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Evolution

Evolution. Who is Charles Darwin? Where were the founding ideas of Evolution? What is evolution? Where are the Galapagos Islands?. “change over time”. Evolution. Well tested and supported idea You do not have to agree with a theory Evidence to support. Theory. Born Feb 12 th , 1809

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Evolution

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  1. Evolution Who is Charles Darwin? Where were the founding ideas of Evolution? What is evolution? Where are the Galapagos Islands?

  2. “change over time” Evolution

  3. Well tested and supported idea • You do not have to agree with a theory • Evidence to support Theory

  4. Born Feb 12th, 1809 • England • After college visited many continents as a part of the crew on the HMS Beagle • Naturalist • Observed diversity in organisms Charles Darwin https://www.youtube.com/watch?v=xOl0tHVV6Ck

  5. “characteristics of many animals and plants varied from one island to the next.” – Charles Darwin Galapagos Islands https://www.youtube.com/watch?v=NKG2qH8778U https://www.youtube.com/watch?v=-FT3FU2XOgo

  6. People didn’t believe that things changed…

  7. What does this have to do with Charles Darwin and Evolution?

  8. Two geologists who recognized that the Earth changes • Rocks form/change slowly (rock cycle) • Many forces at work • Proposed that the Earth had to be older than previously thought Charles LyellJames Hutton1795

  9. Present events help to explain past events • Processes are ongoing • Change does occur Charles LyellJames Hutton1795

  10. Can living organisms change as well? • If so…they would change slowly…over time Darwin considers this…

  11. Early theory of evolution • Species descend from others • Living things change over time “selective use or disuse of organs, organisms acquired or lost traits in a lifetime. Traits can be passed to offspring…over time this leads to a change in a species.” Lamarck

  12. 1) Tendency towards perfection (birds want to fly) • 2) Use/Disuse (front legs to wings) • 3) Inheritance of acquired traits Lamarck’s Principles

  13. There were issues with Lamarck’s principles…but it was a start. • Adaptation • Inheritance Lamarck’s Principles

  14. Individual differences among species… Natural variation

  15. Nature’s own variations. • Darwin considered this and decided that species naturally have genetic differences. Artificial selection

  16. Fitness- ability of an individual to survive and reproduce • Adaptation- inherited (behavior or physical) trait that increases an organisms chance of survival. FitnessAdaptation

  17. “Survival of the fittest”- individuals that are better suited for the environment are more likely to survive and therefore reproduce passing off genetic variances to their offspring. Natural Selection https://www.youtube.com/watch?v=AMtT5_AQmLg

  18. Vestigial organs • Fossil record • Homologous body structures • Geographic distribution of species https://www.youtube.com/watch?v=OAfw3akpRe8 https://www.youtube.com/watch?v=GOKW_7KajCU Evidence for evolution

  19. Galapagos finches • Individual traits suggest specific niches for birds and give indicators of feeding habits and habitats. https://www.youtube.com/watch?v=l25MBq8T77w Bird adaptations https://www.youtube.com/watch?v=XzHQ5-lYvrk

  20. Gene Pool- Combined genetic combination of an entire population. • -combinations of alleles (A,B,O,AB blood types), (eye colors etc.) • How often do you see those traits?- Relative frequency Genes and Variation

  21. 1) Genetic shuffling- random draw of genetic traits during meiosis. Crossing over. 8.4 million combos of genes in 23 chromosomes. • 2) Mutations https://www.youtube.com/watch?v=qVmusHZtQms How does a population gain genetic variation?

  22. Review- • Single gene (controlled by a gene with two alleles) Widows Peak • Poly gene (controlled by two or more genes with multiple geno/phenotype possibilities) Height, eye color, skin color. Single Gene vs. Poly Gene traits

  23. Nat selection acts on phenotypesnot so much genotypes • Evolutionacts on populationsnot individuals • What factors can change the frequency of alleles in a population? 16-2 Natural selection and populations

  24. Adding cards to the deck • Removing cards from the deck • (AKA- deaths without reproducing, individuals producing an abundance of offspring) Factors that affect allele frequency

  25. Simpler to calculate and understand • Coloration in an organism… • Allele could altogether disappear • Adaptations that enhance traits will survive Single gene frequency

  26. More complicated to predict • Ex. height Poly gene Frequency

  27. Selection at one end of the curve increases due to higher fitness. Directional selection

  28. Individuals at the center (norm) of curve have a higher fitness than the ends of the curve. • Ex. Baby weight Stabilizing selection

  29. Individuals at high/low extreme of curve have a higher fitness that in the middle (norm) Disruptive selection

  30. Random change in allele frequency • Can cause an allele to become more or less common over time Genetic drift

  31. Allele frequency is constant • Population is not evolving Genetic equilibrium

  32. In order to have genetic equilibrium… • 1- No mutations • 2- No natural selection • 3-Random mating • 4-Large population • 5-No movement into or out of population Hardy-Weinberg principle

  33. Formation of a new species • Organisms that breed with one another and produce fertile offspring. • Common gene pool Speciation

  34. As new species evolve populations become reproductively isolated from one another Reproductive isolation

  35. Species have different behavioral practices such as mating song, and technique so they don’t reproduce together. Behavioral isolation

  36. Reproduction is isolated due to a physical barrier such as water, a landform (mountains) etc. Geographic isolation

  37. Reproduction is isolated due to different reproduction dates/times. (spring/fall) Temporal isolation

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