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2011 HSC Notes from the Marking Centre — Earth and Environmental Science

2011 HSC Notes from the Marking Centre – Earth and Environmental Science

Introduction
Section I – Core
Section II – Options

Introduction

This document has been produced for the teachers and candidates of the Stage 6 course in Earth and Environmental Science. It contains comments on candidate responses to the 2011 Higher School Certificate examination, indicating the quality of the responses and highlighting their relative strengths and weaknesses.

This document should be read along with the relevant syllabus, the 2011 Higher School Certificate examination, the marking guidelines and other support documents developed by the Board of Studies to assist in the teaching and learning of Earth and Environmental Science.

General comments

Teachers and candidates should be aware that examiners may ask questions that address the syllabus outcomes in a manner that requires candidates to respond by integrating their knowledge, understanding and skills developed through studying the course including the prescribed focused areas. It is important to understand that the Preliminary course is assumed knowledge for the HSC course.

Candidates need to be aware that the marks allocated to the question and the answer space (where this is provided on the examination paper) are guides to the length of the required response. A longer response will not in itself lead to higher marks. Writing in excess of the space allocated may reduce the time available for answering other questions.

Candidates need to be familiar with the Board’s Glossary of Key Words, which contains some terms commonly used in examination questions. However, candidates should also be aware that not all questions will start with or contain one of the key words from the glossary. Questions such as ‘how?’, ‘why?’ or ‘to what extent?’ may be asked, or verbs may be used that are not included in the glossary, such as ‘design’, ‘translate’ or ‘list’.

Teachers and candidates should also be aware that questions may be asked that focus on the mandatory skills content in Module 9.1.

Candidates should use examination time to analyse the question and plan responses carefully, working within that framework to produce clear and concise responses that avoid internal contradictions. This is particularly so in holistic questions, which need to be logical and well structured.

In the best responses, candidates:

showed all working where required by the question
did not repeat the question as part of the response
used appropriate equipment, for example pencils and a ruler to draw diagrams and graphs. (A clear plastic ruler would aid candidates to plot points that are further from the axes and rule straight lines of best fit.)

Candidates are reminded to attempt one question only in Section II. Candidates are also strongly advised to answer the option they have studied in class.

Section I – Core

Part B

Question 21

In better responses, candidates clearly identified both types of crust, A as continental crust and B as oceanic crust. In weaker responses, candidates only identified oceanic crust.
In better responses, candidates described two valid differences and provided a supporting reason for each.

In weaker responses, candidates identified two differences.

Question 22

1. In better responses, candidates correctly identified 45%.
2. In better responses, candidates correctly marked and labelled an appropriate area on the graph corresponding to the continuum shown on the horizontal axis.
  
  In weaker responses, candidates plotted a point off the curve.
3. In better responses, candidates correctly plotted and labelled an appropriate area on the graph corresponding to the continuum on the horizontal axis.
  
  In weaker responses, candidates plotted a point on the end of the curve.
In better responses, candidates used information from both the graph and the diagram. They correctly identified the trend in the graph and identified the chain as being created by a hotspot currently located at Kilauea. These responses also described a hotspot volcano and correctly identified the direction in which the plate was moving.

In weaker responses, candidates identified the trend in the graph but did not recognise the chain of volcanoes as being created by a hotspot volcano. In many weaker responses, candidates linked the creation of the volcanoes to the subduction zone associated with Aleutian trench.

In some weaker responses, candidates simply identified a relationship between age of the volcanoes and the distance from Kilauea.

Question 23

In the best responses, candidates described different characteristics of building design as well as providing a clear link to demonstrate how each minimised the damage to the building.

Question 24

Lahar – in the best responses, candidates detailed the impact of a lahar as mudflow covering vegetation causing it to die or be destroyed.

In weaker responses, candidates identified a lahar as something burning anything within its path.

Ash flow – the best responses detailed the impacts as ash flows cover and bury organisms or vegetation, leading to death or vegetation being unable to photosynthesise. Many candidates also provided the positive effects of soil enrichment following the weathering of the ash.

