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.
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.