our first lecture is Introduction to archeology in today's lecture we'll first talk about concepts of time followed by the fundamentals of archeology and the analysis of archaeological material so concepts of time the universe was formed somewhere between 10 and 15 billion years ago during the Big Bang this cosmic explosion set off a course of events that created the universe we know today for example as gases coagulate they were compacted by gravity to form the first star earth was formed as part of this process approximately 4. 6 billion years ago the first life on Earth emerged about 4 billion years ago because it's so difficult to think about time in terms of billions of years here's a timeline of the emergence of life on Earth where one day represents 650 million years an hour represents 25 million years a minute is 400 000 years and a single second is over 6 000 years if we imagine that the earth was formed at 1201 am on Sunday the first molecules were formed by Sunday night by Monday morning bacteria like organisms evolved these bacteria and later algae multiplied and used photosynthesis to begin converting the primordial atmosphere to one um to one that was made of oxygen and this happened on Tuesday by the end of the day on Tuesday the first cells had evolved these cells did not contain genetic material until the early hours of Thursday morning late Friday morning the first invertebrate like jellyfish and worms evolved on the seventh day fish evolved in the morning the amphibians moved to land by 11 am and we're joined by insects swamps and forests dinosaurs evolved around 3 pm the ancestors of mammals evolved around 9 30 pm and at 10 53 PM the first primates began to live in the forests of Africa it wasn't until 11 48 PM that the first hominins were humans human relatives evolved and many of the cultural things that we closely associate with humans like art agriculture domestication of animals and Industry that only occurred in the last five seconds so it's really this last two minutes and especially that last five seconds that archaeologists are primarily interested in so one of the key defining things about archaeologists is that we study people in the things that people leave behind we don't study dinosaurs so as you can see here dinosaurs are they lived and died many many many years millions of years before humans evolved geological time periods um so because geologists study the entire history of the earth they use different time periods than archaeologists do to represent major evolutionary episodes in the entire development creation and existence of the Earth it's the first time period it's the Precambrian era this is the origin of the earth so from The Big Bang to 600 million years ago and you can see here that Mya stands for million years ago the next period is the Paleozoic Era the Paleozoic Era includes the period from 6 000 to 200 and 40 million years ago sorry that's 600. to 65 million years ago um during this time period there was the evolution of the first vertebrae species like fish and the first amphibians in this era plants also move from the sea onto the land in association with the first reptiles the next major time period is the Mesozoic Era the Mesozoic Era lasts from 240 to 65 million years ago this time period is characterized by dinosaurs so again many many many many millions about millions of years ago is when the dinosaurs lived humans never lived on Earth at the same time as dinosaurs and then finally the last major period is the cenozoic era we're currently living during this era that begins 65 million years ago this air era is characterized by modern mammals birds and flowering plants so if we dive a little bit deeper into the cenozoic era we can see that it's characterized by seven eposhes or seven different time periods um and there are four of these that are really relevant and important to the evolution of humans the first is a myosin period from 25 to 5.
5 million years ago this is when the first human like ancestors so not humans but human-like ancestors emerged on the Earth the next time period is the pleistocene that's um oh sorry the next time period is the pliocene from 5. 5 to 2 million years ago during this period a number of varieties of hominins evolved so again these are human-like species but they're not modern humans and then in the pleistocene which is 2 million to 11 000 years ago this period was characterized by a series of major climatic fluctuations and includes what is frequently referred to as the Ice Age by the end of this period the completely modern humans have evolved so we evolved during this time period um and then finally the Holocene from 11 000 years ago to the present so we're currently living during the Holocene and it's during this period that we witnessed the origins of Agriculture urbanization the Industrial Age and the present archaeologists only deal with matters related to humans so we really only study the end of the pleistocene and the Holocene we do not study dinosaurs unfortunately um in terms of archaeological time periods we often refer to these um different types of the era to represent different episodes in human evolution and we talk about the Paleolithic the Neolithic the Bronze Age and the Iron Age and will um we'll talk about that more later in this lecture or later in the course the theory of natural selection was formulated by Charles Darwin and Alfred Russell Wallace in the mid-19th century the theory Builds on Thomas Mathis essay on the principle of population which was written in 1798. in this essay math is argues that humans that um that not all humans can survive famine war and disease long enough to reproduce building on this Darwin developed the concept of natural selection in his 1859 publication on the Origins of Species by means of natural selection natural selection refers to the increased offspring of those who survive and are able to reproduce while an ongoing exploration on the HMS Beagle Darwin noted that plants and animals had a great deal of variation and that individuals with certain advantageous characteristics were more likely to survive to reproduction and pass those traits on to their offspring this concept is referred to as the survival of the fittest this change can happen slowly and gradually as Darwin initially proposed but can also happen in Rapid spurts following long periods with little change in addition to biological change humans also