1. First, Africa is a continent with more than 50 countries. It is not a country.

2. Africa is the second largest continent, after Asia. Africa is 11.7 million square miles in size. The US would fit into Africa three times over. From north to south, Africa is the same distance as going from Alaska to Panama. From west to east, from Dakar in Senegal to Somalia is like going from New York to Moscow.

3. Africa is populous. Today, more than 732 million people live in Africa. Nigeria is the most populous country in Africa (107 million). Egypt is the second most populous country (65 million). Mountainous Ethiopia is third, with 59 million people.

4. The geography of Africa is diverse.

a) Many people think of Africa as a jungle, which is to say tropical rain forest. At the equator, Africa is tropical rain forest. It is incredibly humid and it rains every day. Congo-Zaire is the great example of the equatorial rain forest. But only 8 percent of Africa consists of rain forest.

b) Forty percent of Africa consists of desert. The Sahara Desert covers most of North Africa, and the Kalahari and Namib Desert are in the southwest, along the Atlantic.

c) Almost half of Africa (50%) consists of dry grassland, called the savanna. There is a rainy season, but when the rainy season occurs varies from country to country. The savanna has another name. There is a band of grassland that stretches across the entire length of Africa between the Sahara Desert in the north and the woodlands to the south. There is also a savanna region between the woodlands and rain forest at the equator, and the southern tip of Africa. Basically a savanna occurs at a certain distance from the equator, as rainfall diminishes. The great prairies of America are similar to the grasslands of the savanna. The Arabs call the grassland or savanna, south of the Sahara Desert, the bilad al'sudan. It means the land of the blacks, or the land of the black man, or the black people, as in the country or region of the black-skinned people. From this Arabic phrase, the savanna is also called "the sudan," as in a geographic region. To add to the confusion, there is also a country, to the immediate south of Egypt, that is called Sudan. The country capitalizes the name. When one says sudan in the lower case, it refers to the generic savanna grassland region, south of the desert but north of the forests or woodland.

d) At the extreme edges of the continent there is a cool, mild, moderate, temperate climate. It is sometimes called "Mediterranean" climate. This exists along the coast in Morocco and Tunisia in north Africa, and in south Africa. The tip of South African is sufficiently close to Antarctica that there are penguins there. This cooler, milder climate can also be found in the highlands of Kenya, in the region of Mt. Kilimanjaro (19,340 feet). The mountain is located close to the equator, but because of its great elevation it is snow-capped. On the other hand, due to global warming, the ice cap is melting. The temperate climate can also be found in the mountains of Ethiopia. Mt. Kilimajaro, Mt. Kenya and many of the mountains in the Rift region are actually extinct volcanoes.

5. There are five major rivers in Africa. The Nile starts at Lake Victoria and flows north 4,037 miles to the Mediterranean. Water flows from high elevation to low elevation, and north Africa slopes toward the sea. The Niger is the great bending river of west Africa. The Congo flows west to the Atlantic, from central Africa. But there is a cataract or waterfall near its entrance to the Atlantic. The Zambesi and Limpopo are in southern Africa, and flow east to the Indian Ocean.

6. The singular most spectacular geologic feature of Africa is the Great Rift Valley, also called the African Rift. It can actually be seen from outer space. It is a geological fault, and resembles the Grand Canyon (but not as deep). The Rift is a great crack in the surface of the earth, and runs for 4,000 miles. The northern terminus is the Dead Sea, in Palestine, between Jordan and the West Bank. The southern terminus is in Mozambique. The walls of the Rift resemble cliffs, and in some places it is more than 50 miles wide. The Red Sea is actually a portion of the Rift that has filled with sea water. Lake Victoria and the African Great lakes are simply low points in the Rift that have filled with water. Geologically, the Somali plate is separating from the African plate and moving away from it. As this separation occurs, the Rift grows wider. However much of the Rift lies in mountainous areas, and the area is dry and arid during part of the year. Therefore ancient materials such as fossils have been preserved here. In areas that are moist, the water causes things to decay and decompose. In tropical climates, the decay of vegetation and the salts in the soil eat up everything, and fossils do not survive. Many of the oldest hominid fossils have been found in the Rift Valley, in Africa, because the relatively dry climate preserves them.

7. The area that is NOW the Sahara Desert was not always a desert. Throughout prehistory there have been repeated Ice Ages. The last Ica Age lasted from 65,000 years go to about 10,000 years ago. During that period Europe or much of it may have been covered in glaciers and ice sheets. But the Sahara was then a combination of grassland and woodland. Scientists have found the fossilized remains (bones) of fish and aquatic birds. They have found rock carvings that depict human beings hunting birds and animals, and depict people with harpoons and nets trying to trap fish. Scientists have even found the fossilized remains of prehistoric crocodiles in the desert. The process of dessication (drying out) or desertification set in about 5,000 BC, and by 2,000 BC the desert that we know today came into being. The people who lived in the Sahara practiced a type of harpoon culture that was common in Africa.

B. THEORIES ABOUT CREATION

There are several theories about human origins. We will mention three. One theory is called Darwin's theory of evolution. A second perspective is called Biblical Creationism, and comes out of the Biblical account of the Creation as given in the Hebrew Scriptures in the Book of Genesis. A third perspective agrees with Darwin in part, but also disagrees in part. It is called catastrophism or punctuated equilibrium, and was championed by the late Stephen J. Gould of Harvard.

