Ecological Intelligence (5 page)

A similar symbiotic process occurred in plant cells as well, but where the new bacterial tenants (cyanobacteria) are what are known as chloroplasts—the “green stuff” of plants. Instead of using oxygen, they combine carbon dioxide with water and light to produce oxygen. As with mitochondria, chloroplasts too, have their own DNA.

I
t should therefore not be surprising to learn that other biological partnerships followed. One of the most important of these partnerships is described by the science writers John Briggs and F. David Peat in their book
Turbulent Mirror
as “the taking into the cell in another intrusionturned- marriage the highly mobile, corkscrew-shaped bacteria”—the spirochetes. Once again, in return for nourishment and protection, the spirochetes, or “wrigglers,” as neuroscientist and author Lynn Margulis calls them, made their sluggish hosts an offer they couldn’t refuse. They brought with them their stout cilia, or hairlike propelling strands, to act as miniature outboard motors for their new hosts. Could this have been a hint of the future legs and wings to come? Perhaps so, but not all wrigglers became propelling mechanisms. Some of them developed into microtubules within the host cell, eventually joining and elongating to become what is believed to be primitive axons and dendrites—the “business ends” of neurons, as Margulis describes them. As she suggests, it is not improbable that the growing network of connecting tubules developed into neurological tissue and later, much later, the first brains.

Moving on to four cosmic years ago (900 million years), we would have found ourselves in the company of the planet’s first multicellular plants. Known as stromatolites from the Greek
stroma
, meaning “matrix” or “tissue,” they established themselves in networks of algae or algal beds. One galactic turn later we would have seen the first jelly-fish, coelenterata, and only two cosmic years ago, the trilobites—the world’s first insects. Marine and land invertebrates were developing their first shells, or exoskeletons, and then came the glaciation of an African landmass very different to its modern shape. With the receding of the ice roughly one and a half cosmic years ago, the sea became home to horn corals and boneless fish—the predecessors of modern sharks.

With a steady increase in temperatures, the Earth produced its first tree ferns, sharks, and early amphibians. The stage was set for what seemed to be an inevitable explosion of life, but it was not to be. Instead, as a result of large-scale volcanic activity and global warming, carbon dioxide levels rose to toxic proportions, wiping out 95 percent of the Earth’s species! This catastrophic occurrence, a fraction more than one cosmic year ago and now referred to as the Permian Extinction, heralded a new geological period on our planet—the Triassic. The survivors regrouped themselves. New forms began to take shape, among them the ancestors of modern turtles, sharks, and the much-maligned crocodile, surely the greatest survivor of all modern animals. Gymnosperms (our nonflowering trees and plants) began to carpet many parts of the world, contributing not only to an increase in the Earth’s atmospheric oxygen, but to a change in the weather too. Increasing forestation meant increasing rainfall. The rivers began to flow freely, providing a niche for countless riverine plants, fish, and insects. Nine “months” (180 million years) ago, in a new period known as the Jurassic, the dinosaurs (from the Greek words
deinos
, meaning “terrible,” and
sauros
, meaning “lizard”), became the food-chain champions of the world.

A “month” later, accompanied by a splash of colors, plants with sexual organs made their first appearance. The flowers of the fields opened their petals and sepals to expose stamens and pistils—the respective male (pollen producing) and female (seed producing) components of flowers. Drawn to the plethora of colors and perfumes came an equal plethora of unwitting pollinators in the forms of wasps, flies, butterflies, and bees.

S
piders and crustaceans introduced themselves to the Earth’s ecosystems at about the same time as the flowering plants, while behind the scenes, a group of dinosaurs (they weren’t all as big as
Tyrannosaurus rex
) evolved a new way of escaping their larger, hungry relatives: their scales softened into feathers. Examine a reptilian scale through a powerful microscope and you will discover that its molecular architecture is practically identical to that of a feather.And so it was, only seven “months” (about 130 million years) ago that
Archaeopteryx
, the first known feathered creature (with teeth!)—a true ancestor of the birds—took to the sky. Escaping predators was a huge benefit to the winged creatures, but there were other advantages as well: flight provided new and wonderful opportunities for insulation, feeding, nesting, and travel.

