Tuesday, June 12, 2012

Transients in Space and Time


We do not live in a closed system and it is hard to keep any system closed, as any biologist, chemist, or physicist can attest when trying to perform a controlled experiment.  Since our world is constantly in flux, entropy rules (2nd law of thermodynamics).  But in the midst of disorder, there arises order and “rules” by which the universe operates.  The organizing of raw materials and forming of complex ecosystems shows us this is so.  The movement of these raw materials between spatially separated habitats/ecosystems in many cases provides stability to both systems.  

Think of human populations for example.  When people are moving from one place to another (e.g. Iowa to LA), Iowa has less demand for resources and LA has more demand for resources.  Demographers are always thinking about these sort of ideas.  What communities are growing?  What communities are shrinking?  If you look at this on strictly on a consumption basis, the more people there are in a place, the more that place will need resources.  If you look at on an economic basis, more people equals more tax revenue.  There are negatives and positives to the flow of people from one place to another.  However, there is usually an equilibrium.  For example, 10 people might move from Iowa to LA, but then 10 other people move from LA to Denver, and then at the same time 10 people are moving from Denver to Iowa.  In this case, the net flux is 0.  But if we disregard these transients (whether its organisms, nutrients, predators, or detritus) when we are looking at an ecosystem, we are not really seeing the whole picture.  And in many cases, there might be an equilibrium over the long run, but seasonal inputs can have a strong impact on the health of a community.  

For example, take a small coastal town in Maine, who for the majority of year relies on small businesses for income stream, but really makes most of their money during the summer vacation season.  Temporal variation in inputs allows this community to be stable.  It has been shown the same for some terrestrial consumers; they receive important nutrients via resource subsidies during a critical part of their development or life history cycle (juveniles for growth, adults for reproduction, or before a major migration or hibernation event, etc.).  During the holiday season, retailers can earn between 25-40% of their annual sales.  They wouldn’t be stable without holiday sales.  They can provide services the rest of the year based on the money they make during this season.

We can think of this analogy on a spatial sense, too.  Although times have changed with the advent of the internet and online delivery capabilities, the chant of retailers in times past was always: Location, Location, Location!  You want to be seen, you want to be heard, so people will come to you.  In the same way, animals and plants will be in places where they have access to resources that are cheap and abundant.  If you live in the middle of Nebraska, both the quantity and quality of resources you will find might be lacking.  So, what is the feedback?  Do people live around other people because of availability and variety of resources?  Or is there greater availability and variety of resources because there is more people?  I think historic availability of natural resources may be able to somewhat explain the distribution of the population of humans on earth (about 40% of the world’s population is found within 100 km of the coast).  Now, since the advent of globalization and flattening of the world, it doesn’t matter where you live.  The resources can be brought to you.  

Friday, June 1, 2012

Fish is Fish


So, I'm learning about learning today.  Of course, my goal is to be a college professor someday, but unfortunately in graduate school, they don't really teach you how to be a teacher.  So, I've started to learn a bit on my own by reading a book called "How People Learn" put out by the NRC (National Research Council) back in 1999.

I'll just share something quick I learned today.  Everyone has preconceived notions about a wide range of topics: some of them are correct and some of them are incorrect.  But they are all based on previous knowledge and experience.  There was a children's book written in 1970 by Leo Lionni called "Fish is Fish", which illustrates this principle clearly as a small tadpole becomes a frog and reports back to his friend, the fish, what life on land is like.  If you have the time, watch this short 5-minute video which reads the story with some animations taken from the illustrations from the book itself.


When you teach, you need to realize not everyone has the same background, upbringing, and personal experience.  Providing an atmosphere that allows the student to discover the truth from themselves is one of the keys to successful teaching.  Hopefully, when I have my own classes someday, I can provide a wonderful atmosphere for learning and students can internalize and remember what is taught (not just for the test at the end of the semester, but for life).