experience change related to learn behaviors we call this type of change culture which is or which is the means of human adaptation based on experience learning and the use of tools and that's the definition of culture that's used in the textbook so for example to adapt to cold humans and animals could change biologically like woolly mammoths who grew more body hair to keep warm but humans could also use culture as a means to adapt so instead of growing you know bushy hair like woolly mammoths we created fires and we were able to use fire to keep us warm so culture allows us to adapt to changing situations without having to change our genetic makeup so that makes us a lot more Nimble and able to adapt fundamentals of archeology archeology is a study of the past using material remains archaeologists study past Behavior over the last several million years and across all continents other than Antarctica but who knows maybe maybe it's the ice sheets keep melting we'll be we'll be there soon but it seems unlikely that there were any humans living there archeology is one of the greatest mystery stories of all time unlike most detective stories and crimes the evidence for archaeologists is often broken incomplete and decomposed as such piecing together the remains of our ancestors to tell their stories can be very challenging and involves many techniques and methods like chemistry biology history geology zoology human biology stone tools human fossils Ceramics Classics computers and much more so who are archaeologists in the United States archaeologists the discovery of archaeological sites much of the information we use to understand past societies comes from artifacts and archaeological sites artifacts are the materials that individuals in the past made and used archaeological sites are the areas where these items accumulated on the landscape these are usually areas where people used to live or carry out certain activities by identifying and recording the sites and interpreting the artifacts archaeologists are able to learn about the past artifacts and sites are often discovered accidentally by farmers in their fields and individuals hiking if you find an archaeological site please please make sure to report it to a local historical Society a university or Museum don't touch it don't move anything because that's the evidence that archaeologists use to understand what the site was used for sites are so valuable because of this and because they provide a great deal of information to archaeologists that they can then share with local communities so that we can all understand human history better archaeological fieldwork includes survey and excavation surveys are used to locate artifacts and sites and excavation is used to expose buried materials at archaeological sites so here's a picture of myself actually from some excavations that we did in the former moat of Angkor Tom which is an archaeological site in Cambodia as you can see we were working in a moat and it rained so our trench ended up flooding but you can see all of the building blocks especially the one that I'm standing on those are all used over a thousand years ago to build a very very massive site in Cambodia so here's a picture of field work survey on the ground so these individuals are walking back and forth in this field and they're looking for archaeological materials do you see how they have um the person in front as a handful of red flags and whenever they see an archaeological uh features that could be a part of a building or an artifact or even just a brick that looks really old they'll put that flag down and then the other team members will come and record information about the artifact that was found um archaeological survey systematically searches landscapes for sites and artifacts this can be done using various methods from walking over the landscape to using remotely sensed data like aerial photography or lidar data field walking is the most basic method to do this teams walk systematically through the landscape on grid patterns in equal intervals when sites and artifacts are found archaeologists record their location so the geographic look coordinates of the site they also identify the site so they create an identification number site number and then artifact numbers for any artifacts that are noted any notable elements or observations about the feature in the surroundings are also recorded when artifacts are found they're sometimes collected and other times they are photographed and recorded but left on the landscape for future people to do more studies and understand more about the site so here actually um this is the type of work that I do I use remotely sends data to try and find archaeological sites so if you look closely at this picture can you see anything on the landscape Well turns out there's the temple there so I can look at the satellite imagery and I can see these patterns on the landscape there's a big horseshoe shaped moat that surrounds the temple and then to the right of that is a large Reservoir and even though there's no Temple there today and the reservoir isn't functioning today I can see that that exists on the landscape and then basically what we do is we record those locations and then I have an understanding of how many temples there were and that helps me understand how the city functioned and here's a picture of some individuals um that are Excavating so they're in an archaeological site and they're digging down into the Earth to see what they can find so archaeologists use the archaeological record to understand more about the past the archaeological record includes all the evidence that we assess like artifacts sites materials and their context their context is where the materials are found we use context to assume relationships between artifacts or sites so for example if two artifacts are found in the same layer or sediment we can assume that they are related in terms of time and the activity that they were used for the context is also important in terms of understanding the authenticity and significance of artifacts so the arrowheads that you collected with your grandparents growing up do you know exactly where you found them and what the context was like if not there are no use to archaeologists that's why it's so important to leave artifacts where you find them and notify Historical Society or a local archaeologist who can record all of the important