The BioGeek Memoirs: Conifers

Conifers. Oh, my goodness, who doesn’t love conifers? As in wonderful smells, pinecones, Christmas trees, snowy days, and fun trips to the mountains. I grew up in southern California and the conifer that I loved as a child was the ponderosa pine. It had bark that pulled apart into jigsaw shaped pieces. The bark smelled like butterscotch (or maybe vanilla), and the long needles grew in little bundles of three… perfect for braiding!! The cones are perfect for dabbing with white paint, sprinkling with glitter, and then using for holiday decorating. Perfect tree, the ponderosa pine. It is beautiful and kind of feathery with clumps of needles near the ends of branches.

Then I moved to Colorado.

Trees in Rocky Mountain National Park. The large tree on the left is a ponderosa pine.

Oh, boy, did I need to learn a lot more about these trees. There are a lot of conifers in Colorado, and they grow in different environments and elevations as you drive up into our mountains. The ponderosa pines are found at lower elevations (5,000 – 7,000 feet) and then as you drive up into higher elevations different trees start to show up as the ponderosas disappear. In high elevations they are nowhere to be found, and the trees that are around 10,000 feet are specialized and designed to live in challenging environments. One tree has branches that are so flexible you can tie them in knots (limber pine), and another is just dripping in anti-freeze sap (bristlecone pine).

One summer I took a forestry class and spent a couple of weeks coring trees and recording their elevation and growth into a large data base maintained by the U.S. Forest Service. I learned to shield my coring activity from casual hikers (Yeah. People in the Boulder, Colorado might take extreme exception to your activities if they suspect that you are harming a tree… tree huggers are alive and well here!) and developed an appreciation for the impact of local environmental conditions on trees.

As a biology teacher I struggled to teach plants (yawn) and taxonomy (super-yawn) to my students. I searched for hands-on activities that could be used to teach these units, and finally remembered that the teachers in the high school where I did my student teaching ran a big lab where students used keys to identify Colorado’s conifers. Another teacher had keys that we could adapt to use with the activity and off I went on a road trip to collect conifer samples in the Rocky Mountains west of the town where I live.

Why use conifers? Well, they are pretty darn interesting if you think about it. The plants produce two different types of cones (seed, on the left, and pollen, on the right) and have leaves that are needle like. They are older than flowering plants in evolutionary terms and have some cool adaptations. They use wind to reproduce and have turpentine and other organic compounds that allow them to stay alive in cold climates. Cut branches are hardy enough to survive handling by hundreds of students as they worked the activity. Yeah. Conifers were the ticket!!

So, how did this work? The students picked up bins with samples of branches and cones from the plants and, using the keys, figured out what conifer they had. The key took the students through a decision tree using needle and cone characteristics that became more and more detailed as they moved down the decision tree.

For instance, were needles single or in clusters? Were they round or flat? Were they sharp or soft to the touch? (Left to right, these three are the blue spruce, the bristlecone pine, and the white fir. Spruce needles are round and sharp, pine needles grow in clusters, and firs are flat needled and soft to the touch.)

Differences in cones can be extremely helpful in identifying the species. Left is the seed cone from a Douglas-Fir and to the right the seed cone from an Engelmann spruce.

The end result of the activity: this student has colored conifers in each genus a different color. See what happened?

I bet you can see it without me saying anything. Conifers that are closely related have very similar characteristics; closely related species are very difficult to tell apart and the differences are subtle. In the real world the final sorting is sometimes done by differences in DNA. It was easy after this activity to move into the more abstract topics of classification (Kingdom, Phylum, Class, Order, Family, Genus, Species) and then link back to evolution with the tree observations: some closely related species actually grow at different elevations on the mountain. Living in different environments, these trees don’t reproduce with each other and have gradually grown apart into different species.

I struggled to key out conifer samples as a new biology teacher. Nowadays I can identify the tree while driving by on the road and I didn’t bother to drive up into the mountains anymore at the end of my teaching days. I would just pull the car over and clip off a little branch and grab some cones if I could: gone in 60 seconds was my motto! There are some great trees in my local park and the high school where I used to teach had 5 different Colorado conifers on the property. I have a Douglas-Fir in my back yard. I can get at least 11 different conifer samples in a one-hour drive around town. I haven’t taught this activity in years and yet I still look for great trees while out on errands.

