Evolution and Darwin Visit  www.worldofteaching.com For 100’s of free powerpoints
Evolution <ul><li>The  processes  that have transformed life on earth from it’s  earliest forms  to the vast  diversity  t...
Old Theories of Evolution <ul><li>Jean Baptiste Lamarck   (early 1800’s) proposed: </li></ul><ul><li>“ The inheritance of ...
“ The Inheritance of Acquired Characteristics” <ul><li>Example: </li></ul><ul><li>A giraffe acquired its long neck because...
Charles Darwin <ul><li>Influenced by Charles Lyell  who published  “Principles of Geology”. </li></ul><ul><li>This publica...
Charles Darwin <ul><li>Darwin set sail on the  H.M.S. Beagle  (1831-1836) to survey the south seas  (mainly South America ...
Charles Darwin <ul><li>Wrote in 1859 : “On the Origin of Species by Means of Natural Selection” </li></ul><ul><li>Two main...
Natural Selection <ul><li>Individuals  with  favorable   traits  are more likely to leave more offspring better suited for...
Artificial Selection <ul><li>The  selective breeding  of domesticated plants and animals by man. </li></ul><ul><li>Questio...
Evidence of Evolution <ul><li>1.   Biogeography: </li></ul><ul><li>Geographical distribution of species. </li></ul><ul><li...
Eastern Long Necked Turtle
Evidence of Evolution <ul><li>3.  Taxonomy: </li></ul><ul><li>Classification of life forms. </li></ul><ul><li>4.  Homologo...
Evidence of Evolution <ul><li>5.  Comparative embryology: </li></ul><ul><li>Study of structures that appear during  embryo...
Population Genetics <ul><li>The  science  of  genetic change  in population. </li></ul><ul><li>Remember: Hardy-Weinberg eq...
Population <ul><li>A localized group of  individuals  belonging to the  same species . </li></ul>
Species <ul><li>A group of  populations  whose  individuals  have the potential to  interbreed  and produce  viable  offsp...
Gene Pool <ul><li>The total  collection of genes  in a population at any one time. </li></ul>
Hardy-Weinberg Principle <ul><li>The  concept  that the  shuffling of genes  that occur during sexual reproduction, by its...
Hardy-Weinberg Principle <ul><li>This  principle  will be maintained in nature only if all  five  of the following conditi...
Hardy-Weinberg Principle <ul><li>Remember: </li></ul><ul><li>If these conditions are met, the  population is at  equilibri...
Macroevolution <ul><li>The origin of taxonomic groups  higher than the species level . </li></ul>
Microevolution <ul><li>A change in a  population’s gene pool  over a secession of generations. </li></ul><ul><li>Evolution...
Five Mechanisms of Microevolution <ul><li>1.  Genetic drift: </li></ul><ul><li>Change in the gene pool of a small  populat...
a.  Bottleneck Effect <ul><li>Genetic drift  (reduction of alleles in a population) resulting from a  disaster  that drast...
b.  Founder Effect <ul><li>Genetic drift  resulting from the  colonization  of a new location by a small number of individ...
Five Mechanisms of Microevolution <ul><li>2.  Gene Flow: </li></ul><ul><li>T he  gain or loss of alleles  from a  populati...
Five Mechanisms of Microevolution <ul><li>3.  Mutation: </li></ul><ul><li>Change in an organism’s DNA that creates a new a...
Modes of Action <ul><li>Natural selection  has  three modes  of action: </li></ul><ul><li>1. Stabilizing selection </li></...
1. Stabilizing Selection <ul><li>Acts  upon  extremes  and  favors  the  intermediate . </li></ul>Number of Individuals Si...
2. Directional Selection <ul><li>Favors  variants of  one extreme . </li></ul>Number of Individuals Size of individuals Sm...
3. Diversifying Selection <ul><li>Favors  variants of  opposite extremes . </li></ul>Number of Individuals Size of individ...
