Biodiversity - Unit 2 OCR

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  • Created on: 01-06-13 17:21
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  • Biodiversity
    • Investigating It
      • Biodiversity - refers to the variety of living organisms in an area, divided into three different levels
        • 1. Habitat Diversity - habitat is an area inhabited by a species, includes physical factors like soil and temperature range and living factors like food availability or presence of predators : habitat diversity is number of different habitats in an area
        • 2. Species Diversity - species is a group of similar organisms able to reproduce for fertile offspring : species diversity is the number of different species and abundance of each in an area
        • 3. Genetic Diversity - the variation of alleles within a species or population of species
      • Collecting Data - usually means finding out number of different species in a habitat or number of individuals in a species, in most cases it would be too time consuming to count every individual so instead a sample of population is taken so estimates about whole habitat are based on this
        • 1. Choose an area to sample, should be random to avoid bias and is more likely that sample is representative of population you're sampling - in random sample every individual has chance
        • 2. Record the number of different species or count individuals : use a quadrat for plants which is a frame you place on the groups, a pitfall trap for groups insects, a sweepnet for flying insects and a net for aquatic animals - make sure you use the appropriate equipment for organism you are studying
        • 3. Repeat the process for as many samples as possible for reliability and calculate mean
        • 4. Number of individuals for whole area can be estimates by taking average of data collected in each sample and multiply it by size of whole area
        • 5. Sampling different habitats and comparing you must use the same sampling technique
      • Species Richness and Evenness
        • Richness is the number of different species in an area, higher the number of species the greater the richness, measured by taking random sample of habitat and counting the number of species
        • Evenness  i a measure of relative abundance of each species in an area, more similar the population size the greater the species evenness, measured by random samples of habitat and counting number of individuals of each different species
        • Greater the richness and evenness the higher the biodiversity and vice versa
      • Simpson's Index of Diversity
        • Richness and evenness are simple ways of measuring diversity, but species are present in a habitat in very small numbers shouldn't be treated the same as those with bigger populations - this is where Simpson's Index of Diversity comes in
        • Useful way of measuring species diversity, calculates using an equation that takes into account both richness and evenness - value always between 0 and 1, closer it is to 1 the more diverse the habitat and greater its ability to cope with change, closer to 0 suggests habitat more easily damaged by change making it less stable
        • Greater the richness and evenness the higher the value of Simpson's Index
          • Calculating the index can get tricky so if you've got lots of data you might find it easier to put in a table
    • Global Biodiversity
      • Estimating  - this is the total number of species on Earth and includes named species (scientists have named between 1.5 and 1.75 million species) and unnamed species (scientists agree a large proportion of species on Earth have not been names)
        • Scientists estimate total number of species on Earth ranges from 5 million to 100 million, some more recent estimates are around 14 million, reasons for different ideas - different scientists have used different techniques, little is known about some groups of organisms (could be more than we think), biodiversity differs around the world, estimates of global change as new evidence is found
      • Climate Change and Global Biodiversity
        • Climate change is long-term change in area's climate (average temperature or rainfall pattern), occurs naturally but scientific consequences of change at the moment is due to human increase of emissions of greenhouse gasses - causes global warming
        • 1. Changing Environmental Conditions - affect different areas in different ways, some get warmer some get colder but all changes are likely to affect global biodiversity
          • Most species need particular climate to survive so changes mean an area previously inhabitable becomes uninhabitable causing increase or decrease in range of some species so increase or decrease biodiversity
            • Changing environment may force some to migrate to more suitable area changing species distribution, this usually decreases biodiversity in ares they migrate from and increase areas migrated to
              • If no suitable area to migrate to or the species is a plant or if change is too fast the species may become extinct decreasing biodiversity
        • 2. Causing Spread of DIsease - ranges of some insects that carry disease may increase, change in distribution may lead to increase in biodiversity though spread of disease may reduce it with some species suffering population decline or extinction
          • Warmer and wetter conditions may encourage spread of fungal diseases which could lead to increase or decrease in biodiversity
        • 3. Changing Agricultural Patterns - change in temperature or rainfall or time of season or frequency of flood or drought will affect agriculture pattern
          • May also affect biodiversity, different crops need different conditions so as climate changes so will crops grown, disrupt food chain as some species will be left without food source, new food source for other species so increase or decrease biodiversity