Because conifers make me happy!!

After all, who doesn’t love conifers?

The view from my front window this morning.

DNA, Evolution, and The Signature of All Things

It seems that my life has become an exercise in synchronicity and random coincidences. I checked a book out of the library, read one that had been sitting on my NOOK for weeks, picked up a book on a sale table at Barnes & Noble, and remembered a video that I used to show my biology classes each winter. Strangely, they all fit together. No matter what I thought the book would be about, it began to talk about DNA and evolution at some point. How bizarre! All three books (The Signature of All Things, The Sociopath Next Door , and Orfeo) echoed things that I remembered from the video series Intimate Strangers: Unseen Life on Earth, which was broadcast in November 1999 on PBS. All these connections are just churning around in my head; here’s my thoughts about the video and one of the books, The Signature of All Things by Elizabeth Gilbert..

The episode that I’ve become fixated upon while reading these books is the first one in the Intimate Strangers series, The Tree of Life. If you would like to actually watch this episode (and all the others, of course) they are housed at Microbe World. The  biology classes saw this video when they were learning about taxonomy and the kingdoms of life.  In the video we meet Dr. Carl Woese,  a microbiologist of singular vision and drive. Working alone for years, chasing patterns in the mutations of a small, heavily conserved region of DNA, he pieced together the pattern of relationships between living things on earth. Using this information, Woese was able to determine the sequence of descent, establish common ancestors and eventually created a new “Tree of Life”. His work shook up the taxonomy world as domains were created (a grouping above “kingdom” in the normal sequence of “kingdom, phylum, class, order, family, genus, species”), and our understanding of evolution was enriched and altered forever. One man, working alone, chasing patterns in the musical score of life that is DNA, was able to change our view of the natural world.

This is what Dr. Woese says on camera in the video:

You have to have your own particular sensitivity to the world, and there has to be parts of it that are beautiful to you, because they’re beautiful to you regardless of what anyone else ever thinks. You see this all the time in an artist, and you see it also in good scientists.

This brings me to The Signature of All Things. In this book we meet Alma Whittaker, the daughter of a botanical robber baron. Raised in a wealthy and enriched environment that encourages learning and allows Alma to meet many eminent people in the scientific world, and possessing the logical mind of her mother, Alma is nonetheless trapped within the small world of her father’s estate. She sets up a lab in the carriage house, explores the land around her, and spends the majority of her life studying the world of mosses and liverworts. Small as her life becomes contained within the estate as she handles her father’s business and the details of life, it allows her to follow her “own particular sensitivity to the world” as she observes the interactions and changes in her moss populations; in truth she sees that mosses living within a timeframe much slower than our own engage in the same behaviors as the animal kingdom around her. It is a life of study in a world that is beautiful to her, and Alma is a good scientist.  Life altering events cause her to leave the estate following her marriage and the death of her father, and she travels to Tahiti and Holland, where the glory and chaos of a larger world help her develop a theory of evolution based on her understanding of mosses. This theory, while never published, propels her into a new life within her mother’s Dutch family and she obtains standing in the scientific community based on her own merits.

This was a good book. I’m a biology geek, so of course I liked it! Is it believable that Alma could have slowly come to a theory of evolution on her own? Sure. This book is a glimpse into the world that gave birth to the original theory. Science can always be pursued by a committed individual of observant and reflective nature. This was the time of Charles Darwin, Gregor Mendel, and Alfred Russel Wallace; Alma would have had access to the same ideas and published works that they had. All three of these men worked alone as gentlemen scientists, observed nature, designed experiments and looked for patterns. They wrote each other and shared their scientific ideas. Darwin and Wallace arrived at the mechanism of natural selection through independent work at about the same time; they published jointly in 1858. Mendel published his work in 1866, which would have been extremely helpful to Wallace and Darwin, but they missed the boat on that one! It will be almost 100 more years before we understood that the molecule of inheritance is DNA, and many more years before Carl Woese read the musical score of DNA to finally see the signature of all things.

Alma never publishes her theory because it can’t explain why all people aren’t sociopaths. Why does altruism exist, she wonders? How can natural selection account for what we see in people around us? Richard Dawkins addresses this very issue in The Selfish Gene. Guess what’s next on my reading list?