Speciation <ul><li>The  evolution  of new species. </li></ul>
Reproductive Barriers <ul><li>Any  mechanism  that  impedes  two species from producing  fertile and/or viable hybrid offs...
1. Pre-zygotic Barriers <ul><li>a.  Temporal isolation: </li></ul><ul><li>Breeding occurs at different times for  differen...
1. Pre-zygotic Barriers <ul><li>d.  Mechanical isolation: </li></ul><ul><li>Structural differences prevent gamete  exchang...
2. Post-zygotic Barriers <ul><li>a.  Hybrid inviability: </li></ul><ul><li>Hybrid zygotes fail to develop or fail to  reac...
Allopatric Speciation <ul><li>Induced when the  ancestral  population becomes  separated  by a  geographical barrier. </li...
Adaptive Radiation <ul><li>Emergence of numerous species  from a  common ancestor  introduced to new and diverse environme...
Sympatric Speciation <ul><li>Result of a radical change in the genome that produces a  reproductively isolated sub-populat...
Interpretations of Speciation <ul><li>Two theories: </li></ul><ul><li>1. Gradualist Model (Neo-Darwinian): </li></ul><ul><...
Convergent Evolution <ul><li>Species  from different  evolutionary branches  may come to resemble one another if they live...
Coevolution <ul><li>Evolutionary change , in which one species act as a  selective force  on a  second  species, inducing ...
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Darwin

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Darwin

  1. 1. Evolution and Darwin Visit www.worldofteaching.com For 100’s of free powerpoints
  2. 2. Evolution <ul><li>The processes that have transformed life on earth from it’s earliest forms to the vast diversity that characterizes it today. </li></ul><ul><li>A change in the genes!!!!!!!! </li></ul>
  3. 3. Old Theories of Evolution <ul><li>Jean Baptiste Lamarck (early 1800’s) proposed: </li></ul><ul><li>“ The inheritance of acquired characteristics” </li></ul><ul><li>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 . </li></ul>
  4. 4. “ The Inheritance of Acquired Characteristics” <ul><li>Example: </li></ul><ul><li>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. </li></ul>
  5. 5. Charles Darwin <ul><li>Influenced by Charles Lyell who published “Principles of Geology”. </li></ul><ul><li>This publication led Darwin to realize that natural forces gradually change Earth’s surface and that the forces of the past are still operating in modern times. </li></ul>
  6. 6. Charles Darwin <ul><li>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. </li></ul><ul><li>On the Galapagos Islands, Darwin observed species that lived no where else in the world. </li></ul><ul><li>These observations led Darwin to write a book. </li></ul>
  7. 7. Charles Darwin <ul><li>Wrote in 1859 : “On the Origin of Species by Means of Natural Selection” </li></ul><ul><li>Two main points: </li></ul><ul><li>1. Species were not created in their present form, but evolved from ancestral species. </li></ul><ul><li>2. Proposed a mechanism for evolution: NATURAL SELECTION </li></ul>
  8. 8. Natural Selection <ul><li>Individuals with favorable traits are more likely to leave more offspring better suited for their environment . </li></ul><ul><li>Also known as “Differential Reproduction” </li></ul><ul><li>Example: </li></ul><ul><li>English peppered moth ( Biston betularia ) </li></ul><ul><li>- light and dark phases </li></ul>
  9. 9. Artificial Selection <ul><li>The selective breeding of domesticated plants and animals by man. </li></ul><ul><li>Question: </li></ul><ul><li>What’s the ancestor of the domesticated dog? </li></ul><ul><li>Answer: WOLF </li></ul>
  10. 10. Evidence of Evolution <ul><li>1. Biogeography: </li></ul><ul><li>Geographical distribution of species. </li></ul><ul><li>2. Fossil Record: </li></ul><ul><li>Fossils and the order in which they appear in layers of sedimentary rock (strongest evidence). </li></ul>