Poisonous gas – the better responses correctly identified an impact as asphyxiation causing death. Some also mentioned death due to the toxicity of the ash.

Question 25

The best responses were characterised by clear flowcharts and clearly differentiated the composition and origin of the iron-rich and iron-poor bands. In these responses, candidates identified the sources of dissolved iron and oxygen, as well as the reaction that produced the iron precipitate.

In mid-range responses, candidates recognised the cyclic nature of deposition.
In the best responses, candidates clearly described the relationship between oxygen and the formation of banded-iron formations as well as the relationship between the presence of oxygen and its origin in photosynthesis by living organisms.

Question 26

In better responses, candidates identified the features of amphibians as:
- aquatic and terrestrial as the main environment
- gills and lungs as the method for obtaining oxygen
- the age range as beginning near the middle of the Palaeozoic

terrestrial as the main environment
lungs as the method for getting oxygen
the age range as beginning near the end of the Palaeozoic.

The best responses were often done as tables, which showed clear comparisons of the challenges. Challenges were clearly defined and strategies given for both amphibians and reptiles in regard to each. Candidates were required to compare the same challenges for both reptiles and amphibians when looking at strategies to overcome these challenges.

Question 27

In stronger responses, candidates demonstrated a sound knowledge of mass extinctions and smaller extinctions by giving a cause, effect and an example of each type of extinction.

In weaker responses, candidates failed to effectively compare the two types of extinctions.

Some candidates provided their responses in a table. This was an effective way to answer the question as all required parts of the response were clearly demonstrated.

In weaker responses, candidates nominated non-extinct species, eg Tasmanian devils and/or confused mass extinctions with smaller extinctions.

Question 28

In better responses, candidates adequately outlined two environmental problems. In weaker responses, candidates provided incorrect problems or real problems that didn’t relate to the mine.

Solutions needed to relate to the problem outlined. In better responses, candidates provided appropriate solutions. In weaker responses, candidates included simple but not very effective or appropriate solutions, such as moving the piles of waste rock away from the site.

Question 29

In better responses, candidates clearly demonstrated an understanding of a secondary source as opposed to a primary source or a research strategy. In these responses, candidates addressed the question requirements by providing two specific examples of sources of information rather than alternatives to pesticides.
1. In better responses, candidates addressed the concept of validity related secondary sources. In these responses, candidates listed strategies that would ensure the validity of information gathered or highlighted the difference between valid and invalid sources.
2. In better responses, candidates addressed the concept of gathering data from secondary sources and explained the relevance of their strategy in determining the reliability data from the information source.

Question 30

In better responses, candidates outlined two farming practices. Where candidates referred to erosion or compaction, they related these concepts to salinity.
In better responses, candidates justified their suggested strategy for the rehabilitation of this site, not just describing the effect of the management strategy or detailing a strategy. In better responses, candidates showed a number of supporting reasons or linked points to their justification.

Question 31

In better responses, candidates clearly related the earth processes and environmental factors to Australia’s fragility and linked these effectively, showing cause and effect to explain the management strategies. In these responses, candidates demonstrated a clear understanding of an earth process and associated environmental factors.

In weaker responses, candidates listed environmental factors and/or earth processes with simple links or no links to management strategies.

Many candidates did not address the term ‘evaluate’ in relation to management.

Section II – Options

Question 32 – Introduced Species and the Australian Environment

1. In weaker responses, candidates confused the concepts of distribution and abundance while others failed to provide detail on location of the distributions. These responses did not answer the question, but rather gave reasons for the changes in distribution.
2. In better responses, candidates indicated a predicted increase in distribution and provided a reason for the increase.
In better responses, candidates referred to the stimulus material and made a judgement about the potential impact of the treaty. In weaker responses, candidates did not support the judgement with relevant scientific information.

