TheJourney of Man describes a 'time machine' we can use to trace our heritage. This time machine is the genetics in our blood. We all have genetic markers or mutations or inherited mutations, which is like a "badge of descent." The Y chromosome is the best place to look for genetic markers becuase it does not get chopped off every generation and it remains the same when passed from father to son.

Our first ancestors were traced from Africa, the tribe of the first ancestors of mankind being the Sanbushmen or the 'San.' The San had significant hunting advantages over their competition for the following reasons: they all communicated in a common language, they quickly advanced in weapon making (they used bone instead of stone for arrow tips) and they had hunting strategies (following animal footprints in order to catch them).

The next place our ancestors showed up were in caves. However, they suddenly disappeared. Scientists hypothesize that there was a temperature change which caused a sever drought, forcing the cavemen to leave their caves (which were once by the coast) to an area closer to the sea.

We can also trace our ancestors to Australia, where there is evidence that shows that people lived at a lake called Lake Mungo 40,000 years ago. There are fire place stains with remains of fishbones as well as remains which date about 40-45,000 years old. We know that the Africans were ancestors of the Aborigines (oldest Australian tribe) and not the other way around because genetic markers prove so.

Why would some of our ancestors leave Africa in the middle of an ice age? This is because the Ice Age blocked moisture from North Pole Caps, turning Africa into a landmass of mostly desert, so people (who were smart enough to move) moved.

Why do some populations have lighter skin than others? And why do some have darker skin? Isolation by geography (living by the sea as compared to by the mountain) plays a part in their skin tone. People by hotter areas, where sunlight and UV rays are abundant have darker skin because they dark skin indicates that they have more melanin (natural sunscreen) in their bodies. Pale skin helps absorb more light for people who live in colder areas. Clothes also played a part in skin tone, because wearing clothes means less skin being exposed to the sun.

The Chuchki's are Nomadic tribes which survived the rock-bottom ice age. Bergmann's and Allen's rules apply to the evolution of the Chuchki's because they suggested that surface area and appendiges are reduced to retain heat by avoiding heat loss (since the Chuchki's lived in an extremely cold climate).

Rachel Putri Utomo
Block F, Honors Biology
Mr. Kevin Quick
Academic Year 2013-2014