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The New Ecology
The following are notes taken on Eugene P. Odum's lecture "The New Ecology: How Systems' Behavior Changes With Scale" given at the Institute of Ecology, Georgia University in the year 2000.
Please note that the following sections are presented in an order slightly different from the lecture itself. This was done so as to make it easy to understand from beginning-to-end. Some extra explanations and resources are also given throughout.
What is "Ecology"?
The word "Ecology" is derived from the Greek word οἶκος ("oikos"), meaning "household". [Funnily enough, it is the same root of the word "economy", hence the prefix "eco-".] Ecology covers a broad range of information from many different sciences, such as the "Earth Sciences" (e.g.: Geology, Biology, Meteorology, Oceanography, etc.), as well as the "Social Sciences" (e.g.: Anthropology, Psychology, History, etc.).
This is because Ecology studies "Ecosystems". Ecosystems take into account the whole "household", the biological environment (i.e.: organisms, including human beings) and the physical environment (i.e.: minerals, climate, etc.). The environment is not simply a "stage" in which organisms exist. Organisms both respond and adapt to environments, but they can also change environments. For example, "cyanobacteria" within the sea put oxygen into the air, thus changing the entire environment of the early Earth.
Photos taken of the whole Earth during the space missions of the 1960's lead to a worldwide "ecological awareness". Generally, it gave people a visceral understanding of the fragility and finite nature of many of the Earth's resources to see all of it at a glance. [Although we might take it for granted now, please keep in mind that there were no well-known photographs of the entire Earth before this time!]
Levels of Organization
What one sees on a small scale can be quite different from what one sees on a large scale. There is an "ecological hierarchy":
Image adapted from one within the book Fundamentals of Ecology (5th Edition)
There are two different ways that things are regulated depending upon their size:
• Homeostasis ("Set-Point Control")
This is when a specific trigger maintains a system at a steady-state (e.g.: hormones and genes that stop growth at a certain point).
• Homeorhesis ("Pulsing Paradigm")
This is when a system maintains a particular trajectory by oscillating back and forth (e.g.: boom-bust cycles within the stock market).
Notice that, from the organism-level down, things use Set-Point Control. From the organism-level up, things follow the Pulsing Paradigm.
There are also two types of hierarchy:
• Nested Hierarchy
This is when each level is the sum of levels below it. The above diagram is a Nested Hierarchy. Natural systems have a tendency to do this (e.g.: an Ecosystem is a collection of "Populations"). The "Ecosphere" contains the entire Earth.
• Non-Nested Hierarchy
This is when each level is distinct from the others. Human-made systems have a tendency to do this (e.g.: a "sergeant" within the army is not simply a collection of "privates").
It is easy to move between levels in a Nested Hierarchy, while it is less easy to move between levels in a Non-Nested Hierarchy. The former is flexible and inclusive, while the latter is more rigid and narrow.
Some functions are the same throughout different levels of the hierarchy, while others are different for each level. Functions that stay the same are referred to as "transcending functions".
Transcending functions include:
• Regulation (such as Homeostasis and Homeorhesis)
• Energetics (such as "The Laws of Thermodynamics", which describe how heat 'moves')
• Development, Growth
• Behavior (such as cycling, like the "Krebs Cycle" within the Cell or the "Biogeochemical Cycles" within the Ecosphere)
Important Concepts of System's Behavior
New properties start to emerge when things are put together. These are called "emergent properties". This sometimes leads to behavior that may not be obvious. We will talk about seven important concepts here...
Systems have a tendency to transition from Set-Point Control to the Pulsing Paradigm.
Nature does not go permanently into a steady-state equilibrium. Things continually oscillate between limits. Therefore, the Pulsing Paradigm is predominant. Growth beyond these limits leads to a crash.
Enrichment (or "Eutrophication") is to increase the amount of nutrients in a system. It increases activity but reduces diversity (i.e.: the thing that is nourished becomes dominant).
