Ecosystems

Question 1

What is an ecosystem?

Answer 1

A system formed by the interaction of all living organisms. Within an ecosystem, all of these elements are interacting with each other all of the time. All energy is coming from the sun. `

Question 2

What are diverse ecosystems?

Answer 2

• a result of unique biophysical interactions at varying scales, the interaction of the biotic and abiotic elements result in diverse ecosystems
• e.g. coastal dunes, freshwater wetlands, intertidal wetlands, coral reefs, arid areas, alpine, rainforests

Question 3

How are diverse ecosystems shaped?

Answer 3

• spatial patterns of these ecosystems depend on 4 spheres (bio, litho, hydro, atmo)
• result of climactic factors (temperature + precipitation)
• hydrologic processes (surface water flow, snow melt, ocean currents)
• geomorphic processes (aspect, altitude, gradient, soils)

Question 4

How and what is ecosystem functioning

Answer 4

Ecosystem functioning = the ability of an ecosystem to capture, store and transfer energy, nutrients and water throughout the system

This depends on 2 key processes: energy flows and nutrients cycling

Question 5

What are energy flows

Answer 5

Energy flows through an ecosystem from the sun to the plants (producers, producing energy via photosynthesis) and animals through the trophic levels.
Energy is lost as heat is produced at each level of consumption - there are fewer organisms at the top of the chain.

Question 6

How does latitude impact energy flow

Answer 6

Equatorial ecosystems receive more regular and stronger daily insolation –> more energy available.
therefore tend to have higher biodiversity

Question 7

What are the trophic levels

Answer 7

Top - bottom: 
Tertiary consumers (large carnivores) 
Secondary consumers (small carnivores) 
Primary consumers (herbivores) 
Producers 

(greatest number found at the bottom)

Question 8

What are nutrients cycles

Answer 8

• nutrients are central to the functioning and growth of organisms
• fixed supply of nutrients, continually cycles through biosphere
• ecosystems with higher biodiversity have higher amounts of nutrients as the amount of matter that decomposers affects the amount of nutrients that can be recycled
• net primary productivity
• nitrates, carbon, sulfur, phosphorus, water and oxygen

Question 9

Net primary productivity

Answer 9

based on the biodiversity and nutrients cycled - the amount of material that an ecosystem produces.

Tropical rainforests = 1800g/m2/year (similar to kelp forests)
Deserts = 80g/m2/year

Question 10

Optimal Functioning - Climax Communities

Answer 10

• ecosystems go through stages of development
• successions
• climax community = an ecological community that has reached the final stage of ecological succession and cannot support additional flora and fauna, it is highly functional

Question 11

Succession

Answer 11

• succession: process that begins after a significant disturbance or extinction of existing community, can occur in areas that have never been colonised b4, leads to species diversity as new species adapt to change and find a niche

Question 12

Disturbances preceding succession include:

Answer 12

Human impacts: deforestation, pollution

Natural stresses: fire, drought, tropical cyclones, tsunami

Question 13

Ecosystem at risk:

Answer 13

• one that is subject to difficult environmental conditions (aridity, high salinity, extreme temperatures, lack of nutrients) or those slow to develop and or regenerate after change

Question 14

dynamic equilibrium

Answer 14

a situation in which stability is achieved in an ecosystem

- all ecosystems function in a state of dynamic equilibrium or a continual state of balanced change

Question 15

beyond the limits of equilibrium

Answer 15

a change beyond the limits means that the system as a whole cannot exist in its original state –> concept of elasticity

Question 16

vulnerability

Answer 16

the lack of defence an ecosystem has against unforeseen changes in the environment

Question 17

resilience

Answer 17

the ability to adapt to changes in the environment, the speed which ecosystems recover their typical features after disturbance
(stress - disequilibrium - succession - new equilibrium/climax)

Question 18

what makes ecosystems vulnerable

Answer 18

• lack the ability to / are slow to develop or regenerate after change
• low nutrients levels and energy supply, low net primary productivity, low biomass, lack of decomposers

Question 19

BELL influences vulnerability and resilience

Answer 19

Biodiversity = number of species / variety 
Extent = size 
Location = where it is (latitude, proximity to human population) 
Linkages = complexity of the food web

Question 20

define biodiversity

Answer 20

the variety of all living things; the genetic information they contain and the ecosystems they form

Question 21

define extent

Answer 21

refers to the size of a particular ecosystem
- ecosystems that are restricted to a relatively small area and have a disturbance are particularly vulnerable as they cannot relocate

Question 22

define location

Answer 22

latitude, distance from the sea, proximity to human population

Question 23

define linkages

Answer 23

(aka interdependence)

- the higher the interdependence, the higher an ecosystems ability to change

Question 24

Characteristics of a resilient ecosystem

Answer 24

high: genetic and species biodiversity, ecosystem biodiversity, size of ecosystem, interdependence
low: duration and magnitude of stress, neighbouring human populations

Question 25

Impacts due to human induced modifications

Answer 25

deforestation, overgrazing, mining, urbanisation

Question 26

Stress and disturbances can be classified as:

Answer 26

natural / human induced intentional / unintentional gradual / catastrophic

Question 27

HUGIT

Answer 27

``` heritage utility genetic diversity intrinsic value the need to allow natural chnage ```

Question 28

heritage value

Answer 28

universal / national value for future generations (particularly traditional and cultural value) example = uluru and the great barrier reef

Question 29

utility value

Answer 29

either an existing or potential utility value (sources of food, medicine, chemicals, fibres) - ecosystems also protect catchments, regulating temperature, recycle nutrients and have a role in human activities like tourism (monetary value)

Question 30

maintenance of genetic diversity

Answer 30

greater resilience | diminished biodiversity puts ecosystems at risk

Question 31

intrinsic value

Answer 31

inspirational, aesthetic and spiritual needs; contributing to emotional + spiritual wellbeing - particularly within indigenous communities also the commodification of beauty

Question 32

the need to allow natural change to occur

Answer 32

allowing the evolutionary process to continue. Natural disturbance and even human disturbance within ecosystems will allow for ecological succession and unique adaptation

Question 33

Services that ecosystems provide

Answer 33

include land, water, vegetation and atmosphere into a flow of essential goods and services (clean air, water, food)

Question 34

global economic value of all ecosystem services

Answer 34

$46 trillion, which is greater than the GDP of all nations combined

Question 35

value of protecting land

Answer 35

protective land gives 100 times more value than converting it to some other use

Question 36

coral reef value

Answer 36

greater than 1 trillion dollars annually

Question 37

coastal wetland value

Answer 37

greater than 1 trillion dollars annually

Question 38

management strategies: contemporary and traditional

Answer 38

agreement that ecosystems need to be managed throughout the world and there are two approaches to management: traditional (aka indigenous approach) contemporary

Question 39

Traditional management

Answer 39

Stewardship: people have a responsibility to protect and nurture the land for the benefit of future generations (people currently living on the land are custodians / caretakers of the land) Often traditional management is undertaken by indigenous ppls

Question 40

Contemporary mangement

Answer 40

Prescription: the protection of a habitat, involving the prevention of human activity in that area Conservation: planned use of natural resources in an efffort to reduce waste and environmental damage Utilisation: replacement of an ecosystem with a manmade environment that is capable of generating a yield or income (agriculture, ski fields) these are sacrifice zones Exploitation: use of an ecosystems resources with little regard for the ecological consequences

Question 41

Management at a variety of scales

Answer 41

1. local: local governments (cutting down trees, etc) 2. regional: laws governing 3. global: unesco