The living environment (2023)

Atmosphere

The mass of Earth and force of gravity retained an atmosphere.

The atmosphere provided gaseous resources: carbon dioxide, methane, nitrogen.

Atmospheric pressure and temperature maintained liquid water.

Insolation

A suitable temperature range was controlled by incoming insolation and its behaviour in the atmosphere. This was controlled by the surface albedo, absorption of infrared energy and the presence of the atmosphere.

Position in the solar system

Suitable temperatures were maintained by the distance from the Sun.

Orbital behaviour

The rotation and tilt of the Earth on its axis and its orbit around the Sun, controlled daily and seasonal variations in insolation and temperatures.

Magnetosphere

The magnetosphere provides protection from radiation: the Earth’s molten core produced a magnetic field (magnetosphere) that deflects solar radiation.

Oxygen was first produced by photosynthetic bacteria, then by algae and plants.

Ozone was produced by chemical reactions involving oxygen and ultraviolet light in the stratosphere.

Atmospheric carbon dioxide concentrations were reduced by photoautotrophs.

The processes of biogeochemical cycles are linked by living organisms, preventing the build-up of waste products or shortages of resources.

Limitations of early methods.

• Lack of ancient historical data.
• Limited reliability of proxy data for ancient conditions.
• Limited coordination between researchers.
• Lack of sophisticated equipment for accurate measurements.
• Inability to measure many factors.
• Lack of data collection in many areas.
• Reliance on proxy data, eg dendrochronology, pollen analysis.

Improved methods.

• Collection of long-term data sets.
• The use of electronic monitoring equipment.
• Gas analysis of ice cores.
• Isotope analysis of ice cores.
• Improved carriers for monitoring equipment, eg helium balloons, aircraft, satellites.

(See Research methods)

Timber for structural uses.

Plant and animal fibres.

Uses of vegetable oils.

Biofuels.

Many plant species have the potential for commercial cultivation.

Students should understand that features of living organisms can be copied in the development of new structures and materials, eg:

• vehicle design
• architecture
• structures
• adhesion
• materials
• ultrasound diagnosis.

New medicines can be developed from the chemicals produced by plants and animals.

Animal species may be more useful or practical than humans for physiological research.

Many wildlife species can be used to control agricultural pests. They may be predators, herbivores, parasites orpathogens.

New genes to improve crop genetic characteristics may be found in the wild relatives of the cultivated crops.

The importance of Centres of Diversity/Vavilov centres for crop wild relatives (CWRs).

The importance of living organisms in biogeochemical cycles.

Populations of many species have been reduced by over-exploitation for resources or deliberate eradication, eg:

• food
• fashion
• entertainment
• furniture and ornaments
• traditional medicines
• other products.

Human activities may change the abiotic features of a habitat, making it more or less suitable for the survival of wildlife.

• The changes may be caused by an action, or by inactivity, eg stopping plagioclimax management.
• Water availability, eg by drainage or flooding.
• Light levels, eg by forest clearance.
• Oxygen availability, eg by pollution of water with organic matter.
• Nutrient levels, eg fertiliser runoff from farmland.
• pH, eg acid mine drainage.
• Temperature, eg thermal pollution from power stations.

Changing the population size of one species often has an impact on the population size of other species.

• Introduced species.
• Loss of inter-species relationships.

Many human activities remove the natural communities of species:

• deforestation
• expansion of farmland
• urbanisation
• mineral extraction
• flooding by reservoirs.

Students should understand that the conservation of biodiversity requires setting priorities about which species and communities are to be conserved.

The roles of the IUCN:

• coordinating global data on biodiversity conservation
• increasing understanding of the importance of biodiversity
• deploying nature-based solutions to global challenges in climate, food and sustainable development.

Students should have knowledge of the criteria used by the IUCN to identify the species that should be prioritized for conservation. These are developed further elsewhere in the specification:

• red list categories for threatened species
• classification of habitats, threats and required actions
• evolutionary uniqueness
• endemic species
• keystone species
• flagship species
• threats to survival
• population dispersal.

EDGE species (Evolutionary Distinct and Globally Endangered) are threatened by extinction and diverged from other taxa long ago so they have greater genetic differences.

