Alpha Omega

During the Cenozoic Era the mammals developed into a wide variety of animals. Diverging into more than 2600 genera of 28 different orders, many of which are, like the trilobites, the placoderms and the dinosaurs, now extinct. As with the plants and the invertebrates, it is far too intricate a subject for one to discuss their origin at this time.

For now it is enough to point out that nearly all paleontologists agree that the placental mammals evolved, either directly or indirectly, from the Subclass Prototheria during the Cretaceous Period. The Order Insectivora was probably the first to evolve, although there is some disagreement among scientists on this latter. There is even some disagreement among the paleoanthropologists that the Order Primate evolved from an insectivore genealogy during the latter part of the Cretaceous Period. Some anthropologists believe that the primates did not evlove until after the mass extinctions of the Mesozoic Era.

Changes in the environment, caused by the asteroid that killed the dinosaurs at the end of the Cretaceous Period, pushed many animals and plants into extinction. Many environments were changed. Encroaching tropical forests engulfed many plains and savannas and the ecological niches of the insectivores were disrupted. There were also the ecological niches left vacant by the mass extinctions of the Mesozoic Era.

Those species that could not adopt soon perished. Fortunately for the advanced primates that were to evolve later on, many insectivores had already started to change to a different mode of living just before the asteroid struck the earth; they had become omnivorous tree dwellers. Then, without competition from the dinosaurs, the survivors of the asteroid strike soon began to proliferate.

Most insectivores live on the ground and do not have the prehensile hand, stereoscopic vision or the large brain that is characteristic of all primates. When the insectivore forerunners of the primates began their migration to the trees they also began to develop such traits.

Modern tree shrews show just such a transition. The thumb and great toe of these animals are set apart from the other four digitals, although it is not completely opposable as in primates. Many species are frugivorous rather than insectivorous. However, there are a few that eat both fruit and insects. The brain of the tree shrew is larger than that of other insectivores but smaller than the primate brain. Two other intermediate traits are their middle ears, which resembles the ear of the primates and their small olfactory region, which is necessary for stereoscopic vision.

In fact, it is a subject of some debate among scientists as to which order the primitive tree shrews of the family Tupaiidae should be placed. Some scientists want to put them with the insectivores, while others want to place them among the primates. At present time, both genera and their cousins are placed in the Order Insectivora. There are several other transitional insectivores that have characteristics of both the Order Insectivora and Order Primate; each manifests intermediate traits between the two orders.

Never-the-less, by the close of the Cretaceous Period — when the dinosaurs became extinct — the crossover was complete; the primates had evolved. This can be seen in Purgatorius, the earliest primate found to date. The fossils of this species come from the Cretaceous rock beds of what is now Montana in which are also found the fossils of extinct dinosaurs. Because it has characteristics of both plesiadapiforms and true primates, some anthropologists call it a proto-primate. But either way, its dental evidence and teeth morphology do manifest a close link with the primates.

The earliest prosimians of the following Tertiary Period also have some borderline characteristics. For example, their skeletal remains manifest an arboreal adaptation but they had incisors and molars similar to rodents and insectivores. One example of an early prosimian is the genus Plesiadapis, from the Early Paleocene Epoch of the Tertiary Period. This animal had a rather generalized primate skeleton that was not fully developed for full arboreal locomotion.

It is the evidence from the fossils of this genus and the fossils of other primate genera of the same time that anthropologists base their conclusion that the suborder Prosimii evolved from an insectivore genealogy toward the end of the Cretaceous Period.

After a rapid radiation during the Paleocene Epoch and the following Eocene Epoch, the prosimians gave rise to the Ceboidea (new world monkeys) in the Late Eocene or the Early Oligocene Epoch. The oldest Ceboidea yet found is of the genus Branisella, which manifests the characteristics of both the prosimians and the anthropoids. The prosimians also gave rise to the Cercopithecoidae (old world monkeys) during the Oligocene Epoch. A well-known representative of the Cercopithecoidae is from the genus Victoriapithecus, dated by potassium-argon at around 19 million years ago.

Many anthropologists believe that it was the former group of monkeys, the ceboids, that gave rise, in the middle part of the Oligocene Epoch, to Propliopithecus, an anthropoid with a mixture of cercopithecoid and hominoid characteristics. This primitive ape is the ancestral stock of many early apes, which are exemplified by the genera Aegyptopithecus and Dryopithecus.

