3.1 The living environment

The emphasis should be placed on the interaction of living organisms with each other and their abiotic environment, and how an understanding of this can inform decisions that lead to sustainable human activities. Students must apply their understanding of these interactions in a wide range of contexts throughout this area.

Conditions for life on Earth

How the main conditions, which allowed early life to develop and survive on planet Earth, came about

Students should understand how the conditions of planet Earth allowed early life to develop and survive.

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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.

How the presence of life on Earth has brought about environmental change

How biota have helped to maintain stability

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Oxygen production

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

Ozone layer

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

Carbon sequestration

Atmospheric carbon dioxide concentrations were reduced by photoautotrophs.

Biogeochemical cycles

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

How historical conditions for life were monitored in the past and how these methods have been developed over time

Students should understand how changes in monitoring methods have allowed more accurate estimation of past conditions on Earth.

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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)

Conservation of biodiversity

The importance of the conservation of biodiversity

Resources and how sustainable habitat management strategies can be used to secure future supplies

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Wood

Timber for structural uses.

Fibres

Plant and animal fibres.

Oils

Uses of vegetable oils.

Fuels

Biofuels.

New foods

Many plant species have the potential for commercial cultivation.

Knowledge and how decisions over habitat conservation can be made to protect those species that have not yet been investigated

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Biomimetics

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

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

Physiological research

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

Wildlife species as pest control agents

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

Genetic resources

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).

Ecosystem services and their interaction with each other

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Atmospheric compositionThe role of living organisms in the regulation of the composition of the atmosphere: O2, CO2, water vapour.
Biogeochemical cycles

The importance of living organisms in biogeochemical cycles.

Interspecies relationshipsLiving organisms often provide services that aid the survival of other species, eg pollination, seed dispersal and habitat provision.
Soil maintenanceLiving organisims are important in soil formation and erosion control, eg plants, detritivores, decomposers.

How humans influence biodiversity, with examples in a range of different context

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Direct exploitation

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.
Deliberate eradication Eradication of predators and competitors.
Changes in abiotic factors

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.
Changes in biotic factors

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.
Habitat destruction

Many human activities remove the natural communities of species:

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

Methods of conserving biodiversity

Setting conservation priorities

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

International Union for Conservation of Nature (IUCN) criteria

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.
Evolutionary uniqueness

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

Endemic species Species found within a single area, especially if the population is small.
Keystone species

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

Legislation/protocols

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

Protection of habitats and species

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).
Trade Controls How the Convention on International Trade in Endangered Species (CITES) protects selected species:
  • Appendix I.
  • Appendix II.
Regulation of sustainable exploitation

Organisations that aim to exploit living resources sustainably:

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

Captive breeding and release programmes (CBR)

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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.

Methods of increasing breeding success
  • Provision of essential conditions for breeding.
  • Group dynamics.
  • Difficulties in providing required abiotic conditions.
  • Artificial insemination.
  • Embryo transfer.
Soft and hard release programmes

The selection of suitable release sites:

Soft release.

Hard release.

Post-release monitoring.

Habitat conservation

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

 
Habitat creation

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.
Management and conservation of habitats

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.
 
Threats
  • 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.
 
Threats:
  • 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.
 
Importance:
  • research
  • fisheries.
 
Threats:
  • 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.

 
Threats:
  • 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.
 
Importance:
  • coastal erosion protection
  • fisheries
  • timber supplies
  • trap suspended solids.
 
Threats:
  • clearance for urban development/aquaculture
  • coral reef destruction
  • pollution
  • global climate change.
 

Conservation efforts:

  • 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.
 
Importance:
  • water store
  • ice albedo
  • carbon sequestration
  • resources
  • research.
 
Threats:
  • global climate change
  • ozone depletion
  • tourism
  • overfishing
  • future mineral exploitation
  • scientific research.
 

Conservation efforts:

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

The importance of ecological monitoring in conservation planning

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

Population dynamics:
  • size
  • distribution
  • survival rate
  • age structure.
(See Research methods)

The development of new technologies for ecological monitoring

Students should understand how new technologies improve the validity of ecological research by allowing the collection of more representative data and new information.

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New technologies used in ecological research
  • Satellite/radio tracking.
  • DNA databases, eDNA.
  • Image recognition, including software
  • Acoustic monitoring, sonograms.

(See Research methods)

Life processes in the biosphere and conservation planning

How adaptation to the environment affects species’ habitat requirements and influences conservation decision-making

Students should be able to use examples of habitat management which benefit species that are adapted to particular abiotic and biotic factors. The deliberate provision of these conditions may increase species’ survival.

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Abiotic factors:
  • light
  • water
  • nutrients
  • pH
  • abiotic habitat provision.
 
Biotic factors:
  • food
  • control of predation
  • pollination
  • seed dispersal
  • biotic habitat provision
  • other inter-species relationships.
 

