Science 10 Chapter 1 Page 8 to 45 Page 2

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Across
  1. 5. Extinction theories involve ? crashing into Earth. A collision would raise tremendous amounts of dust, blocking light from the Sun and set off many volcanoes, quickly altering environmental conditions.
  2. 9. One hypothesis links ? global temperatures with the increased use of fossil fuels such as coal, oil and gasoline.
  3. 10. Any species that is t risk because of low or declining numbers at the fringe of its range or in some restricted area is called ?.
  4. 12. The thin skin of the frog is also susceptible to ? radiation. This invisible radiation from the Sun causes sunburns, but it has also been linked with more serious cell damage.
  5. 14. High levels of ? caused eggshells of the bald eagle and some other birds, such as the double-crested cormorant and the herring gull, to become unusually thin.
  6. 15. ? also affects frogs' ability to reproduce. Researchers have noted that if the water is even slightly acidic, it reduces the mobility of frog sperm cells.
  7. 16. Any species that is likely to become endangered if factors that make it vulnerable are not reversed is called ?.
  8. 19. ? extinction rates are increasing dramatically as the human population grows.
  9. 20. Over the long term hundreds of millions of years, all species eventually encounter conditions to which they cannot ? and they become extinct.
  10. 22. ? also have a delicate skin and are affected by the increase in UV rays.
  11. 23. In the early years of the 21st century, the projection is that one species will become extinct every 30 ?.
Down
  1. 1. A species that is no longer found anywhere is called ?.
  2. 2. A species that is better at finding ?, reproducing, or defending its territory could force competing species into extinction.
  3. 3. ? changes and the pressure of competition from other species force organisms to adapt or die.
  4. 4. A species that is close to extinction in all parts of Canada or in a significantly large location is called ?.
  5. 6. Climate changes can cause important changes in local ?.
  6. 7. The amount of UV radiation reaching the Earth's surface is increasing because of damage to the protective ? layer surrounding our planet.
  7. 8. Humans, a recent addition to the planet, have had a profound effect on other ?.
  8. 11. Any species that no longer exists in one part of Canada, but can be found in others is called ?.
  9. 13. In modern times, however, human ? are the major causes of extinction.
  10. 17. Frogs at higher ?, where the problem of UV is greater, seem to be the ones that are most endangered.
  11. 18. Even if mating is successful, ? affects the frog's development.
  12. 21. In Canada there are more than 250 species of ? and animals at various degrees of risk.