BioDiversity Lecture Notes

BioDiversity Lecture Notes - BioPl 2400 Biodiversity...

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Unformatted text preview: BioPl 2400 Biodiversity Lecture Outlines Lecture 1 –Thurs 10/06 • Loss of Biodiversity • Biodiversity is decreasing; we are losing species on the planet • Global extinction rate is estimated to be anywhere from 10 to 10,000 times higher before human existence • Bigger than mass extinctions in the past • Regions of the planet haven’t been investigated and new species are being discovered everyday • 2-200 species/day become extinct • Estimated that 34% of fish species, 25% of amphibians, and 20% of reptiles, 14% of plant species are facing premature extinction (declining at a very rapid rate) • In the USA its estimated that 33% of plant and animal species are vulnerable to extinction • Brown bears! - Focus on fuzzy animals • Plant species are disappearing as well- orchid species native to USA- number of orchid species - pitcher plant native to southern USA • poaching is a problem with both plant and animal species • Human Factors Relating to decreased biodiversity • Worth nothing that extinction is a part of life • If you look at the evolutionary geologic history of the planet - 99% of species that have existed are extinct- Extinction events occur by cataclysmic events (asteroids, etc.) • Habitat loss and degradation- Removing natural ecosystems to make ways for our own activity and development • Invasive species- Introducing species to an area w/o natural predators • Hunting, poaching, overfishing- There is an economic value of biodiversity • Sale of exotic species (animal & plants) • Pollution • Climate change • Effect of Human Activity on Biodiversity • 40% to 50% of the earth’s surface has been taken over, disturbed or degraded- Conversion of forests & grasslands to crop fields or urban areas- Filling in wetlands serious problem; play an important role in ecosystems- Potential solutions is to create artificial wetlands • Global forest cover has been reduced by 20-50% • Amazon rainforest cleared for agriculture • United States • 95% of virgin forests in the USA have been cleared since 1620 • 98% of tallgrass prairie cleared in the midest USA • 99% of grassland, 91% of wetlands, 85% • Clear cut forest in Oregon- Put in new roads and cut down all the trees • New invasive species- purpose loosestrife is an invasive species in wetlands • brought into the country as a perennial plant • commonly planted on roadsides • once it invades a wetland it has no predators • it takes over and chokes out naturally occurring species of wetlands • short term: introduce natural predator- spotted knapweed; an invasive species- zebra mussel- northern snakehead • ugly fish!...
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BioDiversity Lecture Notes - BioPl 2400 Biodiversity...

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