1. 1 Unit Three Evolution, Biodiversity, and Community Processes A. C. Mosley High School Mrs. Dow Chapter 5

2. 2 The Just-Right Planet Read Case study on page 87.

3. 3 Origins of Life (5-1) Chemical evolution of organic molecules, biopolymers & systems Chemical evolution of organic molecules, biopolymers & systems Took about 1 billion years! Took about 1 billion years!

4. 4 Miller-Urey Experiment conducted in 1953 by Stanley Miller with Harold Urey the first experiment about the evolution of prebiotic chemicals and the origin of life on Earth mixture of methane, ammonia, hydrogen, and water vapor introduced into a 5-liter flask (simulate the Earth's primitive, reducing atmosphere) energized by an electrical discharge apparatus to represent ultraviolet radiation from the Sun products were allowed to condense and collect in a lower flask which modeled a body of water on the Earth's surface

5. 5 Miller-Urey Experiment heat supplied to this flask recycled the water vapor just as water evaporates from lakes and seas, before moving into the atmosphere and condensing again as rain after a day of continuous operation a thin layer of hydrocarbons on the surface of the water after about a week of operation a dark brown scum had collected in the lower flask and was found to contain several types of amino acids, including glycine and alanine, together with sugars, tars, and various other unidentified organic chemicals

6. 6 EVOLUTION is Gradual Change

7. 7 Origins of Life (5-1) Next, biological evolution Single-celled prokaryotic bacteria  single- celled eukaryotes  multicellular organisms Evidence from fossils, ice-core drilling, chemical analysis & DNA

8. 8 Plants begin invading land Evolution and expansion of life First fossil record of animals Age of reptiles Age of mammals Insects and amphibians invade the land Modern humans (Homo sapiens) appear about 2 seconds before midnight Recorded human history begins 1/4 second before midnight Origin of life (3.6–3.8 billion years ago) Page 89 noon midnight

9. 9 Fossils Oldest fossils are the approximately 3.465 billion-year-old microfossils from the Apex Chert, Australia colonies of cyanobacteria (formerly called blue-green algae) which built real reefs

10. 10 History of Theories of Evolution

11. 11 Old Theories of Evolution Jean Baptiste Lamarck (early 1800’s) proposed: “The inheritance of acquired characteristics” He proposed that by using or not using its body parts, an individual tends to develop certain characteristics, which it passes on to its offspring. Lamarck's scientific theories were largely ignored or attacked during his lifetime, Today, the name of Lamarck is associated merely with a discredited theory of heredity

12. 12 “The Inheritance of Acquired Characteristics” Example: A giraffe acquired its long neck because its ancestor stretched higher and higher into the trees to reach leaves, and that the animal’s increasingly lengthened neck was passed on to its offspring.

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14. 14 Charles Darwin Darwin set sail on the H.M.S. Beagle (1831-1836) to survey the south seas (mainly South America and the Galapagos Islands) to collect plants and animals. On the Galapagos Islands, Darwin observed species that lived no where else in the world. These observations led Darwin to write a book

15. 15 Darwin’s Journey on the H.M.S. Beagle

16. 16 Pinta Island Intermediate shell Pinta Isabela Island Dome-shaped shell Hood Island Saddle-backed shell Hood Floreana Santa Fe Santa Cruz James Marchena Fernandina Isabela Tower Giant Tortoises of the Galápagos Islands

17. 17 http://www.galapagosislands.com

18. 18 Charles Darwin Wrote in 1859: “On the Origin of Species by Means of Natural Selection” Two main conclusions: 1.Species were not created in their present form, but evolved from ancestral species. 2.Proposed a mechanism for evolution: NATURAL SELECTION

19. 19 Darwin’s Observations 1.Most species produce more offspring than can be supported by the environment 2.Environmental resources are limited 3.Most populations are stable in size 4.Individuals vary greatly in their characteristics (phenotypes) 5.Variation is heritable (genotypes)

20. 20 Natural Selection Individuals with favorable traits are more likely to leave more offspring better suited for their environment Also known as “Differential Reproduction” Example: English peppered moth (Biston betularia)Biston betularia

21. 21 Evolution & Adaptation (5-2) Change in a population’s genetic makeup over time Theory of evolution  all species came from a earlier, ancestral species Microevolution (genes mutate  individuals are selected  populations evolve) Small genetic changes over time (traits are passed on) Sexual reproduction leads to diversity Gene pool (all the genes in a populations offspring) Variability is created by mutations DNA exposed to external agents Random mistakes

22. 22 Microevolution - Microevolution works through a combination of four processes that change the genetic composition of a population: Mutation – involving random changes in the structure or number of DNA molecules in a cell and is the ultimate source of genetic variability in a population. Natural selection – occurs when some individuals of a population have genetically based traits that cause them to survive and produce more offspring than other individuals Gene flow – which involves movement of genes between populations and can lead to changes in the genetic composition of local populations. Genetic drift – involves changes in the genetic composition of a population by chance and is especially important for small populations.