  11. 11. Eastern Long Necked Turtle
  12. 12. Evidence of Evolution <ul><li>3. Taxonomy: </li></ul><ul><li>Classification of life forms. </li></ul><ul><li>4. Homologous structures: </li></ul><ul><li>Structures that are similar because of common ancestry (comparative anatomy) </li></ul>
  13. 13. Evidence of Evolution <ul><li>5. Comparative embryology: </li></ul><ul><li>Study of structures that appear during embryonic development. </li></ul><ul><li>6. Molecular biology: </li></ul><ul><li>DNA and proteins (amino acids) </li></ul>
  14. 14. Population Genetics <ul><li>The science of genetic change in population. </li></ul><ul><li>Remember: Hardy-Weinberg equation. </li></ul>
  15. 15. Population <ul><li>A localized group of individuals belonging to the same species . </li></ul>
  16. 16. Species <ul><li>A group of populations whose individuals have the potential to interbreed and produce viable offspring. </li></ul>
  17. 17. Gene Pool <ul><li>The total collection of genes in a population at any one time. </li></ul>
  18. 18. Hardy-Weinberg Principle <ul><li>The concept that the shuffling of genes that occur during sexual reproduction, by itself, cannot change the overall genetic makeup of a population. </li></ul>
  19. 19. Hardy-Weinberg Principle <ul><li>This principle will be maintained in nature only if all five of the following conditions are met: </li></ul><ul><li>1. Very large population </li></ul><ul><li>2. Isolation from other populations </li></ul><ul><li>3. No net mutations </li></ul><ul><li>4. Random mating </li></ul><ul><li>5. No natural selection </li></ul>
  20. 20. Hardy-Weinberg Principle <ul><li>Remember: </li></ul><ul><li>If these conditions are met, the population is at equilibrium . </li></ul><ul><li>This means “No Change” or “No Evolution”. </li></ul>
  21. 21. Macroevolution <ul><li>The origin of taxonomic groups higher than the species level . </li></ul>
  22. 22. Microevolution <ul><li>A change in a population’s gene pool over a secession of generations. </li></ul><ul><li>Evolutionary changes in species over relatively brief periods of geological time . </li></ul>
  23. 23. Five Mechanisms of Microevolution <ul><li>1. Genetic drift: </li></ul><ul><li>Change in the gene pool of a small population due to chance. </li></ul><ul><li>Two examples: </li></ul><ul><li>a. Bottleneck effect </li></ul><ul><li>b. Founder effect </li></ul>
  24. 24. a. Bottleneck Effect <ul><li>Genetic drift (reduction of alleles in a population) resulting from a disaster that drastically reduces population size . </li></ul><ul><li>Examples: </li></ul><ul><li>1. Earthquakes </li></ul><ul><li>2. Volcano’s </li></ul>
  25. 25. b. Founder Effect <ul><li>Genetic drift resulting from the colonization of a new location by a small number of individuals. </li></ul><ul><li>Results in random change of the gene pool. </li></ul><ul><li>Example: </li></ul><ul><li>1. Islands (first Darwin finch) </li></ul>
  26. 26. Five Mechanisms of Microevolution <ul><li>2. Gene Flow: </li></ul><ul><li>T he gain or loss of alleles from a population by the movement of individuals or gametes. </li></ul><ul><li>Immigration or emigration . </li></ul>
  27. 27. Five Mechanisms of Microevolution <ul><li>3. Mutation: </li></ul><ul><li>Change in an organism’s DNA that creates a new allele. </li></ul><ul><li>4. Non-random mating: </li></ul><ul><li>The selection of mates other than by chance. </li></ul><ul><li>5. Natural selection: </li></ul><ul><li>Differential reproduction. </li></ul>
  28. 28. Modes of Action <ul><li>Natural selection has three modes of action: </li></ul><ul><li>1. Stabilizing selection </li></ul><ul><li>2. Directional selection </li></ul><ul><li>3. Diversifying selection </li></ul>Number of Individuals Size of individuals Small Large
