The Human Saga

Notes from the 5th class of the Big Ecology Conservation Course by Course Volunteer Bob Herbert

In the Big Ecology course’s fifth class, given by retired anthropology professor Carol McMillan, we continued our search for answers about how humans have arrived at our place in time and how we fit in as one of thousands of species on this ever-changing planet.  Carol McMillan started off by explaining that she lived with Rhesus monkeys many years ago when she was just getting starting in anthropology.  There are not very many people who have been assimilated into the animal kingdom to the point of being accepted as a member of the group, and Carol is one of those rare individuals.

Rhesus monkeys are highly social, raising their young in a communal atmosphere.

The first thing that Carol revealed is the fact that the dominant male does not always get the girl (which may be good news for some of us guys!).  It was originally thought that the alpha male mated with the majority of the females, however, Carol discovered first hand that this is not always the case.  The dominant male dedicates more time to the mating ritual, and the lower ranking males take advantage of this.  While the alpha male takes his time making his moves, the lower ranking males are sneaking into the bushes with females.

We were also reminded of the interestingly subtle fact that all species have evolved for the same amount of time.  At the bottom of the tree of life we find nothing but bacteria.  They have existed for four billion years, and they remain a major part of our ecosystem.  At the top of that tree are humans, whales, monkeys, birds, insects, etc.  Everyone has been evolving side by side, but we have all evolved differently.  This explains why all monkeys didn’t wind up walking erect like Homo sapiens.  Some species changed/evolved while others found no need to change.  The environment around us has dictated these changes over long periods of time.  If a species has unlimited sources of food and space and they are prolific enough, then the need to evolve is less pronounced.  Once climate, geography or food availability changes, species are forced to adapt and evolve.  Carol also shared the unsettling fact that 99% of all species have gone extinct over time.

Carol impressed upon us that human evolution went through a genetic bottleneck and one of the explanations for this is geographic.  The northern and southern hemispheres of the Americas have a very narrow restriction in the middle, and the same holds true with Africa and Europe.  As humanity passed through these narrow trade routes they began to populate these bottlenecks.  All walks of life passed through these geographic bottlenecks and as they reproduced on the way through, our genetic diversity was restricted.      

The next thing we learned was the fact that brains expand in size when bodies are unable to turn quickly.  Heads that can change direction rapidly have smaller brains.  Slower moving creatures with better protected skulls show an increase in brain size, and in turn complexity.  The human brain is 200,000 years old and it was the development of the prefrontal cortex that allows humans to do algebra.  This is also where personality comes from and decision-making occurs.  Human’s prefrontal lobe is the second largest, proportionately speaking, next to whales.  Behind humans are chimpanzees, and man’s best friend (dogs) are after chimps.  We walk around with the egocentric belief that we are the smartest thing on the planet, but Carol pointed out that chimps can identify and memorize images three times faster than humans.  We also learned that whale’s and dolphin’s brains have been developing for 12 million years, so human brains are young by comparison (60 times).  Carol emphasized that “smart” can be many different things in different animals.  

As human population expanded around the globe there was a transition from tribal living into larger, more organized agricultural societies.  Societies developed as more and more people began living together in population clusters.  Two main types of societies ultimately evolved; egalitarian and hierarchical.  The symbol for an egalitarian society is a circle and a hierarchical society is symbolized by a pyramid.  Carol had us work in small groups and discuss characteristics that comprise these two types of societies.  Generally speaking, this is what we came up with:  An egalitarian society is governed by council (often elders) and a hierarchal society is ruled by a King or President.  Egalitarian societies are anchored with a strong set of values such as equality in fundamental worth or social status, and they typically live in synch with the natural world around them.  Hierarchical societies have classes and social inequalities and their values tend to be material based.  Hierarchical societies rule through power and control, where egalitarian societies rely on discussions, the needs of the people and equality.

The Khoisan of South Africa © South African Tourism

As it turns out, egalitarian hunter-gatherer societies work far less (time-wise) than hierarchical agricultural societies do for the same amount of food, allowing them more free time.  It is estimated that an Aborigine in the bush of Australia hunts and gathers less than twenty hours a week in order to maintain a healthier diet than the majority of Americans.  They average 90 grams of protein per day and the remainder of their diet includes with fruits, nuts, berries, and roots to keep them healthy.  The Aborigines see no need to change their way of life, even with knowledge of other ways of living, and when you break it down into diet and leisure time, I can’t blame them.  They may not have iPhones, but the parents don’t have to grind through forty+ hour work weeks either.  This additional freedom allows them more time to raise their children.

Population centers were trading points and they also were agricultural centers.  The more people you pack into a small area, the more rules and regulations are required to keep the peace, and the harder it is to feed everyone.  Carol believes that the Anasazi of what is now the southwest US were an egalitarian society for thousands of years then became hierarchical due to increased population only to discover many down sides.  Carol thinks they decided to abandon their brief stint with hierarchical society (and the largest “apartment building” in the world) and return to an egalitarian way of life in smaller groups.  No civilization has ever achieved a large scale egalitarian society, so perhaps the Anasazi saw the writing on the wall.

Human population is exploding on the planet at a time when biodiversity and resources are plummeting.  The majority of the world now lives on an electrical grid supplied by unclean sources of energy.  More and more energy is needed for agriculture each decade, which further reduces the availability of those natural resources for our grandchildren.  It took a couple hundred thousand years for humanity to fill the planet with seven billion people, but that number is expected to double within a few decades.  Understanding our past mistakes (and moments of brilliance) is the best way for humanity to provide itself with a sustainable future.  This Big Ecology course has provided the attendees with a wealth of information about how we got to where we are today and Carol showed us that we could still learn a thing or two from our hairy cousins.