3.3 Threats to biodiversity

Here are some good resources for #IBDP #ibess topic 3.3 Threats to #biodiversity via @bradleymkremer

Significant idea:

  • While global biodiversity is difficult to quantify, it is decreasing rapidly due to human activity. Classification of species conservation status can provide a useful tool in the conservation of biodiversity.

Knowledge and understanding:

  1. Estimates of the total number of species on Earth vary considerably. They are based on mathematical models, which are influenced by classification issues and a lack of finance for scientific research, resulting in many habitats and groups being significantly under-recorded.
  2. The current rates of species loss are far greater now than in the recent past, due to increased human influence. The human activities that cause species extinctions include habitat destruction, introduction of invasive species, pollution, overharvesting and hunting.
  3. The International Union of Conservation of Nature (IUCN) publishes data in the “Red List of Threatened Species” in several categories. Factors used to determine the conservation status of a species include: population size, degree of specialization, distribution, reproductive potential and behaviour, geographic range and degree of fragmentation, quality of habitat, trophic level, and the probability of extinction.
  4. Tropical biomes contain some of the most globally biodiverse areas and their unsustainable exploitation results in massive losses in biodiversity and their ability to perform globally important ecological services.
  5. Most tropical biomes occur in less economically developed countries (LEDCs) and therefore there is conflict between exploitation, sustainable development and conservation.

Applications and skills:

  • Discuss the case histories of three different species: one that has become extinct due to human activity, another that is critically endangered, and a third species whose conservation status has been improved by intervention.
  • Describe the threats to biodiversity from human activity in a given natural area of biological significance or conservation area.
  • Evaluate the impact of human activity on the biodiversity of tropical biomes.
  • Discuss the conflict between exploitation, sustainable development and conservation in tropical biomes.


  • Conservation needs to work at the local grass roots level to create meaningful change in the communities that live alongside conservation areas. International organizations are important for enforcing the Convention on International Trade in Endangered Species (CITES) agreement, assessing global status of species’ numbers and influencing governments.
  • The science of taxonomy is important to understand species extinction. Major surveys are carried out using international teams of specialists.

Theory of knowledge:

  • There may be long-term consequences when biodiversity is lost—should people be held morally responsible for the long-term consequences of their actions?


  • Sustainability (1.4)
  • Communities and ecosystems (2.2)
  • Water pollution (4.4)
  • Soil degradation and conservation (5.3)
  • Resource use in society (8.2)