At the same time the birds (now warm-blooded) began taking flight, the Earth’s surface began to split up again. It was the start of a significant land migration, otherwise known as continental drift. This major breakup and spread of the southerly landmass took about four cosmic months (70 million years) to give us the recognizable continents of South America, Africa, Antarctica, and Australia as well as the subcontinent of India. The Earth’s anatomy, like a huge geological embryo, had, in a sense, differentiated itself.

Need we be reminded that the same pattern of anatomical differentiation occurs in every living embryo, from stem cells to livers, kidneys, hearts, spleens, and brains? Is global anatomy a metaphor worth taking seriously? Can we learn from our own bodies? To me, the human anatomy is one of the finest examples I know of biological differentiation and diversity. It is a living definition of ecology, an embodiment of the interactions and interdependence between molecules, cells, tissues, organs, and systems, sensitive to both inner and outer environments. Sociologically it would appear to be the same—we are a body of humans, drifting and differentiated at the same time, interacting and relating to each other and we do it because we have to. As we shall see, it is part of our survival as biopsycho-social beings.

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little over three cosmic months ago (65 million years), not too long before the establishment of the continents as we know them today, the dinosaurs’ reign ended. It is chillingly speculated that the cause of this abrupt end to the dinosaurs’ 120 million-year existence was a massive asteroid impact on the Yucatan peninsula of present-day northern Mexico. It is thought that the event caused so much dust to be thrown into the atmosphere that the sun all but disappeared from the sky. The resulting drop in temperature was so severe that the sun-dependent creatures stood no chance of survival.

How do we know that this theory is the correct one? Well, we don’t know for sure, but it seems to be the most likely one. What we do know is that there was indeed an asteroid impact as described. The element iridium is the signature of asteroid impacts and there is plenty of it in a huge but well-defined area on the Yucatan peninsula. It is dated to 65 million years ago. We also know that the dinosaurs made their surprisingly rapid exit at about that time. As plausible as they might seem, two contending theories—a decimating epidemic or an intolerable atmospheric/ climatic change of another kind—have not been substantiated. Of the three possibilities for extinction, which one could the human animal be facing?

And so, in what could be described as a huge coincidence, the demise of the dinosaurs gave the burrowing, warm-blooded placentals, class Mammalia, the opportunity to establish themselves. While this is our class, there were no mammalian forms at that time even vaguely ready to put up their hands or wiggle their thumbs. The geological period known as the Cretaceous, from the Latin word for “chalk,” had ended and a warm-blooded class of creatures tentatively tiptoed into the Tertiary. The burrowing lemurs, shrews, rats, and mice showed their daytime faces. Ancestral ungulates and other ancient carnivores announced themselves, along with a fresh spurt of newly evolving birds, insects, frogs, worms, mosses, and flowering plants.

AFRICAN ORIGINS

A
bout two cosmic months ago, the Great Rift Valley began to open up and, peering into it and out of it, were the tiny evolutionary cousins of the elephant, the family Procaviidae—the hyraxes of bush, trees, and rocks. The aardvark and the early rhino made their acquaintance with Africa about one “month” ago. Then, with the worldwide expansion of grasslands only twelve cosmic days later, the hollow-horned antelopes showed up alongside their slightly older ruminant companions, the giraffes, with their horns of solid bone. Bulk-feeders such as the buffalo,
Syncerus caffer
, began herding themselves out of Europe and into the African grasslands while the zebra (family Equidae), whose ancestors hail from South America, declared their savannah stripes. As if to balance the wilderness equation, the modern carnivores, such as the lion and the hyena, left their European origins to become part of the African food chain. This all took place about six “days” (3 to 4 million years) ago.

Twenty-four cosmic hours later, not far from the foothills of the newly formed volcanic slopes of Kilimanjaro, an astonishingly odd-looking primate stood up. It was an apelike being of the genus
Australopithecus
(from the Latin
australis
, meaning “southern,” and the Greek
pithekos
, meaning “ape”). Genetically different to the hominids that are linked to modern orangutans, these bipedal creatures of the subfamily Homininae, now extinct, are our earliest hominid ancestors.

