prediction summary

A comprehensive set of flashcards covering critical environmental science topics including the circular economy, aquatic food production, forest management, captive breeding, conditions for life, succession, biodiversity conservation, and agriculture, based on predicted 2026 exam trends.

What is the difference between negative and positive feedback loops in the context of sustainability?

Negative feedback is self-correcting, while positive feedback is self-amplifying, such as methane release from permafrost.

What effect do tipping points like Amazon dieback or ice-albedo feedback have on a system?

They lead to self-sustaining change.

In the context of the circular economy, what is the principle regarding waste?

Waste should be treated as a raw material for another process.

How do human systems and natural systems differ in terms of efficiency and change?

Natural systems have high energy density, involve slow change, and are renewable; human systems have low efficiency, are linear, and are depleting.

What are the nine principles of the circular economy regarding materials and energy?

Cycle materials at highest quality, use renewable energy, waste is raw material, optimum not maximum production, design for end-of-life reuse, reduce non-renewable reliance, and apply to land, water, and energy.

What is the definition of an ecological footprint?

The land and water area needed to support a lifestyle and absorb the resulting waste.

What is biocapacity?

The actual productive capacity of the land and water available.

When does ecological 'overshoot' occur?

When the ecological footprint is greater than the biocapacity.

Why might a low-income country be in an ecological deficit despite having a small footprint per person?

Due to high rates of resource extraction.

What is the difference between a pelagic trawl and a demersal trawl?

A pelagic trawl is used in the mid-water for open ocean species, while a demersal trawl is used on the bottom and causes high seabed damage.

What environmental risk is specifically associated with purse seine fishing?

High risk of bycatch as it encircles shoals.

Why are drift nets a significant concern in international waters?

They are banned in international waters due to their environmental impact.

What is 'ghost fishing'?

The continued trapping of marine life by lost or discarded fishing gear.

What is the mathematical formula for Maximum Sustainable Yield (MSY)?

$$\text{Biomass} = \text{previous biomass} + \text{recruitment} + \text{growth} - \text{mortality} - \text{catch}$$

What does a declining CPUE (catch per unit effort) indicate about a fish stock?

It indicates that the fish stock is declining.

What are 'pingers' in the context of fishing?

Acoustic deterrents used as a strategy to reduce bycatch.

How does extensive aquaculture differ from intensive aquaculture?

Extensive aquaculture has low input/output and less environmental impact; intensive has high input/output, more control, and more waste.

What are the primary abiotic factors controlled in intensive aquaculture?

Temperature, $O_2$, light, and flow rate.

What is one mitigation strategy for reducing disease or parasite transfer from aquaculture to wild fish?

Site rotation, polyculture, or closed containment systems.

List four ecosystem services provided by forest resources.

Atmospheric $O_2$ and $CO_2$ regulation, habitat provision, hydrological cycle support, and soil stabilisation.

What are the primary causes of deforestation according to the notes?

Logging above MSY, agricultural clearance (palm oil, cattle), urbanisation, and mining.

How does deforestation impact the hydrological cycle?

Reduced interception leads to increased surface runoff/flooding, and reduced transpiration leads to reduced cloud formation.

What are the consequences of deforestation for soil quality?

Erosion, loss of organic matter, compaction, and loss of root binding.

How does deforestation affect regional climate?

Reduced carbon sequestration, increased $CO_2$, reduced downwind rainfall, and increased albedo.

What does FSC certification ensure in forest management?

It ensures that timber products are sourced from sustainably managed forests.

Why is a mixed age structure preferred over clear-felling in sustainable forestry?

It maintains structural diversity and ensures a continuous resource supply compared to clear-cutting.

When is Captive Breeding and Release (CBR) typically triggered?

When in-situ conservation is insufficient and the population is too small to recover naturally.

What criteria are used to select species for CBR programmes?

Extinction risk, feasibility of captive maintenance, ecological role (e.g., keystone species), and public appeal for funding.

What methods are used in captivity to increase breeding success?

Artificial insemination, embryo transfer, hormone treatment, and establishing correct social groupings.

Define the 'soft release' method in CBR.

A gradual acclimatisation process involving feeding support, electric fencing, and phased withdrawal.

What are the risks associated with 'hard release' in CBR?

Immediate release carries a higher mortality risk and is usually only used if the habitat is already familiar.

What is a 'genetic bottleneck' in the context of CBR?

A limitation where the small gene pool of captive animals reduces genetic diversity.

List four methods for post-release monitoring of captive-bred animals.

GPS tracking, camera traps, eDNA sampling, and acoustic monitoring.

Name four conditions that enabled life to develop on Earth.

Liquid water, stable temperature, an atmosphere, and a magnetosphere for UV protection.

