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Lecture 4
- 1. Evolution Makes Sense of Homologies 1
- 2. Evolution Makes Sense of Homologies The “Universal” Genetic Code 2
- 3. Evolution Makes Sense of Homologies The tetrapod limb 3
- 4. Evolution Makes Sense of Homologies The tetrapod limb 3
- 5. 4 Evolution Makes Sense of Homologies New Functions Evolve from Pre-existing Structures http://www.entomology.umn.edu/museum/links/coursefiles/ JPEG%20images/Hymenoptera%20web%20jpeg/Siricidae.jpg Stinger http://www.sphoto.com/photo.php?photo=781&u=12%7C21%7C...
- 6. Evolution Makes Sense of Homologies Vestiges http://www.ups.edu/Images/ SlaterMuseum/WhaleInstall068Large.jpg 5
- 7. Evolution Makes Sense of Homologies Vestiges http://www.ups.edu/Images/ SlaterMuseum/WhaleInstall068Large.jpg 5
- 8. Evolution Makes Sense of Homologies Vestiges http://www.ups.edu/Images/ SlaterMuseum/WhaleInstall068Large.jpg 5
- 14. Homologies are Nested Nested homologies
- 15. Homologies are Nested Nested homologies
- 16. Homologies are Nested Nested homologies
- 17. Homologies are Nested Nested homologies
- 18. Homologies are Nested Nested homologies
- 19. Homologies are Nested Nested homologies
- 20. Homologies are Nested Non-nested homologies Nested homologies
- 21. Homologies are Nested Non-nested homologies Nested homologies Time
- 22. Homologies are Nested Non-nested homologies Nested homologies Time
- 23. Homologies are Nested Non-nested homologies Nested homologies Time
- 24. Homologies are Nested Non-nested homologies Nested homologies Time
- 25. Homologies are Nested 7 Plant phylogeny Asa Gray, c. 1860
- 26. Homologies are Nested 7 Plant phylogeny Non-flowering plants Flowering plants Asa Gray, c. 1860
- 27. Homologies are Nested 7 Plant phylogeny Non-flowering plants Monocots Dicots Gymnosperms Flowering plants Asa Gray, c. 1860
- 28. Homologies are Nested 7 Plant phylogeny Non-flowering plants Moss Algae Ferns Monocots Dicots Gymnosperms Flowering plants Asa Gray, c. 1860
- 29. Homologies are Nested 7 Plant phylogeny Non-flowering plants Moss Algae Ferns Monocots haw Dicots et al., 2000 Gymnosperms Flowering plants Asa Gray, c. 1860
- 30. Homologies are Nested Primate phylogeny Human Chimp Orangutan Gibbon
- 31. Homologies are Nested Primate phylogeny Human Chimp Orangutan Gibbon
- 32. Homologies are Nested Primate phylogeny Human Chimp Orangutan Gibbon
- 33. Homologies are Nested Primate phylogeny Human Chimp Orangutan Gibbon
- 34. Homologies are Nested Primate phylogeny Human Chimp Orangutan Gibbon
- 35. Homologies are Nested Primate phylogeny mitochondrial DNA testis-specific Human Chimp protein Orangutan Gibbon ß-globin
- 36. Homologies are Nested Primate phylogeny mitochondrial DNA testis-specific Human Chimp protein Orangutan Gibbon ß-globin
- 37. Homologies are Nested Primate phylogeny mitochondrial DNA testis-specific Human Chimp protein Orangutan Gibbon ß-globin
- 38. Homologies are Nested Primate phylogeny mitochondrial DNA testis-specific Human Chimp protein Orangutan Gibbon ß-globin
- 39. Homologies are Nested Multispecies interactions Currie CR, Wong B, Stuart AE, et al. Ancient tripartite coevolution in the attine ant-microbe symbiosis SCIENCE 299 (5605): 386-388 JAN 17 2003
- 40. Evidence for Evolution: the Fossil Record Trilobite Evolution
- 41. Evidence for Evolution: the Fossil Record Foraminiferan Evolution http://evolution.berkeley.edu/evosite/evo101/ VIIA1bPunctuated.shtml
Editor's Notes
- Homologies: structural similarities among organisms. (Richard Owen, 1848)
- Modern definitions:
- similarities between species that are shared because of common ancestry.
- Or: similarities that exist despite several alternatives that would do the job as well or better.
- Owen: similarities indicated that organisms were created following a common plan or archetype (e.g., design plans of a Honda Civic & a Honda Prelude might be similar).
- While this idea might explain many individual homologies, it runs into problems when we consider several PATTERNS OF HOMOLOGIES
- (e.g., why some organisms share so many similarities, while others share very few;
- existence of similarities with no functional basis: why would cave-dwelling fish have eyes that can’t see?
- Nearly every prokaryote & eukaryote on the planet shares the identical genetic code
- Exceptions include most mitochondria & a few nuclear genomes (Tetrahymena, Mycoplasma)
- But why should this be? There’s nothing particularly special about this genetic code – many of equally good alternatives exist.
- Example: the tRNAs that do the translation from nucleic acid to protein.
- No chemical reason to associate a given codon with a given amino acid – in fact, they’re as far apart as they can possibly be in the molecule.
- Evolution, via common descent, offers a simple explanation for the fact that we all share a genetic code:
- The common ancestor of all life had a genetic code similar to this one.
- Was passed on almost unchanged from generation to generation
- What would happen to an organism that had a mutation in the code itself?
- (MOSTLY) THRU THIS SLIDE, LECTURE 5 2007
- All eukaryotes & prokaryotes have similar structure to their plasma membranes: the phospholipid bilayer.
- (Hydrophilic group is glycerol phosphoric acid)
- This similarity, with no “design” reason to it, is easily explained if all organisms share a common ancestor who had this structure
- Again, once this structure was in place, fundamental changes to any of it would be disastrous
- Pentadactyl (five-fingered limb)
- All four-limbed (tetrapod) vertebrates have five-digit limbs at some point during development
- Birds start with five digits, then lose two during development
- If the bird doesn’t need five digits, why would five develop in the embryo, only to be lost?