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ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Recent Biological Changes to H. sapiens
Evolution did not stop 300,000 years ago. Consider our teeth.
A shift to eating cereals and eventually processed foods has contributed to the every-shrinking jaw bones and
muscles. Our teeth continue to grow as though there was plenty of space, resulting in many humans
having too little room for their teeth and, hence, overcrowded, crooked teeth.
Our biology has been strongly impacted by the dietary and behavioral trends of the last 10,000 years.
We continue to evolve.
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Agricultural Revolution: New Foods and New Adaptations
~10,000yBP, all humans hunter-gathers. Transition from Pleistocene to Holocene (~12,000yBP) also referred
to a Neolithic.
Shift to gathering plants had profound impact on our biology. Domestication is a fairly simple process.
But, why did we do it?
Au. afarensis
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Agricultural Revolution: New Foods and New Adaptations
Climate certainly played a role. For majority of last 100,000 years climate was cooler, drier, and more variable.
By 10,000yBP, Earth emerged out of the last glacial cycle and grew steadily warmer. More importantly, it
became stable. Stability is predictable.
Au. afarensis
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Agricultural Revolution: New Foods and New Adaptations
By 10,000yBP, Earth emerged out of the last glacial cycle and grew steadily warmer. More importantly, it
became stable. Stability is predictable.
As glaciers retreated, sea levels rose. Modern coastlines did not take shape until ~6,000yBP.
Au. afarensis
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Agricultural Revolution: New Foods and New Adaptations
Some of the earliest evidence of plant domestication we have is from the New World. Around 10,000yBP
humans in Central America began to interact with a local grass, teosinte and encouraged larger seed
production.
This signaled the beginning of maize domestication. Plant domestication typically results in population growth,
which sets in motion complex cultural changes.
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Plant & Animal Domestication Around the World
Domestication is the intentional intervention into the biological reproduction of other species (selective
breeding). The first domesticate was not a plant, but rather an animal – the dog. There were likely
multiple domesticating events resulting from humans and dogs living together (to varying degrees) over
the past 20,000 years or so.
Also, we have domesticated 5 cattle species in last 10,000+ years.
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Agriculture: An Adaptive Trade-Off
Domestication allowed humans to grow enough food to sustain a massive population growth at the beginning
of the Holocene. This population boom continues to this day.
Recent genetic studies have suggested that population boom may predate domestication
of plants (but probably not animals).
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Agriculture: An Adaptive Trade-Off
Drawbacks include overdependence prohibiting a return to foraging.
Land was no longer freely available.
Populations grew.
Overreliance on monocropping.
Ju/’hoansi experienced upswing in fertility after switching to diet rich in cereals.
Au. afarensis
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Agriculture: An Adaptive Trade-Off
Growing populations led to more competition for resources, and more competition led to violence and
organized warfare. This is not to say that humans were all peaceful prior to the Neolithic.
There is archaeological evidence that interpersonal conflict increased in frequency. Skeletal evidence for this
warfare can be found in the Neolithic.
Au. afarensis
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Mass Grave Site of Schöneck-Kilianstädten
Includes skeletons of 13 adults, one teenager, and 12 children. The skeletons were dated to ~7,000yBP. The skulls
showed signs of lethal blows, and more than 50% of the shin bones recovered from the grave were broken.
Researchers suspect victims were tortured or mutilated shortly after death.
Au. afarensis
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Agriculture and Human Biology
Human evolution is a constant process. A general trend over the past 2my is size reduction in chewing muscles
and teeth. The follows appearance of stone tools and transition from Australopithecus to Homo.
Recent version of this trend related to agriculture. The masticatory-functional hypothesis states that
softer foods played a part in reducing our chewing muscles and produced a flatter face.
Au. afarensis
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Agriculture’s Affect on the Human Skeleton
Interested in hunter-gathers? Well, we can study them today!
Lee and DeVore (and their conference) explored the life of modern hunter-gatherers. Work by them and others
help us understand this era of human development as the “original affluent society.” Ecology = Variation.
Is this a good model for Neolithic peoples? Can we reconstruct activity patterns from skeletal remains?
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Agriculture’s Affect on the Human Skeleton
Biomechanics is the study of the ways bones change during development. Larger, thicker bones tend to reflect
higher levels of activity.
The “I beam” principle; a ruler can be snapped in half by bending it in one direction (along the flat edge), but
is stronger along the other axis.
So, in this image of the femur, it is stronger in the up and down direction (more bone farther from the center)
than in the side-to-side direction.
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Agriculture’s Affect on the Human Skeleton
Transition from hunter–gatherers to agriculturalists resulted in a significant decline in bone strength. Here is a
comparison of the cross-section of the humerus and femur between hunter–gatherers and early
agriculturalists from the southeastern United States.
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
Agriculture’s Affect on the Human Skeleton
Reduced activity patterns also led to a reduction of degenerative joint diseases, like osteoarthritis.
Shown here is the osteophytic lipping, or “spurs”, that can form from arthritis of the lower back. Of course, for
some individuals, the shift to farming dramatically increased workload and osteoarthritis in those individuals.
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Agricultural Revolution & Health
Shift to sedentary lifestyle contributed to overcrowding, which is a recipe for infectious diseases.
Our evolution has been strongly shaped in the last 10,000 years by these diseases. Infections, such as those
caused by the staphylococcal bacterium impacts bone growth, causing a swollen region called a periosteal
reaction. Other infections include a group of diseases called treponematoses, which can include syphilis
and yaws. These leave impressions and scars on bones. They are also bacterial infections.
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Agricultural Revolution & Health
Syphilis is a well-studied disease, but its exact origin remains unknown.
Two theories, Columbian Theory (as part of the Columbian Exchange) and pre-Columbian Theory. Possible that
it was a combination and interaction of bacteria from both areas as no cases are reported prior to 1490s.
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Agricultural Revolution & Tooth Decay
Domesticate plants = cavities! Carbohydrate-rich plants produce bacteria that produce lactic acid, which
dissolves enamel.
For Neolithic humans, cavities could lead to gum infections death. Some foods worse than other (rice is not
bad, but corn is very bad).
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Agricultural Revolution & Nutrition
Iron deficiency may signal lack of fruit or (more often) meat in the diet; also by infection (e.g., hookworm).
This leaves a mark on the skeleton, since the marrow-producing regions of the body (especially in the skull)
become more porous to increase the surface area of blood cell production. These skeletal indicators of
iron deficiency are quite rare before the Neolithic and appear in many skeletal populations after the
advent of agriculture.
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Future of Human Evolution
Our impact on the global environment will change which areas can produce food.
Higher temperatures also means more mosquitos. This will favor humans with sickle-cell genes. New diseases
will develop and spread.
Au. afarensis
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Future of Human Evolution
Transhumanism (Electronic Immortality) – Nick Bostrom (University of Oxford) things that are leading to
changes in the human condition include cloning, genetic enhancement, robotics, artificial intelligence,
and nanotechnology.
Au. afarensis
ANT 2511 – Human Species
Chapter 13: The Last 10,000 Years
The Future of Human Evolution
Space Exploration and Planetary Colonization – “if you think about it, a small group of people went on a oneway voyage to [the Americas] 14,000 years ago, and then when new people [Europeans] showed up 500
years ago, they were still the same species.” – John Hawks.
Au. afarensis
Refer to the lecture and lecture notes for a discussion of this week’s exercise. Specifically, answer the following
question. Based on what we’ve discussed this semester, what do you think the future of human evolution looks like?
Make sure to address both our biological and cultural evolution.

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