BILD 3 Lecture Notes - Lecture 4: Mexican Tetra, Vestigiality, Bt Cotton
Document Summary
Vestigial organs: functionless or rudimentary organ in one species that has important function in other species. 2. (a) mexican tetra (b) blind cave tetra: vestigial eyes in cave dwelling vertebrates, bottom: blind cave salamander with vestigial eye. Homology: similarity due to inheritance of traits from a common ancestor. Molecular homology: genetic engineering of crop plants: bacteria (bacillus thuringiensis) produces a toxin that is lethal to caterpillars that eat cotton (e. g. , cotton bollworm, bacterial genes that encode for the toxin can be inserted into crop plants - Bt cotton expresses toxin, kills pests: grown on millions acres worldwide, all because bacteria and plants share common ancestor, use the same genetic code (molecular homology), so can be inserted into crops. Are bird and insect wings a structural homology: no they are analogous structures, the structures are similar, but they did not evolve from a common ancestor, the ability to fly has evolved independently, example: birds, bats, insects.
