Natural Selection and Variation

2. One of Darwin’s four observations states that more offspring are produced than survive to ______.
4. Gene _____ is the movement of genes from one population to another.
5. One of Darwin’s four observations stated that characteristics are ______.
7. Another name for reproductive isolation is ______ speciation.
8. Struggle for ______.
10. Reproductive isolation is a form of ______ isolation.
14. A species is defined as a group of interbreeding populations that are ______ isolated from other groups.
15. Darwin and Alfred ______ proposed similar theories
17. Lamarck proposed that ______ characteristics were inherited.
19. This type of natural selection occurs when selective pressures favour the two extremes of a characteristic.
21. What animal is used to explain Lamarck’s theory?
23. The name given to mutations that cause death
24. This causes variation. It can be harmful, beneficial or neutral.
27. Genetic ______ brings together new combinations of genes

1. One of Darwin’s four observations detailed that individuals within a species differ from each other.
3. One of Darwin’s four observations states that populations are fairly ______ in size.
6. This type of natural selection occurs when the environment changes.
9. This type of mutation is the only type that will contribute to large scale evolution (_____ - _____).
11. This isolation occurs when a population becomes divided by a physical barrier such as water, mountains, desert, etc.
12. This type of natural selection occurs when the environment does not change.
13. Another name for geographical isolation is ______ speciation.
16. Survival of the ______.
18. Charles ______ first proposed natural selection.
20. The development of a new species.
22. ______ Selection.
25. Variation is the differences in ______ of genes.
26. This type of mutation will not be passed on to offspring.
27. Book title – 'On the Origin of ______ by means of natural selection, or the preservation of favoured races in the struggle for life'.