set with many different kinds of  small Lego blocks, carbohydrates would be a set with lots of blocks that were all the same, but each of which had several places it could be connected to another block.

We also looked at nucleic acids, which look a bit like proteins, but actually hold all of our genetic information, and at lipids, which make up the membranes of all of our cells and the specialized organelles within those cells. The cell is an amazing structure, functioning on a scale we can scarcely understand, even though we are made of cells. Gravity doesn’t really matter to a cell, the forces that dominate the cellular environment are electrochemical gradients, concentrations of various ions and molecules and electrons that push and pull substances to one side of a cell membrane or another. The pull is passive, it happens without any work involved. The push however, requires an energy source. To push a substance against a concentration gradient takes energy, just like pushing something heavy uphill. And what we find in cellular function is that, just like Sisyphus, our cells keep pushing things up hill, just to let them roll down again. In the Greek myth this was a punishment, but in cellular respiration it is a clever trick. Our cells use spontaneous reactions, reactions that result in a release of free energy, reactions that roll down hill on their own, to power non spontaneous, energy absorbing reactions, up hill reactions in a perfect system of energetic coupling.

We learned that at this level, biology is really chemistry. Life is just an organized system that fights entropy, the tendency of a system towards disorder in the absence of input of energy. Life organizes and inputs that energy, pushing the burden back up the hill, over and over and over again, forming the chemical bonds that would otherwise NOT form. I hope my students have been touched by this wonder. I know I certainly have.