1 / 13

Theories and Patterns of Evolution: Understanding Biological Change

Explore theories like Lamarck's and Darwin's, learn about natural and artificial selection, and understand adaptation and patterns like coevolution, convergent, and divergent evolution. Discover how organisms evolve and adapt over time.

odakota
Download Presentation

Theories and Patterns of Evolution: Understanding Biological Change

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Theories and Patterns of Evolution Chapter 15

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

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

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

  5. Modern Evolutionary Thought • Natural Selection: organisms best suited to their environments will reproduce more successfully • 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” • 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 • The pattern & speed with which organisms adapt is dependent upon their environment • 3 Patterns: • 1) Coevolution • 2) Convergent Evolution • 3) Divergent Evolution

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

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

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

More Related