1. Evolution Descent with Modification Within a species, each individual has slightly different characteristics Natural Selection Nature chooses who is best suited to live in each environment Chapter 13

2. What is Natural Selection Video

3. Natural Selection  Nature decides which organisms are the best suited for their environment.  These organisms survive & reproduce  The stronger, better genes move into the next generation.

4.  Survivor Island Lab

5.  Evolution: “CHANGE over time.”  Descendents look different than their ancestors.  Evolution: “CHANGE over time.”  Descendents look different than their ancestors.

6. Charles Darwin 1809 – 1892

7. FYI - Three Main Parts of Charles Darwin’s Life 1809 – 1831: Age 0 - 22 Childhood, education, college 1831 – 1836: Age 22 to 27 Voyaging on the HMS Beagle 1836 – 1882: Age 27 to 73 Scientist and author (geology, experimental and evolutionary biology - 1859)

8. Charles Darwin H.M.S. Beagle  Darwin set sail on the H.M.S. Beagle (1831-1836) to circumvent the world.  Hired as a naturalist.  Collected fossils, made sketches and notes on flora & fauna of the areas he visited  Galapagos Islands:  Galapagos Islands: Darwin observed species that lived no where else in the world.  These observations led Darwin to write a book. H.M.S. Beagle  Darwin set sail on the H.M.S. Beagle (1831-1836) to circumvent the world.  Hired as a naturalist.  Collected fossils, made sketches and notes on flora & fauna of the areas he visited  Galapagos Islands:  Galapagos Islands: Darwin observed species that lived no where else in the world.  These observations led Darwin to write a book.

9. The Beagle Only 90 foot long, but carrying 74 people.

10. Voyage of the HMS Beagle, 1831 – 1836

11. Charles Darwin  Wrote “On the Origin of Species by Means of Natural Selection” of Natural Selection”  Two main points: 1.Species were not created in their present form, but evolved from an ancestral species. 2.The mechanism for evolution: NATURAL SELECTION  Wrote “On the Origin of Species by Means of Natural Selection” of Natural Selection”  Two main points: 1.Species were not created in their present form, but evolved from an ancestral species. 2.The mechanism for evolution: NATURAL SELECTION

12. Many Factors Affect Populations This Chapter Deals with Natural Selection

13.  Variation: a difference in a physical trait.  Galápagos tortoises that live in areas with tall plants have long necks and legs.  Galápagos finches that live in areas with hard-shelled nuts have strong beaks.  Variation: a difference in a physical trait.  Galápagos tortoises that live in areas with tall plants have long necks and legs.  Galápagos finches that live in areas with hard-shelled nuts have strong beaks.

14.  Adaptation: a feature that allows an organism to better survive in its environment. - Adaptations can lead to genetic change in a population. –Adaptations do not “happen.” The species is already born with the adaptation.

15. Evidences of Evolution 1.Fossil Record 2.Geographic Distribution of Living Species 3.Homologous Body structures 4.Similarities in Embryology 5.Molecular or Genetic Similarities 1.Fossil Record 2.Geographic Distribution of Living Species 3.Homologous Body structures 4.Similarities in Embryology 5.Molecular or Genetic Similarities

16. Evidence of evolution: #1: Fossils  Paleontology is the study of fossils or extinct organisms.

17.  Evidence of evolution: fossils  (relative of whale)  Evidence of evolution: fossils  (relative of whale)

18. Darwin found fossils of extinct animals that resemble modern animals.

19.  Evidence of Evolution: #2 Geography  Evidence of Evolution: #2 Geography –island species most closely resemble nearest mainland species –populations can show variation from one island to another

20.  Evidence of Evolution: #3 Anatomy  Evidence of Evolution: #3 Anatomy Human hand Bat wingMole foot –Homologous structures : –similar in structure but different in function. –evidence of a common ancestor.

21. Homologous Body Structures

22. Human hand Bat wing Mole foot Fly wing  Analogous structures are not evidence of a common ancestor. Not all structures are evidence of a common ancestor. –Analogous structures have a similar function.

23. Vestigial structures: remnants of organs or structures that had a function in an early ancestor. Ostrich wings are examples of vestigial structures. Structural features are a clue to a species history.

24. Evidence of Evolution: #4 Embryology  In their early stages of development, chickens, turtles, fish and humans look similar, providing evidence that they probably shared a common ancestry.

25. Evidence of Evolution: #5: Molecular and genetic evidence  Two closely-related organisms will have similar DNA & protein sequences.

