This brief rendition of the story of human evo-lution attempts to capture some of the highlightsof the human evolutionary journey. The most im-portant of these evolutionary highlights in termsof understanding the current human situation are1) the natural self-centeredness that all living or-ganisms have to some to degree, a prerequisite forsurvival, 2) the emergence in humans of ‘symbolicthought’ (thought is in fact always symbolic, forexample the word or thought ‘tree’ is never actual-ly a tree) and 3) intelligence. Unfortunately thelatter two phenomena are not the same thing.

Our species, Homo sapiens, is in the mammali-an order called Primates, which means ‘of the firstrank,’ or ‘numeral uno’ (there are a total of 26mammal orders). Primates are composed of themonkeys and the apes. Both groups are character-ized by having forward-facing eyes (which givesthem stereoscopic vision and good depth percep-tion, very handy when jumping 10 or 20 feet fromone tree to another), grasping hands (usually withan opposable thumb), and relatively large brainscompared to other vertebrates. There are over 300species of monkeys, and only 24 species of apes,the latter made up of gibbons (17), orangutans (2),chimpazees (2), gorillas (2), and humans.

The oldest primate fossils are about 60 millionyears old, and the lineage is thought to be some-

what older, dating to 80 million years ago. Thehuman genetic line owes its inception to thisgroup.

Life in the trees probably initiated the charac-teristic larger brain and enhanced ‘cognitive abili-ties’ of primates--by which we mean the capacityto solve problems by ‘visualizing’ them ratherthan via autonomic genetic programming. Life intrees is three-dimensional, and so it takes moreawareness of one’s environment than life on thetwo-dimensional ground. It selected the traits thatenhanced stereo vision and grasping hands,which are critical to our species, and probablybumped the functioning of the forebrain up anotch.

Why did our ancestors leave the shelter of thetrees 6 million years ago for a dangerous life onthe savannah? Surprisingly, the current answer isclimate change, which was in turn induced byplate tectonics. 40 million years ago the subconti-nent of India, which had broken away from Africalong before, began to be pushed into Asia, givingrise to the Himalayas. This changed atmosphericcurrents and blocked moisture from falling oneastern Africa, transforming rainforest into grass-land. Our ancestors did not leave the trees somuch as the trees left them.

Human Evolutionby Dana Visalli

Skull shapes & sizes: Chimpanzee, Australopithecus,Homo habilis, H. erectus, H. neanderthalensis, H. sapiens

Dana Visalli/dana@methownet.com/The Methow Naturalist/www.methownaturalist.com

There is very little fossil evidence for the splitof the human lineage (hominins) from those ofgorillas and chimpanzees. Chimps and homininssplit from gorillas about 8 million years ago, fol-lowed by a split from the chimp line approximate-ly 7 million years ago.

One genus of presumed human antecedentsthat has risen to prominence is Australopitecus(translates as ‘southern ape’), to which the famousfossil called Lucy (discovered in 1974 in Ethiopiaand dated to 3.2 million years ago) belongs, aswell as the so-called Laetoli footprints found near-by by Mary Leakey in 1978. Both finds indicatedthat there was a hominin that by 3 million yearsago had the skeletal structure that allowed it towalk completely upright. However the brain sizeof the Australopithecines was just barely largerthan the brain of a chimpanzee. The paleoanthro-pologists like to say that hominins stood up first,and got smart later.

Survival must have been challenging for thelikes of Australopithecus afarensis, because they hadgiven up the refuge of the trees but had no way toprotect themselves against the numerous preda-tors, especially lions and other wild cats, that fre-quented the savanna. They were incapable ofutilizing either fire or weapons; one Australopithe-cus skull has been found in a cave with leopardcanine teeth puncture marks in it.

Another informative find is a red pebble in anAustralopithicene cave dated to 3 million years ago.The little rock is known as the Makapansgat peb-ble; it has natural pockmarks on it that make itlook like a human face. The rock type of the peb-ble is unknown in the immediate area, and must

therefore have been carried into the cave, proba-bly by an Australopithecus who recognized thehominid resemblance. It would take symbolicthought to execute such an action; no dog or cat orchimpanzee has ever brought a rock home be-cause they thought it looked like them. It is consid-ered to be the first sign of symbolic thought in thehistory of our evolutionary line.

One of the Australopithecines evolved into thefirst species in our genus just over 2 million yearsago, Homo habilis (homo means ‘man’ or ‘human’and habilis means ‘handy’). Chimpanzees have abrain case capacity of about 400 cm3; Australopith-ecines have about 500 cm3, and H. habilis checks inat approximately 600 cm3; so the brain was grow-ing over time. The reason is probably that the lat-ter two creatures were able to scavenge meat.Australopithecus would have been able to use‘sticks and stones’ to chase predators off of kills,and H. habilis was able to make stone tools. Theywere clearly not able to fully defend themselvesthough, as ample fossil evidence indicates that H.habilis was a staple in the diet of large predatorcats.