Species whose survival is important for the survival of many other species.

How legislation and protocols protect species and habitats by establishing restrictions and management agreements.

The key features of the Wildlife and Countryside Act (1981).

Students should understand the different ways in which designated areas protect species and habitats by restricting activities and establishing management plans.

Designated protected areas in the UK, eg:

• Sites of Special Scientific Interest (SSSI)
• National Nature Reserve (NNR)
• Special Area of Conservation (SAC)
• Special Protection Area (SPA)
• Natura 2000 sites
• Ramsar sites
• Marine Nature Reserve (MNR)
• Local Nature Reserve (LNR)
• Marine Protected Area (MPA)
• Marine Conservation Zone (MCZ).

• Appendix I.
• Appendix II.

Organisations that aim to exploit living resources sustainably:

• International Whaling Commission (IWC)
• European Union Common Fisheries Policy (EU CFP)
• International Tropical Timber Organisation (ITTO).

Ex-situ conservation is needed when conservation of species in their natural habitat is impossible or insufficient to protect the species.

• Criteria for the selection of species for captive breeding programmes.
• Difficulties in keeping a captive population.

Reasons why keeping species in captivity may be difficult.

• Provision of essential conditions for breeding.
• Group dynamics.
• Difficulties in providing required abiotic conditions.
• Artificial insemination.
• Embryo transfer.

The selection of suitable release sites:

Soft release.

Hard release.

Post-release monitoring.

In-situ conservation protects communities of species not just individual selected species.

New habitats may be created as a consequence of other human activities.

New habitats may be created when wildlife conservation is the main aim.

• New conservation habitats: wetlands, woodlands.
• Habitat restoration – rewilding.

Structural features of habitats may affect the success of conservation programmes:

• habitat area
• habitat shape
• age structure
• ease of colonization/need for introduction
• biological corridors.

Students should use a range of ecosystems and habitat areas to analyse their similarities and differences, especially the controlling ecological features and how this can inform conservation strategies. The importance of conservation should be related to the threats from human activities.

Temperate broadleaf woodland

Features:

• regular water supply
• summers not very hot
• winters not very cold
• seasonality.

Importance:

• high biodiversity
• resources
• climate control
• soil erosion control
• recreation.

Threats:

• deforestation for other land uses
• fragmentation of remaining woodland
• management change.

Conservation efforts:

• designated protected areas
• legal protection of ancient woodland in the UK
• conservation management.

Tropical rainforest

Features:

• warm/hot
• high rainfall
• high light levels
• inter-species relationships
• low seasonality.

Importance:

• high biodiversity
• resources
• carbon sequestration
• hydrological cycle
• soil erosion control.

• fuelwood collection
• timber for construction and furniture
• agricultural expansion
• mineral extraction
• reservoirs
• global climate change
• exploitation of individual species.

Conservation efforts:

• establishment of protected areas
• debt for Nature Swaps
• sustainable exploitation.

Tropical coral reefs

Features:

• cnidarians
• nutrition systems
• high light levels
• warm, stable temperatures
• low turbidity
• constant salinity.

Importance:

• fisheries
• erosion protection
• medicinal discoveries
• climate control
• tourism.

• physical damage caused by human activities
• souvenir collection
• sedimentation
• climate change
• pollution
• fishing
• introduced species.

Conservation efforts:

• control of damaging activities
• establishment of protected areas.

Deep-water coral reefs.

Features:

• cold and dark
• slow coral growth.

• research
• fisheries.

• trawling
• oil and gas exploration
• ocean acidification.

Conservation efforts:

• establishment of protected areas
• control of damaging activities.

Oceanic islands

Features:

• isolation
• few or no indigenous mammal predators
• endemic species.

Importance: endemic species.

• species exploitation
• introduced species
• habitat change/destruction
• sea level rise.

Conservation efforts:

• eradication of introduced species
• control of developments and visitors.

Mangroves

Features:

• tropical climates
• halophytic trees
• low oxygen availability.

• coastal erosion protection
• fisheries
• timber supplies
• trap suspended solids.

• clearance for urban development/aquaculture
• coral reef destruction
• pollution
• global climate change.

• reforestation
• control of damaging activities
• establishment of protected areas.

