Biologists would like to understand how a bear, who eats continuously throughout the summer to lay down fat reserves for the winter, can have cholesterol levels that would be high for a human, but not suffer the hardening of arteries that one might expect. And what about the bone loss one would expect from months of inactivity?  Humans on bed rest can lose 3-4% of their hip bone minerals from lack of weight bearing exercise.  Bears show no signs of bone loss or osteoporosis as a result of their long rests.  It is likely that the genes involved exist in our cells too, but they just aren’t being used in the same way.

We clearly have a lot to learn from our hibernating friends. Teams of researchers in Sweden have actually been studying Brown bears to learn about these interesting phenomena.  How do you study wild Brown bears you ask?  You tranquilize them while they are hibernating, collect as many samples as you can, and get out before they wake up!  For the full story on hibernation, go to: http://www.sciencenews.org/view/feature/id/338318/title/Lessons_from_the_Torpid.

For most of the year, deciduous trees are green because of chlorophyll in the chloroplasts.  This pigment helps harness energy from the sun to fuel photosynthesis, or food production.  In the fall, days become shorter and sunlight more sparse, so plants begin to prepare for the winter – a period during which they rely on stored nutrients.   Nutrients are stored and superfluous leaves are shed , but before that, the chlorophyll begins to disappear, revealing other pigments such as yellow and orange that weren’t visible before.  Sometimes during this process, new pigments (such as reds) are produced as well.

This is controlled by up to 35 genes that can turn on and off in response to the reduction of sunlight hours.  It is a great example of the interaction between an organism’s DNA and its environment, a phenomenon many people are unaware of.  The traits and characteristics of all living things are the result of a combination of its genetic makeup and its physical and chemical surroundings.  To learn more about this type of interaction, go to chapter 35, “DNA responds to signals from outside the cell.”

I happen to work at an institution where evolution is revered as the underlying theme that explains life and all of its processes.  For a biology teacher it’s a comfortable place to be.  I suppose I am spoiled. When I travel to schools, I am on occasion told by teachers how happy they are that I am presenting evolution for them.  It is a required part of the New York State science curriculum, but some of the teachers who are supposed to teach it, don’t want to.   It makes me wonder.  Are they uncomfortable with the science?  Are they afraid of parents or students lashing out at them?  Does the scientific theory of evolution somehow conflict with their religious beliefs?   I don’t know the answer.  I’m sure it’s a combination of several factors. 

My gut feeling is that most teacher reticence is due to lack of understanding.   I would feel very uncomfortable if asked to teach a topic I didn’t fully understand, and unfortunately this is what’s happening.   I think we need better teacher training, especially for elementary teachers who receive very little training in science.  Everyone who receives a degree in general education or in science education should have to complete a course in basic genetics and/or evolution.   This would significantly reduce the negativity associated with teaching evolution, and could help produce much happier teachers!