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Evolution

Explore the process of evolution through natural selection and the evidence that supports it. Learn about species, adaptation, and the mechanisms of evolution. Discover how new species emerge over time and the different patterns of evolution.

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Evolution

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  1. Evolution Natural Selection and Evidence for Evolution

  2. Life • How did we come from this? • To this.

  3. Change in a population over a long time or MANY generations A population is a group of a single species Humans…or Lions Evolution occurs through Natural Selection (“That is the Key!”) What is Evolution?

  4. What is a Species? • A Species is defined as a group of organisms that share similar characteristics and that are capable of interbreeding and producing fertile offspring

  5. Lamarck • French scientist Jean Baptiste de Lamarck (1744 – 1829) • First to propose a unifying hypothesis of species modification • Acquired Traits – trait that is not determined by genes • Lamarck – these were passed on to offspring

  6. Darwin – individuals struggle to survive (competing for food and space, escaping predators, finding mates, locating shelter). Only some individuals survive the struggle and produce offspring Charles Darwin

  7. Darwin – Descent with Modification Modification by Natural Selection Charles Darwin

  8. Darwin and Natural Selection • Four things that drive N.S. • Fitness • Ability to survive and reproduce • Variation • Differences among species • Adaptation • Variation that improves chances of survival • Adaptations develop over many generations • Competition • Fight for survival (food, shelter)

  9. Selection • Artificial Selection • Breeding organisms with specific traits • Natural Selection • Mechanism for change in population • Organisms with certain variations survive, reproduce and pass their traits to offspring • Survival of the Fittest!

  10. Variation A variation is an inherited trait that makes an individual different from other members of the species. Some traits are “better” or more favorable than others

  11. Adaptation • Adaptation: any variation that aids an organism’s chances of survival in its environment

  12. 1. Structural Adaptation: allow a species to defend against predation. Mimicry: The ability species to resemble another species; two types. Camouflage: The ability of species to blend in with their surroundings Evidence of Evolution Monarch • Viceroy

  13. What is this?

  14. Structural Adaptations cont • Mimicry

  15. Leafhoppers

  16. Treehopper

  17. Leaf Hopper

  18. Ants

  19. Warning Coloration

  20. Other Evidence 2. Physiological Adaptations: • Develop rapidly…(antibiotic resistance; pesticide resistance) • This is Direct Evidence • 3 – 6. Indirect Evidence

  21. 3. Fossils • Fossils show evolutionary history

  22. Homologous Structures Common ancestry Analogous Structures No Common ancestry Vestigial Structures No visible function or use any longer 4. Anatomy

  23. Anatomy Revisited • Homologous Structures • Common Ancestor • Can have similar arrangement and function • Analogous Structures • No common ancestor • Similar function; different anatomy

  24. Vestigial Structures • Flightless Cormorant

  25. Vestigial Structures • Human Ear Muscles • Baleen Whale Pelvic Bone • Vestigial Video

  26. 5. Embryology • Similarities in Embryos • Suggest a common ancestor

  27. Embryology and Evolution

  28. 6. Biochemistry • Comparison of DNA and RNA • Determine evolutionary relationship

  29. Evolution and History How Evolution Happens - YouTube

  30. Industrial Melanism • Peppered moths – • Before the Industrial Revolution • After the Industrial Revolution

  31. Mechanisms of Evolution

  32. Disruption of Equilibrium shows Evolution • Mutation – change in the DNA of an organism • Genetic Drift • Alleles frequency changes by random events or chance • Non-Random Mating • Assortative Mating – Selection of mate based on similar characteristics • Migration • into or out of population • Gene Flow: genes moving from one pop to another • Natural Selection – See Below

  33. Assortative Mating

  34. Review Natural Selection • Natural Selection – • The idea that organisms with traits best suited to their environment are more likely to survive and reproduce

  35. Types of Natural Selection • Stabilizing Selection • Favors average individuals • Disruptive Selection • Favors both extremes of a variation • Directional Selection • Favors a single extreme variation

  36. Speciation • What is Speciation? • The evolution of new species • Geographic Isolation • Occurs when a small part of the population becomes separated; over generations, different variations become more common • Reproductive Isolation • Members of a species change from one another over time so much that they can no longer reproduce fertile offspring

  37. How long does speciation take? • Gradualism • The model that describes evolution as a slow ongoing process • Punctuated Equilibrium • States that rapid evolution comes about when the mutations of a few genes results in the appearance of a new species over a relatively short period of time

  38. Patterns of Evolution • Divergent Evolution • Adaptive Radiation • Single species evolves into an array • Convergent Evolution • The acquisition of the same biological trait in unrelated lineages

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