Unit 9 Natural Selection

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Across
  1. 7. - geologic theory stating that the earth's surface is broken into several huge plates that move slowly on a partially molten rock layer
  2. 9. ____Dating - method used to determine the age of rocks using the rate of decay of radioactive isotopes
  3. 11. - when a species has evolved morphological adaptations that allow them to blend in with their environments.
  4. 12. ____Generation - the mistaken idea that life arises from nonliving sources
  5. 14. ____structures - structures that are reduced forms of functional structures in other organisms.
  6. 16. ____structure - anatomically similar structures inherited from a common ancestor.
  7. 17. - defines cumulative changes in groups of organisms through time.
  8. 18. - a type of morphological adaptation where one species evolves to resemble another species .
  9. 19. ____selection - given enough time a population might breed into a new species.
Down
  1. 1. ____Dating - method of determining the age of a rocks by comparing the rocks with younger and older rock layers
  2. 2. ____selection - selective breeding by humans.
  3. 3. - the study of the distribution of plants and animals around the world.
  4. 4. - amount of time required for half of a radioactive isotope to decay
  5. 5. - preserved evidence of an organism, often found in sedimentary rock, that provides evidence of past life
  6. 6. - a measure of the relative contribution an individual trait makes to the next generation.
  7. 8. ____Time Scale - model showing major geological and biological events in Earth's history; time scale established by geologists that reflects a consistent sequence of historical periods, grouped into four eras: Precambrian, Paleozoic, Mesozoic, and Cenozoic.
  8. 10. ____structure - can be used for the same purpose and can be superficially similar in construction, but are not inherited from a common ancestor.
  9. 13. - inherited characteristic of a species that develops over time in response to an environmental factor, increases an organism's chance of survival
  10. 15. ____Theory - explains that eukaryotic cells may have evolved from prokaryotic cells