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Evolution and Biodiversity

Evolution and Biodiversity. Chapter 4. Concept 4-3 As a result of biological evolution, each species plays a specific ecological role called its niche. Niche – sometimes thought of as the job or vocation of a species; involves all of its environment

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Evolution and Biodiversity

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  1. Evolution and Biodiversity Chapter 4

  2. Concept 4-3 As a result of biological evolution, each species plays a specific ecological role called its niche. • Niche – sometimes thought of as the job or vocation of a species; involves all of its environment • Habitat – the place where an organism lives; where you would go to find this organism

  3. Unique Roles for Species • Generalist species • Specialist species • Specialists prone to extinction – giant panda

  4. Core Case Study: Life on Earth • Uniquely suited for life • Temperature range • Liquid water • Gravitational mass • Oxygen • Organisms contribute to relatively consistent planetary conditions – resilient and adaptive • Biodiversity and sustainability

  5. Panda and its Food

  6. Niches of Specialist and Generalist Species • Specialist species • with a narrow niche • Generalist species • with a broad niche • Niche • separation • Number of individuals • Niche • breadth • Region of • niche overlap • Resource use • Fig. 4-4, p. 68

  7. Specialized Feeding Niches in Birds

  8. Ruddy turnstone searches under shells and pebbles for small invertebrates Herring gull is a tireless scavenger Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Brown pelican dives for fish, which it locates from the air Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Black skimmer seizes small fish at water surface Flamingo feeds on minute organisms in mud Louisiana heron wades into water to seize small fish Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Piping plover feeds on insects and tiny crustaceans on sandy beaches Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation Knot (sandpiper) picks up worms and small crustaceans left by receding tide Fig. 4-5, p. 68

  9. Science Focus: Cockroaches • Existed for 350 million years – 3,500 known species • Highly adapted, rapidly producing generalists • Consume almost anything • Endure food shortage • Survive everywhere except polar regions • Avoid predation • Carry human diseases

  10. Cockroaches: Nature’s Ultimate Survivors • Fig. 4-A, p. 69

  11. The Right Mix of Conditions Fig. 4-1, p. 63

  12. 4-1 What Is Biological Evolution and How Does It Occur? • Concept 4-1A The scientific theory of evolution explains how life on earth changes over time through changes in the genes of populations. • Concept 4-1B 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).

  13. Theory of Evolution • 4.7 billion years • Explains why life so diverse • Supported by fossils, chemical analysis of primitive rock, DNA, and ice cores

  14. Fossilized Skeleton of a Cenozoic Herbivore Fig. 4-2, p. 65

  15. Population Changes over Time • Populations evolve by becoming genetically different • Genetic variability – mutation

  16. Natural Selection • Genetically favorable traits to survive and reproduce • Trait – heritable and lead to differential reproduction • Faced with environmental change • Adapt • Migrate • Become extinct

  17. Coevolution • Changes in gene pool of one species lead to changes in gene pool of the other • Bats and moths

  18. Science Focus: How Did We Become Such a Powerful Species? • Key adaptations – also enabled us to modify environment • Evolved very recently • Technology dominates earth’s life support systems and NPP

  19. 4-2 How Do Geological and Climate Changes Affect Evolution? • Concept 4-2 Tectonic plate movements, volcanic eruptions, earthquakes, and climate change have shifted wildlife habitats, wiped out large numbers of species, and created opportunities for the evolution of new species.

  20. Plate Tectonics • Locations of continents and oceans determine earth’s climate • Movement of continents allow species to move and adapt • Earthquakes and volcanoes affect biological evolution

  21. Movement of Continents

  22. 225 million years ago 135 million years ago 65 million years ago Present Fig. 4-3, p. 67

  23. 225 million years ago 65 million years ago 135 million years ago Present Stepped Art Fig. 4-3, p. 67

  24. Earth’s Long-term Climate Changes • Cooling and warming periods – affect evolution and extinction of species • Five mass extinctions • Eliminated half of the earth’s species • Many theories why this occurred • Opportunities for the evolution of new species

  25. Northern Hemisphere over 18,000 Years

  26. 18,000 years before present Northern Hemisphere Ice coverage Modern day (August) Fig. 4-4, p. 67

  27. 4-3 What Is an Ecological Niche? • Concept 4-3 As a result of biological evolution, each species plays a specific ecological role called its niche.

