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Pages 183-205

Pages 183-205. Plate Tectonics. Rift Valleys Rift Valleys are created by continental plates that drift apart. They typically for deep lakes, seas, or new lands. The new lands and bodies of water drive speciation. Hot Spots

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Pages 183-205

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  1. Pages 183-205

  2. Plate Tectonics • Rift Valleys • Rift Valleys are created by continental plates that drift apart. They typically for deep lakes, seas, or new lands. • The new lands and bodies of water drive speciation. • Hot Spots • Not actually made by continental plates, but rather magma that breaks through the ocean crust. • However movement of plates over hot spots can create chain of islands.

  3. Ecosystem Stability and Succession • Organisms cancolonize isolated areas by: • Air • Sea • Animal

  4. Specific Types of Dispersal • Jump Dispersal • Long-distance dispersal to remote area by few individuals. • Diffusion • Spread of a species from the edge of their range into a new area • Secular Migration • Dispersal over long time period. Evolutionary changes to species while diffusing into new area.

  5. Process of Primary Succession • Primary Succession- The formation of an ecosystem from bare rock. • Pioneer species arrive and colonize bare rock. Soil is created when species die. • New plant growth changes environment. • Plants needing soil arrive, using their roots to retain the soil. • Physical conditions change again • New species arrive (more complex and larger). • Animals arrive in search of food sources. • Climax community is reached.

  6. Secondary Succession • Succession that occurs in an area that already has soil. • Can be caused by human activities or natural processes (natural disasters). • Succession can be halted at any time and the climax community may not be reached. • A Sereis the set of communities that succeed one another over the course of succession at a given location.

  7. Disturbance • Three factors determine the ability of an ecosystem to recover after an disturbance: • Inertia- or persistence, resistance to being altered, • Resilience- ability of a system to recover after a disturbance, • Diversity- the number and proportions of species present.

  8. Disturbance Contin. • A complex ecosystem that has complex food webs allow animals and plants to respond to disturbances in many ways, thus providing an high inertia. • Ecosystems with high resilience have nutrient-rich soils, which promote new growth.

  9. Case Study Disturbance of Grass Prairie • The tall grass prairie in the US provided a high diversity, complex ecosystem that maintained stability. • The prairie would recover quickly following fires because of the high build up of organic matter. • Farming has replaced the native ecosystem, causing low diversity, inertia, and soils that need to be maintained artificially.

  10. Evaluating Biodiversity and Vulnerability 4.2 page 187

  11. Loss of Diversity • Natural disasters have lead to periods of diversity loss in the past. • Changes in Earth’s orbit and tilt and plate movements have lead to repeated long-term cold periods.

  12. Factors of Diversity Loss • Natural disasters • Habitat degradation • Agricultural practices • Introduction of non-native species • Hunting, collecting, and harvesting

  13. Tropical Rainforest • Consists of emergent layer, canopy layer, understory layer, ground layer. • Considered “biodiversity hotspot” • 50% of plant species, 42% terrestrial vertebrates. • Deforestation • Some species live in the upper layer for entire life e.g.. Rhacophorus gadingensis (tree frog) • Thin, nutrient-poor soils • Difficult to regrow (sometimes!)

  14. Green Politics • An ideology which places an importance on ecological and environmental goals. • Through broad-based, grassroots, and participatory democracy. • Stimulated in part by the threats to rainforests. • Principle goal- to obtain sustainable development by reducing deforestation and encouraging reforestation. • Anti-capitalism an important feature

  15. Present and Past Extinctions • There have been five mass extinctions • Mass extinction- a large proportion of the total number of species on the Earth at one time are wiped out. • Earth is undergoing the sixth mass extinction, believe to be caused by human activities.

  16. Extinctions • Cretaceous-Tertiary (65 million years ago) • End Triassic (199 – 214 million years ago) • Permian-Triassic (251 million years ago) • Late Devonian (364 million years ago) • Ordovician-Silurian (439 million years ago) • Impact of an asteroid or gradual climate change and flood-like eruptions. • Massive floods of lava • Largest event, suspected asteroid or flood volcanism. • Unknown cause. • Drop in sea levels as glaciers formed and then rising sea levels as glaciers melted.

  17. Our Current Situation • The evolution of life and the mass extinctions has wiped out 99 percent of all species that have lived on Earth. • Sixth Extinction • First abiotic extinction • Phase 1 began 100,000 years ago when humans dispersed to different parts of the world. • Phase 2: 10,000 years ago when humans turned to agriculture. • Over-population, invasive species, over-exploitation, global warming, pollution • Before 100 species lost per year, now 27,000.