  29. 29. 1. Stabilizing Selection <ul><li>Acts upon extremes and favors the intermediate . </li></ul>Number of Individuals Size of individuals Small Large
  30. 30. 2. Directional Selection <ul><li>Favors variants of one extreme . </li></ul>Number of Individuals Size of individuals Small Large
  31. 31. 3. Diversifying Selection <ul><li>Favors variants of opposite extremes . </li></ul>Number of Individuals Size of individuals Small Large
  32. 32. Speciation <ul><li>The evolution of new species. </li></ul>
  33. 33. Reproductive Barriers <ul><li>Any mechanism that impedes two species from producing fertile and/or viable hybrid offspring . </li></ul><ul><li>Two barriers: </li></ul><ul><li>1. Pre-zygotic barriers </li></ul><ul><li>2. Post-zygotic barriers </li></ul>
  34. 34. 1. Pre-zygotic Barriers <ul><li>a. Temporal isolation: </li></ul><ul><li>Breeding occurs at different times for different species. </li></ul><ul><li>b. Habitat isolation: </li></ul><ul><li>Species breed in different habitats. </li></ul><ul><li>c. Behavioral isolation: </li></ul><ul><li>Little or no sexual attraction between species. </li></ul>
  35. 35. 1. Pre-zygotic Barriers <ul><li>d. Mechanical isolation: </li></ul><ul><li>Structural differences prevent gamete exchange. </li></ul><ul><li>e. Gametic isolation: </li></ul><ul><li>Gametes die before uniting with gametes of other species, or gametes fail to unite. </li></ul>
  36. 36. 2. Post-zygotic Barriers <ul><li>a. Hybrid inviability: </li></ul><ul><li>Hybrid zygotes fail to develop or fail to reach sexual maturity. </li></ul><ul><li>b. Hybrid sterility: </li></ul><ul><li>Hybrid fails to produce functional gametes. </li></ul><ul><li>c. Hybrid breakdown: </li></ul><ul><li>Offspring of hybrids are weak or infertile. </li></ul>
  37. 37. Allopatric Speciation <ul><li>Induced when the ancestral population becomes separated by a geographical barrier. </li></ul><ul><li>Example: </li></ul><ul><li>Grand Canyon and ground squirrels </li></ul>
  38. 38. Adaptive Radiation <ul><li>Emergence of numerous species from a common ancestor introduced to new and diverse environments. </li></ul><ul><li>Example: </li></ul><ul><li>Darwin’s Finches </li></ul>
  39. 39. Sympatric Speciation <ul><li>Result of a radical change in the genome that produces a reproductively isolated sub-population within the parent population (rare). </li></ul><ul><li>Example: Plant evolution - polyploid </li></ul><ul><li>A species doubles it’s chromosome # to become tetraploid. </li></ul>reproductive sub-population Parent population
  40. 40. Interpretations of Speciation <ul><li>Two theories: </li></ul><ul><li>1. Gradualist Model (Neo-Darwinian): </li></ul><ul><li>Slow changes in species overtime. </li></ul><ul><li>2. Punctuated Equilibrium: </li></ul><ul><li>Evolution occurs in spurts of relatively rapid change. </li></ul>
  41. 41. Convergent Evolution <ul><li>Species from different evolutionary branches may come to resemble one another if they live in very similar environments. </li></ul><ul><li>Example: </li></ul><ul><li>1. Ostrich (Africa) and Emu (Australia). </li></ul><ul><li>2. Sidewinder (Mojave Desert) and </li></ul><ul><li>Horned Viper (Middle East Desert) </li></ul>
  42. 42. Coevolution <ul><li>Evolutionary change , in which one species act as a selective force on a second species, inducing adaptations that in turn act as selective force on the first species. </li></ul><ul><li>Example: </li></ul><ul><li>1. Acacia ants and acacia trees </li></ul><ul><li>2. Humming birds and plants with flowers with long tubes </li></ul>

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