Antarctica

Features:

• very low temperatures
• low precipitation
• high albedo
• high levels of marine nutrients
• large variations in ice cover
• extreme seasonal changes.

• water store
• ice albedo
• carbon sequestration
• resources
• research.

• global climate change
• ozone depletion
• tourism
• overfishing
• future mineral exploitation
• scientific research.

Conservation efforts:

• The Antarctic Treaty (1959)
• fisheries control
• waste management
• tourism control.

It is important to identify the species present and features of their populations in planning conservation strategies.

• size
• distribution
• survival rate
• age structure.

New technologies used in ecological research

• Satellite/radio tracking.
• DNA databases, eDNA.
• Image recognition, including software
• Acoustic monitoring, sonograms.

(See Research methods)

• light
• water
• nutrients
• pH
• abiotic habitat provision.

• food
• control of predation
• pollination
• seed dispersal
• biotic habitat provision
• other inter-species relationships.

Ecological terminology

• Species.
• Taxon.
• Ecological niche.
• Population.
• Community of species.
• Ecosystem.
• Biome.

Ecological succession

• Colonisation and pioneer species.
• Seres.
• The modification of abiotic conditions by new colonisers.
• Climax communities.
• Deflected succession.
• Secondary succession.
• Plagioclimax communities.

Methods of maintaining plagioclimax communities:

• grazing
• mowing
• burning
• coppicing
• pollarding.

• release programmes
• habitat management.

r- and k- selection strategies and how they affect the ease with which species can be over-exploited.

Students could compare and analyse data collected by random sampling and systematic, eg use Simpson’s index of diversity to compare the biodiversity of habitats with different management regimes.

Students could assess the knowledge required to solve an environmental problem, eg:

• population size
• population density
• biomass
• distribution
• movements.

Students could analyse existing knowledge and data eg:

• changes in species abundances
• changes in age structure
• current biomass.

Students could evaluate and explain the contribution that the results of the planned study would make to solving the problem eg:

• how changes in abiotic factors may cause changes in woodland floor plant survival
• how a change in population of trees may be caused by the loss of forest elephants
• how a change in age structure in an MCZ may indicate the effectiveness of protection.

Students could analyse their method and the results produced to identify limitations in the method and any inaccuracies in results eg:

• limitations of population estimates from population sub-samples and the Lincoln Index
• inaccuracies caused by the use of data that fluctuate unpredictably, eg abiotic factors related to weather.

Students could identify the other variables that could also affect their results eg: in a study of the effect of light levels on ground flora: soil pH, temperature, humidity, wind velocity. In a study of increased forest biomass caused by rising CO₂ levels: changes in water availability, temperature and forest management.

Students could use a variety of methods to present data:

• construct a table of raw data eg abundances of species found in each quadrat
• construct a table of changing abiotic factors along a transect across a habitat.

Students could plan the collection of samples using random sampling. Eg: Ground flora in woodland or grasslands.

Students could plan the collection of samples using systematic sampling eg:

• abiotic factors along a transect
• species abundance or distribution along a transect
• data from moth or bat surveys at regular intervals, eg weekly.

Students could carry out a preliminary study and analyse the results to assess the smallest number of samples that produce reliable results eg:

Using increasing numbers of quadrats to estimate the total population. Eg estimating total population using mean values from 5, 10, 25, 50, 100 etc quadrats.

The reduction in fluctuations in overall mean values will enable students to select an appropriate sample number for further studies.

Students could carry out a preliminary study and analyse the results to assess the smallest sample size that produces reliable results.

eg: estimating lichen percentage cover on bark using increasing sizes of sample area. The minimum size is that where using larger areas does not cause the value to change significantly and reliability to increase.

Students could identify appropriate timings for surveys to be carried out eg:

• moth surveys carried out overnight with standardized conditions of temperature, precipitation, wind velocity
• population surveys related to breeding cycles
• plant surveys related to periods of emergence/flowering.

Students could carry out statistical tests to assess the significance of the data eg: Spearman’s Rank Correlation Coefficient for abundance of a species and an abiotic factor along a transect.

Students could analyse the effect of wind velocity or temperature on the activity of bats or moths to consider the possible impacts of climate change.