VCE Unit 3

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Victorian Association for Environmental
Education Investing in environmental education
for a sustainable future

• VCE Unit 3
• Environmental Science
• Revision Lecture
• June 2007
• Examination Technique
• Area of Study 2 Diversity in the Biosphere
• Danny McCoppin, Melbourne Grammar School

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Examination TechniqueReading Time

• The reading time is extremely important. Use it
  wisely! Do not make faces at others, stare out
  the window or at the ceiling, scratch multiple
  choice responses on your answer sheet or try to
  formulate a detailed response to the first short
  answer question!
• You should use the reading time to
• Get comfortable quickly arrange pencils, watch,
  calculator relax (deep breathsyour good work
  this semester will give you confidence to do well
  in this exam ie the power of positive thinking
  is amazing!).
• Check that you have the right number of pages and
  sections as listed on the front cover. Check that
  you have a question/answer booklet and a
  multi-choice answer sheet check the number and
  mark allocation given to a) multiple choice and
  b) short answer questions. Confirm the amount of
  time you should therefore spend on each section
  probably about 20-30 minutes on the multi-choice.
  
• Briefly scan the multi-choice questions to see
  what data is provided.
• Briefly read through the short answer questions
  looking for linked questions.
• Confirm or modify your intended plan to start the
  examination (ie MC or SA?)
• If you do this carefully then you are more likely
  to a) start the exam confidently and b) not put
  information/knowledge in the first part of a
  linked question that is more relevant to the
  second part.

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Outcome 2Types of Value of...Conservation
categoriesAssessment ofThreats to
A of S 2 - Outline of Outcomes 2 3
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Outcome 2 cont
A of S 2 - Outline of Outcomes 2 3

• Methods of protecting environments populations
• Using scientific data in managing biodiversity
• Including sections of FFGA that relate to
  selected endangered animal.

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Outcome 3EIAPrecautionary Principle
Extinction risk
A of S 2 - Outline of Outcomes 2 3
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What is biodiversity?

• Variety of life on earth
• The number and variety of all species that
  inhabit the earth, the genetic variation within
  and between different populations as well as the
  differences between the ecosystems in which they
  live.

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Examination TechniqueShort Answer (Section B)

• Command Words
• TIP 1. You should consider physically or mentally
  underlining or highlighting command words on the
  question booklet.
• TIP 2. Remember that you are demonstrating your
  understanding to the examiner, therefore make
  sure that your responses can be read and are
  concise. You should be demonstrating your
  understanding of the scientific language used in
  the course.
• In an Environmental Science examination paper, a
  variety of command words are used. Some command
  words demand more of the candidate than others.
  Some require a simple task to be performed
  others require greater intellectual thought and
  synthesis. There is, therefore, a hierarchy of
  command words.

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Question 5 2002 VCAA

• Three types of biodiversity are genetic, species
  and ecosystem. Explain what each term means,
  showing the different meaning of each term. (3
  Marks)
• genetic
• species
• ecosystem

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What are the three levels of biodiversity?
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Why is variety so important?

• Variation at all scales is generally considered a
  good thing. Why?
• A genetically variable population is less
  vulnerable to extinction through changes in its
  environment.
• Variation in ecosystems (i.e. complexity) tends
  to give greater stability or resilience to
  changes.

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Types of Biodiversity?Conservation biologists
routinely characterise biodiversity into three
levels

• Variety within species
• genetic diversity
• Variety between species
• species diversity
• Variety of ecosystems
• ecosystem diversity
• Helps to establish conservation priorities

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Genetic Diversity

• Variety of genotypes within and between distinct
  populations of the same species
• Eg
• or different varieties of apples or
  rice
• Maximises survival potential of a species
• -increased no. of different alleles in gene pool
• -increased chance of adaptation to change/threat

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Examination TechniqueMultiple Choice Questions
(Section A)

• Remember that you are to only select ONE (THE
  BEST) response.
• Carefully read the background information in the
  stem of the statement/question.
• Physically or mentally underline key words in the
  question/statement.
• Identify the two most unlikely responses because
  they are irrelevant, too specific or too general
  to match clearly with the stem.
• Decide which of the two remaining is the BEST
  selection and mark it on the answer sheet.
• If you are stuck on a selection or experience a
  mental block, put a big mark on the question
  booklet beside that question, mark your answer
  sheet (in pencil) with your gut feeling selection
  and come back to it later (at the end of the
  exam).
• Although you do not want to rush the
  multiple-choice section, you should not spend
  more than three minutes on anyone multiple-choice
  question.
• You do not lose marks for an incorrect selection
  so have a go!

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MC question 13 2002 VCAA

• Genetic diversity of a population can be measured
  by determining the number of
• A. different species in an ecosystem
• B. genetic differences within the population
• C. genetic differences between different
  populations
• D. different species in an area and their
  relative population sizes

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Species diversity

• Variety of different species in a defined area
  and the number of individuals within each
  species.
• Approx. 2 million species have been identified
  and described.

