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Biodiversity Is a Crucial Part of the Earth’s Natural Capital

Biodiversity Is a Crucial Part of the Earth’s Natural Capital. Species : set of individuals who can mate and produce fertile offspring 8 million to 100 million species ONLY 1.9 million identified!!! Unidentified are mostly in rain forests and oceans.

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Biodiversity Is a Crucial Part of the Earth’s Natural Capital

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  1. Biodiversity Is a Crucial Part of the Earth’s Natural Capital • Species: set of individuals who can mate and produce fertile offspring • 8 million to 100 million species • ONLY 1.9 million identified!!! • Unidentified are mostly in rain forests and oceans

  2. Biodiversity Is a Crucial Part of the Earth’s Natural Capital • Biodiversity is an important part of natural capital • Functional diversity = variety of processes to move nutrients and energy through a system • Species diversity = # of species • Genetic diversity = different genes w/in a species • Ecosystem diversity = # of types of ecosystems • Biomes: regions with distinct climates/species

  3. Classifying Homo Sapiens Supplement 5, Fig. 2, p. S19

  4. Natural Capital: Major Components of the Earth’s Biodiversity Fig. 4-2, p. 82

  5. Species Diversity: Columbine Lily and Great Egret Fig. 4-3, p. 82

  6. Genetic Diversity Fig. 4-4, p. 83

  7. Major Biomes Fig. 4-5, p. 84

  8. Importance of Insects • Pollination: lets flowering plants reproduce sexually • Free pest control: insects eat other insects • Food/energy source at bottom of food chain • We need insects more than they need us!!!

  9. Importance of Insects Fig. 4-A, p. 83

  10. Biological Evolution by Natural Selection Explains How Life Changes over Time (1) • Fossils • Physical evidence of ancient organisms • Reveal what their external structures looked like • Fossil record: entire body of fossil evidence • Only have fossils of 1% of all species that lived on earth

  11. Fossilized Skeleton of an Herbivore that Lived during the Cenozoic Era Fig. 4-6, p. 86

  12. Biological Evolution by Natural Selection Explains How Life Changes over Time (2) • Biological evolution: how earth’s life changes over time through changes in the genetic characteristics of populations • Darwin: Origin of Species • Natural selection: individuals with certain traits are more likely to survive and reproduce under a certain set of environmental conditions • Huge body of evidence

  13. Evolution by Natural Selection Works through Mutations and Adaptations (1) • Populations evolve by becoming genetically different • Genetic variations • First step in biological evolution • Occurs through mutations in reproductive cells • Mutations: random changes in DNA molecules

  14. Evolution by Natural Selection Works through Mutations and Adaptations (2) • Natural selection: acts on individuals • Second step in biological evolution • Adaptation: a behavioral characteristic due to the genetic makeup of an individual • may lead to differential reproduction • Genetic resistance: ability of one or more members of a population to resist a chemical designed to kill it • Happening with use of antibiotics • Happening with use of chemicals used on crops

  15. Evolution by Natural Selection Fig. 4-7, p. 87

  16. Adaptation through Natural Selection Has Limits • Adaptive genetic traits must precede change in the environmental conditions • Reproductive capacity • Species that reproduce rapidly and in largenumbers are better able to adapt to change (ex. Bacteria) • Species that reproduce slowly and in smallnumbers are less able to adapt to change (ex. Elephants) • Greater risk to population decline

  17. Case Study: How Did Humans Become Such a Powerful Species? • Strong opposable thumbs • Walk upright • Complex brain • Are we still evolving?

  18. Three Common Myths about Evolution through Natural Selection • “Survival of the fittest” is not “survival of the strongest” • Organisms do not develop traits out of need or want • No grand plan of nature for perfect adaptation

  19. Geologic Processes Affect Natural Selection • Tectonic plates affect evolution and the location of life on earth • Locations of continents and oceans have shifted • Species physically move, or adapt, or form new species through natural selection • Catastrophic events can lead to rapid ecosystem changes and possibly extinctions: • Earthquakes • Volcanic eruptions • Meteorite Impacts

  20. Movement of the Earth’s Continents over Millions of Years Fig. 4-8, p. 89

  21. Climate Change and Catastrophes Affect Natural Selection • Ice ages followed by warming temperatures • Collisions between the earth and large asteroids • New species • Extinctions