H. habilis appears to have persisted until 1.4million years ago, when a larger brained (1000cm3), larger-bodied hominid, Homo erectus(‘upright human’), becomes dominant (there issome overlap in the presence of the two species).It first appears in the fossil record 2 million yearsago, and seems to have migrated out of Africa asfar east as Indonesia and Vietnam by 1.5 millionyears ago. A H. erectus skull found in Dmanisi,

Australopithecus, having a good day

Dmanisi Man, a H. erectus that lived on after losing his teeth

Georgia dated at 1.8 mil-lion years had not onlylost its teeth while it wasalive, but bone hadgrown into the teeth sock-ets. Thought to belong toan old man of 40 years,such a toothless creaturewould have no way ofsurviving without thedaily support of his clan,possibly even to thepoint of pre-chewingfood for him. This is tak-en as the first evidence ofloving care and compassion among hominids inthe fossil record.

It appears likely that H. erectus tamed and uti-lized fire as long as 1.4 million years ago. Firewould have made all the difference on the trail tomodern humans, as it made the nights safe frompredators, made body hair unnecessary, and al-lowed its masters to cook food and thereby bothchew less and obtain far more nutrition from bothanimal and plant food. Both the gut and the lowerjaw could recede as they did not need to work sohard to break down food, making more energyavailable to other parts of the body--like the brain.H. erectus also improved on the tools of H. habilis,although the degree of improvement was greaterin Africa and not particularly pronounced in Asia.

It is not known to what degree H. erectus couldcommunicate through speech, but some workersthink that fossil evidence reflect vocal capabilitieswithin the range of H. sapiens. The species persist-ed for over a million years, with some dating thelast fossils to be only 50,000 years old, in China.

The dominant story at present is that about 2million years ago H. erectus migrated out of Africa,the first hominin to do so. Outside of Africa it re-mained H. erectus, while inside of Africa the evolu-tionary pressures of an increasing population ofmultiple Homo species led to the emergence of onethat became our immediate ancestor, Homo heidel-bergensis. This is curious German name for an Afri-can species, but so it goes. Its brain was just aboutas large as our own. 400,000 years ago some heidel-bergensis migrated out of Africa and apparentlyturned left instead of right, straight into the Pleis-tocene Ice Ages in Europe, where it was trans-

formed over time into theNeanderthals (Homo nean-derthalensis). Others ofthe species remained inAfrica and evolved intoHomo sapiens, which thenfirst left Africa 70,000years ago (this date is hot-ly contested), encounter-ing the Neanderthals inEurope upon arrivalthere 40,000 years ago,and possibly H. erectus inAsia.

Neanderthals seem tohave existed from about 300,000 years ago to per-haps as recently as 25,000 years ago (again, datesare uncertain). While they are best known as in-habiting Europe, which has had the most paleon-tological work, they populated a large swath ofEurasia extending from Britain in the west to Ka-zakhstan and Russia in the East.

Two aspects of the Neanderthals stand out.One is that they had a brain slightly larger thanour own species, about 1400 cm3 as opposed toour own average of 1250 cm3. They clearly hadsome smarts, being as especially forebrain size isstrongly associated with cultural learning and be-haviors that are relatively independent of geneticprogramming. On the other hand, their culturalexpression and tool making abilities changed verylittle over their almost 300,000 existence. One pale-ontologist described their tool making as brilliant,but stupid, because it was well done but neverchanged. A likely reason for this is that they prob-ably lived in isolated clans and with relatively lowpopulation numbers, so there was little opportuni-ty for extended cultural learning.

Neanderthals did create a complex culture in-dicative of bountiful symbolic thought. They wereknown to build dwellings out of animal bones(and presumably animal skins) and to constructwater craft. Neanderthal tools (known as Mouste-rian tools) as old as 170,000 years are found onislands throughout the Mediterranean. There issome evidence that they buried their dead in asymbolic way, and even that they made beer! Re-cent artists’ renderings of Neanderthals showthem as much more intelligent and modern hu-man-like than previously.

Artist’s concept of Homo erectus taming fire

Our species seems to have left Africa about125,000 years ago, migrating into the Near East(Syria and Palestine). There was probably competi-tion with Neanderthals at this time, and this first

‘out of Africa’ populationof modern humans ap-pears to have died out rath-er quickly. About 70,000years ago modern humansleft Africa by crossingfrom what is now Ethiopiato today’s Yemen, andthence spreading aroundthe world. They reachedAustralia by 46,000 yearsago, Europe by 43,000years ago, and traveled toAlaska via the Bering LandBridge (now submerged under the Bering Sea)about 20,000 years ago (all dates are uncertain).The oldest DNA evidence of human habitation inthe ‘lower 48’ is fossilized human coprolites(feces) found in the Paisley Caves in southcentralOregon dated to 14,300 yeears ago. Mysteriously,there is a modern human site now accepted inChile called Monte Verde that is dated to 14,800years old.

Homo sapiens, which first appeared in Africaabout 250,000 years ago, showed the same slowcultural development as did Neanderthals(‘brilliant but stupid’) for perhaps 200,000 years.There is some minimal evidence of ‘symbolic art’created by modern humans in Africa dating to150,000 years ago, but evidence of an expressiveexplosion dates to Europe starting 40,000 yearsago.