            • Possible that extreme weather events and unexpected conditions may result in crop failure which could disrupt food chains and decrease biodiversity
    • Biodiversity and Conservation
      • Importance of Biodiversity
        • 1. Economic Reasons - many species of animals and plants are important to global economy, products derived from species are traded on a local and global scale (food, drink, clothes, drugs, fuels)
        • 2. Ecological Reasons - all down to the complex relationship between prg and their environment (disruption of food chain or nutrient cycle, loss of habitat, climate change)
        • 3. Ethical Reasons - some people believe we should conserve species as it's the right thing to do, many believe they have right to exist and shouldn't become extinct as result of our activities, some believe we have moral responsibility conserve biodiversity for future generations, also religious and spiritual reasons as harmony with natural world is important in many beliefs
        • 4. Aesthetic Reasons - others believe we should conserve biodiversity as it brings joy to millions of people, areas rich in biodiversity provide a pleasant attractive environment that people enjoy and the more biodiversity in an area the more visitors the area is likely to attract which has economic advantages
        • 5. Agricultural Reasons - it provides pollinators, protection against disasters, a source of food, new varieties and pest control
      • Maintaining Biodiversity Through Conservation
        • The protection and management of species and habitats, conservations are important to ensure survival of endangered species (species at risk of extinction due to low population or threatened habitat), critically endangered species likely to become extinct as population size is too small
      • Types of Conservation
        • In situ - conservation on site involving protecting species in their natural habitat, method includes
          • 1. Establishing protected areas i.e. national parks of nature reserves
          • 2. Controlling or preventing introduction of  species that threaten local biodiversity
          • 3. Protecting habitat allowing organisms to continue living in natural habitat
          • 4. Restoring damaged areas
          • 5. Promoting particular species
          • 6. Giving legal protection to endangered soecies
          • Advantages - both species and habitat are conserved so larger populations can be protected and it's less disruptive than removing from habitat, chances of population recovering are greater
          • Disadvantages - difficult to control some factors that threaten a species such as predators poachers of climate change
        • Es situ  - conservation off site and involves protecting species by removing part of population from threatened habitat and placing in new location, often a last resort, method includes :
          • 1.Relocating  organisms to a safer area
          • 2. Breeding organisms in captivity then reintroducing them to the wild when strong enough
          • 3. Botanic gardens are controlled environments used to grow a variety of rare plants, endangered and extinct plant species can be grown and reintroduced
          • Advantages -used to protect individual animals in controlled environment so predators and hunting easier to control, competition for resources reduced, possible to check and treat for diseases, breeding can be manipulated, can be used to reintroduce species that left the area
          • Disadvantages - only small number cared for, difficult and expensive to create and sustain right environment, usually less successful as many species can't breed in captivity or don't adapt to new environment
      • Conservation and EIAs
        • Environmental Impact Assessment - assessment of impact a development project might have on the environment (building a new shopping centre or power station)
        • EIA involves estimating biodiversity on project site and evaluating how development may affect biodiversity, identify ways it could be conserved or any threatened / endangered species on site and laws relating to conservation, they're then used to decide on planning stipulations (measures that will have to be implemented if project proceeds)
        • Local authorities are often under pressure from conservationists who argue developments damage environment and disturb wildlife as feel habitats should be left alone
          • EIA ensures decision makers consider environmental impact of development project and they're used by local authorities to decide if and how a project proceeds
      • Conservation and International Cooperation
        • Conservation more likely to be successful when countries work together, e.g. endangered species found in lots of countries so pointless making hunting illegal in one country if it is legal in another
          • Information must be shared about biodiversity threats and countries must decide on conservation methods and implement them together
        • Rio Conservation on Biodiversity
          • An international agreement that aims to develop international strategies on conservation of biodiversity and how to use animal and plant resources in a sustainable way
            • Convention made it part of international law than conserving biodiversity is everyone's responsibility and it also provides guidance to governments on how to conserve biodiversity
        • CITES Agreement
          • Convention on International Trade in Endangered Species
          • An agreement designed to increase international cooperation in regulating trade in wild animals and plant specimens
            • Member countries all agreed to make it illegal to kill endangered  species, agreement helps conserve species by limiting trade through licensing and making it illegal to trade in products made from endangered animals (rhino ivory and leopard skin), also designed to raise awareness of threats to biodiversity through education

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