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- 1. The Origin ofSpecies The Origin of Species AP Biology AP Biology Crosby High School Crosby High School
- 2. Reproductive Isolation Reproductive Isolation PrezygoticBarriers: Prezygotic Barriers: – Habitat Isolation: Parasites in different hosts Habitat Isolation: Parasites in different hosts – Behavioral Isolation: Generally courtship Behavioral Isolation: Generally courtship rituals rituals – Temporal Isolation: Different time, day, Temporal Isolation: Different time, day, season, or year season, or year – Mechanical Isolation: Square peg, round hole Mechanical Isolation: Square peg, round hole – Gametic Isolation: Gamete recognition doesn’t Gametic Isolation: Gamete recognition doesn’t match match
- 3. Reproductive Isolation (cont.) ReproductiveIsolation (cont.) Postzygotic Barriers: Postzygotic Barriers: – Reduced Hybrid Viability: Embryo may abort Reduced Hybrid Viability: Embryo may abort due to genetic incompatibility due to genetic incompatibility – Reduced Hybrid Fertility: Hybrid can not Reduced Hybrid Fertility: Hybrid can not backbreed due to sterility backbreed due to sterility – Hybrid Breakdown: May produce one Hybrid Breakdown: May produce one generation of viable and fertile offspring, but generation of viable and fertile offspring, but future generations are not future generations are not
- 4. Classifying a Species Classifyinga Species Biological Species: emphasizes Biological Species: emphasizes reproductive isolation reproductive isolation Ecological Species: Species defined by Ecological Species: Species defined by ecological niche ecological niche Pluralistic Species: Reproductive or niche Pluralistic Species: Reproductive or niche Morphological Species: Unique set of Morphological Species: Unique set of structural features structural features Geneological Species: Unique genetic Geneological Species: Unique genetic history history
- 5. Allopatric Speciation Allopatric Speciation Conditions Conditions –Separated by a geographical feature Separated by a geographical feature – Changes must prevent interbreeding Changes must prevent interbreeding Ring Species Ring Species – California Salamanders more distant to the California Salamanders more distant to the south south Adaptive Radiation Adaptive Radiation – Diversely adapted species from common Diversely adapted species from common ancestor ancestor
- 6. Evolution of ReproductiveBarriers Evolution of Reproductive Barriers Prezygotic: Prezygotic: – Two populations of Two populations of D. melanogaster D. melanogaster – Starch vs. Maltose for generations Starch vs. Maltose for generations – Maltose females only breed with maltose males Maltose females only breed with maltose males
- 7. Sympatric Speciation Sympatric Speciation PolyploidSpeciation in Plants Polyploid Speciation in Plants – 2n 2n 4n 4n – 4n can self pollinate or mate with other 4n 4n can self pollinate or mate with other 4n – Oats, cotton, potatoes, tabacco, wheat Oats, cotton, potatoes, tabacco, wheat Sympatric Speciation in Animals Sympatric Speciation in Animals – Pundamilia pundamilia Pundamilia pundamilia vs. vs. Pundamilia Pundamilia nyererei nyererei – Normal light vs. monochromatic orange Normal light vs. monochromatic orange
- 8. Evolutionary Time Evolutionary Time “ “Althougheach species must have passed Although each species must have passed through numerous transitional stages, it is through numerous transitional stages, it is probable that the periods during which probable that the periods during which each underwent modification, though each underwent modification, though many and long as measured by years, many and long as measured by years, have been short in comparison with the have been short in comparison with the periods during which each remained in an periods during which each remained in an unchanged condition.” unchanged condition.” -Charles Darwin -Charles Darwin
- 9. Punctuated Equilibrium Punctuated Equilibrium Evolutionoccurs so rapidly that there is no fossil Evolution occurs so rapidly that there is no fossil record record
- 10. Eye Development Eye Development PigmentedCells Pigmented Cells Eyecup Eyecup Pinhole camera-type Pinhole camera-type Eye w/ Primitive lens Eye w/ Primitive lens Complex Camera- Complex Camera- type type
- 11. Exaptations Exaptations Develop for onepurpose, but later end up Develop for one purpose, but later end up serving another serving another Birds Birds – Honeycombed bones Honeycombed bones Original: light for agility Original: light for agility Present: light for flight Present: light for flight – Feathers Feathers Original: Display for mating Original: Display for mating Present: flight Present: flight
- 12. Evo - Devo Evo- Devo Allometric Growth: Growth rates create Allometric Growth: Growth rates create proportioning for each species proportioning for each species – Heterochrony: Evolutionary change in rate or Heterochrony: Evolutionary change in rate or timing of developmental events timing of developmental events – Paedomorphosis: Rate of reproductive Paedomorphosis: Rate of reproductive development accelerates compared to development accelerates compared to somatic somatic – Homeotic genes: Determine placement and Homeotic genes: Determine placement and spatial organization of body parts spatial organization of body parts Hox genes Hox genes
- 13. Evolutionary Trends Evolutionary Trends Evolutionis not goal oriented Evolution is not goal oriented Horse Evolution Horse Evolution – Equus Equus is only surviving genus of the tree is only surviving genus of the tree – Not all adaptive radiations lead to same result Not all adaptive radiations lead to same result Parahippus: Parahippus: Grazers Grazers Miohippus: Miohippus: Browsers Browsers Species Selection: Species that endure Species Selection: Species that endure the longest and reproduce the most set the longest and reproduce the most set the trend for macroevolution the trend for macroevolution
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