Conservation of biodiversity, ecosystem stability and climate change

Learning objectives

Describe biodiversity at the level of ecosystems, species and genes, outline how it is estimated, and explain the causes of the current loss of biodiversity, including habitat destruction, overexploitation, pollution and invasive species

Explain the evidence for a sixth mass extinction from rates of extinction in the fossil record and in the present day, and describe conservation measures including protected areas, rewilding, captive breeding and seed banks, with reference to how species are prioritised for conservation

Explain the requirements for ecosystem stability, including a supply of energy, the recycling of nutrients, genetic diversity and climatic stability, and describe the use of a sealed mesocosm to investigate stability experimentally

Explain the role of keystone species in maintaining community structure, and describe a tipping point as a threshold beyond which an ecosystem shifts to a different stable state, using the collapse of a coral reef or the loss of tropical forest as an example

Explain the greenhouse effect and the enhanced greenhouse effect in terms of the absorption and re-emission of longwave radiation by carbon dioxide, methane, water vapour and nitrous oxide, and interpret data from ice cores and from direct atmospheric measurement

Explain the consequences of rising temperature and rising carbon dioxide concentration for ecosystems, including shifts in the geographical range of species, changes in the timing of seasonal events, the melting of polar ice, and ocean acidification with its effect on the calcification of coral and shelled organisms