Friday, April 30, 2010
The teaching of evolution is very near and dear to my heart and I was excited to find out a coworker of mine is doing a project about measuring people’s familiarity and comfort level talking about evolution by means of natural selection. I may have mentioned this but improving evolution literacy in the
Yesterday I made a comment about my primary mode of instruction being to talk explicitly about evolution unless directly told not to in front of some other coworkers. I had been teaching at a Catholic school that day and the reactions were generally of surprise. “Really? You aren’t afraid to talk about evolution?” No. Absolutely not. I am just as sure about evolution being a part of science as I am the water cycle or force being a product of mass and acceleration. The really weird thing is that we are constantly talking about adaptations as if they are this completely separate aspect of animal science. They are not. Adaptations are a product of evolution by means of natural selection. If you tell students that an animal has an adaptation for living in its environment you are telling students that the animal has evolved. Plain and simple.
We’re also constantly talking about animal relationships. Seastars are related to urchins. Octopuses are related to squid. Just like adaptations, phylogeny is a direct admission to our belief in evolution. If animals did not change they would not be related. So why then are we afraid to use the “e” word or talk about my hero Charles Darwin?
More to the point, I firmly believe that we will get nowhere if all we’re doing is taking baby steps towards teaching evolution. We don’t play this awful game with cosmology or geology or really any other branch of science. It is only evolution that remains a political battle.
So I’ve been wondering for a while: how do you talk about evolution? Do you hold back and reserve your comments and teaching to things related like adaptations and relationships? Or do you really insist on the truth of evolution by being unabashedly afraid to talk about the topic with students and the public? Do you believe as I do that it is our responsibility as science educators to encourage a belief in evolution or do you see it as an unimportant and/or evolving (no pun intended) aspect of the publics view of science? Is it inevitable that an acceptance of evolution by means of natural selection eventually become common? And how long will that take if we are not making active strides towards its acceptance?
As always any thoughts, comments, personal attacks on my character are welcome.
Friday, April 23, 2010
Thursday, April 22, 2010
Sunday, April 18, 2010
This walk in the “woods” had me thinking about two things related to natural history education. First is the notion that this isn’t really natural at all. Our guide even said, fairly close to the start, that the arboretum is more like a museum. I do love museums but you can’t get the same experience of exploring in a real ecosystem from strolling along wide boulevards and seeing intentionally planted plots that are mostly carefully manicured with non-native plants. After having visited the arboretum so many times, getting the tour felt almost like viewing taxidermied animals under glass. There was certainly something educational going on but my brain was thirsty for something different. Something more wild.
The second thing related to natural history education was reinforced by a talk I went to Monday night by a science writer. This is the role of the non-expert in science education. Now, I am certainly not an expert in science. I have a master’s degree but it is in education so I certainly fall into this category. Also, I would hazard that most science education below the university level is being done by non-experts. But I was struck by the amount of “I don’t knows” given by the tour guide and dubious or downright incorrect information given by the speaker on Monday. There’s nothing wrong with saying I don’t know. It is much preferable to giving out incorrect information. But I had come to the tour to learn about plants and there were very few plants I really feel like I learned anything about. And I cringed several times at Monday’s talk when I heard something that I knew would be taken the wrong way by the average listener.
Both of these experiences got me thinking: what is the role of the non-expert? What responsibility do any and all of us who teach science to young people have to make certain we have our facts straight and that we keep current with new research that may alter those facts? What methods and sources do we use to do this?
For myself I believe in nearly constant learning. I try to read science news on at least a weekly basis if not every day. When I don’t know the answer to a question someone asks me I almost always look it up. But then I have the time and curiosity for this. So I’ll leave you with the photos of arboretum plants.
Lavalle Cork Tree
Assorted Cherry Trees
Friday, April 9, 2010
Recently I have been trying hard to not take for granted
There are a number of ways to use squirrels to teach about animals. They can illustrate habitats and populations by encouraging students/young people to count the number of squirrels they can find in and around their yard or school. You can try to see if these numbers change seasonally or from year to year. It is often fairly easy to watch these creatures building nests and finding food. These interactions with their environment can show how animals get all they need from their habitats.
Getting even simpler than that, even the very young can practice their animal observation skills. This can be done in a couple of ways. The most basic practice can be done from in doors. Watch the squirrels for maybe fifteen or twenty minutes, of course depending on interest and attention span, and try to describe the kinds of behaviors you see. Maybe you can repeat the exercise a few times and see which behaviors are most common and which are the least common. Another way to use squirrels is to practice up-close wildlife observations. Encourage young people to be careful and quiet while approaching the animals. See how close you can get and how much of their behavior you can observe before the squirrel takes flight. Try it out with yard birds too.
The inner nerd can’t resist suggesting you introduce some basic phylogeny with squirrels. Talk about the fact that they are mammals. Find some birds, insects, maybe even a reptile or amphibian (it’s getting to be the time of year you can usually find toads and salamanders around) and discuss how they are similar and different.
Another great model organism is the ant. Ants, like squirrels, are ubiquitous. They also have very different behavior and societies from squirrels. They are vastly different phylogenetically, being part of the world’s biggest family of animals, the arthropods. Watching and studying insects can provide a great gateway to discuss animal relationships with young people. How are these creatures similar? How are they different? What makes an insect an insect?
One of the most rewarding natural history education experiences I have had was working with young people in community centers during my AmeriCorps year at the Providence Children’s Museum and taking them outside to look for wildlife. Two coworkers and I led “nature walks” out in whatever green space was available at the community centers and we were always able to find living things, especially insects. I remember one student in particular watching ants for probably twenty or thirty minutes, making detailed notes about their behaviors and social interactions. It really was a pleasure to see young people engaged in such amazing science. We also had very productive conversations about what it meant for something to be alive.
