IB ESS HL 3.2 Human Impact on Biodiversity Questions

Practise IB ESS HL 3.2 by evaluating threat evidence, invasive-species control, hotspot conservation and biosphere-integrity risks.

Exam points

Analyse Red List percentages and criteria to compare taxa and explain status changes.
Evaluate species vulnerability from range, life history, pollution, climate and exploitation.
Evaluate invasive-species removal and conservation interventions against ecological evidence and limitations.
Justify hotspot conservation using endemism, habitat diversity, human threat and urgency.
Evaluate biosphere-integrity risk using extinction trends, keystone effects and human causes.

Covered syllabus points

3.2.1—Threats to biodiversity 3.2.2—Multiple human impacts 3.2.3—Invasive alien species 3.2.4—IUCN Red List 3.2.5—Conservation status benefits 3.2.6—Species case studies 3.2.7—Tragedy of the commons 3.2.8 (HL)—Biodiversity hotspots 3.2.9 (HL)—Key Biodiversity Areas (KBAs)3.2.10 (HL)—KBA conflicts 3.2.11 (HL)—Traditional indigenous land management 3.2.12 (HL)—Environmental justice in conservation 3.2.13 (HL)—Biosphere integrity planetary boundary

[Maximum number: 2]

Figure:Photographs showing examples of species found in Brazil

Golden lion tamarin (Leontopithecus rosalia) IUCN Red List status - endangered

Brazilian merganser (Mergus octosetaceus) IUCN Red List status - Critically endangered

Giant metallic ceiba borer (Euchroma gigantea) IUCN Red List status - none, has not yet been assessed by the IUCN

Figure:Deforestation in the Atlantic Rainforest and the Cerrado

Figure:Photographs showing examples of species found in Brazil

Parana pine: critically endangered. Golden lion tamarin: endangered. Broad-snouted caiman: least concern. Pau brasil: endangered. Brazilian merganser: critically endangered. Giant metallic ceiba borer: not yet assessed by the IUCN.

With reference to the species listed in Figure 4, identify two factors that may have contributed to their status given on the IUCN Red List.

[Maximum number: 9]

The introduction of a species into an ecosystem could be considered a form of pollution. Discuss this statement.

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.

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.

Section B, part (c) markbands
0: The response does not reach a standard described by the descriptors below and is not relevant to the question.

1–3: The response contains:
• minimal evidence of knowledge and understanding of ESS issues or concepts
• fragmented knowledge statements poorly linked to the context of the question
• some appropriate use of ESS terminology
• no examples where required, or examples with insufficient explanation/relevance
• superficial analysis that amounts to no more than a list of facts/ideas
• judgments/conclusions that are vague or not supported by evidence/argument.

4–6: The response contains:
• some evidence of sound knowledge and understanding of ESS issues and concepts
• knowledge statements effectively linked to the context of the question
• largely appropriate use of ESS terminology
• some use of relevant examples where required, but with limited explanation
• clear analysis that shows a degree of balance
• some clear judgments/conclusions, supported by limited evidence/arguments.

7–9: The response contains:
• substantial evidence of sound knowledge and understanding of ESS issues and concepts
• a wide breadth of knowledge statements effectively linked with each other, and to the context of the question
• consistently appropriate and precise use of ESS terminology
• effective use of pertinent, well-explained examples, where required, showing some originality
• thorough, well-balanced, insightful analysis
• explicit judgments/conclusions that are well-supported by evidence/arguments and that include some critical reflection.

[Maximum number: 1]

Figure 2(c): Conservation status of indigenous species groups in New Zealand

Figure:Conservation status of indigenous species groups in New Zealand

With reference to Figure 2(c), identify the group of species most 'at risk of becoming threatened'.

[Maximum number: 8]

Outline two reasons for the extinction of a named species and suggest how intervention measures can improve the conservation status of a species.

[Maximum number: 9]

To what extent is the need for conservation more significant in tropical biomes?

• understanding concepts and terminology of biodiversity; conservation strategies; tropical biomes; rainforests; swamps; coral reefs; hotspots; LEDCs & MEDCs; international v national conservation bodies; environmental value systems; productivity; carbon sinks; global warming; unsustainable exploitation; resources of tropical ecosystems; medicines; indigenous cultures; endangered species; Red List, etc;
• breadth in addressing and linking threats to biodiversity with different societies, ecosystems, conservation strategies; the global dependence upon and significance of tropical biomes compared with others; implications of economic development in tropical regions with challenges of conservation; different EVS perspectives on reasons for conservation, etc;
• examples of tropical biomes/ecosystems; their local societies; conservation efforts; reasons/needs for conservation, etc;
• balanced analysis evaluating the extent to which conservation efforts are of particular importance for tropical biomes along with relevant limitations and counterarguments, etc;
• a conclusion that is consistent with, and supported by, analysis and examples given eg "although the loss of any species may be considered of equal significance from an ecocentric point of view, the high productivity and biodiversity that characterize tropical biomes, along with the limited facility of local societies, which are often less developed, make tropical biomes a priority for international conservation efforts";

The following guide for using the markbands suggests certain features that may be offered in responses. The five headings coincide with the criteria given 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 markband and the specific mark within that band.

These are possible inclusions, not required points. Assess with the official Section B, part (c) markbands below.

Marks	Level descriptor
0	The response does not reach a standard described by the descriptors below and is not relevant to the question.
1–3	The response contains: • minimal evidence of knowledge and understanding of ESS issues or concepts • fragmented knowledge statements poorly linked to the context of the question • some appropriate use of ESS terminology • no examples where required, or examples with insufficient explanation/relevance • superficial analysis that amounts to no more than a list of facts/ideas • judgments/conclusions that are vague or not supported by evidence/argument.
4–6	The response contains: • some evidence of sound knowledge and understanding of ESS issues and concepts • knowledge statements effectively linked to the context of the question • largely appropriate use of ESS terminology • some use of relevant examples where required, but with limited explanation • clear analysis that shows a degree of balance • some clear judgments/conclusions, supported by limited evidence/arguments.
7–9	The response contains: • substantial evidence of sound knowledge and understanding of ESS issues and concepts • a wide breadth of knowledge statements effectively linked with each other, and to the context of the question • consistently appropriate and precise use of ESS terminology • effective use of pertinent, well-explained examples, where required, showing some originality • thorough, well-balanced, insightful analysis • explicit judgments/conclusions that are well-supported by evidence/arguments and that include some critical reflection.

Section B, part (c) markbands (official markscheme p18)

[Maximum number: 4]

Outline how global rates of extinction have changed over time.

global rates of extinction have been relatively constant over long periods; ...and relatively low as extinction was balanced by rates of speciation;
there have been major peaks / 5 mass extinctions with unusually high extinction rates; ... associated with relatively sudden changes in natural global cycles eg ice age/volcanic activity/plate tectonics; ...or catastrophic events eg, Asteroid impact;
...most recent/current peak is anthropogenic / $6^{\text {th }}$ mass extinction due to human causes;
eg hunting/urbanisation/global warming/habitat destruction;

All question bank results loaded

Covered syllabus points

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6