Sustainability and Systems (task 1)

What is a system?

A set of interconnected elements that interact and function together as a whole.

What makes a system complex?

Multiple interacting elements, feedback loops, and relationships that make outcomes difficult to predict.

What is emergence?

When a system displays patterns or behaviours that cannot be understood by examining its individual parts alone.

Why are complex systems difficult to predict?

Interactions and feedback loops can produce unexpected outcomes that cannot be determined from individual elements alone.

What is a feedback loop?

A circular process in which the output of a system influences its future behaviour.

What is a positive feedback loop?

A feedback loop that amplifies or reinforces an initial change.

What is a negative feedback loop?

A feedback loop that counteracts a change and can stabilise a system.

What is an example of a positive feedback loop?

Ice melts, reducing sunlight reflection, which increases heat absorption and causes more ice to melt.

How do feedback loops contribute to complexity?

They continuously influence interactions between system elements, producing changing and sometimes unpredictable outcomes.

What is a social-ecological system?

A coupled system in which human social and economic activities interact with natural ecosystems.

Why are social and ecological systems coupled?

Humans depend on ecosystems and also modify them, while environmental changes affect human societies.

What is the metacoupling framework?

A framework for understanding human-nature interactions within, between nearby, and between distant systems.

What is intracoupling?

Human-nature interactions occurring within the boundaries of a single system.

What is pericoupling?

Human-nature interactions between adjacent or nearby systems.

What is an example of pericoupling?

Interactions between neighbouring river systems, such as the Meuse and Rhine.

What is telecoupling?

Human-nature interactions between geographically distant systems.

What is an example of telecoupling?

Global markets connect distant producers and consumers through supply and demand.

How can migratory birds create connections between distant ecosystems?

Birds transport nutrients, organisms, or pathogens between geographically distant ecosystems.

What does the metacoupling framework add to systems thinking?

It distinguishes interactions within a system, between nearby systems, and between distant systems.

What is energy flow through an ecosystem?

The transfer of energy from primary producers to consumers and decomposers through trophic levels.

What is primary production?

The process by which primary producers, such as plants, convert sunlight into chemical energy through photosynthesis.

What do plants need for photosynthesis?

Sunlight, water, and carbon dioxide to produce glucose and release oxygen.

What is gross primary production (GPP)?

The total amount of chemical energy fixed by primary producers through photosynthesis.

What is net primary production (NPP)?

The energy remaining after plants use some of their GPP for respiration.

What is the formula for net primary production?

NPP = GPP − respiration.

Why is NPP important to consumers?

NPP represents the energy stored in new plant biomass that can become available to consumers.

How can energy in ecosystems be measured?

Energy can be measured in joules or kilojoules, while biomass can measure stored organic matter.

What is a trophic level?

A feeding position in a food chain, such as producer, primary consumer, or secondary consumer.

What is the 10% rule?

On average, roughly 10% of energy at one trophic level is transferred to the next.

Why is energy transfer between trophic levels inefficient?

Energy is used for respiration and other life processes, lost as heat, or remains in uneaten and undigested material.

How does the 10% rule affect food chains?

Less energy is available at higher trophic levels, limiting the energy that can support top consumers.

What is a keystone species?

A species whose ecological impact is disproportionately large relative to its abundance.

Can keystone species be ecosystem engineers?

Yes. Some keystone species physically modify habitats and strongly influence ecosystem structure.

What are examples of keystone species?

Wolves, beavers, and certain bee species can have major ecological effects in particular ecosystems.

Why can removing a keystone species change an entire ecosystem?

Its removal can alter species interactions, food webs, habitats, and ecosystem processes.

What is a trophic cascade?

A chain reaction across multiple trophic levels caused by changes in the abundance or activity of organisms at one level.

What is a top-down trophic cascade?

A cascade in which changes in predators affect lower trophic levels and can alter ecosystem structure.

What is an example of a top-down trophic cascade?

Removing wolves can increase herbivores, which may reduce vegetation through increased grazing.

What is a bottom-up trophic cascade?

A cascade in which changes in resources or primary producers affect consumers at higher trophic levels.

How can El Niño trigger a bottom-up trophic cascade?

Changes in ocean temperature and nutrient upwelling can reduce marine primary production and affect higher trophic levels.

What do keystone species and trophic cascades demonstrate?

A species' influence on an ecosystem is not necessarily proportional to its abundance.

What is ecological succession?

The process through which the composition and structure of an ecological community change over time.

How do disturbance and succession make ecosystems dynamic?

Disturbances alter ecosystems, while succession drives the recovery and development of ecological communities.

What is primary succession?

Community development on a surface where soil is absent, such as newly exposed rock after a volcanic eruption.

Why is primary succession usually slow?

Soil must develop through processes such as weathering, erosion, and the accumulation of organic matter.

What is secondary succession?

Community recovery after disturbance where soil or an existing substrate remains.

What are examples of disturbances that cause secondary succession?

Wildfires, deforestation, and other disturbances that leave soil intact.

What are pioneer species?

The first organisms to colonise a newly available or disturbed habitat.

What are examples of pioneer species?

Lichens and mosses can colonise bare surfaces and help initiate soil development.

How do pioneer species contribute to succession?

They colonise surfaces, add organic matter, and help create conditions for other plants to establish.

What is the typical sequence of ecological succession?

Pioneer species establish, followed by grasses and small plants, then shrubs and eventually trees where conditions permit.

What is a climax community?

A traditionally described relatively stable community that develops late in succession under particular environmental conditions.

Is a climax community permanently fixed?

No. Further disturbances, environmental changes, and species interactions can alter the community.

What is sustainability?

Meeting present needs while maintaining the ecological and social conditions needed for future well-being.

What are the three dimensions of sustainability?

Environmental or ecological, social, and economic sustainability.

Why does sustainability require systems thinking?

Environmental, social, and economic systems interact, so changes in one can affect the others.

What is systems thinking?

An approach that examines relationships, interactions, feedback loops, and the behaviour of an entire system.

What is reductionism in systems analysis?

Studying individual parts separately to understand a system.

When is studying parts in isolation useful?

When elements have relatively low interconnectivity and interdependence, making their behaviour easier to analyse separately.

What can studying parts in isolation fail to identify?

Feedback loops, indirect effects, interdependencies, emergent behaviours, and unintended consequences.

Why is systems thinking important for sustainable development?

It reveals connections and feedbacks across ecological, social, and economic systems that isolated analysis may miss.