Terminology to describe the roles of living organisms in their habitats and their interactions with the physical environment

Students should be able to use appropriate terminology to describe the roles of living organisms in their habitats and their interactions with the physical environment.

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

The control of ecological succession in conserving plagioclimax habitats

Students should understand that many wildlife communities have developed in plagioclimax habitats maintained by long-term human activities. They should understand the processes in ecological succession that can inform conservation strategies.

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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.
 

How population control and the management of desired and undesired species affects the conservation of biodiversity

Students should understand the concept of carrying capacity and the influence of density and density-independent factors on regulating populations.

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Management of desirable species:
  • release programmes
  • habitat management.
 
Control of undesirable species: culling/eradication.  

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

 

Opportunities for skills development and independent thinking

Mathematical skill number Opportunities for skills development and independent thinking
MS 0.2 Students could use an appropriate number of decimal places in calculations, eg calculating mean population density from multiple sample sites in a habitat.
MS 0.3 Students could calculate and compare percentages loss, eg of rain forests over a given time period of declining populations of endangered species.
MS 0.5 Students should demonstrate their ability to interpret population growth curves.
MS 1.1 Students could report calculations to an appropriate number of significant figures given raw data quoted to varying numbers of significant figures, eg in calculating indices of biodiversity.
MS 1.2 Students could calculate mean population density from multiple quadrats.
MS 1.5 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.
MS 1.10 Students should demonstrate their understanding of standard deviation as a useful measure of dispersion for a given set of data, eg for comparison with other data sets with different means such as populations of endangered species under different management regimes.
MS 1.11 Students could calculate percentage error where there are uncertainties in measurement, eg estimating total population using sub-samples in a preliminary study.
MS 2.1 Students could use = < << >> > when estimating maximum sustainable yield.
MS 2.3 Students could use Simpson’s index of diversity to assess the impact of a new habitat management regime.
MS 3.1 Students could construct a kite diagram of the change in population density of species along a transect.
MS 3.3 Students could plot changes in species abundance with changes in abiotic factors, eg temperature water, pH.
MS 3.7 Students could measure the gradient of a point on a curve, eg rate of population growth.
MS 4.1 Students could calculate the circumference and area of nature reserves to assess the impact of the edge effect on wildlife conservation programmes.

Working scientifically

Students could plan activities to investigate environmental issues which they could carry out eg:

  • population surveys in a habitat to be visited
  • measurement of abiotic factors in a habitat to be visited.

Students could plan activities to investigate environmental issues in broader environmental contexts where first-hand experience would not be possible eg:

  • monitoring the impact of invasive species on indigenous species
  • monitoring the impact of the local extinction of forest elephants on plant species with animal-dispersed seeds
  • monitoring changes in population size, age structure and diversity after an area gains protected status, eg new MCZs
  • monitoring the survival and dispersal of animals in captive breeding programmes after release
  • estimating increases in biomass of tropical forests in response to increases in CO2 levels
  • monitor changes in water turbidity on coral reefs caused by land use changes, eg deforestation
  • monitor changes in penguin populations in Antarctica using satellite imagery
  • monitor the impact of fishing controls by the EU CFP on fish populations
  • monitor colonisation and changes in community composition in a recently created habitat.
Practical skill number Opportunities for skills development and independent thinking
PS 1.1

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

  • population size
  • population density
  • biomass
  • distribution
  • movements.
PS 1.2

Students could analyse existing knowledge and data eg:

  • changes in species abundances
  • changes in age structure
  • current biomass.
PS 1.3

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.
PS 1.4 Students could plan studies to gain representative, reliable data, using the selected methodologies and sampling technique below.
PS 2.1 Students could evaluate the methods of previous studies and analyse the reliability of the data produced.
PS 2.2

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.
PS 2.3

Students could identify the other variables that could also affect their results eg: in a study of the affect 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.

PS 2.4

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.
PS 3.1 Students could construct line graphs to show changes in data over time or correlations between variables.
PS 3.2 Students could use data on species richness and abundance to calculate Simpson’s Index of diversity.
PS 3.3 Students could compare estimates of population size for the same habitat produced by different groups to consider possible causes of the variation.
PS 4.1 The practical skills of using equipment within scientific environmental studies are expanded in the selected methodologies and sampling technique below.

Opportunities to investigate the required methodologies of which students must have first hand experience. Further details can be found in Appendix A: Working scientifically

Methodology skill number Opportunities for skills development and independent thinking
Me 1

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

Me 2

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.
Me 3

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.

Opportunities to investigate the required sampling techniques of which students must have first hand experience. Further details can be found in Appendix A: Working scientifically

Sampling techniques number Opportunities for skills development and independent thinking
ST 1

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.

ST 2 Students could compare plant biodiversity in grasslands with different mowing regimes.