archaeologist william sanders. i think all human societies are the product of a process of cultural evolution. in general, this evolution leads to an increase in the size of societies, an increase in the complexity of their interaction and institutions. it also leads to more economic interdependence among households within a society, and among societies. keach: to trace the evolution of human societies in the new world, an archaeological team comes here to mexico's tehuacan valley. the team is led by veteran archaeologist scotty macneish. they are seeking evidence of the first inhabitants of the valley. when macneish first excavated here in 1962, he discovered a time capsule of human occupation at a site called purron cave. macneish: here we are back at purron cave. we really haven't dug in it in almost 30 years. walls all preserved. even the trowel marks we made to mark off strata are still preserved and we have all sorts of neat floors of charcoal one on top of the other. the amazing thing about this cave is that

keach: archaeologist william sanders has been leading excavations in the copan valley since 1980.e decided to do a series of large-scale excavations out in the countryside to get an idea what the farming population was like. what kind of houses did they live in ? what was their lifestyle like ? probably 80% of the population of copan was in that social category. keach: unlike ceren, the ancient houses of copan had been exposed to centuries of erosion. very few artifacts remained intact or in their original location. still the team finds significant clues. in one structure, the team discovers a razed platform of stone, the remnants of a sleeping bench. in another, they find evidence for a kitchen -- shattered obsidian blades that once were knives and broken pieces of pottery that were once used for cooking. the layout of ancient maya houses is quite different from our own. the maya constructed separate buildings for sleeping, cooking and storing food. they organized these buildings around patios. after two seasons of work up here, what can we say ? we have almost fully excavated a

archaeologist william sanders. the economy of any given human group, any culture, is a powerful factor that affects the rest of that culture -- the social organization, the political institutions, even the ideology, the religion of a people. from my perspective, the economy of a group is one of the most powerful determinants of human behavior. keach: to archaeologists, all economies fall somewhere on a spectrum from simple to complex. in a simple economy, people grow or gather all the food they eat. they make all the things they use. households in such simple economies are almost completely self-sufficient. at the other end of the spectrum are highly complex economies in which people specialize in one particular job, like these shoe salesmen in morocco. specialization means people are no longer self-sufficient, but depend on each other. the shoe salesmen are dependent on the shoemakers, and the shoemakers are dependent on the tanners, and so on. this dependence on others makes society in general more complex, so sp

that in a moment with senator bernie sanders and the weather channel's bryan norcross, but first let's get you the latest on what's happening on the ground. ian williams is in manila for us today. how are the rescue and relief efforts going? >> reporter: well, they're getting under way and of course the u.s. are making their effort as well, getting marines in there typhoon's normally go. this is down in the center. that's unusual. last year there was one even farther south which is unusual which is also category 5. so this trend towards having these strong winds to the south, is that a symbol or signal of something changing in the climate or is just mother nature, we don't know at this point. >> obviously when you look over the last 10, 20 years there has been an increase in extreme weather. massive flooding in colorado, hurricane sandy last year, the hurricane in haiti, of course hurricane katrina in 2005. what is the latest thinking in the science community on the global change connection? >> well, you have a couple of different things there. in terms of these tropical systems, hurricanes and typhoons. they're exactly the same system, just different

sanders could not haul it in. incomplete. that's all she wrote. baltimore winning a mail bitter. ravens improved 6 and 6. in dallas the cowboys having issues against the raiders. terence williams. you have to be kidding me. tosses the piggy. raiders jumped out to 7-0. buckle up. rashad jennings runs into the camera man. he's okay. the cowboys down by 14 points, but tony romeo and company - they anyhow up. tying it up for 21. the cowboys playing smash-mouth football. demarco murray powering in. how about them cowboys. they go on to win 31-24. >> obviously when you fumble the opening kick off and they return for a touch down it's not good. i thought our team tried to respond. it was important after the win to come back and put a couple together. i was proud of the guys and their ability to concentrate in a tough situation, being where we were. teens can go one of two ways. i was proud of the guys. >> the packers haven't won a game. lions gave it away. burnett scooped up the mack and cheese. packers out to a 10-3 lead. the lions got their boogie on. jeremy ross, detroit tying it up at 10. matt stafford finding his favourite target, finding the big fellow. megatron taking it 20 ya