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Ecosystem Diversity

• Variety of communities of organisms (biotic),
  their physical environments (abiotic) and all
  interactions between them in a defined area.
• Occurs on different spatial scales
• eg Biomes large scale patterns of insolation,
  moisture latitude/longitude
• Community/habitat small scale variations in
  altitude, soil type, shading (micro-climates).

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Significance and value (benefits) of biodiversity
to ecosystem function and human survival

• Ecosystem services that contribute to human
  survival and good health through protection and
  regeneration processes eg purification of air
  water, soil formation and protection, nutrient
  storage and cycling, pollination, pollution
  breakdown and storage.
• Biological resources where organisms are used
  directly by humans eg Production of goods food,
  medicines, industrial production, wood products,
  ornamental plants, breeding stocks and population
  reservoirs
• Social benefits including life-fulfilling
  functions eg aesthetics, cultural intellectual
  inspiration, research and education, cultural
  values, recreation preservation of options
  (intergenerational equity).

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Conservation of Biodiversity

• The main aim of ecological conservation is to
  maximise the resilience and survival potential so
  that critical ecological processes and
  biodiversity are maintained, external threats are
  minimised, evolutionary processes are
  conserved.
• Operates at three levels
• - ecosystem conservation
• - populations and species
• - genetic diversity (micro scale)
• It is most successful when all three levels are
  considered together.

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Ecosystem Conservation

• Key goals
• - minimise human disturbance of biotic and
  abiotic components of habitats
• - habitat destruction
• - habitat modification
• - preserve ecosystem
  function

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Species Conservation

• Species group of organisms that have sufficient
  genetic similiarities that they can interbreed to
  produce fertile offspring
• Conservation strategies revolve around one
  central ecological question
• .what limits this species?

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Population Conservation

• Key goal
• - maximise ability of populations to adapt to
  changing circumstances
• - major demographic factors
• births, deaths, net migration
• - minor demographic factors
• sex ratios, age structure

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Genetics Conservation

• Key goals
• - Preserve significant amounts of genetic
  variation in populations
• - Prevent accumulation of deleterious
  mutations/alleles
• - limit inbreeding depression reduced chance
  of survival/ability to reproduce

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Genetic threats to small populations

• Genetic drift loss of alleles from population
  due to chance alone
• - the loss of genetic diversity is
  directly related to population size
• - drop in pop size gives greater chance
  that the gene frequency will change perhaps
  leading to the decreased abundance of a
  potentially favourable allele
• - leads to decrease in in ability of
  population to adapt to changing conditions.

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Genetic threats to small populations

• Inbreeding mating between close relatives
• Results in
• - greatly reduced genetic variability
• - increased chance of inheriting two
  copies of the same deleterious allele
• Leads to lower reproduction survivability rates
• Is a particular problem for zoo populations and
  captive breeding programs.

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Genetic threats to small populations

• Genetic swamping where the genes of a two
  geographically separated populations come into
  contact with one another.
• If one of the populations is relatively small in
  size its genetic pool might be swamped with the
  reintroduction of genes from the bigger
  population of the species.
• Results in lower overall genetic variation.

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MC question 15 2004 VCAA

• What is inbreeding?
• A. breeding between different species
• B. breeding attempts that are unsuccessful
• C. breeding in very large populations of a
  species
• D. breeding between individuals that are
  genetically related

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MC question 13 2004 VCAA

• Genetic swamping is most likely to occur when
• A. a species moves into a different ecosystem
• B. a number of previously isolated species come
  into contact
• C. geographic isolation of a population of a
  species leads to inbreeding
• D. a small, previously isolated population of a
  species comes into contact with with a larger
  population.

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Assessment of biodiversity

• Species Richness (number of different species in
  a defined area)
• Species Diversity (number of different species
  present AND the relative abundance of each)
• Endemism (number of species that only occur in
  that area)

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Application of simple diversity indices

• Mathematical/probability tools used to
  quantitively measure species diversity
• Used for comparing biodiversity of a site before
  and after a disturbance or between two different
  sites.
• Chief Examiner suggests that since 2006 you do
  not have to know how to calculate the indices but
  be able to make reasonable interpretations of
  them.

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Threats to biodiversity

• Global Biodiversity Strategy identified six major
  causes of reduction in biodiversity
• Habitat loss/change/modification/ fragmentation
  and degradation.
• Overexpoitation
• Introduced Species
• Pollution
• Global climate Change
• Industrial agriculture/forestry biotechnology

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Threats to biodiversity

• Biotechnology
• Traditional farmers bred/maintained wide
  diversity of crops livestock
• Modern farming practices
• - crop breeding programs
• - monoculture tree programs
• Leads to reduced diversity of gene pool and
  increased potential for entire ecosystem to be
  wiped out by a single disease agent.

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Impacts of loss of biodiversity

• Long term consequences as ecosystems are
  interrelated and interdependent
• Symbionts (where organisms are intimately
  associated)
• - parasitism one way benefit, host is harmed
• - Commensalism one way benefit, no harm
• - Mutualism mutual benefit, no harm
• Many species of plants are dependent on insects
  or birds for pollination or for the dispersal of
  seed. Clearly the loss of bird or insect species
  could threaten the survival of some plant
  species.