Which three orbital behaviors affect long-term climate cycles (Milankovitch cycles)?

Axial tilt, eccentricity, and precession.

How did photosynthetic bacteria change the Earth's atmosphere?

They caused a rise in $O_2$, which led to the formation of the ozone layer and enabled the colonisation of land.

How did life contribute to the cooling of the Earth?

Through carbon sequestration, which reduced atmospheric $CO_2$ levels.

What proxy data methods are used to study past climates?

Dendrochronology, pollen analysis, and isotope ratios in sediment or ice cores.

What do gas bubbles trapped in ice cores provide a record of?

A direct record of ancient atmospheric $CO_2$ and $CH_4$ levels.

Define 'ecological succession'.

The process of change in species structure from bare ground to a climax community over time.

What roles do pioneer species play in the beginning of succession?

They tolerate extreme abiotic conditions and modify the environment by adding organic matter or performing nitrogen fixation.

How does secondary succession differ from primary succession?

Secondary succession occurs on disturbed land with existing soil and is faster than primary succession.

What is a 'plagioclimax'?

A stable plant community maintained by ongoing human management rather than natural progression to a climax community.

How does swaling (controlled burning) manage heathland?

It removes rank vegetation and stimulates fresh growth.

What is the purpose of coppicing in woodland management?

Cutting trees at the base to regrow multiple stems, which increases structural diversity.

What is pollarding?

Cutting trees at a height to prevent livestock from browsing the regrowth, while increasing structural diversity.

What happens to a plagioclimax community if human management stops?

Succession resumes, leading to a woodland climax and the loss of specialist open-habitat species.

Give an example of a UK habitat maintained by grazing.

Chalk grassland.

Name three types of legally designated areas used for in-situ conservation.

SSSI (Site of Special Scientific Interest), NNR (National Nature Reserve), and SAC (Special Area of Conservation).

What is the difference between Appendix I and Appendix II of CITES?

Appendix I is a complete trade ban; Appendix II regulates trade to prevent overexploitation.

What are Vavilov centres?

Source regions for wild varieties of crops, often where seed banks are established.

What is an EDGE species?

A species that is Evolutionarily Distinct and Globally Endangered, representing an irreplaceable loss if it goes extinct.

Define a 'keystone species'.

A species that has a disproportionate ecological role relative to its abundance.

What is a 'flagship species'?

A species used to create public engagement and raise funding for conservation.

Which international framework is responsible for regulating the global timber trade?

ITTO (International Tropical Timber Organization).

Name three cultural pest control techniques.

Crop rotation, pheromone traps, and the sterile male technique.

What is a major risk of using biological control?

The introduced natural predator or pathogen may become an invasive species.

What are the characteristics of organochlorine pesticides like DDT?

They are persistent and tend to bioaccumulate.

Why are neonicotinoids restricted in the UK and EU?

They are systemic pesticides that are toxic to pollinators.

What is Integrated Pest Management (IPM)?

A strategy that combines cultural, biological, and chemical methods to minimize chemical use.

How can nitrogen-fixing legumes be used for sustainable nutrient supply?

By including them in crop rotations to naturally enrich the soil with nitrogen.

What are the benefits of low-tillage or no-till farming?

It reduces soil disturbance, preserves soil structure, and lowers carbon release.

How is 'permaculture' defined in agricultural terms?

A multi-layered, multi-species system with minimal external inputs.

What does the Simpson’s Diversity Index measure?

It is used to quantify the biodiversity of a specific area based on species richness and evenness.

What is the Spearman's Rank Correlation used for in environmental science?

To determine the strength and direction of a relationship between two ranked variables.

What is the Lincoln Index used to estimate?

Total population size using mark-recapture data.

What is 'biomimetics'?

The design and production of materials or structures modeled on biological entities and processes.

What IUCN Red List category indicates a species is 'Extinct in the Wild'?

EW

What does the acronym eDNA stand for in monitoring settings?

Environmental DNA.

In CBR, what is meant by 'habituation'?

The loss of natural behaviors and the development of a lack of fear toward humans, which is a limitation for release.

What three components are regulated and established by life on Earth according to the biogeochemical section?

The Carbon ($C$), Nitrogen ($N$), and Phosphorus ($P$) cycles.

What is 'CPUE' an abbreviation for?

Catch Per Unit Effort.

What is an MCZ?

Marine Conservation Zone.

What are the 'Svalbard Global Seed Vault' and 'Vavilov centres' examples of?

Ex-situ conservation (specifically seed banks).

What is 'swaling'?

The practice of controlled burning used to manage habitats like heathland.

What is the primary goal of the EU Common Fisheries Policy (CFP)?

To manage fish stocks through measures like fishing quotas.