Aegyptopithecus, which is also known as the Dawn Ape, dates from the Miocene Epoch and is a good example of a transitional form, for it has characteristics of prosimians and monkeys. Yet its dentition, its eye sockets, and its olfactory region manifest a similarity with the hominoids. While the dryopithecines, which some anthropologists believe evolved from the aegyptopithecine genealogy, have a number of characteristics of the modern apes and are believed to be the ancestor of the genus Proconsul.

It is the species Proconsul africanus that some believe to be the ancestor of the Hominidae during the Miocene Epoch. However, there are other anthropologists who profess that it was Ramapithecus, which also evolved from an African dryopithecine ape in the Miocene Epoch, from which the hominids evolved. This is because of the affinity the features of Ramapithecus have with the family Hominidae. So similar are a number of their features that some anthropologists place the ramapithecines in the family Hominidae.

One should note that the Suborder Prosimii, which includes the lemurs, the lorises and the tarsiers, are considered lower primates. While the Suborder Anthropoidea, which includes the Ceboidea, the Cercopithecoidea and the Hominoidea are considered higher primates. The Hominoidea is further divided into three families: the Hylobatidae (gibbons and siamangs), the Pongidae (apes) and the hominids. The anthropoids evolved from the prosimians; there is no dispute in this. What is in dispute, however, is exactly how the anthropoids later branched into their various ancestries and where the hominids fit on this evolutionary tree.

Diverse anthropologists have different opinions. There is no contradiction here, for it is often difficult to tell where unique species are represented in the long history of life. The fossil record is usually incomplete and what fossils are there are frequently interpreted differently by dissimilar scientists.

Some want to lump similar fossils into one large species or place similar fossils into one large genus with several species, thus merging the taxonomy of fossils. While others want a different classification for each different fossil, thus splitting the taxonomy of the fossils.

This is compounded by the fact that it is often impossible to say where a certain species ends and another begins, for nature does not draw precise lines. With every species of living organism there was a gradual evolution from one organism to the other. Only by the discovery and comparing of a number of transitional species can one link two different organisms.

For example, only by comparing amphibians with fish and reptiles or by comparing prosimians with insectivores and anthropoids can one make a connecting link between the different life forms. It is not an easy task. Paleontologists, anthropologists and other interested scientists must not only properly reconstruct the fossil fragments that they find but they must also place the restored fossil to its proper niche on the tree of life.

Often a fossil is moved several times up or down the evolutionary ladder before its proper place in the history of life is found. Sometimes even its name may change before its niche in life is finally discovered. One would be wise in not demanding immediate, strict adherence to taxonomic divisions for fossils and species but rather wait until all the evidence has been seen.

The family Ramapithecidae has two subfamilies, the Sivapithecinae, which has one genus, Sivapithecus and the Ramapithecinae, which has two genera, Gigantopithecus and Ramapithecus.

Gigantopithecus has been estimated to have been between 2.9 and 3.1 meters (9.5 to 10 ft.) high and weigh as much as 544 kilograms (about 1200 lbs.). While no King Kong, it was one of the largest primates to ever live, being twice the size of a modern Gorilla. Although it had many features that appear hominid-like, Gigantopithecus represents a divergent line of ape-like evolutionary form that became extinct during the Lower Pleistocene Epoch.

It is the genus Ramapithecus that many believe is the most probable ancestral stock of the hominids. The fossil record of the ramapithecines is sparse but what has been discovered reveals quite a lot. There are some fossils that have characteristics that contrast sharply with the hominids but the overall morphological pattern of the ramapithecines has an affinity to the family Hominidae, which has two genera Australopithecus and Homo.

For example, a humerus (upper arm), dated around the beginning of the Pliocene Epoch, while resembling a quadruped ramapithecine foreleg, shows a similarity with the arm of the upright walking Australopithecus. (One should note that many anthropologists distinguish between the bipedal locomotion of the dinosaurs and birds and the upright posture of Australopithecus and Homo. This is because upright walking does not need a tail for balance as did the dinosaurs.)

Other fossils dated around the same time also manifest characteristics of both the ramapithecines and the australopithecines. It is for this reason that many anthropologists believe that the australopithecines evolved from a ramapithecine stock in the latter part of the Miocene Epoch.