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Assessing threats to biodiversity

• Species classified into conservation categories
• Framework for allocating limited resources
• Establish priorities
• Organisms classified according to relative threat
  of extinction.
• No immediate threat vulnerable endangered
  critically endangered - extinct

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MC question 12 2006 VCAA

• Which one of the following categories indicates
  that a species is most at risk of extinction?
• A. exotic
• B. critical
• C. vulnerable
• D. endangered

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Strategies for protecting biodiversity

• Four key strategies
• Establish biodiversity reserves eg National
  Parks
• Network remnant populations with wildlife
  corridors
• Translocate or reintroduce species
• Develop captive breeding programs

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Management of Biodiversity

• Problems associated with assessing biodiversity
  to produce meaningful management plans
• Assessment is sometimes a subjective process
• Results should be statistically valid reliable
• Statistical analysis of assessment are used to
  support environmental decision making
• What if wrong decision is made? Error
• Two major consequences of this error
• Economic damage
• Environmental/Ecological damage

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Management of Biodiversity

• Ramsar Convention
• Aims to protect internationally significant
  wetlands, particularly with respect to their
  function as waterbird habitat
• Australia is a signatory to the convention

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Management of Biodiversity

• Sections of the Flora
• and Fauna Guarantee Act that relate to the
  protection of an endangered animal
• - The endangered animal could be your selected
  endangered animal or it could be one provided.

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Question 4 2006 VCAA

• Like many other threatened species, the New
  Holland Mouse is listed under the Flora and Fauna
  Guarantee Act 1988, and an Action Statement has
  been prepared.
• What is the purpose of an Action Statement for a
  threatened species under the Flora and Fauna
  Guarantee Act?
• (3 Marks)

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Management of Biodiversity

• Use of scientific data to establish biodiversity
  treaties, agreements and regulatory frameworks
• CITES convention on the international trade of
  endangered species (of wild flora and fauna)
• Protects over 30,000 species

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Management of biodiversity

• Environmental scientists use different tools to
  help the data analysis process
• - Diversity indices
• - Environmental Impact Assessment (EIA)
• - Precautionary Principle
• - Population Viability Analysis (PVA)
• - Bioclimatic modelling and others

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Environmental Impact Assessment

• Assesses environmental impact of proposal for
  development or change before any decision is made
• Does not aim to stop development from proceeding
  (even if environmentally damaging)
• Information gathering process
• Informs decision makers

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Precautionary Principle

• Where there are threats of serious or
  irreversible environmental damage, lack of full
  scientific certainty should not be used as a
  reason for postponing measures to prevent
  environmental degradation
• Not intended to stop development from proceeding
• Concerned with balancing relative costs

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Assessment of Risk Extinction Risk

• Risk assessment involves using data to estimate
  the probability of some harmful event occurring.
• Extinction risk is the probability that a
  population or species will become extinct. The
  probability maybe expressed as a percentage or
  decimal. Eg 30 ER or 0.3 ER of becoming extinct
  in 5 years if X and Y take place.
• Alternatively the risk assessment may estimate
  the number of species that can be maintained in a
  given area.

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Assessment of Risk Extinction Risk

• Population Viability Analysis (PVA)
• Refers to extinction probability of a population
  under various management scenarios.
• Uses computer based models of risks of extinction
  by collecting two types of data
• - ecological
• - demographic

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Outcome 2evaluate strategies to reduce the
effects of threatening processes on one selected
endangered animal

• Question 3 2006 VCAA June exam
• Name one endangered (threatened) animal species
  you have studied
• Explain why this species is considered
  threatened. Include the degree of threat and
  reference to the main threats. (3 marks)

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Outcome 2evaluate strategies to reduce the
effects of threatening processes on one selected
endangered animal

• b. Describe one known population of this
  species, including reference to the population
  size, the long-term survivability of this
  population, and a description of a geographic
  location of a population of the species.
  (4 marks)

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Outcome 2evaluate strategies to reduce the
effects of threatening processes on one selected
endangered animal

• Comment on how important this population is to
  the survival of the species as a whole. (2 marks)

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Outcome 2evaluate strategies to reduce the
effects of threatening processes on one selected
endangered animal

• Describe a management strategy that is being
  used, or could be used, for the protection of
  this population. Relate this strategy to the
  location and habitat of the population.
• You should include a description of the
  monitoring process, and one method of evaluating
  the effectiveness of the management
  strategy. (5 marks)

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Examination TechniqueFinishing the exam

• Remember that an examination is a chance for you
  to demonstrate your understanding ATTEMPT ALL
  QUESTIONS. You have nothing to gain and
  everything to lose by not having a go or not
  writing something in response to a question.
• Therefore check that you have responded to all
  questions.
• Check any Multiple-choice questions that you got
  stuck on or were unhappy with. Only change your
  response if you are certain. Most changes are
  incorrect and your first selection is more likely
  to be the best.
• Check your short answer responses and make sure
  that the examiner will be able to read your
  writing.
• GOOD LUCK IF YOUVE MANAGED TO DO ALL OF THIS,
  ENJOY IT!