23. 23 Natural selection Members of a population have favorable traits that are passed on 3 necessary conditions Must have genetic variability Must be heritable Must allow for further offspring Some mutations are harmful/some beneficial

24. 24 Adaptive traits (adaptation) Heritable traits that help organisms survive and reproduce Helps to: Adapt to new conditions Migrate to a new area Become extinct

25. Adaptive Radiation Emergence of numerous species from a common ancestor introduced to new and diverse environments ExampleExample: Hawaiian Honeycreepers

26. Convergent Evolution Species from different evolutionary branches may come to resemble one another if they live in very similar environments Example: 1. Ostrich (Africa) and Emu (Australia). 2. Sidewinder (Mojave Desert) and Horned Viper (Middle East Desert)

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28. 28 Three Types of Natural Selection and Co evolution Three types of natural selection Biologists recognize three types of natural selection – depending on environmental conditions. 1.Directional natural selection 2.Stabilizing natural selection 3.Diversifying natural selection

29. 29 Click to view animation. Example of directional selection animation. Animation (watch on CD)

30. 30 Animation (watch on CD) Click to view animation. Stabilizing selection animation.

31. 31 Animation (watch on CD) Click to view animation. Disruptive selection animation.

32. 32  What is co evolution?  It is an evolution in which two or more species interact and exert selective pressures on each other that can lead each species to undergo various adaptations. Bats and Moths

33. Coevolution Evolutionary change One species acts as a selective force on a second species Inducing adaptations that act as selective force on the first species Example: 1.Wolf and Moose 2.Acacia ants and Acacia trees 2.Yucca Plants and Yucca moths 3.Lichen

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35. 35 Ecological Niches and Adaptation (5-3) Niche Species way of life and every thing that affects it Includes member’s adaptations Range of tolerance Role of energy flow Habitat Where an organism lives Conditions and resources it needs

36. 36 Niche is the species’ occupation and its Habitat location of species (its address)

37. 37 Niche Realized niche: more restricted set of conditions under which the species actually exists due to interactions with other species Fundamental niche: set of conditions under which a species might exist in the absence of interactions with other species

38. 38 Generalists Broad ecological role Living in many places Eat a variety of foods Will adapt easily Ability to develop genetic resistance to poisons

39. 39 Specialists Specialists Live in specific environments Live in specific environments Prone to extinction Prone to extinction Competition may cause them to evolve Competition may cause them to evolve Panda eat mostly bamboo, are separated into small isolated groups and have low birth rates and litter size Panda eat mostly bamboo, are separated into small isolated groups and have low birth rates and litter size  Organism is classified a generalist or a specialist based on its  Range of tolerance  Niche  Limiting factors  Response to changing conditions

40. 40 Region of niche overlap Generalist species with a broad niche Specialist species with a narrow niche Niche breadth Niche separation Number of individuals Resource use Overlap of the niches of two different species

41. 41 Specialized feeding niches of various birds species in a coastal wetland Black skimmer seizes small fish at water surface Flamingo feeds on minute organisms in mud Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation Brown pelican dives for fish, which it locates from the air Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Louisiana heron wades into water to seize small fish Oystercatcher feeds on clams, mussels, and other shellfish into which it pries its narrow beak Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans Knot (a sandpiper) picks up worms and small crustaceans left by receding tide Herring gull is a tireless scavenger Ruddy turnstone searches under shells and pebbles for small invertebrates Piping plover feeds on insects and tiny crustaceans on sandy beaches Resource partitioning reduces competition

42. 42 “Evolution is concerned about leaving the most descendents, not the strongest”

43. 43 Macroevolution What is macroevolution? Macroevolution is concerned with how evolution takes place above the level of species and over much longer periods than microevolution, and macro evolutionary patterns include genetic persistence, genetic divergence, and genetic loss.