  28. Unique Roles for Species • Generalist species • Specialist species • Specialists prone to extinction – giant panda

  29. Panda and its Food

  30. Panda and its Food

  31. Niches of Specialist and Generalist Species • Specialist species • with a narrow niche • Generalist species • with a broad niche • Niche • separation • Number of individuals • Niche • breadth • Region of • niche overlap • Resource use • Fig. 4-4, p. 68

  32. Specialized Feeding Niches in Birds

  33. Ruddy turnstone searches under shells and pebbles for small invertebrates Herring gull is a tireless scavenger Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Brown pelican dives for fish, which it locates from the air Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Black skimmer seizes small fish at water surface Flamingo feeds on minute organisms in mud Louisiana heron wades into water to seize small fish Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Piping plover feeds on insects and tiny crustaceans on sandy beaches Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation Knot (sandpiper) picks up worms and small crustaceans left by receding tide Fig. 4-5, p. 68

  34. Science Focus: Cockroaches • Existed for 350 million years – 3,500 known species • Highly adapted, rapidly producing generalists • Consume almost anything • Endure food shortage • Survive everywhere except polar regions • Avoid predation • Carry human diseases

  35. Cockroaches: Nature’s Ultimate Survivors • Fig. 4-A, p. 69

  36. 4-4 How Do Extinction, Speciation, and Human Activities Affect Biodiversity? • Concept 4-4A As environmental conditions change, the balance between formation of new species and extinction of existing ones determines the earth’s biodiversity. • Concept 4-4B Human activities decrease the earth’s biodiversity by causing the premature extinction of species and by destroying or degrading habitats needed for the development of new species.

  37. Speciation • Geographic isolation • Reproductive isolation • Millions of years in slow-producing species • Hundreds of years in rapidly reproducing species

  38. Geographic Isolation

  39. Adapted to cold through heavier fur, short ears, short legs, and short nose. White fur matches snow for camouflage. Arctic Fox Northern population Spreads northward and southward and separates Different environmental conditions lead to different selective pressures and evolution into two different species. Early fox population Gray Fox Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Southern population Fig. 4-6, p. 70

  40. Extinction • Endemic species vulnerable to extinction • Background extinction • Mass extinction • Balance between speciation and extinction determines biodiversity of earth • Speciation generally more rapid than extinction

  41. Extinction through Habitat Loss Fig. 4-7, p. 70

  42. Human Activities and Extinction • Cause premature extinction of species • Earth took millions of years to recover from previous mass extinctions

  43. 4-5 How Might Genetic Engineering Affect the Earth’s Life? • Concept 4-5 Genetic engineering enables scientists to transfer genetic traits between different species – a process that holds great promise and raises difficult issues.

  44. Humans Change Population Genetics • Artificial selection – slow process • Selective breeding • Crossbreeding – not a form of speciation • Genetic engineering

  45. Results of Genetic Engineering • Genetically modified organisms (GMOs) • Gene splitting rapid vs. artificial selection • Modified crops, new drugs, fast-growing animals

  46. Steps in Genetic Engineering (1)

  47. Steps in Genetic Engineering (2)

  48. Fig. 4-8, p. 72

  49. Phase 1 Gene Transfer Preparations A. tumefaciens Plant cell Extract plasmid Extract DNA plasmid Foreign gene if interest Foreign gene integrated into plasmid DNA, which can be used as a vector Agrobacterium takes up plasmid Phase 2 Make Transgenic Cell A. tumefaciens (agrobacterium) Enzymes integrate plasmid into host cell DNA. Host cell Fig. 4-8a, p. 72

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