7. "Selection Strength" refers to the amount of pressure the environment puts on an organism to change. It is measured in the survival rates of those organisms that have (or do not have) a particular trait. The greater the strength of selection, the faster evolution will occur. How could biologists in a controlled environment increase the speed of evolution in the stickleback fish. Explain your answer.

1. emigration the movement of people from one place to another 2. immigration a situation in which resources are being used up at a faster rate than they can be replenished 3. migration the leaving of one's homeland to settle in a new place 4. overpopulation the movement of people to a new country 5. sustainable development a situation in which the birth rate is not sufficient to replace the existing population 6. underpopulation the ability to meet current needs without reducing the ability to meet future needs 7. unsustainable development the increase in the population of a city 8. urbanization a situation in which the number of people exceeds the available natural resources in an area

Which two criteria must be met before scientist can use radiocarbon dating? explain your answer

18. over time, how do sand dunes tend to migrate? a. perpendicular to the movement of the wind b. in the same direction as the wind blows c. toward the wind d. in random directions