In addition to founder effects, the new population is often a very small population and so shows increased sensitivity to genetic drift, an increase in inbreeding, and relatively low genetic variation.
The short answer for how long does it take to become a lawyer is that in the United States it takes a minimum of three years. In order to practice law anywhere in the western world, one must pass an examination in the geographic jurisdiction that the proposed lawyer wants to practice law.
Four-Year Degree. To get on track to becoming a criminal defense lawyer, you must obtain a four-year degree from an accredited four-year institution. While pursuing your undergraduate degree, you don't need to take any particular course of study.