Many weaker responses lacked detail about the introduction of species via ballast water or the treatment of ballast water to remove pests, or did not provide specific examples of species introduced via ballast water.
In weaker responses, candidates compared two strategies for control of different species, rather than providing strategies for the one animal. In some weaker responses, candidates discussed control only in general terms and some used plant examples rather than animals.
1. In better responses, candidates produced a well-drawn table or column graph. Some provided a series of pie graphs.
2. In better responses, candidates described at least two trends and included specific data to further clarify or support the trends identified. In these responses, candidates also provided a suitable conclusion for the investigation in which they clearly highlighted a relationship between the numbers of introduced species and eucalypt and grass seedlings.
  
  In weaker responses, candidates did not include specific data about the trends and/or did not write a relevant conclusion.
3. In better responses, candidates identified that the investigation should be repeated by counting the number of seedlings at other locations so that the results could be compared to see if the same trends were observed.
  
  In weaker responses, candidates identified the need to repeat the investigation but failed to justify the reason for repeating the experiment. In some of these responses, candidates confused validity with reliability.
In better responses, candidates demonstrated an understanding of the fragile nature of the biotic and abiotic Australian environment and introduced species. They described the impact on the Australian environment of both deliberately and accidently introducing new species. They provided a clear judgement relating to the role of humans in the introduction of these species. In these responses, candidates also demonstrated a coherent and logical progression of thought and included scientific principles and ideas. Some better responses also included a positive impact on the Australian environment of an introduced species, for example the eradication of prickly pear by the moth – cactoblastis cactorum.

In weaker responses, candidates made a judgement relating to the impact that humans have made on the Australian environment by introducing other species. They lacked specific detail or focused on deliberately introduced species only.

Question 33 – Option – Organic Geology

1. Most candidates defined the term ‘non-renewable’ and provided an example. The most common examples were fossil fuels, eg coal.
2. Candidates generally understood why the process of catalytic cracking is used, but many did not mention that the process requires a catalyst.
  
  In better responses, candidates included the name of a catalyst used in the industry.
  
  In weaker responses, candidates failed to describe the process of catalytic cracking (in reference to the use of a catalyst) where large molecules are broken down. Some also failed to link the products to use. Some candidates confused catalytic cracking with fractional distillation.
In better responses, candidates outlined drilling and one geophysical technique used to locate oil, and argued for the combination of the named processes to increase success, using the diagram as a reference point.

Many candidates understood the processes individually, but failed to link them to one another to ensure more accurate ways of locating reservoir(s).

In weaker responses, candidates did not understand or adequately describe the processes used to locate oil. There was confusion about the temporal relationship of the standard practice – drilling follows a geophysical method.
In better responses, candidates demonstrated understanding of the two named processes and stated both similarities and/or differences.

Many candidates were familiar with only one of the processes, making it difficult to find similarities and/or differences.

In weaker responses, candidates gave little or no information on the named processes or described the process for only one of the named products.
1. In better responses, candidates used data tables or graphs. In weaker responses, candidates used inaccurate data or poorly organised data.
2. In better responses, candidates used data to outline the trends and linked the data to the first-hand experiment carried out in class.
  
  Many candidates failed to use data in their outlining of trends.
  
  In weaker responses, candidates did not analyse the data to recognise trends in the data or draw conclusions.
3. In better responses, candidates identified that repetition ensures reliability and justified why experiments are repeated, eg to compare data sets for consistency.
  
  Many candidates recognised repetition, but failed to justify why it was required.
  
  In weaker responses, candidates failed to recognise repetition.
  
  Many candidates confused the terms accuracy and validity with reliability.
Candidates who made an evaluation of the need to make a change from fossil fuels generally also gave numerous relevant examples.

In better responses, candidates described the current use and current estimates of availability of fossil fuels and assessed alternatives, displaying a depth of knowledge about resources and solutions.

In weaker responses, candidates often lacked knowledge of current uses of fossil fuels or alternatives.

Some candidates failed to mention either fossil fuels or alternative sources.

