Unit 2 - Environmental Systems

system

is a network of interdependent

components and processes with materials

and energy flowing from one component of

the system to another.

An ecosystem

is a complex assemblage of

animals, plants, and their environment,

through which materials and energy move.

A simple system consists of:

• state variables (also called compartments),

which store resources such as energy,

matter, or water.

• flows,

or the pathways by which those

resources move from one state variable to

another.

Open systems

are those that receive inputs from

their surroundings and produce outputs that leave

the system.

A closed system e

xchanges no energy or matter with

its surroundings.

Throughput

is a term we can use to describe the

energy and matter that flow into, through, and out

of a system.

A positive feedback loop

tends to increase a process

or component.

A negative feedback loop

diminishes a process or component

The term emergent properties

is used when the

characteristics of a whole system are greater than

the sum of its parts.

Heat

describes the energy that can be transferred

between objects of different temperatures.

The first law of thermodynamics

states that energy is

conserved.

The second law of thermodynamics

states that, with

each successive energy transfer or transformation in

a system, less energy is available to do work

chemosynthesis,

a process which allows them to

extract energy from inorganic chemical compounds

such as hydrogen sulfide

species

refers to all organisms of the same kind that

are genetically similar enough to breed in nature and

produce live, fertile offspring

population

consists of all the members of a species

living in a given area at the same time.

ecosystem

is composed of a biological community

and its physical environment.

A trophic level

is an organism’s feeding status in an

ecosystem.

The carbon cycle

begins with photosynthetic

organisms taking up carbon dioxide. This is called

carbon fixation

nitrogen

reenters the environment through the

death of organisms.

excess phosphates

in bodies of water can stimulate

explosive growth of algae, upsetting ecosystem

stability.