1. THEORIES AND PATTERNS OF EVOLUTION Chapter 15

2. Theories of Evolution Biological Evolution: the change of populations of organisms over time NNew life forms are really modified versions of older ones in same geographic area 22 Explanations: Lamarck’s Darwin’s

3. Jean Baptiste Lamarck TThought acquired traits (learned, not inherited) could be passed to offspring NNot True!!

4. Charles Darwin Spent 5 years aboard H.M.S. Beagle traveling world & recording observations AAnimal adaptations and geographic changes required VERY LONG periods of time to occur

5. Modern Evolutionary Thought NNatural Selection: organisms best suited to their environments will reproduce more successfully OOver time, # organisms with favorable traits increases within a population Artificial Selection: Breeding organisms with specific traits to produce desired offspring

6. Modification by Natural Selection The Process:  1) Organisms better equipped to survive environment will produce more offspring  2) Eventually, popltn made up of only successful members  3) Over time, an entirely new species may form!!

7. Descent with Modification ““Newer forms appearing in fossil record are actually modified descendants of older species” IImplies that ALL species descended from only a few ancient organisms

8. Adaptation  Populations adapt as their # of favorable traits increases  The types of traits that are favorable depends on the environment  Examples: Mimicry: a harmless species resembles a dangerous one; both are avoided by predators Camouflage: enables species to blend with surroundings Penicillin-resistant bacteria, rose thorns, etc.  As genetic makeup of popltn changes, evolution occurs

9. CAMOUFLAGE MIMICRY

10. Patterns of Evolution TThe pattern & speed with which organisms adapt is dependent upon their environment 33 Patterns: 11) Coevolution 22) Convergent Evolution 33) Divergent Evolution

11. Coevolution CCoevolution: the change of 2 or more species in close association ii.e. predator/prey; parasite/host; plants/herbivores

12. Convergent Evolution CConvergent Evolution: occurs when environment selects phenotype RResults in similar phenotypes of different organisms ii.e.: body shape of dolphin (mammal) & shark (fish)

13. Divergent Evolution DDivergent Evolution: when 2 related species become more dissimilar AAdaptive Radiation: when different species evolve from common ancestor ii.e.: Galapagos finches