Question 34 – Option – Mining in the Australian Environment

1. Most candidates had difficulty in identifying either metal, and did not correctly identify a mineral province.
2. Most candidates lacked an understanding of styles of mineral genesis.
Most candidates accounted for the trends in the graph and their relationships to the mining process.

In weaker responses, candidates misunderstood the links between profit/loss and the mining processes over time.
Many candidates identified a government policy and a legal landmark decision, but failed to appreciate how these affect mining.

In better responses, candidates linked the processes with an impact.

In weaker responses, candidates only identified a policy or decision.
1. In better responses, candidates used data tables or graphs. In weaker responses, candidates used inaccurate data or poorly organised the data.
2. In better responses, candidates used data to outline the trends in the data and linked it to the first-hand experiment.
  
  In weaker responses, candidates did not analyse the data to recognise trends in the data or draw conclusions.
3. In better responses, candidates identified that repetition ensures reliability and justified why experiments are repeated, eg to compare data sets.
  
  Many candidates recognised repetition, but failed to justify why it is required.
  
  In weaker responses, candidates failed to recognise repetition.
  
  Some candidates confused the terms accuracy and validity with reliability.
In better responses, candidates had a good understanding and described mining exploration and exploitation with a focus on the environmental impacts.

In mid-range responses, candidates had some concept of the environmental issues relating to exploring and exploiting a mineral resource. However, some failed to detail the impacts in all cases.

In weaker responses, candidates had little understanding of the differences between exploring and exploiting a mineral resource. Many candidates only referred to pollution in general terms.

Question 35 – Option – Oceanography

1. Most candidates recognised that light was used for the process of photosynthesis and linked this to food chains. It was also noted that most life exists in the top 150 m.
  
  In weaker responses, candidates failed to link the process of photosynthesis with food chains.
  
  Some candidates erroneously stated that light was available at great depths (600–1500+ m).
2. In better responses, candidates provided a clear explanation of hydrothermal vents and the process of chemosynthesis as the beginning of a unique food chain. This was followed by a statement about current knowledge of the extension of the distribution of life.
  
  Many candidates had a very clear understanding of what a hydrothermal vent was.
  
  Some candidates were confused about how the chemosynthesis worked.
  
  In weaker responses, candidates made no link to hydrothermal vents and life (food chains).
Most candidates had a broad knowledge about the types of technology used to survey the oceans. However, many were unsure of how the technology had improved our current understanding from that of the past. A clear link was required between the technology and the findings.

In better responses, candidates knew the name of the technology, understood what data/information was being gathered and how the data from a specific piece of technology would be used.

In weaker responses, candidates described a piece of technology, but failed to name it and only attempted to describe its appearance.
The position of ‘X’ proved to be confusing to some candidates. Answers ranged from coastal sediments to oozes found at shallower levels.

In better responses, candidates had a clear understanding of the type of sediment, its general structure and formation process (origins).

Many candidates knew the names of the sediments, but failed to state how they formed. The processes that form oozes were also poorly described in many responses.
1. In better responses, candidates used data tables or graphs. In weaker responses, candidates used inaccurate data or poorly organised the data.
2. In better responses, candidates used data to outline the trends in the data and linked it to the first-hand experiment.
  
  Many candidates failed to use data in their outlining of trends.
  
  In weaker responses, candidates did not analyse the data to recognise trends in the data or conclusions.
3. In better responses, candidates identified that repetition ensures reliability and justified why experiments are repeated, eg to compare data sets.
  
  Many candidates recognised repetition, but failed to justify why it was required.
  
  In weaker responses, candidates failed to recognise repetition.
  
  Some candidates confused the terms accuracy and validity with reliability.
In better responses, candidates acknowledged and made a judgement on impacts that humans have had directly on the oceans and the impact on biological resources in the oceans. Many candidates also gave both positive and negative impacts.

In better responses, candidates distinguished between impacts on the ocean and the biological systems in the ocean. Some candidates failed to understand the difference and saw the system as one whole structure.

In weaker responses, candidates had a lack of knowledge about the systems, often quoting incorrect facts or data.