Protozoans, primitive animals, first appeared on our planet
about 600 million years ago, according to the fossil record. After the miracle of plant life, particularly
photosynthetic forms, animal life is more of a reaction, a kind of spontaneous
combustion. Some plant forms evolved to
became parasitic on other plant species, primitive analogs of strangler figs
and English ivy. Subsistence is much
easier if one can simply prey on your neighbors, and in earliest warm oceans,
life ran riot, a truly target rich environment.
In short order, some parasitic species developed locomotion, enabling
them to eat more and reproduce more successfully.
Evolution took care of the rest. Within a couple hundred million years, plants
and insects covered the previously barren land.
With all that plant life converting sunlight, water and soil into edible
hydrocarbons, animals proliferated, converting plant hydrocarbons into energy,
water and ash.
Given the proliferation of plant eaters, it was just a
matter of time before some animals evolved into carnivores, subsisting off the
flesh of their neighbors. Animal flesh
contains far more digestible carbohydrates and proteins than plant food. Carnivores can devote more body mass to
muscle, tooth and nail, than can the lowly herbivore. Such is the chain of life - each transaction
is a tragic end for one living thing and sustenance for another.
Some of these carnivores evolved into social animals. By social, I mean possessing the instincts to
form groups of individuals, not from the same nuclear family, living together
permanently or semi-permanently and working together for the common good. Coyotes and wolves are examples. Coyotes are solitary animals that live
together in nuclear families, but separately as adults. Wolves live together in permanent packs of related
and unrelated individuals.
By 200 million years ago, a natural hierarchy of lifeforms
had settled in, a continuous food chain that led from the apex predators down
to the lowest plant life. For some
species in some environments, instinctive social organization worked best, for
other species, solitary existence remained less risky and more productive. Consider the medium sized Theropod dinosaurs
of the Cretaceous age. They were
carnivores, probably warm-blooded. Some
paleontologists believe they lived and hunted in packs like modern-day
wolves. Because they were bipedal, they
had the use of their forearms and 3-fingered hands. Over time, as they evolved, their brains grew
larger, possibly as an adaptation to enhance their social hunting skills. A few paleontologists have gone so far as to
propose these “Velociraptor” animals were on their way to making tools and
starting fires. Unfortunately, the mass
extinctions at the K-T boundary eliminated most Theropods, leaving only the
birds to continue the line.
This hierarchical pattern of dog eat dog continued,
interrupted by the mass extinction of all terrestrial animals larger than 25
kilograms approximately 65 million years ago, but returning with the rise of mammals
and birds. There is nothing to indicate
that life was very different for the mammalian apex predators of the late
Tertiary period, than it was for the Theropod dinosaurs of the mid Cretaceous
period 100 million years earlier.
Somewhere around 5 million years ago a new genus, Homo,
predecessors of modern humans, came into this relatively settled
existence. Because they were bi-pedal,
carnivorous and social, these Hominid species, as they are called, gradually
improved their tool making abilities well beyond their primate ancestors. Living on the savannah, they preyed on large
ungulates and carrion of same. They
encamped in sheltered spots, near food and water, but only for short stays of a
few days or weeks at most.
Their tool
making abilities were aimed at the obvious – sharpened sticks for killing game,
gourds for carrying water, stone choppers for butchering the carcasses and
simple rucksacks for carrying the meat back to their camps for sharing with the
women with children and old folks who depended on the hunters. Of these supposed artifacts, only stone
choppers remain as archeological evidence.
About a million years ago, some of these hominids made a giant leap
forward in their tool making – fire.
It’s highly likely they picked up on the uses for fire from
their natural surroundings.
Lightning-started fires are common on the savannah. The great leap came with the techniques
needed to start fire. Simple friction tools
made of wood can be used to start a fire.
Once learned and passed on to successive generations, it changed
everything. With fire, you can roast
meat, thereby sanitizing it and make it more digestible. With fire, many tubers that were previously
inedible became rich sources of hydrocarbons and other nutrients. Most importantly, with fire and furs,
hominids could thrive in seasonably cold climates.
Throughout this 5-million-year long period, the brains of
the hominid grew larger, gradually in the beginning and faster during the last
million years, especially the cerebral cortex and parts of the brain involving
speech and abstract thinking. No other
species in the history of life on earth has grown its brain as quickly and as
large as the hominids. The combination
of living in groups and a growing repertory of toolmaking skills transformed
the Homo genus into the crown of creation, capable of living almost anywhere on
earth and dominating all other species.
Changing climate conditions allowed several hominid species
to break out of Africa as early as 1.8 million years ago. Several other hominid species followed. Meanwhile, about 200,000 years ago, the first
modern humans, Homo sapiens appeared in Africa, obviously descended from an earlier
Homo species. By 125,000 years ago,
modern humans had expanded their range to the Levant in the Near East. By 40,000 years ago they reached Australia
and Europe and the rest of Asia.
Everywhere they went; this superior species proceeded to replace the
hominids that had arrived earlier. One
can imagine the brutal competition for food sources, with the smarter modern
humans killing their less sophisticated competitors, and in some cases,
breeding with them as their slaves.
All of the advanced capabilities we identify in modern
humans are present to a lesser degree in other animals and particularly evident
among our hominid predecessors. The
biggest advances we can claim for Homo are tool making (technology) and
language. With our ever larger brains
and increasingly sophisticated language skills, hominids became increasingly
aware of their own mental state and that of others, thereby giving rise to
complex communications.
Mammalian brain size is limited by the ability of newborns
to pass through their mother’s birth canal.
