IB ESS SL 3.2 Human Impact on Biodiversity Questions

reduction in population size;
population size / numbers of mature individuals / number of individuals able to reproduce;
geographical range / area of occupancy (ie where species are normally found) / extent of occurrence (boundary line that can be drawn around sites that the species occupies);
reduction in number of locations (the species is found in);
degree of fragmentation (eg via road or urban development);
quality of habitat / loss of habitat / habitat degradation;
probability/high risk of extinction;

Marking guidance:

Do not accept "availability of food/water/shelter".
Do not accept "deforestation/hunting/low reproductive potential/habitat threatened" unless a link is made to the IUCN factors, as listed above.

The following guide for using the markbands suggests certain features that may be offered in responses. The five headings coincide with the criteria in each of the markbands (although ESS terminology has been conflated with 'understanding concepts'). This guide simply provides some possible inclusions and should not be seen as requisite or comprehensive. It outlines the kind of elements to look for when deciding on the appropriate mark band and the specific mark within that band.

Answers may demonstrate:
- understanding concepts terminology: definition of pollution;
chemical/thermal/biotic pollution;
anthropogenic;
toxicity;
environmental impacts;
alien/invasive/native species;
competition;
competitive exclusion;
predation;
disease;
disruption;
biodiversity;
genetic diversity;
pest control;
steady state equilibrium;
resilience;
adaptability;
habitat degradation,
- breadth in addressing and linking a range of advantageous and disadvantageous aspects of various introduced species with characteristic features of environmental pollution
- examples of a number of introduced species and a range of their characteristic negative and positive impacts on the equilibrium of ecosystems.
- balanced analysis evaluating the extent to which introduced species may, or may not, validly be identified as a form of pollution, acknowledging both similarities and differences from other forms of pollution, and advantages and disadvantages to natural ecosystems.
- a conclusion that is consistent with, and supported by, analysis and examples given e.g. While it is important to recognise that alien species may have potential benefits on ecosystems and human societies, a number of factors indicate that alien species being classified as pollutants as they are anthropogenic in origin and have detrimental effects on the equilibrium of native ecosystems and biodiversity.

Please see markbands on page 19.