Natural Systems

Question 1

What is a system?

Answer 1

A system is a complex arrangement of interconnections between energy and matter which are organised as a series of inputs, stores, flows / transfers and outputs.

Question 1

What is an ecosystem?

Answer 1

An ecosystem describes the interrelationships between living (biotic) and non - living (abiotic) components within a particular environment.

Question 2

What is matter?

Answer 2

Matter is any physical substance involved in a system, e.g. water or carbon.

Question 3

What is energy?

Answer 3

Energy is a power or driving force.

Question 4

What is an input?

Answer 4

Inputs are when matter or energy (e.g. solar energy) is added to the system from the outside.

Question 5

What is an output?

Answer 5

Outputs are when matter or energy leaves the system to the outside.

Question 6

What are stores or components?

Answer 6

Stores and components are where matter or energy builds up and they are the individual elements or parts of a system.

Question 7

What are flows / transfers?

Answer 7

Flows or transfers are when matter or energy moves from one store to another and they are also the links or relationships between the components.

Question 8

What are boundaries?

Answer 8

Boundaries are the limits of a system.

Question 9

What can systems either be?

Answer 9

Systems can either be open or closed.

Question 10

What is an open system?

Answer 10

In an open system both energy and matter CAN enter and leave an open system - there are inputs and outputs of both and it involves a flow or exchange of material.

Question 11

What is an example of an open system?

Answer 11

For example, drainage basins are open systems - energy from the sun enters and leaves the system.Water is input as precipitation, and output as river discharge into the sea.

Question 12

What is a closed system?

Answer 12

In a closed system matter CAN’T enter or leave a closed system - it can only cycle between stores in and and around a closed loop. Energy CAN enter and leave a closed system - it can be input or output.

Question 13

What is an example of a closed system?

Answer 13

For example, the carbon cycle is a closed system - energy is input (e.g. from the sun by photosynthesis) and output (e.g. by respiration), but the amount of carbon on Earth stays the same because there are no inputs or outputs of matter.

Question 14

What does it mean if a system is in equilibrium?

Answer 14

If the inputs and outputs of a system are balanced, the system is in equilibrium - flows and processes continue to happen, but in the same way at all times, so there are no overall changes to the system.

Question 15

What does it mean if a system is in dynamic equilibrium?

Answer 15

There are lots of small variations in the inputs and outputs of a system (e.g. the amount of precipitation entering a drainage basin system constantly varies). These variations are usually small, so the inputs and outputs remain about balanced on average. The system is said to be in dynamic equilibrium.

Question 16

What does dynamic equilibrium represent within a system?

Answer 16

Dynamic equilibrium represents a state of balance within a constantly changing system.

Question 17

How can a system establish a new dynamic equilibrium?

Answer 17

Large, long term changes to the balance of inputs and outputs can cause a system to change and establish a new dynamic equilibrium. changes can trigger positive or negative feedback.

Question 18

What is positive feedback?

Answer 18

Positive feedback mechanisms amplify the change in the inputs or outputs. This means that the system responds by increasing further from its previous state.

Question 19

What is negative feedback?

Answer 19

Negative feedback mechanisms counteract the change in the inputs or outputs. This means that the system responds by decreasing the effects of the change, keeping the system closer to its previous state.

Question 20

Is the Earth an open or closed system?

Answer 20

The Earth can be seen as one closed system - energy is input from the sunand output to space, but matter is not input or output to space (except for the odd space probe).

Question 21

What can the whole Earth system be broken down into?

Answer 21

The whole earth system can be broken down into smaller parts called subsystems.

Question 22

What are the names of the five subsystems and what is their mnemonic?

Answer 22

A = Atmopshere
Bird = Biosphere
Loves = Lithosphere
Her = Hydrosphere
Chicks = Cryosphere

Question 23

What is the cryosphere?

Answer 23

The cryosphere includes all the parts of the Earth system where it’s cold enough for water to freeze, e.g. glacial landscapes.

Question 24

What is the lithosphere?

Answer 24

The lithosphere is the outermost part of the Earth. It includes the crust and the upper parts of the mantle.

Question 25

What is the biosphere?

Answer 25

The biosphere is the part of the Earth’s systems where living things are found. It includes all the living parts of the Earth - plants, animals, birds, fungi, insects, bacteria etc.

Question 26

What is the hydrosphere?

Answer 26

The hydrosphere includes all of the water on Earth. It may be in liquid form (e.g. in lakes and rivers), solid form (ice stored in the cryosphere) or gas form (e.g. water vapour stored in the atmosphere). It can also be saline (salty) or fresh.

Question 27

What is the atmosphere?

Answer 27

The atmosphere is the layer of gas between the Earth’s surface and space, held in place by gravity.

Question 28

What are the subsystems interlinked by?

Answer 28

The subsystems are all interlinked (connected together) by the cycles and processes that keep the Earth system as a whole running as normal (**e.g. the water cycle and carbon cycle).

Question 29

What type of system is the Earth system said to be?

Answer 29

Matter (e.g. Water and Carbon) and energy move between the subsystems - the output of one cycle is the input of the next, then the output of that cycle is the input of the next, and so on… because of the way that matter and energy move from one subsystem to the next, the Earth’s system is said to be a cascading system.

Question 30

Can the different subsystems affect each other?

Answer 30

Changes that occur in one subsystem CAN affect what happens in the others.

Question 31

What is an isolated system?

Answer 31

Isolated systems have no interactions with anything outside of the system boundary. There is no input or output of energy or matter and (neither matter nor energy) can enter or leave. However isolated systems are not found in nature but instead in science.