Revision Guide
Environmental systems and societies for the IB Diploma
Andrew Davis and Garrett Nagle
Topic 1 Systems and models
  Concept and characteristics of systems
  Transfer and transformation processes
  The systems concept on a range of scales
  Open systems, closed systems and isolated systems
  The first and second laws of thermodynamics and their relevance to environmental systems
  The nature of equilibria
  Positive feedback and negative feedback
  Models
Topic 2 The ecosystem
  Structure
Biotic and abiotic components
Food chains and food webs
Pyramids of numbers, biomass and productivity
Pyramids structure and ecosystem functioning
Species, populations, habitats and niches
Population interactions
Measuring abiotic components of the systems
Measuring biotic components of the system
Methods for estimating the abundance of organisms
Methods for estimating the biomass of trophic levels
Diversity and the Simpson’s diversity index
  Biomes
  Function
The role of producers, consumers and decomposers
Photosynthesis and respiration
Transfer and transformation of energy
Transfer and transformation of materials within an ecosystem
Gross productivity, net productivity, primary productivity and secondary productivity
Gross primary productivity and net primary productivity
Gross secondary productivity and net secondary productivity
  Changes
Limiting factors and carrying capacity
S- and J-population curves
Density-dependent and density-independent factors
Survivorship curves
Succession and zonation
Changes through a succession
Climax communities
  Measuring changes in the system
Measuring changes along an environmental gradient
Measuring changes due to a specific human activity
Environmental impact assessments
Topic 3 Human population, carrying capacity and resource use
  Population dynamics
The nature and implications of exponential growth in human populations
Birth rate, crude death rate, fertility, doubling time and natural increase rate
Age-sex (population pyramids)
The demographic transition model
The use of models in predicting the growth of human population
  Resources: natural capital
Resources and natural income
Renewable, replenishable and non-renewable natural capital
The dynamic nature of the concept of a resource
The intrinsic value of the environment
Sustainability, natural capital and natural income
Sustainable development
Sustainable yield
  Energy resources
The range of energy resources available to society
The advantages and disadvantages of contrasting energy sources
  The soil system
Soil characteristics
Soil degradation
Soil conservation measures
Food resourceseditor evaluating revision
Issues involved in the imbalance in global food supply
The efficiency of terrestrial and aquatic food production systems
Contrasting food production systems
Links between social systems and food production
  Water resources
The earth’s water budget
The sustainability of freshwater resources usage
Limits to growth
Carrying capacity and local human populations
Carrying capacity and recycling, reuse and reduction
Environmental demands of human populations
Ecological footprints
Calculating ecological footprint
Ecological footprints in LEDCs and MEDCs
National and development policies and cultural influences on human population dynamics and growth
The role of technology
Topic 4 Conservation and biodiversity
  Biodiversity in ecosystems
Species, habitat and genetic diversity
Natural selection
The role of isolation in forming new species
Plate activity
Ecosystem stability and succession
  Evaluating biodiversity and vulnerability
Factors that lead to loss of diversity
Vulnerability of tropical rain forests
Past and present rates of species extinction
Factors that make species prone to extinction
Determining a species’ Red List conservation status
Extinct, critically endangered and back from the brink
Natural area of biological significance under threat
Conservation of biodiversity
Arguments for preserving species and habitats
The role of intergovernmental and non-governmental organisations
Designing a protected area
Evaluating the success of a protected area
Strengths and weaknesses of the species-based approach to conservation
Topic 5 Pollution management