biology crossword

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Across
  1. 4. a biome of or pertaining to land as in terrestrial ecosystem
  2. 6. the first species to populate an area
  3. 11. reestablisment of a damaged ecosystem in an area were the soil was left intact
  4. 13. a gradual increase in average global temperature
  5. 15. symbiotic association between a fungus and a photosynthetic organism
  6. 17. permanently dark layer of the oceans
  7. 19. release of harmul materials into the enviroment
  8. 20. a biome that occurs in water
  9. 21. a species has an unusually large effect on its ecosystem
Down
  1. 1. a zone of the ocean were light penetration is high
  2. 2. the tidal mouth of a large river
  3. 3. no two species can occupy the same niche in the same habitat
  4. 5. succession that occurs on surfaces were no soil exists
  5. 7. a group of ecosystems that share similar climates and organisms
  6. 8. an opening in the sea floor out of which heated mineral-rich water flows
  7. 9. a stable community that no longer goes through major ecoogical changes
  8. 10. destruction of forests
  9. 12. the variety of life in the world or in a particular habitat
  10. 14. plants and animals that have migrated to places there not native
  11. 16. too many people in an area
  12. 18. a system of interlocking and independent food chains