Class 18

      Today we finished the movie "Journey of Man" and our worksheets. We learned about the importance of the Y chromosome as it is the best place to look for a genetic marker because it does not get recorded every time like the X chromosome, instead it gets passed down unchanged through generations. The narrator goes to an isolated village with indigenous people that have not had outside encounters so he could find the genetic marker. We learned that Africa had a drought were animals and resources were scarce so they migrated. The environment of different places changed the human race to either be lighter or darker complected. We learned that the first Americans arrived on the continent 13,000 to 11,000 years ago.