  22. Chicxulub Impact Crater

  23. Changes in Ice Coverage in the Northern Hemisphere During the last 18,000 Years Fig. 4-9, p. 89

  24. Science Focus: Earth Is Just Right for Life to Thrive • Temperature range: supports life • Orbit size: moderate temperatures • Liquid water: necessary for life • Rotation speed: sun doesn’t overheat surface • Size: gravity keeps atmosphere

  25. Extinction is Forever • Extinction • Biological extinction • Local extinction • Endemic species • Found only in one area • Particularly vulnerable • Background extinction: typical low rate of extinction • Mass extinction: 3-5 over 500 million years

  26. Golden Toad of Costa Rica, Extinct Fig. 4-11, p. 92

  27. Science Focus: Changing the Genetic Traits of Populations • Artificial selection • Use selective breeding/crossbreeding • Been used by humans for 1000s of years • Almost all of our crops created in this way • Genetic engineering, gene splicing • “GMO” crops • Consider • Ethics • Benficial vs. Harmful effects

  28. Artificial Selection Fig. 4-C, p. 92

  29. How Corn Has Been Modified Artificial Selection: Selecting for specific traits in corn plants over the last 10,000 years has led to this change type of change

  30. How Corn Has Been Modified Genetic Modification: Inserting genes from another organism into the DNA of corn

  31. Genetically Engineered Mice The mouse on the right has a human growth hormone gene inserted into its cells Fig. 4-D, p. 92

  32. Common Genetically Modified Crops

  33. Species Diversity: Variety, Abundance of Species in a Particular Place (1) • Species diversity: • Species richness: • The number of different species in a given area • Species evenness: • Comparative number of individuals

  34. Variations in Species Richness and Species Evenness High species richness (coral reef) Low species richness (aspen grove) Fig. 4-12, p. 93

  35. Species Diversity: Variety, Abundance of Species in a Particular Place (2) • Diversity varies with geographical location • The most species-rich communities • Tropical rain forests • Coral reefs • Ocean bottom zone • Large tropical lakes

  36. Global Map of Plant Biodiversity Supplement 8, Fig. 6, p. S36

  37. Species-Rich Ecosystems Tend to Be Productive and Sustainable • Species richness seems to: • increase ecosystem productivity • Increase ecosystem stability or sustainability • provide insurance against catastrophe • How much species richness is needed is debatable

  38. Each Species Plays a Unique Role in Its Ecosystem • Ecological niche • Pattern of living: everything that affects survival and reproduction • Water, space, sunlight, food, temperatures • Generalist species (ex. rats, racoons, cockroaches) • Broad niche: wide range of tolerance • Specialist species (ex. pandas, koalas) • Narrow niche: narrow range of tolerance

  39. Specialist Species and Generalist Species Niches Fig. 4-13, p. 95

  40. Specialized Feeding Niches of Various Bird Species in a Coastal Wetland Fig. 4-14, p. 96

  41. Case Study: Cockroaches: Nature’s Ultimate Survivors • 3500 species • Generalists • Eat almost anything • Live in almost any climate • High reproductive rates

  42. Species Can Play Five Major Roles within Ecosystems • Native species: indigenous to a location/habitat • Nonnative species: introduced by humans (intentionally or unintentionally) • Indicator species • Keystone species • Foundation species

  43. Non-native Species • Examples of non-native species in New England: • Purple Loosestrife • Native to Europe • Zebra Mussel • Native to Eastern Europe

  44. Indicator Species Serve as Biological Smoke Alarms • Indicator species • Sensitive to environmental change • Provide early warning of damage to a community • Can monitor environmental quality • Trout • Birds • Butterflies • Frogs

  45. Keystone Species Play Critical Roles in Their Ecosystems • Keystone species: roles have a large effect on the types and abundances of other species • Pollinators • Bees • Top predators • Sea urchins • Wolves

  46. Case Study: Why Should We Care about the American Alligator? • Largest reptile in North America • 1930s: Hunters and poachers • Importance of gator holes and nesting mounds: a keystone species • 1967: endangered species • 1977: comeback, threatened species

  47. American Alligator Fig. 4-18, p. 99

  48. Foundation Species Help to Form the Bases of Ecosystems • Foundation species: Create or enhance their habitats, which benefit others • Elephants • Beavers

  49. Three Big Ideas • Populations evolve when genes mutate and give some individuals genetic traits that enhance their abilities to survive and to produce offspring with these traits (natural selection). • Human activities are decreasing the earth’s vital biodiversity by causing the extinction of species and by disrupting habitats needed for the development of new species.

  50. Three Big Ideas • Each species plays a specific ecological role (ecological niche) in the ecosystem where it is found.

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