Some anthropologists say that the genus Homo also evolved from a Ramapithecus genealogy during this time period. If this is true, then the genus Australopithecus was an ancient cousin of the genus Homo. However, others say that the australopithecines, in particular the gracile species, are the ancestors to the genus Homo during the latter part of the Pliocene Epoch. The confusion arises from the discovery of fossils of both the genus Australopithecus and the genus Homo often being found in the same rock strata. This manifests that, at least for a brief time, both lived contemporaneously.

The issue is further complicated from the interpretation of both the fossils and the effects of the changing environment during this time. Tropical forests gave way to savannas, grasslands and woodlands. The habitats of many species changed drastically. The fossil record shows the extinction of many species that were unable to adapt and the rise of other new species that did adapt.

The australopithecines were also affected by the harsh, new environment. Many anthropologists believe that two lines of descent in the hominid lineage emerged from these climatic changes. One branch led to a robust form of australopithecine, while the other branch evolved into the genus Homo. However, others believe that these climatic changes forced the australopithecines to divide into a robust form and a gracile form, while enhancing the evolution of the genus Homo and that the genus Homo eventually pushed all the australopithecines into extinction.

At least five species of the genus Australopithecus are known to have evolved. Although the exact line of descent among these australopithecines is debatable, almost all anthropologists agree that they have a common ancestor in Australopithecus afarensis. However, some believe that A. anemensis was the first to evolve and that A. afarensis evolved from it, while other anthropologists believe that A. anemensis was an aberrant offshoot of A. afarensis.

Most anthropologists believe that A. africanus and A. robustus evolved from A. afarensis. The former maintained the gracile form of its ancestor, while the latter species branched into two different directions: A. robustus and a larger A. boisei. Both of these became extinct about one million years ago. Before leaving the australopithecines, one should note that some anthropologists list more and others list less than the five species of Australopithecus listed here, each with various ancestries.

Those who follow the theory that the australopithecines were the ancestors to the genus Homo believe that Homo habilis, a species some anthropologists believe had the neurological equipment for at least rudimentary speech, evolved from a gracile australopithecine similar to “Lucy.” Lucy is an incomplete A. afarensis skeleton found in three million year old rock strata at Hadar, Ethiopia in 1974, by an international expedition headed by Dr. Donald C. Johanson. Lucy walked upright but had a less efficient bipedalism than the genus Homo, as is evident from an analysis of her femur or thighbone.

However, a set of footprints excavated from rock strata at Laetoli in northern Tanzania in 1978, by a team headed by Dr. Mary Leakey, shows that there was a species, which appears to be of the genus Homo, that clearly walked upright as early as 3.7 million years ago. Those who believe that the australopithecines are cousins of the genus Homo use this to help show how the two genera were living together after evolving from a yet unknown common ancestor.

Never-the-less, whether the genus Homo evolved from the genus Australopithecus or had a common ancestor with them, by the Pleistocene Epoch — about two million years ago — the genus Homo was rapidly becoming widely distributed throughout Africa, while the genus Australopithecus was being slowly pushed into extinction.

Among the first of the genus homo to evolve was Homo habilis; this was the species that lived contemporaneously with A. africanus. It was Homo ergaster or working man, the descendant of H. habilis, who lived with the more robust australopithecines in the Lower Paleolithic Age. One should note that some anthropologists distinguish between the African H. ergaster and the Eurasian H. erectus. These scientists consider H. ergaster to be a subspecies of H. erectus. While other anthropologists see too little differences between the two specimens to establish a subspecies.

One glacial period during the Lower Paleolithic Age and a second glacial period during the Middle Paleolithic Age brought about worldwide climatic changes (or were the results of these changes) and made living conditions more austere. The contours of the land changed due to the lowering of seas. Many temperate, subtropical and tropical areas shifted. Such changes forced widespread migration and new adaptations in both flora and fauna life. Thus, the Paleolithic Age, which comprises most of the Pleistocene Epoch, may be seen as a time period that tested and stimulated the adaptive capabilities of the life forms that lived during this interval.

These harsh conditions secured the extinction of all the australopithecines, while the more intelligent brain of the genus Homo assured its survival. A third glacial period during the Middle Paleolithic Age and a fourth glacial period during the Upper Paleolithic Age enhanced the evolutionary development of the hominids by forcing them to make better and more diverse tools. These latter two glacial periods helped further improve the hominid brain and helped push Homo erectus into extinction about 500,000 years ago. The result was the evolution of an archaic Homo sapien, the direct ancestor of Homo erectus.

