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Published byLorin Shelton Modified over 9 years ago
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What is Biodiversity? The number and variety of species in an ecosystem More inclusive of all diversity: the totality of genes, species, and ecosystems of a region
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How many species are there on Earth? Estimates range from 5 to 100 million........... 10,000 ×500........... minimum
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Phylogenetic Tree Click Click The relatedness of identified species can be found here: Click Click
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How do we know? It can be hard to estimate total diversity within an ecosystem 4 main sampling techniques are used SEE TABLE 3.1 ON PAGE 90 – Canopy fogging – Quadrant sampling – Transect Sampling – Netting
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Why is Biodiversity Important? Still a topic of much scientific research Main Idea more biodiversity = more resistance to change
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What happens if insecticides are used? What happens if Grouse are hunted?
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Why is Biodiversity Important? More biodiversity = more resistance to change Maintenance of ecosystem services Potential for new discoveries (eg. medicines) Economic benefits (exploitation / ecotourism) Natural beauty / fascination / personal connection
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What are Ecosystem Services? Through the natural processes that take place in nature, ecosystems perform a number of seemingly free services which sustain humanity and all other life on earth
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eg 1 - Transfer of energy The sun’s energy is captured and moved through food webs which provides food for all creatures on the planet
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eg 2 - Water purification Many ecosystems ultimately provide clean purified water as a result of the biotic and abiotic features within them. Marsh ecosystems are particularly important natural water filters.
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eg 3 - Oxygen cycle The huge variety of autotrophs on Earth remove carbon dioxide from the atmosphere and replenish oxygen supplies
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More Ecosystem Services When there is more biodiversity, there is: more nutrient cycling (eg. Carbon / Nitrogen) more photosynthesis = more total productivity + reduced climate change less spread of disease More forested land: Holds soil in place Reduces runoff Increases rainfall / reduces evaporation
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What is Currently Happening To Biodiversity?
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Looking Backwards
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6 th Mass Extinction?
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Biodiversity Hotspots
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Originally 25 regions Today, 34 identified regions of particularly large, unique plant diversity, under strong threat of habitat loss – must contain at least 0.5% or 1,500 species of vascular plants as endemics – has to have lost at least 70% of its primary vegetation.
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Biodiversity Hotspots When established in 1999, covered about 11.8% of earth’s land surface and contained were believed to contain 44% of earth’s plant species and 35% of terrestrial vertebrates Today they are increasingly depleted and believed to contain about 60% of the world's plant, bird, mammal, reptile, and amphibian species
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Threats to Biodiversity Habitat Loss Over-exploitation Pollution Invasive species Climate Change
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Habitat Loss
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Threats to Biodiversity Habitat Loss – Changes in land use by humans Growing cities / urban sprawl Expansion of farmland / habitat fragmentation Draining wetlands – Habitat Fragmentation Larger habitats become divided into smaller sections by highways, roads, farms, urbanization, etc.
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Over-exploitation
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Threats to Biodiversity Over-exploitation – Over-hunting eg. Dodo bird hunted to extinction – Over-fishing eg. in 1992 it became illegal to catch Atlantic cod – Deforestation See http://rainforests.mongabay.com/deforestation.htmlhttp://rainforests.mongabay.com/deforestation.html – Relentless consumption eg. The average Canadian ecological footprint may be around 7 or 8 times larger than the footprint of countries in the developing world
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Pollution
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Threats to Biodiversity Pollution – Pollutant are chemicals with known toxic effects on one or many species – Human activity has introduced waste products and contaminants throughout the biosphere – Air, land and water have been affected nearly everywhere Egs. Industrial waste, municipal waste, pesticides, sewage containing hormones, heavy metals, pharmaceuticals, etc.
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Invasive Species
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Threats to Biodiversity Invasive species – Non-native species of plants and animals that establish in new habitats – These may disrupt local ecosystems and/or displace local species causing extinction or population reduction Eg. in Canada: purple loostrife, mountain pine beetle, asian longhorned beetles, zebra muscles Eg. in Australia: prickly pear cactus, cane toads, feral pigs, red foxes, european rabbits, camels
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Climate Change
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Threats to Biodiversity Climate Change – Rapid disruption of ecosystem stability – Changes in global geography (eg. melting of permafrost) – Unpredictable changes to ecosystems around the world
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Biodiversity Hotspots 34 identified regions of particularly large plant diversity which are under particularly strong threats of habitat loss (at least 70% lost of original habitat) Established in 1999 Some estimated that they contained 44% of earth’s plant species and 35% of terrestrial vertebrates They covered about 11.8% of earth’s land surface Now they have been reduced to only about 1.4%
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