Presentation on theme: "Option G Higher Level An outline of the main areas"— Presentation transcript:
1 Option G Higher Level An outline of the main areas A focus on ConservationMultiple choice questionsLong-answer questions
2 An Outline of HL Option G: For ‘Conservation of biodiversity’ we need to:Explain the use of biotic indices and indicator species in monitoring environmental change.Outline the factors that contributed to the extinction of one named animal species.Outline the biogeographical features of nature reserves (edge effects, size and habitat conditions) that promote the conservation of diversityDiscuss the role of active management techniques in conservationDiscuss the advantages of in situ conservation of endangered species (terrestrial and aquatic nature reserves)Outline the use of ex situ conservation measures (captive breeding, botanic gardens and seed banks)
3 For ‘Popualation ecology’ Distinguish between r-strategies and k-strategies and discuss the environmental conditions that favour either oneDescribe one technique used to estimate the population size of an animal species (based on a capture-mark-release-recapture method)Describe the methods used to estimate the size of commercial fish stocksOutline the concept of maximum sustainable yield in the conservation of fish stocks.Discuss international measure that would promote the conservation of fish
5 Monitoring Environmental Change... Frequent environmental monitoring can detect problems in natural ecosystems quicklyAs well as measuring abiotic factors, living organisms can be used to detect changes....INDICATOR SPECIESUseful – need particular environmental conditionsShow – what conditions in an ecosystem are
6 Indicator Species SO2 : Lichens Tolerance to sulphur dioxide varies from most tolerant to least tolerant species.
7 More indicator species... Pollution levels in aquatic ecosystemIndicators of high O2 concentrations: (require unpolluted, well oxygenated water)Stonefly nymphMayfly larvaCaddisfly larvaIndicators of low O2 concentrations: (and excessive levels of suspended organic matter, from untreated sewage)ChironomidRat-tailed maggot larvaTubifex
8 Environmental assessment: A biotic index can be calculated:Number of individuals of each indicator species x pollution tolerance ratingAn abundance of tolerant species gives a low overall scoreAn abundance of intolerant species gives a high overall score.
9 In-situ conservation methods: In its own habitat – the best way because:Species remain adapted to their habitatsA greater genetic diversity is conservedNatural behaviour patternsSpecies interact – whole ecosystem conserved
10 Biogeographical features of nature reserves: SIZE: Large ones promote conservation of biodiversity moreEDGE EFFECTS: ecology of edges of ecosystems different from central areas due to edge effectsEg: egg laying habits of the cowbird of the western US. Feeds in open areas but lays eggs in nests of other bids near edges of forests. Fragmentation of forests: increase in cowbirds (and the nest parasitism due to them) = because of incerase in forest edge.WILDLIFE CORRIDORS: allow organisms to move between different parts of a fragmented habitatEg. Tunnels under busy roads
11 Ex-situ conservation methods Not always enough to ensure survival of species:Some species too rare so its not safe to leave them unprotected in wildDestruction of natural habitat makes it essential to remove threatened species from it
12 CAPTIVE BREEDING: BOTANIC GARDENS: SEED BANKS: Some or all members moved to zoo. When numbers are high enough some are released again to wild to re-establish a natural populationEg – Hawaiin kestrelBOTANIC GARDENS:Sites where many different species are cultivatedEg – Royal Botanic Gardens of Kew. – has more than 50,000 of words 250,000 known species in itSEED BANKS:Cold storage -10OC to -20OC or germinated to produce replacement seedEg – Kew Millenium Seed Bank will hold 25,000 of endangered speces
13 Active Management Techniques Often humans cause changes to nature reserve so active management techniques are needed to ensure survival of rare/endangered speciesEg – The North Downs in Kent raising of sheep continues to preserve rare plants and invertebrates due to the feeding habits of the sheep
14 Multiple choice questions: The capture-mark-release-recapture method is used to:Estimate plant population sizesEstimate animal population sizesEstimate abiotic environmental changeEstimate pollution changes
15 B – it is suitable for animals that move around and are difficult to find
16 R-strategies are used by: Animals in an unstable environmentAnimals with no habitatAnimals in a stable environmentAnimals with no paternal care
17 A - animals : Grow to a small body size Mature early Produce many offspringReproduce only onceGive offspring little or no parental care
18 Long answer questions: 1a) Describe the international measures taken to conserve fish (5) 1b) Describe and compare 2 methods to estimate the size of fish stocks (4)
19 Monitoring of stocks and of reproduction sites Quotas for catches of species with low stocksClosed seasons in which fishing is now allowed (especially during breeding seasons)Exclusion zones in which fishing is bannedMoratoria on catching endangered speciesMinimum net sizes, so that immature species are not caughtBanning of drift nets
20 b) Collecting data on fish catches =The numbers of fish of each age are counted and an age distribution for the population is obtained. Survivorship curves and spawning rates can be deduced = But there are great uncertainties (what proportion of the total population has been caught) Capture-mark-release-recapture method: = works well in lakes but less successful in the open sea (too large an area – all the marked fish have gone by the time they are recaptured) Echo Sounders: = used to measure the size of shoals of fish/ individuals. But fish must not be swimming too deeply & trawls must also be used for calibration and to check which species of fish has been detected by echolocation. None of these estimate with absolute certainty As a result, disputes between the fishing industry and conservation agencies about stocks are very common.