Apes B/k Chapter 3

Front 1

Define "open system"

Back 1

System type in which exchanges of mass or energy occur with other systems.

Front 2

Define "closed system"

Back 2

A system in which there are definite boundaries to mass and energy and thus exchange of these factors with other systems does not occur.

Front 3

Define "feedback"

Back 3

Feedback is when one part of a system changes, then those changes in turn affect another part of the system, which affects the first. Or, the output of the system also serves as the input.

Front 4

Define "negative feedback"

Back 4

Increase in output leads to a later decrease in output. Negative feedback is self-regulating/stabilizing.

Front 5

Define "positive feedback"

Back 5

Increase in output leads to a further increase in the output. "vicious cycle", destabilizing

Front 6

What is a stable system?

Back 6

A system that has a condition that it remains in unless disturbed, and that it returns to if the cause of the disturbance stops.

Front 7

Define "exponential growth"

Back 7

growth that occurs at a constant rate per time period

Front 8

Define "doubling time"

Back 8

The time necessary for a quantity to double.

Front 9

What is doubling time approximately equal to?

Back 9

70÷(annual percentage growth rate)

Front 10

Define "environmental unity"

Back 10

The principle of environmental sciences that states that everything affects everything else.

Front 11

Define "uniformitarianism"

Back 11

The principle stating that processes that operate today operated in the past. Therefore, observations of processes today can explain events that occurred in the past.

Front 12

Define "steady state"

Back 12

When input equals the output in a system. There is no net change.

Front 13

Define "average residence time"

Back 13

This is the average amount of time it takes for a given part of the total reservoir of a particular material to be cycled through the system.

Front 14

How is average residence time computed? (assuming involved values are constant)

Back 14

(total size of reservoir)÷(average rate of transfer through the reservoir)

Front 15

What important environmental concern is affected by average residence time?

Back 15

Average residence time would determine how long a pollutant stays in a reservoir.

Front 16

How are "steady states" found in nature?

Back 16

Steady states are seldom obtained or maintained for very long. Systems are characterized by human and natural disturbances. Changes over time can be expected.

Front 17

How does life interact with its environment? (and vice versa)

Back 17

The environment enables life and life helps control the makeup of air, oceans, and sediments.

Front 18

Define "biota"

Back 18

all living things within a given area

Front 19

Define "biosphere" (2 meanings)

Back 19

1. The biosphere is the region of Earth where life exists; the global habitat for life.
2. The system that includes and sustains all life, not just where life exists.

Front 20

Define "ecosystem"

Back 20

An ecosystem is a community of organisms and its local nonliving environment in which matter (chemical elements) cycles and energy flows.

Front 21

What is sustained life on Earth a characteristic of?

Back 21

ecosystems

Front 22

Define "Gaia hypothesis"

Back 22

States that (1) life, since its inception, has greatly altered the planetary environment and (2) that these changes have allowed life to persist. Some extend this, nonscientifically, to assert that life did it on purpose.

Front 23

Why might the extended part of the Gaia hypothesis have merit in the future?

Back 23

Humans have become conscious of our effects on the planet, some of which influence future changes in the global environment.

Front 24

Define "lag time"

Back 24

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

Front 25

How could long lag times lead to misconceptions? (2)

Back 25

Long lag times can make it difficult to determine what is the cause and what is the effect. Long lag times can also lead people to believe that a possible cause is not having a detrimental effect, when in reality the effect is only delayed.

Front 26

What do short lag times do for researchers?

Back 26

Consequences are easier to identify if lag times are short.

Front 27

Define "overshoot and collapse"

Back 27

This occurs when growth in one part of a system over time exceeds carrying capacity, resulting in a sudden decline in one or both parts of a system.

Front 28

What is overshoot and collapse caused by?

Back 28

long lag times

Front 29

What is generally meant by "irreversible consequences"?

Back 29

Consequences that may not be easily rectified on a human scale of decades or a few hundred years.

Front 30

Which three aspects of the global environment system make finding solutions to environmental problems difficult?

Back 30

1. exponential growth
2. long lag time
3. the possibility of irreversible consequences