Natural Selection and Variation

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Across
  1. 1. Darwin and Alfred ______ proposed similar theories
  2. 6. One of Darwin’s four observations states that more offspring are produced than survive to ______.
  3. 8. The name given to mutations that cause death
  4. 9. This type of natural selection occurs when the environment does not change.
  5. 11. What animal is used to explain Lamarck’s theory?
  6. 15. A species is defined as a group of interbreeding populations that are ______ isolated from other groups.
  7. 17. Lamarck proposed that ______ characteristics were inherited.
  8. 18. Reproductive isolation is a form of ______ isolation.
  9. 20. The development of a new species.
  10. 23. One of Darwin’s four observations detailed that individuals within a species differ from each other.
  11. 26. This type of mutation will not be passed on to offspring.
  12. 27. Charles ______ first proposed natural selection.
Down
  1. 2. One of Darwin’s four observations states that populations are fairly ______ in size.
  2. 3. Survival of the ______.
  3. 4. Genetic ______ brings together new combinations of genes
  4. 5. This isolation occurs when a population becomes divided by a physical barrier such as water, mountains, desert, etc.
  5. 7. Variation is the differences in ______ of genes.
  6. 10. This type of mutation is the only type that will contribute to large scale evolution (_____ - _____).
  7. 12. Gene _____ is the movement of genes from one population to another.
  8. 13. This type of natural selection occurs when selective pressures favour the two extremes of a characteristic.
  9. 14. Another name for geographical isolation is ______ speciation.
  10. 16. This type of natural selection occurs when the environment changes.
  11. 19. This causes variation. It can be harmful, beneficial or neutral.
  12. 20. Another name for reproductive isolation is ______ speciation.
  13. 21. Struggle for ______.
  14. 22. One of Darwin’s four observations stated that characteristics are ______.
  15. 24. ______ Selection.
  16. 25. Book title – 'On the Origin of ______ by means of natural selection, or the preservation of favoured races in the struggle for life'.