The first known symbolic expression or ‘art’by Homo sapiens is found in caves on the coast inSouth Africa, with quantities of ochre presumablyused for body painting dating to 165,000 yearsago have been found, and pierced shells for beadsare dated at 100,000 years.

The oldest undisputed work of figurine art isthe Venus of Hohle Fels, found in a cave in Germa-ny and dating to 40,000 years ago. It depicts a ex-aggeratedly reproductive female, and no doubtwas associated with human fertility and reproduc-tion. The earliest cave paintings are newly datedimages on the wall of a cave in Sulewesi, Indone-sia, also dated at 40,000 years. There is ‘open air’Paleolithic art on rock walls in Europe dating to40,000 years ago, and cave painting seems to havebeen initiated there soon after.

Agriculture arose independently in threecore areas of the world—southwest Asia, China andMesoamerica. The fact thatit arose independently ondifferent continents sug-gest there is natural trajec-tory for humanity in thatdirection. By 7500 BCE oneof the first known agricul-tural villages, Jarmo, hademerged in northern Iraq.Jarmo was a collection ofabout 25 houses, the inhab-itants of which depended

on a system of mixed farming and husbandry.They grew domesticated barley, emmer and peascombined with herding sheep and goats, whilehunting provided only about 5% of their totalfood.

The 40,000 year-old Venus of Hohle Fels

40,000 year-old cave art in Indonesia

A 35,000 year-old panel of horses in Chavet Cave, France

Agriculture did not evolve because it is an eas-ier option than hunting and gathering. It requiresfar more effort in clearing land, sowing, tendingand harvesting crops and in looking after domesti-cated animals. It does not necessarily providemore nutritious food. The one advantage agricul-ture has over other forms of existence is that inreturn for a greater degree of effort it can providemore food from a smaller area of land. The explanation for the appearance of agricul-ture that best fits modern knowledge is based onincreasing population pressure. The population ofthe world 10,000 years ago was about four million,rising to about five million by 5000 years ago. Itthen began doubling every millennium, to reach50 million by 1000 BCE and 200 million by 0 CE.The upward trend has continued every since, sothat agriculture today supports a world popula-tion of over seven billion. The adoption of agriculture was the secondmost fundamental change in human history, afterthe psychological journey into symbolic thought.Hunting and gathering societies were essentiallyegalitarian (except when they had abundant food,see for example the story of Sungir in Russia, a28,000 year old hunting society with all the mam-moth meat they could eat and a very hierarchicalsocial structure). Sedentary communities, almostfrom the beginning, resulted in increased special-ization and the emergence of religious, politicaland military elites with the power to direct therest of society. Genetic proclivities seem to har-ness the mind to fabricate an abstract set of beliefsfor the purpose of of unifying individuals en-sured obedience to group leaders and group val-ues. Agriculture also gave rise to the concepts ofproperty and ownership. All organisms are genetically programmed tofavor themselves, their own survival and repro-duction. This is evident in the names groups ofpeople give themselves; for example the word Inu-it means ‘human beings,’ Dine (the Navajo) means

‘the people,’ Ani-Yunwiya (the Cherokee name forthemselves) means ‘the principal people.’ Theword ‘Mediterranean means ‘the center of theEarth,’ which is where the Mediterraneans imag-ined themselves to be due to their genetic pro-gramming. A brief glance of U.S. history shows us thatboth South Korea and Vietnam declared indepen-

dence in September of 1945, and the U.S. went towar in both instances to prevent natives who lived6000 miles from our shores from exercising theirown will, because we are ‘the people’ and they aresomething less than that. In both instances warsresulted that killed 4-5 million of the local popula-tion. More recently another 3 million have beenkilled in Iraq by U.S. violence. But all humans areprogrammed to submit to authority and the peo-ple who inhabit North America are equally sub-ject to this pre-programmed behavior. It isbecause of this that almost no one speaks out oracts out against the institutionalized murder ofother human beings. The plasticity of human behavior and thespecie’s unprecedented ability to learn new behav-iors suggests we can to some degree choosemodes of existence that are adaptive and function-al. We are more controlled by our genes than wehave realized, and so it would seem that the morewe discover about the mechanisms of geneticallycontrolled behavior, the more possible it will be-come to transcend these controls through aware-ness and conscious choice. We may then in thewords of A. Rosenfeld, "for the first time in ourhistory, work for ourselves instead of for ourgenes, exercise truly free will and free choice, givefree rein to our minds and spirits, attain some-thing close to our full humanhood.''

Let My Country AwakeRabindranath Tagore

Where the mind is without fearand the head is held high,Where knowledge is free,Where the world has not beenbroken up into fragmentsby narrow domestic walls,Where words come outfrom the depth of truth,Where tireless strivingstretches its arms towards perfection,Where the clear stream of reasonhas not lost its wayinto the dreary desert sand of dead habit,Where the mind is led forwardinto ever-widening thought and action,Into that heaven of freedomlet my country awake.

Dana Visalli/dana@methownet.com/The Methow Naturalist/www.methownaturalist.com