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Option G Higher Level An outline of the main areas

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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 Conservation Multiple choice questions Long-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 diversity Discuss the role of active management techniques in conservation Discuss 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 one Describe 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 stocks Outline the concept of maximum sustainable yield in the conservation of fish stocks. Discuss international measure that would promote the conservation of fish

4 Focus: Conservation

5 Monitoring Environmental Change...
Frequent environmental monitoring can detect problems in natural ecosystems quickly As well as measuring abiotic factors, living organisms can be used to detect changes.... INDICATOR SPECIES Useful – need particular environmental conditions Show – 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 ecosystem Indicators of high O2 concentrations: (require unpolluted, well oxygenated water) Stonefly nymph Mayfly larva Caddisfly larva Indicators of low O2 concentrations: (and excessive levels of suspended organic matter, from untreated sewage) Chironomid Rat-tailed maggot larva Tubifex

8 Environmental assessment:
A biotic index can be calculated: Number of individuals of each indicator species x pollution tolerance rating An abundance of tolerant species gives a low overall score An 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 habitats A greater genetic diversity is conserved Natural behaviour patterns Species interact – whole ecosystem conserved

10 Biogeographical features of nature reserves:
SIZE: Large ones promote conservation of biodiversity more EDGE EFFECTS: ecology of edges of ecosystems different from central areas due to edge effects Eg: 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 habitat Eg. 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 wild Destruction of natural habitat makes it essential to remove threatened species from it

Some or all members moved to zoo. When numbers are high enough some are released again to wild to re-establish a natural population Eg – Hawaiin kestrel BOTANIC GARDENS: Sites where many different species are cultivated Eg – Royal Botanic Gardens of Kew. – has more than 50,000 of words 250,000 known species in it SEED BANKS: Cold storage -10OC to -20OC or germinated to produce replacement seed Eg – 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 species Eg – 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 sizes Estimate animal population sizes Estimate abiotic environmental change Estimate 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 environment Animals with no habitat Animals in a stable environment Animals with no paternal care

17 A - animals : Grow to a small body size Mature early
Produce many offspring Reproduce only once Give 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 stocks Closed seasons in which fishing is now allowed (especially during breeding seasons) Exclusion zones in which fishing is banned Moratoria on catching endangered species Minimum net sizes, so that immature species are not caught Banning 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.

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