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Evolution

Evolution. Evolution- the gradual accumulation of adaptations over time; a gradual change over time. Adaptation- evolution of a structure, behavior , or internal process that enables an organism to respond to stimuli and better survive in an environment. Fossils.

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Evolution

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  1. Evolution

  2. Evolution- the gradual accumulation of adaptations over time; a gradual change over time

  3. Adaptation- evolution of a structure, behavior , or internal process that enables an organism to respond to stimuli and better survive in an environment

  4. Fossils • Age of earth- estimated 4.6 billion years old • Fossil- physical evidence of an organism that lived long ago that scientist use to study the past; evidence may be in rocks, amber, or ice

  5. Paleontologist- scientist who study ancient life. They are like detectives who use fossils to understand events that happened long ago.

  6. Fossil record- name given to the history of life on earth as shown by fossils

  7. Why is fossil record incomplete- not all fossils have been found, and not all organisms have been preserved

  8. Sedimentary rock- small particles of mud, sand or clay that is compressed over time and hardened

  9. How are fossils formed? Most fossils are formed in sedimentary rock from being buried in the mud, sand, or clay before it hardens

  10. Relative dating- scientist determine the order of appearance and extinction of species that formed fossils in the layers. Layers at the surface must be younger than the deeper layers

  11. Radioactive dating- AKA radiometric dating and carbon dating- utilizes radioactive isotopes in rocks or fossils.

  12. Radioactive dating is more accurate

  13. What is half life? b/c every radioactive isotope has a characteristic decay rate, scientist use the rate of decay as a type of clock

  14. Extinction- when the last members of a species die

  15. Homology • Homologous structures- structures with common evolutionary origins, can be similar in arrangement, in function, or both; provides evidence of evolution of a common ancestor

  16. Examples- 4 limbs of a crocodile • Whales-flippers • Birds-wings

  17. Embryology- study of embryos which is the earliest stage of growth and development of both plants and animals; differences and similarities among embryos can provide evidence of evolution

  18. Example.. Can’t tell the embryo of a fish, bird, or mammal apart. They all have gill slits, tail, and notochord. Fish are the only ones who keep them throughout life.

  19. Biochemical similarities (genetic)- provides evidence for evolution- All organisms have the same DNA and RNA

  20. Vestigial structures- body structure that has no function in a present day organism but was probably useful to an ancestor long ago • Appendix

  21. Analogous structures- structures that do not have a common evolutionary origin but are similar in function

  22. Example- a bird wing and a butterfly wing, both are used for flying; however, they are the same structure.

  23. Natural Selection- mechanism for change in populations; occurs when organisms with certain variations survive, reproduce, and pass their variations to the next generation; can be directional , disruptive, or stabilizing

  24. Charles Darwin- father of evolutionary theory. Proposed the theory of natural selection.

  25. Another name for natural selection- survival of the fittest

  26. Peppered moth- H.B. Kettlewell studied camouflage adaptations of a population of light and dark colored peppered moths. The moths rested on the trunks of trees.

  27. Camouflage- enables species to blend with their surroundings • Ex- peppered moth , snake you do not see

  28. Mimicry- a structural adaptation that enables one species to resemble another species • Ex- butterfly that looks like a wasp

  29. Fittest- how suitable the gene is in the environment for a particular population • Niche- role and position a species has in its environment

  30. Genetic drift-alteration of allelic frequencies in a population by chance events, result in genetic equilibrium

  31. Speciation- process of evolution of new species that occurs when members of a similar populations no longer interbreed to produce fertile offspring

  32. Divergent evolution- evolution in which species that once were similar to ancestral species diverge; occurs when populations adapt to different environmental conditions,

  33. Adaptive radiation- divergent evolution in which an ancestral species evolve into an array of species to fit a number of diverse habitats

  34. Convergent evolution- evolution in which distantly related organisms evolve similar traits, occurs when unrelated species occupy similar environments

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