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EVOLUTION and DIVERSITY • • • A process of change over time Existing Genetic diversity – • Evidence Geologic fossil record shows - The fossil record indicates similarity – • Comparative anatomy- Examples: Forelegs of frogs, horses, arms of humans, flippers of a whale, wings of bats and birds- • Comparative Cytology• Comparative Embryology • …EX. Humans still have gill slits, indicating the ancestor may be sea-like • Comparative Biochemistry- EX. hemoglobin in animals and chlorophyll in plants are similar DARWIN • Natural Selection- - • Only the organisms that can • Characteristics, • The population will change - Conditions for Evolution • Overproduction• Competition• New Traits will arise in a species as a result of variation (unique traits from parents• Selection by environment- organisms with adaptive values will have an advantage and will survive and reproduce… • The changing environment is the - Evolutionary Patterns • Changes in species are related to environment • Species with short repro cycles and many offspring will evolve quickly • Failure to adapt may lead to extinction • Rate of Evolution – gradualism (most), punctuated equilibrium (few- rapid changes) Example: Bacteria and its resistance to antibiotic- resistant bacteria will survive and reproduce Example: Insects become resistant to DDT, pesticide…and reproduce • Geographic Isolation- a species is separated by a barrier (mts, water) different environments select for different traits until the species is unable to interbreed….new species arise…Example: Darwin’s Finches in the Galapagos Islands • Variation in genes lead to new species this is due to Mutations (most are harmful, but few are beneficial to a species) and Genetic Shuffling (a result of crossing over, sexual repro) Results of Genetic Variation • Structural change-changes in bones, skin and limbs • Functional Change- changes in enzymes and proteins • Behavioral Change- changes in mating, thinking • Extinction- disappearance of entire species, usually due to environmental change and failure to adapt (65% of all species that have lived on earth have gone extinct!!!)