While it might seem counterintuitive, pests and diseases usually prosper within an overly enriched environment! For example, feeding cows nutrient-rich corn interferes with their ability to process dry hay with their "rumen" (a stomach-like organ). This is a big reason why the cattle in feed lots often get diseases. Note that the feeding of corn is only done to get a more fatty piece of meat.
The size of a system relates to its maintenence costs through a mathematical relationship called a "power function". To give an example: When a city doubles in size, it costs more than double to maintain it.
As Eugene points out, you cannot have a viable system if the cost of maintaining it is greater than what you can pay. This means that all large cities are literally parasites! For example, the infrastructure of New York is propped up by outside "subsidies" (i.e.: financial aid from the government) because the city does not maintain itself.
In order to understand if an Ecosystem is sustainable, we have to look at its "P/R Ratio". "Production" (represented by "P") is the amount of energy going in. Within a young system, most of this goes towards growth. "Respiration" (represented by "R") is the amount of energy being used to maintain. At a certain size, it doesn't make sense to continue to invest energy in growth.
Many Ecosystems move from a predominance of "r-Selection Species" (i.e.: organisms that have lots of children, but a shorter lifespan) to "K-Selection Species" (i.e.: organisms that have fewer children, but a longer lifespan).
"Mutualism" is when organisms work together. "Competition" is when they struggle against one another. In the early stages of a system, Competition usually dominates. In later stages, Mutualism dominates.
Mutualism increases with Ecosystem development, complexity, and nutrient scarcity. It is Mutualism which maintains communities. For example, "mycorrhizal fungi" (little tube-like mushrooms that connect to plant roots) make underground networks that allow trees that get lots of sunlight to share nutrients with trees that don't get enough. Together, the entire forest is sustained!
In short, "When things get tough, it pays to cooperate." In order for humans to move from being a r-Selection Species to a K-Selection Species, there has to be Mutualism.
Humans not only impact the environment, they have created "Novel Ecosystems" or "Technoecosystems" (such as cities) that have no parallel in Nature. All Technoecosystems combine to form the "Technosphere". At the present moment, nearly all of the Technosphere is antagonistic towards the Ecosphere. How can we make it more Mutualistic?
One of the main differences between the Technosphere and Ecosphere is how they handle energy. Again, we point out that cities are parasitic. They require a huge amount of outside inputs in order to be sustained. In an Ecosystem, the amount of energy available as you go down a "food chain" decreases (i.e: there are fewer "predators"). In other words, if animals eat meat, there has to be fewer of those animals overall if they are going to survive.
There are also differences in how the two obtain energy. The Technosphere is predominantly "fuel-powered". Everytime energy is exchanged, some is "lost" to the environment and some is refined (i.e.: it becomes of a "higher" energy level). Even though nearly all units of energy deal only with quantity, there is also a difference in the "quality" of energy. For example, while "solar energy" is abundant, it is of a "lower" quality. Unless it is concentrated in some way (like it is within "fossil fuels"), it usually cannot exert a lot of power. [The Physics term for this phenomenon is "energy density". Please keep in mind that there have been some developments in solar energy and its applications since this lecture was filmed in 2000.]
If we want it to survive, we have to completely change how the Technosphere both obtains and handles energy. Eugene encourages us to find solutions, and gives a couple of examples of some of the types of things that we could do:
• By making certain crops profitable for small farmers, they do not have to migrate to the cities to make money. This would decrease poverty and minimize the excessive growth of cities.
• By making cities more self-sufficient, such as by growing crops within the city itself, it would be less parasitic to the resources of the countryside and cut down on pollution.
"Reward Feedback" is when an organism sustains its resources. Things "co-evolve to co-exist". For example, grazing animals (like cattle) produce chemicals in their saliva that help the grass that they eat to grow back.
We should value what Nature does for us instead of destroying it for temporary gain. Let's all come together (i.e.: in an "interdisciplinary approach") to take care of each other and to respect Nature.