If you work with young people or have young people in your lives at home I encourage you to help them become young naturalists by using squirrels and ants as model organisms. They are easy to find and really quite interesting animals. A lot of young people have an innate curiosity about the natural world and it often doesn’t take much to produce some really solid science learning.
Thursday, April 8, 2010
I am very excited to bring you another post about an amazing native plant. It has been blooming time for the skunk cabbage for a while now but the rain and the job have held be back from getting out and taking photos. This morning I finally had a chance.
Though the skunk cabbage has a reputation for its pungent smell and is a ubiquitous and perhaps overlooked species around the
The skunk cabbage grows in wet areas, streams, ponds, wet woods, and these buds can often be seen pushing up through ice or snow. How this happens is probably the most amazing feature of the plant. The skunk cabbage actually produces its own heat in much the same way as a warm blooded animal. It only does this at the beginning of its life cycle for about two weeks but can raise the temperature by up to 20 degrees Celsius.
above: the skunk cabbage buds
The roots of the skunk cabbage contain a large supply of starches which are broken down in a biochemical reaction that also consumes oxygen (that’s right, the plant consumes oxygen). These reactions produce the heat that allows the skunk cabbage to be one of the first plants to bloom each spring. Studies have shown that the plant consumes about the same amount of oxygen and produces about the same amount of heat as a mammal of the same size. I think the fact that there are “warm blooded” plants is really a bizarre and fascinating one; even more fascinating that these processes are taking place in plants that are so common in the northeast.
The consumption of oxygen also produces an air current which carries the carrion odor compounds also made by the plant. This twin process spreads the smell of the plant out across its habitat to reach its pollinators: mostly carrion-feeding flies. Scientists have found the same compounds in the skunk cabbage’s family as in actual carrion. These compounds have great names like putrescine and cadavarine.
I managed to find some skunk cabbages still budding this morning so you probably still have time to experience its amazing heat production capacity this year. Go out to a wet area and you should be able to find the plant. If you stick your finger just inside the spathe you will notice that your finger warms noticeably. I really can’t get over how amazing these plants are.
Tuesday, April 6, 2010
I went to the second
In any event the lecture last night was on hermit crabs. I spend a lot of time with hermit crabs at my job right now so it was nice to learn a little bit more about them. The lecturer, Randi Rotjan, is a post-doc fellow at the NEAq and spends most of her time studying corals but during one trip to
The basic focus of her research on these animals is on vacancy chains. This is what happens (not just with hermits but with any organism that uses discrete, limited and reusable resources) when one crab chooses a new shell and leaves his old shell for another crab to occupy who then leaves his old shell behind, etc. etc. Just one switch creates a chain of switches and she has found that around 10% of the population in the wild can end up in a better shell. This process has been compared to human behavior in real estate and also with job openings.
Before going off to
Once studying these behaviors in the lab and in the field with terrestrial hermit crabs she (being a marine biologist) wanted to look at them in marine crabs. Luckily the
So gathering all that together she found two populations of pagurus longicarpus with different living conditions. One had somewhat poor conditions (more damaged shells) and the other had better conditions. It is still unclear why the different areas have these different conditions but it provided her with animals who were accustomed to different social pressures when choosing a shell. Interestingly she found no difference between the two groups in terms of how crowding and damage influencing their vacancy chains. She also found no difference in the average lengths of the vacancy chains. But what she did find were very different social behaviors in the poor condition group such as far more waiting, longer investigations of a single shell, more aggression and generally more interactions with their fellow hermits. More work is going on and I really can’t wait to see how it turns out. Seriously!
Just one more fun fact about hermit crabs: all of them, even terrestrial crabs, have a marine larval phase. I found it interesting to think that these larvae can be carried off to a new island to populate it or to introduce new competition for resources from a previously absent species. It’s a very different lifestyle from either fully marine or fully terrestrial arthropods.
Saturday, April 3, 2010
Friday, April 2, 2010
I’m about to get quite busy for the month of April which is great but I may have to slow the pace of my posting. This will probably be fine considering there hasn’t been a ton of responses to my posts, yet. I wanted to try to answer as many of the questions about lichens as possible. The photo above isn’t the best but it is the only example of a lichen I could find in my collection.
Lichens are a kind of text book example of symbiosis. Symbiosis means “living (bios) together (sym).” It is whenever two organisms form a relationship in which both benefit. Sometimes these relationships are necessary for the survival of one or both members and sometimes the organisms can live without them. In the case of lichens it is a relationship between a fungus and either a green alga or a cyanobacteria. These two kinds of organisms are both single-celled, photosynthetic creatures whose cells contain the same kind of chlorophyll as land plants’ chloroplasts.
Lichens acquire their food entirely through photosynthesis. So why do those little one-celled creatures need the fungus? They don’t. Most species of alga and cyanobacteria that are found in lichens can and do survive by themselves. But there is an advantage to forming a relationship with the fungus. Lichen-forming fungi produce a substance that speeds photosynthesis, making it a bit more efficient. They also absorb enough water for both the fungus and their photosynthetic friends so these cells don’t need to worry about getting water. It seems to be a very good advantage for the unicellular symbionts because many lichen-forming fungus species actually parasitize the chlorophyll containing cells.
They do not, however, tend to parasitize the trees they may be growing on. Most lichens use their growing surface simply as a substrate and do not have roots or other structures that take nutrients from below.
The coolest fact I found about lichens is that some species can live up to 4500 years. I don’t know what the life spans of most fungus are but that seemed pretty impressive.
It’s interesting how much parasitism, symbiosis and commensalism have already come up on the mycelial network. This is a perfect illustration of how the biological world is not set out in discrete parts but forms a web of interactions and relationships; it forms an ecology. What are some of your favorite examples of organisms living together (whether parasitically or not)?