ESS 1.2- systems

examples of models

• diagrams

• mathematical equations

• physical models

• computer models

• text descriptions

advantages of a simple model

• allows inputs to be changed quickly

• results can be shared to scientists and public

• scientists can predict what will happen

disadvantages of a simple model

• complex when oversimplified

• less accurate

• different models show different effects

• can lead to criticism

• rely on the expertise of a person making the model

advantages of STELLA

• shows different inputs

• different pictures

• easy to understand

• many are not oversimplified

disadvantages of STELLA

some of the pictures have a chance of not fitting on the page

systems definition

useful for understanding and explaining a phenomena

explain systems theorey

inputs → process → output → feedback

emergent properties definition

each interaction between components in systems can generate emergent properties where there is a specialized function for each part

biosphere definition

includes earths organisms and matter that has not decomposed

hydrosphere definition

includes liquid ocean, inland water bodies and ground water

cryosphere definition

subset of the hydrosphere, consisting of frozen water

geosphere definition

includes earths layers:

core, mantle, crust, all soil layers

atmosphere definition

thin layer of gases and particles in the air

anthroposphere definition

earths system is created and modified by human activity

explain James lovelock’s Gaia hypothesis

• introduced in the 1960s

• proposed the Earth is a single living system

• earth maintains homeostasis

explain Gaia hypothesis

• all living organisms and their surroundings form a complex system that regulates the conditions for life on earth

• suggests the earths systems work together

  • earths life forms to interact to create a stable system on Earth

explain global system

• global circulation

• each hemisphere has 3 cells

• air circulates through the entire depth of the troposphere

regional systems definition

networks of organisms and their environment within specific areas

environmental systems definition

includes abiotic and biotic components

social systems examples

• value systems

• economic systems

• social systems

effects of a narrow boundary in systems diagram

miss important systems behaviors that affected what is being studied

effects of a wide boundary in a systems diagram

increased complexity and it can hide valuable information

if the sum of the inflows to a storage are greater than the outflows what happens

storage level will increase

if the sum of the outflows to a storage are greater than the inflows what happens

storage levels will decrease

if the sum of the inflows to a storage are equals tothe outflows what happens

storage levels wont change

describe energy

• enters the ecosystem from the sun as light

• connected and stored as chemical potential energy

• organic molecules pass through down chains

  • respiration releases energy

describe matter

• cycles through an ecosystem

• nitrogen is fixed by bacteria

• herbivores consume plants

  • eventually plants and animals are decomposed and break down organic matter

transformations definition

move energy and matter but when doing so, there is a change of state

transfers definition

moving energy from point A to B and staying in the same state

open system definition

both materials and energy are exchanged across the boundaries of the system

most common system

rainforest

closed system definition

a system where energy is exchanged across the boundaries but matter isnt

examples of closed systems

major global systems

• nitrogen cycle

  • carbon cycle

isolated system definition

hypothetical concept where neither energy or matter is exchanged across the boundary

equilibrium definition

stable of balance in an ecosystem

static equilibrium definition

• doesnt apply to natural systems

• no inputs or outputs

• always in balance

  • inatimate objects

describe negative feedback mechanisms

• dampens effects and promotes return to stability

• predator - prey relationships

• regulate each other

describe positive feedback mechanisms

• destabilizing

• amplify changes

• a new equilibrium is adopted

casual loop diagrams definition

• snapshots of all relationships that matter

  • visual representation of key variables

tipping point definition

where a system undergoes a rapid and irreversible change, shifting the equilibrium

• can either be + or -

describe the resilience of a system

• tendancy avoiding tipping points and maintaining stability

• dynamic not static

• resilient systems maintain long term stability

  • different ecosystems have different capacities of handling change

examples of disturbances

• fires

• flooding

• windstorms

• climate change

• population

• urban development

factors effecting resilience

• biodiversity

• climate

• large ecosystems

• size of storage

negative human impacts examples

• amazon

• coral reef

examples of positive human impacts

• Apo island

high resilience meaning

a system able to handle change and can recover quickly, functioning the same as before

moderate resilience meaning

system can cope with some change and still function but more slowly

low resilience meaning

system struggling to cope with change and if disturbed the system could collapse