Chapter 3 Botkin and Keller

Question 1

What is a system?

Answer 1

a set of components, or parts, that function together as a whole

ex: organism, city, river, the earth

Question 2

What is an open system and give examples:

Answer 2

in an open system, some energy or material (solid, gas or liquid) moves into or out of the system

Ex: the ocean, water moves into the ocean from the atmosphere and out again

All real systems that we deal with in the environment are open to the flow of matter, energy and information

Question 3

What is a closed system and give examples:

Answer 3

No matter moves in or out of the system. Energy and and information nmvoes around in the system but does not go in our of of the closed system

ex: the earth’s atmosphere

Question 4

What is a static system?

Answer 4

A static system has a fixed condition

Ex: a birthday balloon attached to a pole - it stays in one place

Question 5

What is a dynamic system?

Answer 5

A dynamic system changes, often continually over time.

ex: a hot air ballon, moves in response to the wind and air density

Question 6

What is classical stability?

Answer 6

A kind of static system, but has a constant condition, and if it disturbed from that condition, it returns to it once the disturbing factor has been removed

Ex: pendulum on a grandfather clock that swings back and forth

Question 7

Is the population, ecosystem and earths biosphere a static system?

Answer 7

It was believed so before, but the more it is studied, the clearer it becomes that these ecological systems are dynamic systems, and require change

Question 8

What are the two important distinctions of open systems?

Answer 8

steady state or non steady state

Question 9

What is a steady state system?

Answer 9

The inputs are equal to the outputs, so the amount stored within the system is constant

In ideal example is a dam or lake into which water flows in and out

Question 10

Does forcing systems into steady state work?

Answer 10

it fails most often, it is difficult to force natural ecological and environmental system into s steady state

Ex: Missouri River

Question 11

What is the idea of “the balance of nature”

Answer 11

The idea that our natural environment, when left undisturbed by people, tent toward some sort of steady state

Also called dynamic equilibrium

Question 12

What is a definition of an ecosystem?

Answer 12

communities of organism and their nonliving environment in which nutrients and other chemicals cycle and energy flows

Question 13

What can cause disruption to the “steady state”?

Answer 13

Primary human intervention, but even when humans no not interfere with the natural environment it does not stay steady for long due to natural disturbances

Question 14

Can systems stay steady state forever?

Answer 14

No, changes over time will happen due to natural disturbances

forests, rivers and coral reefs can be affected by storms, fires or floods

Question 15

What is average residence time?

Answer 15

How long, on average, a unit of something of interests to us will remain in a reservoir

Ex: how much water can be stored for how long in one reservoir

Question 16

What is feedback?

Answer 16

Feedback occurs when the output of a system (or a compartment in a system) affects its input - this can be negative or positive

Ex. human temperature

Question 17

What is negative feedback?

Answer 17

a way of feedback to self-regulates according to input (important for steady-state-systems)

humans sweat (output) to cool down in hot weather (input)

Question 18

What is positive feedback?

Answer 18

this occurs when an increase in output leads to a further increase of the output - it is vicious cycle. Destabilizing

Best example is a forest fire

Question 19

Examples of people’s use of the environment that leads to positive feedback?

Answer 19

Off-road vehicles cause soil erosion

Question 20

Can systems have both positive and negative feedback?

Answer 20

Hell yeah, like the human population in large cities

Positive feedback on the population size happens when people move there for work and higher standards of living, and more people means more opportunities - more migration

Negative feedback occurs in the form of increased air and water pollution, disease and crime

Question 21

Is negative feedback always desirable?

Answer 21

No, despite being the “self-regulating” feedback, it is not always what you want - it depends on the system and the potential changes

Question 22

What is a flow?

Answer 22

the amount transfered

Question 23

what is a flux?

Answer 23

rate of transfer per unit time

Question 24

What is a linear flow?

Answer 24

in a linear flow process, if you add the same amount of anything to a compartment in a system, the change will always be the same, no matter how much you have added before and no matter what else has changed about the system and its environment

Question 25

what are nonlinear flow processes?

Answer 25

the effect of adding a specific amount of something changes depending on how much has been added before

nonlinear process often have lag time or delays

Ex: something fills up (like drinking water)

Question 26

What is lag time?

Answer 26

Lag time is the delay between a cause and the appearance of its effect.

we can fail to recognize the change and know what is the cause and what is the effect. We can also come to believe that a possible cause is not having a detrimental effect, when in reality the effect is only delayed

Question 27

What is exponential growth?

Answer 27

Change is exponential when it increases or decreases at a constant rate per time period, rather than by a constant amount.

Looks like a J-shape

Question 27

What is doubling time?

Answer 27

The doubling time is the time necessary for the quantity being measured to double. A useful rule is that the doubling time is approximately equal to 70 divided by the annual percentage growth rate

Question 27

What is overshoots?

Answer 27

when growth exceeds the carrying capacity - results in a collapse

Question 28

What are some examples of irreversible consequence?

Answer 28

Good examples of this are soil erosion and the harvesting of old-growth forest.

With soil erosion, there may be a long lag time until the soil erodes to the point where crops no longer have their roots in active soil that has the nutrients necessary to produce a successful crop. But once the soil is eroded, it may take hundreds or thousands of years for new soil to form, and so the consequences are irreversible in terms of human planning.

Question 29

What is the idea of environmental unity?

Answer 29

the idea that it is impossible to change only one thing; everything affects everything else.

illustrated by the ideas of urbanization

Question 30

What is the idea of uniformitarianism?

Answer 30

the idea that geological and biological processes that occur today are the same kinds of processes that occurred in the past, and vice versa. Thus, the present is the key to the past, and the past the key to the future.

we can assume that in the future the same physical and biological processes will operate, although the rates will vary as the environment is influenced by natural change and human activity

Question 31

Who introduced the idea of uniformitarianism?

Answer 31

James Hutton in 1785 - father of geology