It is believed that Homo neanderthalensis was an aberrant offshoot of either Homo erectus or the archaic Homo sapiens. Their fossils are found throughout Europe and the Middle East. They became extinct about 100,000 years ago. One should note that some anthropologists prefer calling them Homo sapiens neanderthalensis because of their close affinity with Homo sapiens sapiens.

The disappearance of the Neanderthals was very rapid relative to geologic time, less than 5,000 years. There are currently two hypotheses proposed to explain what happened to them. The first and most probable is that the Neanderthals could not compete with the more intelligent brain of Homo sapiens sapiens. In short, Homo sapiens sapiens, evolved from an archaic Homo sapiens, then either killed its competition or out hunted them for available food, forcing them into extinction.

The second explanation proposes that Homo sapiens sapiens and Homo sapiens neanderthalensis interbred and that the Neanderthal traits are recessive to the more dominant traits of Homo sapiens sapiens. In short, Homo sapiens sapiens absorbed its competition. Whichever hypothesis proves to be correct, one thing almost all anthropologists agree on is that by about 50,000 years ago (some say 60,000 years) distinctly modern populations had evolved to dominate the land. After only a few million years of evolution, man arose from the jungles and plains of Africa the solitary master of his world.

Current anthropologists assign modern man to the animal genus and species of Homo sapiens sapiens, which means wise, wise man. Developing his culture during the Upper Paleolithic Age, Cro-Magnon Man emerged looking as much a modern man as anyone living today. In all his physical appearances Cro-Magnon Man was no different from today’s human beings. Indeed, after considering the stone and bone tools Cro-Magnon Man had to work with, one could not even call his culture crude.

From wood, stones and bones Homo sapiens sapiens had tools and hunting weapons of all shapes, sizes and uses. Using sewing needles made from fish bones, ancient man wore “tailored” clothing of animal skin and he lived in well built, sturdy tents and huts of animal hide and thatch. Ancient man even had tribal laws, beliefs and customs. Surely, Cro-Magnon Man was not a “cave man.”

When one studies the evolution of Homo sapiens sapiens from his ancient ancestors, one becomes confronted with one undeniable fact: Rising from an ape-like pedigree over several million years of time, Cro-Magnon Man evolved as a fully developed species with the necessary intelligence to conquer his unknown world.

Ancient man started to do this about 45,000 years ago and in the next ten thousand years or so spread his culture to every corner of the inhabitable part of the globe. Living more or less a nomadic existence, Homo sapiens sapiens conquered his physical surroundings by the beginning of the Mesolithic Age.

Cro-Magnon Man continued living a nomadic life until finally leaving the hunting plains about 15,000 years ago. (Some anthropologists place the date closer to 12,000 years ago, while others push it as far back as 20,000 years ago.) Whichever time one chooses, one may say that the stage was set for man to assume a new role in life.

With the advent of the Neolithic Age, about ten to twelve thousand years ago, human beings began to cultivate their first crops. This was sporadically at first and then more uniformly as their knowledge increased. In time, man learned how to domesticate cattle, sheep, goats, chickens, pigs and other animals. (Man domesticated the dog during the Mesolithic Age in order to help himself with his hunting.) Humans then began to build small communities for themselves. These eventually developed into the first ancient cities and city states.

In Mesopotamia and Egypt and other scattered areas ancient man developed a writing skill. This was first in the form of pictographs, cuneiform writing and hieroglyphics; later it developed into an alphabet. Man then began to record his own history instead of depending upon nature to do for him it with fossils.

The journey that man has taken has been a long and arduous road. Sometimes filled with heartbreak and hard work, sometimes filled with joy and adventure but he arrived at his destination and that is the important point. Which brings this section of this treatise to a close. Those wishing to know a more detailed explanation on mankind’s evolution or man’s subsequent history may search through the particular book that reveals the information that they seek to know.

The title of this book, the first book of the trilogy Alpha Omega, is Homo animus. One must now rightly ask: Where does Homo animus come in? Who is he? However, the explanation of who Homo animus is, is a philosophical and theological statement and can best be answered in that context. Therefore, these questions, along with the other unanswered “shelved” questions that were asked earlier but left unanswered, can be answered by seeking in a source other than the physical science books of this world.

Alpha Omega

Man Emerges