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Threats to Biodiversity

Threats to Biodiversity. Chapter 5 Section 2. Background Extinction. The gradual process of species becoming extinct Stable ecosystems can be changed by the activity of other organisms, climate changes or natural disasters

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Threats to Biodiversity

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  1. Threats to Biodiversity Chapter 5 Section 2

  2. Background Extinction • The gradual process of species becoming extinct • Stable ecosystems can be changed by the activity of other organisms, climate changes or natural disasters • Predictions say between one-third and two-thirds of all species will be extinct by the end of the century. • Mostly near the equator

  3. Mass Extinction • An event where the majority of all species become extinct in a relatively short period of time • Last mass extinction ~65 million years ago, dinosaurs • Current rate of extinction is 1000 times the normal background extinction rate • Possibly in a period of mass extinction

  4. http://www.amnh.org/science/biodiversity/extinction/Intro/OngoingProcess.htmlhttp://www.amnh.org/science/biodiversity/extinction/Intro/OngoingProcess.html

  5. What threatens Biodiversity? • Homo sapiens • Natural resources • Overexploitation • Habitat loss • Fragmentation of Habitat • Pollution • Introduced Species

  6. Homo Sapiens • Humans • Humans are changing the conditions on Earth faster than species can evolve to cope with the changes

  7. Natural Resources • All materials and organisms found in the biosphere • Includes: minerals, fossil fuels, nuclear fuels, plants, animals, soil, clean water, clean air, solar energy

  8. Overexploitation • Excessive use of a species that have economic value • Ex: Bison that lived on the central plains were hunted to almost extinction because hides and meat could be sold commercially and were hunted for sport

  9. Habitat Loss • Destruction of Habitat: completely removing all native species (ex. Clearing the rain forest) • Disruption of Habitat: a small change in a habitat can cause the food web to collapse and other species to die (ex. Overfishing a certain species could cause sea lion numbers to decrease)

  10. Fragmentation of Habitat • Separation of two parts of an ecosystem into smaller pieces of land • Edge Effects: different environmental conditions along the boundaries of an ecosystem

  11. Pollution • Acid Precipitation: with the burning of fossil fuels sulfur dioxide and nitrogen oxide is released these react with substances in the atmosphere to produce sulfuric acid and nitric acid; removes chemicals plants and animals need • Eutrophication: occurs when fertilizer, animal waste, sewage or other nitrogen rich substances flow into water ways causing extreme algae growth; uses excessive amount of oxygen and other aquatic organisms die

  12. Introduced Species • Nonnative species that are purposely or accidentally released into a new habitat • Uses resources native species would use • Estimates 40% of extinctions since 1750 are due to introduced species • Ex. Asian Carp

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