44. 44 Speciation, Extinction and Biodiversity (5-4) Speciation Two species arise when two species can no longer breed Allopatric speciation  Due to geographical isolation or reproductive isolation  Fox population (next slide) Sympatric speciation  Two species live close together, can’t interbreed  Example: some insects when two populations experience different types of mutations by feeding on different types of plants

45. 45 Early fox population Spreads northward and southward and separates How geographic isolation can lead to reproductive isolation, divergence, and speciation. Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Adapted to cold through heavier fur, short ears, short legs, short nose. White fur matches snow for camouflage. Gray Fox Arctic Fox Different environmental conditions lead to different selective pressures and evolution into two different species. Northern population Southern population Grey Fox

46. 46 Going, Going, Gone Extinction Natural disasters Introduction of new competitive species Environmental changes Adaptive radiation Recovery periods after mass extinction It takes 1 to 10 million years to rebuild biological diversity of a mass extinction

47. 47 Biologist estimate that 99.9% of all the species that ever existed are extinct. When local environmental changes, some species will disappear at a low rate: this is called background extinction Mass extinction is a significant rise in extinction rates above the background extinction (usually 25-70% species lost) Mass depletion extinction rates are higher than normal but not high enough to classify as a mass extinction

48. 48 Mass Extinctions & Depletion 2 Mass extinction & 3 Mass depletions Date of the Extinction Event Percent Species Lost Species Affected 65 mya (million years ago) 85Dinosaurs, plants (except ferns and seed bearing plants), marine vertebrates and invertebrates. Most mammals, birds, turtles, crocodiles, lizards, snakes, and amphibians were unaffected. 213 mya44Marine vertebrates and invertebrates 248 mya75-95Marine vertebrates and invertebrates 380 mya70Marine invertebrates 450 mya50Marine invertebrates http://www.geog.ouc.bc.ca/physgeog/contents/9h.html

49. 49 Pangea

50. 50 EURASIA AFRICA SOUTH AMERICA INDIA 135 million years ago Present 65 million years ago 225 million years ago 120°80°0° 120° 80° 40° 120° GONDWANALAND 120° LAURASIA PANGAEA ANTARCTICA AUSTRALIA MADA- GASCAR MADA- GASCAR Continental drift

51. 51 Natural capital Terrestrial organisms Marine organisms Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian Pre-cambrain 1.80651452052502903554104405005453500 0 1600 1200 800 400 Number of families Millions of years ago Change in the earth’s biodiversity over geological time.

52. 52 Sustainability and Evolution Earth is constantly changing, and throughout the earth’s history the atmosphere has changed, the climate has changed, the geography has changed he types and numbers of organisms have changes, and continental drift has changed the positions of the earth’s continents. Biologists estimate that the current human-accelerated extinction rate of species is 1,000 to 10,000 times higher than natural extinction rates. (100 to 1,000 species per million species) It has been predicted that by the end of the 21 st century we may see the extinction of half of the present species now on Earth.

53. 53 Future of Evolution? (5-5) Artificial selection by humans Selective breeding Genetic breeding/gene splicing Cloning Biopharming

54. 54 Genetic engineering Unpredictable process Ethical Success rate is 1% How will benefit?

55. 55 Crop Crossbreeding Desired trait (color) ApplePear Offspring Crossbreeding Best results New offspring Desired result Figure 5-10 Page 97

56. 56 Phase 1 Make Modified Gene Identify and extract gene with desired trait Identify and remove portion of DNA with desired trait Remove plasmid from DNA of E. coli Insert extracted DNA (step 2) into plasmid (step3) Insert modified plasmid into E. coli Grow in tissue culture to make copies cell gene DNA plasmid E. coli DNA Genetically modified plasmid

57. 57 Phase 2 Make Transgenic Cell Transfer plasmid copies to a carrier agrobacterium Agrobacterium inserts foreign DNA into plant cell to yield transgenic cell Transfer plasmid to surface microscopic metal particle Use gene gun to inject DNA into plant cell A. tumefaciens (agrobacterium) Plant cell Nucleus Host DNA Foreign DNA Figure 5-11b Page 98

58. 58 Phase 3 Grow Genetically Engineered Plant Transgenic cell from Phase 2 Cell division of transgenic cells Culture cells to form plantlets Transgenic plants with new traits Figure 5-11c Page 98 Transfer to soil

59. 59 Animation (watch on CD) Click to view animation. Evolutionary tree of life animation.

60. 60 Animation Click to view animation. Evolutionary tree diagrams interaction.