Among hominids, the obvious workaround is a much longer period of
childhood growth. The human cranium
continues growing into the late teens.
The biological strategy at work here is the largest brain possible and
an extended period of knowledge transfer from adults to children, unmatched by
any other species, past or present.
The result of this evolution is a human mental life that far
exceeds that of all our predecessors.
All animals think, the more advanced species use verbal communication,
some even use tools. Human simply have
more of these capabilities, far more. We
are different by degrees, not by kind, and our capabilities developed
gradually. Our hominid ancestors and
their relatives had a rich mental life, but to a lesser degree than modern
humans. This evolutionary refinement of
the brain, and the mind it contains, continues unabated.
So what does this mean, how should we describe our human
mental condition, our minds? It probably
all began when our hominid ancestors evolved over several million years, from
body posture, augmented with corresponding grunts and cries, to an actual
language, with a vocabulary growing from dozens of words to hundreds that could
be combined in various ways to convey thoughts, metal impressions, to other
members of the social group. It’s fair
to say the typical early hominid vocabulary was originally confined to daily
life, nouns for the animals they chased, verbs for the typical actions they
undertook, prepositions for timing and causal relations, even place names for
their encampments and home territories.
It’s also fair to conclude that singing and beating on pieces of wood,
i.e., music, was part and parcel of their daily life and a clear extension of
their proto-language. By a million years
before present, these essential precursors of human mental life were in
place.
Imagine a band of 25 Homo erectus individuals in this
timeframe, 800,000 years before present.
They are living in a temporary encampment, near running water and timber,
every few days preying on large herds of nearby big game, competing with the
big cats, bears and wolves for the same food source. Unrelated hominid bands operating nearby
would be considered either enemies or prey.
Because these hominids are omnivores, some of the band, including
most females and juveniles, forage daily for fruit, nuts and tubers. Unlike their less evolved hominid ancestors,
they have tools for starting campfires with deadwood - to cook food, including
the otherwise useless tubers, to keep warm and light the night. Every evening, the whole band gathers around
one or more of these campfires. They eat
and engage in some discussion, the nature of which is limited only by their
brain’s gradually evolving language capability and a vocabulary of no more than
a few hundred words. By comparison, the
average modern human in the street has a working vocabulary of at least 1500
words and in some cases many times that.
Although primitive by modern standards, these hominids
already exhibit a key characteristic of the human mind - the sharing of complex
ideas among the social group. Lions,
which also live in social groups, have simple verbal and non-verbal expressions
to convey commands, complaints, etc. between each other, but only certain Paleolithic
hominids, among all animals at that time, were able to conduct a verbal dialog
about concepts, possibilities and events, past and future.
If we could eavesdrop on our little hominid band and their
discussions, as they gathered around the campfire after a successful hunt, we
would consider them to be mentally challenged compared to moderns. Their behavior would be distinctly
uncivilized, with much verbal quarreling and domestic violence. Nevertheless, they were on a path that would
eventually lead to the mental life of modern humans, that rich inner life we
are so familiar with.
About 10,000 years before present, Neolithic humans in
Western Asia, began to cultivate croplands and domesticate animals for food on
a much larger scale than previously. Earlier
Paleolithic peoples also herded wild animals and harvested wild crops, but
Neolithic peoples selectively bred their plants and animals for maximum productivity
and ease of use.
These new methods of cultivation and husbandry produced two
typical cultures. The first were
pastoralists who drove large herds of domesticated ungulates from pasture to
pasture, as the seasons changed. The
second were agriculturalists who began intensively planting cereal grains and
other food crops in riverine flood plains.
People who were skilled at making fire and armed with stone implements
could burn off brush in the late dry season and plant their grains right after the
wet season.
The agriculturists also kept
domestic animals, but on a smaller scale using surplus produce and
by-products. What distinguished the
agriculturalists was their need to live in semi-permanent settlements close to
their cultivated food plots. These
settlements were populated by related and unrelated individuals working for a
common purpose, but their communities were larger in size than previous and
contemporary bands of hunter-gatherers.
In places most suited for agriculture, such as large river
deltas at the temperate latitudes, these agricultural activities and the associated human
settlements became increasingly sophisticated and prosperous. Irrigation agriculture produced large crop
surpluses, enough to support people engaged in vocations other than the usual herding
animals and tending crops. By 7,000
years before present, the first large towns were established in lower
Mesopotamia - inhabited by merchants, tradesmen, priests and soldiers, a true
civilization.
Consider how far hominids have evolved in the 5 million
years since they left the forest and began running around on two legs, killing
other animals with wooden spears for their dinner. Gradually, their bodies, and especially their
brains, evolved to take advantage of their ecological niche. They became the dominant predator in
savannah environments throughout the Old World.
Their use of fire resulted in physical adaptation to a diet of cooked
food. Modern humans cannot easily
subsist on uncooked foodstuffs. Hominid
brains grew larger and better adapted to an enhanced social life, with its
organized hunting, toolmaking and language arts. With the advent of irrigation agriculture,
their cultural development took off at an even higher pace, outstripping their
physical evolution.
We humans are a generalized species, adaptable to diverse
environments. Recently in our
evolutionary history, we left behind our hunter-gatherer mode of subsistence,
moving into permanent agricultural and urban settlements and a very different daily
existence. This rapid shift and our
struggle to adapt, has put stress on our bodies and minds, giving rise to a
host of problems and aberrant behaviors, which we will address in future posts
here. Meanwhile, next is a short essay
on the key characteristics that differentiate modern humans from all other
animals.