information that allows us to better understand and gain information from those artifacts archaeologists also talk about this concept called primary versus secondary context uh primary context refer to artifacts that are found where they were initially left this is also called in situ it's an important term in situ um and in situ is Latin for in place objects that are no longer in their primary context because they have been moved either recently or hundreds of years ago but after they were initially deposited are said to be in secondary contacts these objects have been moved without proper documentation and excavation and all of the contextual information is forever lost so that's like the arrowheads that you collected with your grandparents so this is the part of the reason why looting is so bad for archeology and why archaeologists hate it so much the objects are removed from their location without the proper documentation and as a result archaeologists can determine their authenticity but we also can't learn about their context excavations are designed by archaeologists to answer specific questions like who lived here what did the people who lived here eat what types of activities occurred here how was society organized how did people live and socialize with their neighbors sites are chosen for many reasons but the choice can often be broken down into two categories research and Rescue rescue Salvage excavations are often done when archaeological sites are at danger of being destroyed from environmental processes or Construction in these cases excavation is done quickly to ensure that the information and data is preserved before the site is destroyed these types of excavations are the most common today and are often conducted by cultural resource management archaeologists who are employed by the government or construction companies to complete the excavations before the construction begins the other type are research excavations research excavations are often conducted by graduate students and professors at universities who have specific questions about the past that can be answered through excavation in these cases the choice to excavate a site is often made after survey when the archaeologist has a good idea of what they want to dig and how that will help answer specific questions the quality of the site to be excavated depends on how well preserved it is the preservation of a site is determined by how old it is if there has been much erosion and deposition and bioturbation bioturbation by the way is When Animals root and bury in an area and destroy the archaeological context the type of soil can also affect how well preserved the site is for example things like human remains and animal bones do not preserve very well in very acidic soils in contrast human remains preserve exceptionally well in cold and arid environments like the Iceman who is frozen in the glaciers in Northern Italy there are many different types of excavation one type is called test pits test pits are small areas that are excavated before large-scale excavations and are undertaken at a site these are usually one meter by one meter trenches that can give an archaeologist an idea of what is below the ground surface and how deep the archaeological deposits are this can give an archaeologist an idea of how much the site needs to be excavated to understand the research questions and what types of materials and stratigraphy to expect the location for test pits can be chosen randomly or they can be done in Grid patterns sometimes longer test pits are dug across the site to give an idea of the stratigraphy and context vertical excavations once the archaeologists have decided which areas to excavate they lay out trenches and begin digging archaeologists use the profile at the side of the trench to help map and record the stratigraphy of the trenches the stratigraphy refers to the different soil layers in an area these layers can reveal how the site was transformed and what types of activities were undertaken when the lower the soil layer the older the layer and its Associated artifacts are the ones the myth then are the ones above it so the lower the soil is and the lower those artifacts are the older the artifact is and this is called the law of superposition so the law of superposition the thickness of the layer is determined by the length of occupation and the type of activities that are undertaken for example shell mittens are formed when humans dump shells from oysters mussels and other species these piles can accumulate very quickly and they leave pretty thick layers in the stratigraphy as a result of the quick accumulation of shells in contrast a kill site so the location where an animal was killed and butchered may not leave very much material at all and as such have a very thin layer of stratigraphy associated with them stratigraphy is formed through both human and natural processes for example humans can form a layer stratigraphy by creating a shell Mitten like I mentioned a second ago but a flood can also form a layer of stratigraphy by depositing silt over the shell midden higher magnitude floods can also destroy human stratigraphy by washing away the before mentioned child Mitten so different things could happen with this potential shell Mitten it could accumulate over time and leave there and remain in place there could be a small flood which would leave a little bit of sediment over top of it so we could then use that to date the flood and understand how long the shell Mitten was used or a large flood could come and wash the entire Shaman in a way so then we wouldn't have any evidence to had once been there so archaeologists need to be really careful when determining stratigraphy identifying layers created by humans and those by natural processes they also need to look for signs that some human activity has been destroyed or washed away by these natural processes the stratigraphy gives archaeologists a relative sense of dating of the site so we know what was built before when and then we can we can then have more concrete dating techniques to understand how the whole sequence fits in time for example c14 samples can be used to date a layer and everything under that layer is older than the c14 and everything that is younger than the c14 is above it similarly if archaeologists find a penny from 1952 when they're Excavating they know that everything above that layer is from after 1952.
