One of the most important principles of biology is the main idea of ​​evolution. This theory states that “all living organisms evolved from a common ancestor through natural selection acting on hereditary variations” (Reece, 2011). Today, many people know that humans evolved from a common ancestor; but they do not recognize its importance. Everyone should be informed about how organisms evolved, because humans have evolved over many centuries. Charles Darwin had many theories that incorporated fundamental principles of biology, natural selection, and evolution. Darwin explained natural selection as an evolutionary change in which organisms that adapt better to their environment will survive better than those that do not (Natural, 2004). Through evolution and natural selection, many species, including humans, are present today. Charles Darwin founded the principle of natural selection, which describes how organisms that adapt better to an environment will survive better and produce more offspring (Natural, 2004). Darwin first noticed evolution after being on the Galapagos Islands; here he noticed that geological separation played an important role in how organisms adapted and formed new species (College, 2009). When species live in a new environment, they adapt differently and eventually change over time, which is called evolution (College, 2009). Darwin noticed that birds from another Galapagos island also have similarities and differences. He believed that these birds once belonged to the same species, but due to evolution they became different species. He noted that "different species exhibit different beak morphologies (size and shape) that are well adapted to exploiting different food resources...... middle of article ......7040903504823McCullough, ME , & Pedersen, EJ (2013). The evolution of generosity: how natural selection creates mechanisms to provide benefits. Social Research, 80(2), 387-410. Milot, E. and Pelletier, F. (2013). Human evolution: new playing fields for natural selection. Current biology, (10), doi:10.1016/j.cub.2013.04.040 Natural selection: how evolution works. (2004). Actionbioscience. Accessed February 26, 2014 from http://www.actionbioscience.org/evolution/fNatural Selection: How Evolution Works. (nd). Actionbioscience. Accessed March 16, 2014 from http://www.actionbioscience.org/evolution/fuNatural Selection. (nd). Evolution 101: How It Works. Retrieved February 26, 2014 from http://evolution.berkeley.edu/evosite/evo101/IIReece, JB and Campbell, NA (2011). Campbell biology Jane B. Reece... [et al.]. (9th ed.). Boston: Benjamin Cummings.