26. Natural Selection Or, how did we get here….

27. Vocabulary ndividuals that interbreed viable  Species: A group of individuals that have the potential to interbreed and produce viable offspring. individualssame species  Population: A localized group of individuals belonging to the same species. One specie one place. ndividuals that interbreed viable  Species: A group of individuals that have the potential to interbreed and produce viable offspring. individualssame species  Population: A localized group of individuals belonging to the same species. One specie one place.

28. VocabularyVocabulary  Gene Pool collection of genes  The total collection of genes in a population at any one time.  Divergence: the accumulation of differences between species or populations  Gene Pool collection of genes  The total collection of genes in a population at any one time.  Divergence: the accumulation of differences between species or populations

29. Some of Darwin’s Theory FYI Organisms change in time, usually very slowly (sometimes extremely slowly), or evolve. Darwin wrote of “descent with modification” but the modern term is “evolution.” All organisms – animals, plants, fungi, all organisms – are descended from a remote common ancestor. The main driving force for evolutionary change is natural selection, the survival of certain traits because they better adapt the organism for its survival. Natural selection doesn’t just select against inferior organisms, it selects for superior organisms and leads to even more superior organisms.

30. Natural Selection  Individualsfavorabletraits environment  Individuals with favorable traits are more likely to leave more offspring better suited for their environment.

31. Natural Selection - FYI  How did Darwin come to his idea about Natural Selection?  He considered 3 concepts:  How did Darwin come to his idea about Natural Selection?  He considered 3 concepts:

32. 1 st - FYI  There is change over time in the flora (plants) and fauna (animals) of the Earth  What we would commonly call ‘evolution’ today  The fossil record showed this to be pretty clear, even to people in the mid 1800s  There is change over time in the flora (plants) and fauna (animals) of the Earth  What we would commonly call ‘evolution’ today  The fossil record showed this to be pretty clear, even to people in the mid 1800s

33. 2 nd - FYI  There is a taxonomic (order) relationship among living things  People were big into classifying stuff  It was pretty obvious that there was a relationship between different species  Different birds, different grasses, different cats etc  There is a taxonomic (order) relationship among living things  People were big into classifying stuff  It was pretty obvious that there was a relationship between different species  Different birds, different grasses, different cats etc

34. 3 rd - FYI  Adaptation  Different kinds of teeth for different animals, say carnivore ripping teeth and herbivore grinding teeth  Different tissues within species  Heart vs. eye etc.  Differences in beak structures in similar species  Adaptation  Different kinds of teeth for different animals, say carnivore ripping teeth and herbivore grinding teeth  Different tissues within species  Heart vs. eye etc.  Differences in beak structures in similar species

35. How does it work?  There is competition among living things  More are born or hatched, than survive and reproduce  Reproduction occurs with variation  This variation is inherited  Remember, there was NO genetics back then, Chucky D knew, he just knew….  Realized that it wasn’t ‘blending’  There is competition among living things  More are born or hatched, than survive and reproduce  Reproduction occurs with variation  This variation is inherited  Remember, there was NO genetics back then, Chucky D knew, he just knew….  Realized that it wasn’t ‘blending’

36. How does it work?  Selection determines which individuals enter the adult breeding population 1.This selection is done by the environment 2.Those which are best suited, reproduce 3.The strong, survival characteristics are passed on to the young  Selection determines which individuals enter the adult breeding population 1.This selection is done by the environment 2.Those which are best suited, reproduce 3.The strong, survival characteristics are passed on to the young

37. How does it work?  REPRODUCTION is the key, not just surviving.  An organism must be able to reproduce to pass on traits to the next generation.  REPRODUCTION is the key, not just surviving.  An organism must be able to reproduce to pass on traits to the next generation.

38. This lecture keeps evolving…..  Survival of the Fittest  (Chucky D. NEVER said)  means those who survive tend to have the most offspring that reproduce  Survival of the Fittest  (Chucky D. NEVER said)  means those who survive tend to have the most offspring that reproduce

42. Summary of Darwin’s Theory 1. Organisms differ; variation is inherited 2. Organisms produce more offspring than survive 3. Organisms compete for resources 4. Organisms with advantages survive to pass those advantages to their children 5. Species alive today are descended with modifications from common ancestors 1. Organisms differ; variation is inherited 2. Organisms produce more offspring than survive 3. Organisms compete for resources 4. Organisms with advantages survive to pass those advantages to their children 5. Species alive today are descended with modifications from common ancestors

43. Video: Natural Selection  http://www.youtube.com/watch?v=AMtT 5_AQmLg http://www.youtube.com/watch?v=AMtT 5_AQmLg  http://www.youtube.com/watch?v=AMtT 5_AQmLg http://www.youtube.com/watch?v=AMtT 5_AQmLg