T
here appears to be little doubt about who our early ancestors are, but what is unclear is our ancestry—the line of descent. From
Australopithecus
to modern man, what we do know, however, is that the progressive increase in brain size of our intermediate ancestors and, with it, a consciousness that would eventually define the human animal, has the quality of a quantum leap. The diminishing gaps in time between the increments has forced us to revise our notions of evolution as something slow and purposive. Let’s have a look at these leaps.

With a brain size of 750 cc,
Homo habilis
, our original hominid grandparents, appeared on Earth about four cosmic days ago (2.5 million years). It would appear that they lived in an overlap phase with their smaller-brained but similar-looking cousins,
Australopithecus
africanus
and
A. bosei
. One animal among many others alongside our Australopithecan cousins must have been watching the early development of the hominid family. It was the African elephant,
Loxodonta
africana
, who emerged from its own ancestral line at more or less the same time as
H. habilis
, the world’s first toolmakers.
Habilis
, from the Latin
habilis
, meaning “dexterous,” is linked with the first discovery of concentrations of animal remains, as well as stone collections, many of which had been brought from long distances. These pebble tools, choppers, and waterworn cobbles crudely flaked on one side to form a jagged cutting edge, were mankind’s first embellished stone tools.

Habilis
, along with having a wider range of equipment, also had a different arrangement of teeth to those of their Australopithecan relatives. They were, indeed, a different species. The back teeth of these toolmaking hominids were narrower, suggesting the development of an important change in their diets—they were eating more animal food than their mostly vegetarian ancestors. As for the size of the
habilis
brain, not only was it larger than that of
Australopithecus
, but, for the first time, the bulge of Broca’s area, the convolution of the brain corresponding to the center for executive speech, became evident on a primate skull.

In their book
The Wisdom of Bones
, Alan Walker and Pat Shipman remind us that the anatomical capacity for speech is also a reflection of other particular mental abilities, including the ability to categorize and analyze the world in a complex fashion. It includes the capacity to name and to talk
about
things, as well as to describe actions without performing them. The Earth had a new tongue. Our early hominid grandparents were not only the carriers of stones and bones, they were also the carriers and shapers of words.

A
bout one and a half cosmic days ago (a million years), Africa was witness to another sudden leap in the size of the hominid skull.
Homo erectus
emerged with a 1,200–1,300 cc brain. Also known as
Homo
ergaster
, or “The Work Man,” these ancestors brought with them an up-to-date tool kit containing a variety of large, symmetrically flaked stone bifaces, or hand axes, for chopping, cutting, piercing, and pounding. They, too, were anatomically different to their immediate ancestors. Compared with
habilis
, the faces of
erectus
had become smaller as well as more expressive, while their evenly spaced and smaller back teeth confirmed the early shift from a primarily vegetable diet to one that included significantly more animal protein. This increase in brain size was believed to be a reflection of the cognitive requirements for cooperative hunting and living as well as for the evolutionarily significant gift of storytelling and symbol formation. It was also associated with the capacity to harness that great element of the gods—fire.

Fire meant an extension of the light into the night. It became a gravitational force, gathering people around it not only for warmth and safety, but for storytelling. The dark became less frightening. Essential for the developing brains of the hominids to come, celluloserich plants could be cooked and transformed into energy-providing carbohydrates.With fire, we were able to keep pantries and to establish ourselves in previously formidable geographical areas. Fired by the exploratory flames of human consciousness, we zigzagged our way out of Africa into southeastern and eastern Asia, a poetic, yet cognitive, equivalent of continental drift.

A
bout eight cosmic hours ago (250,000 years), a hominid with a 1,450 cc brain showed up. It was the grand entrance of
Homo sapiens
, from the Latin word
sapia
, which means “wise.” These large-brain ancestors did not include our heavily browed, hairy, and more muscled cousin,
Homo neanderthalensis
. Matthias Krings of the University of Munich has shown that there is a significant difference between the DNA of Neanderthal Man and that of modern human beings, which means, although related to us, they were altogether a different species. It is not known exactly when our Neanderthal relatives became extinct (estimates are between 50,000 and 200,000 years ago), but, in spite of 10,000 years of living side by side with
H. sapiens
in Europe and the Middle East, we think we know why. It is believed they were vanquished by none other than their highly inventive and aggressive hominid cousins—us.