Reading Review

For homework we had to read chapter six of Survival of the Sickest.  This chapter talked about genes and how they develop and change over time.  The first idea that was brought up in this chapter was the old theory of evolution that has been disproved with more recent evidence.  Originally it was thought that DNA changed randomly and mutations were sporadic and extremely rare.  This could not be true though because it could not explain how far humans have changed in a relatively short amount of time.  Knowing that mutations must be intentional geneticists realized that mutation can be caused by virus', bacteria and radiation.  DNA can change when needed based on these outside sources and other genetic factors.  These other factors are things like genetic jumping, where genes can cut and paste elsewhere or copy and show up in another area.  This is where natural selection comes in.  Genes that vary in a beneficial way are passed on because the population will want that gene.  The opposite is true for harmful genes, they will eventually be eradicated from a population if they are not helpful to have.  Genes in everything are ever changing and they always will in any species that survives for multiple generations.