  18. Factors that Make Species Prone to Extinction • Small size and limited distribution • Island species • Habitat specialist • Specific diet or habitat requirements • Low reproductive capacity • Live long time • Poor competitors • Lack of mobility or defensive instincts • Large mammals • Significant source of meat and large amounts of resources • Valuable products • Value as pets, ceremonial objects, food • Altruistic species • Preserve bonds to frighten off predators • Clumping • Large numbers • Position of food chain • Higher up = more vulnerability

  19. Determining Conservation Status (Red Data Book) • Population size • Queen of the Andes • Reduction in population size • European Eel • Number of mature individuals • Geographic range and degree of fragmentation • Peacock Parachute Tarantula • Quality of habitat • Area of occupancy • Probability of extinction

  20. Case Study Extinct Falkland Island Wolf • Ecological Role • Lived in burrows • Diet – ground-nesting birds, grubs, insects, and seashore scavenging. • Pressures • Settlers had sheep which were being killed by the wolves. • Wolf was easily maneuvered into a trap • Consequence of disappearance • Not a significant predator, may have had impact on food chain

  21. Critically Endangered: Iberian Lynx • Ecological Role • Specialized feeder (rabbits) and often kill other carnivore species, but does not eat them. • Pressures • Highly specialized diet, small geographic area, habitat destruction. Not allowed to hunt after 1970s. • Methods of restoring population • Public awareness and education programs changed attitudes. Captive breeding program that allow reintroduction into the wild.

  22. Improved by Intervention: Bald Eagle • Ecological Role • Live near large bodies of water and have specific territories for nesting. Eat small animals and primarily fish. • Pressures • Population plummeted in 1950s (hunting, pesticides on crops, destruction of habitat, contamination of waterways and food sources, and DDT). • Methods of restoring population • DDT was outlaws in 1970s. • Created Acts for the Eagles and were considered endangered (no hunting).

  23. Natural Area Threatened: The Great Barrier Reef • Human threats • Tourism • Over-fishing • Water pollution (fertilizers, pesticides, sewage) • Global warming • Natural threats • Predators and diseases • Storms and cyclones • Coral bleaching • Consequences • Irreversible damage • Loss of biodiversity and valuable role in ecosystem (erosion in mangroves and sea-beds) leads to reduction in its value.

  24. 4.3 Conservation of Biodiversity Pages 202-205

  25. Arguments for Preserving Species and Habitats • Biodiversity can be difficult to quantify. • Good harvested from the ecosystem are easier to evaluate than indirect values. • Value of the ecosystem depends on cultural background and economic status.

  26. Economic Values of Biodiversity • Easy economic value • Natural products • Food • Difficult economic value • Economic productivity • Environmental indicators • Scientific reasons • Education • Genetic diversity • Recreation and ecotourism • Aesthetic value • Human rights • Ethical reasons

  27. Conservation Organizations • Non-governmental Organizations (NGOs)- not run by, or funded by, or influenced by governments of any country. Tend to be more radical and field-based. • Intergovernmental Organizations (GOs)- are bodies established through international agreements to protect the environment and bring together governments to work on an international scale. Tend to be more conservative.

  28. Conservation Organizations NGO GO • Use of Media • Advertise, leaflets, press packs • Speed of Response • Rapid and regular, own decisions • Diplomatic Constraints • Unaffected by politics, may be illegal • Political Influence • No direct influence • Enforceability • Rely on public pressure, no power to enforce laws • Use of Media • Professional liaison officers, international news clips • Speed of Response • Must meet legal requirements of several countries • Diplomatic Constraints • Cannot give opinion w/out lawyer, disagreements cause serious constraints • Political Influence • Direct access to many countries • Enforceability • Through international agreements and laws

  29. International Conventions on Biodiversity • IUNC (World Conservation Union), concerned with conservation of resources for sustainable economic development, has three agendas: • Maintaining ecological processes • Preserving genetic diversity • Using species and ecosystems in a sustainable fashion.

  30. International Conventions on Biodiversity • IUNC established World Conservation Strategy, which outlined series of global priorities for action and recommended that account the conservation of natural resources for long-term human welfare. • Drew attention to a fundamental issue: the importance of making the users of natural resources become their guardians. • Stressed that without understanding the local community and support, the strategies cannot succeed.

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