1. Charles Darwin's theory of natural selection, proposed in 1859, in The Origin of Species, suggests that life-forms evolve slowly over time. Those organisms that adapt to their local environment will survive, those that fail to adapt will die out. This was called "survival of the fittest" by Herbert Spencer. If adaptation to the environment bestows an advantage, more of those creatures will live long enough to reproduce and pass on their genes. Organisms that are not as well adapted are less likely to live long enough to reproduce, and so the species eventually dies out. The lesson might be adapt or perish. For example, an organism that can adapt to an oxygen environment will survive as the atmosphere becomes more oxygenated. Organisms that cannot tolerate oxygen will perish, or can live only in habitats with less oxygen. If bearing live young and caring for them and protecting bestows an advantage, then placental mammals will live while animals that just lay eggs and leave will be more likely to die out (because they get eaten and do not live long enough to reproduce). When Darwin applied his theory to human beings, he speculated that human beings shared a common ancestor with chimpanzees and gorillas. The three species, supposedly, are descended from a common ancestral type or creature. This makes the three species "cousins."

2. The scientist Louis Agassiz disagreed that evolution is always slow. Stephen J. Gould agreed with Agassiz, and argued that evolution sometimes occurs quickly, in spurts. The fossil record shows that there have been mass extinctions, and some scientists speculate that meteors striking the earth could produce an effect that throws up huge amounts of dust. This would block out the sunlight, causing the plankton in the oceans and the plants on the land to die. Then the animals or fish that eat the plants die, and then more and more animals higher up the food chain (carnivores) would die. Entire species might perish. And species that previously had been marginal might suddenly flourish because their predators have been removed. Or an animal that is adapted to cold might flourish if the climate turns cold, while animals that cannot raise their body temperature (cold blooded animals) might die or be at a disadvantage. According to this theory, catastrophes can sometimes bring about rapid changes in natural selection, in the distribution of species. Thus, the theory goes, when a meteor slammed into the earth and produced global winter, the dinosaurs perished and the small, warm-blooded mammals flourished. This theory is also called catastrophism.

3. Creationism

Genesis disagrees with both of these interpretations. The Judeo-Christian tradition teaches that God created the universe out of nothing, in six days. In the beginning God created the heavens and the earth. In the beginning there was only the void, or emptiness, and darkness moved upon the waters. And God spoke, and said "Let there be light." And God made the first man, Adam, from the dirt of the earth, and breathed His breath into Adam, which gave Adam life. And then God created a female, Eve, from one of Adam's ribs, and all of the people of the earth are descended from Adam and Eve.

a) Strict construction: Fundamentalist Christians believe that the Bible contains the literal word of God, and so they take the Creation story literally (it was six days, period).

b) Loose construction: Others, who are not so "fundamentalist," interpret the Genesis story more loosely. They would say that God created the world, but it might not have been in six days. Maybe a day in God's time is millions of years in human time. And these Christians would say that the essence of Genesis is that God is the One who created the universe, no matter how long it took (that is a trivial detail) and no matter how long ago it was. Thus, whether the "Beginning" was 7,000 years ago or 700,000 year ago or 20 billion years ago, it was still God who did it, no matter when it was and no matter how long ago it was (trivial details). And maybe evolution is the way that God works. Likewise, the theory of the "Big Bang" explosion, in which the universe expanded out of an infinitesimal little point (singularity), might correspond to the event that occurred when God said "let there be light." Maybe the people who wrote the Bible did not have words that could explain concepts like "Big Bang," so they describe it as best they could with the limited language and understanding that they possessed at that time.

So, these are competing perspectives or points of view between science and religion, and those who try to reconcile the two perspectives. Which perspective you embrace is a personal decision. For the purposes of this course, there are simply multiple points of view competing in the marketplace of ideas. For the purposes of an exam, just be able to articulate and explain each perspective. Darwinism is a theory. It is the prevailing scientific theory, and widely believed by "scientists," but it is only a theory.

C. RELIGION VS. SCIENCE

Also, bear in mind that religion is based on faith, and a belief in knowledge that has been revealed by a divine being or an other-than-human or greater-than-human power. Thus religion is based on "divine revelation," which may be beyond the ability of human beings to understand. And revelation is usually given to prophets. In contrast, science is based on human reason, and what can be understood with the human mind. Science is based on trial and error, and experiments that can be repeated and replicated and produce the same result over and over again. Science gives rise to technology and the use of things that ordinarily we can predict and control (you flip a switch and the electricity flows through a wire and "turns" the light on. It isn't mysterious magic, it is technology that human beings use, control, manipulate, understand, etc. Science is based on evidence. Religion is based on faith, and we are asked to believe without evidence.

D. FOSSILS AND METHODS OF DATING

If we look at human ancestry through the perspective of Darwinian evolution, we notice the fossil record. Fossils are ancient bones or plants that fill with minerals and, if the scientists are correct, are millions of years old. This theory is based on radio-carbon dating. Elements decay at a given rate, and produce radioactive isotopes (such as carbon 14). The more of the radioactive isotope that is present, the older a bone is believed to be. Potassium decays at a given rate, and after many millions of years produces traces of a gas called argon. The more argon that is present, the older a fossil must be.

Another principle is stratigraphy (examining layers of the earth). In undisturbed earth, the deeper down that an object is, the older that it is presumed to be. Something that is buried recently should be ear the surface. The farther down that an object is, the older it must be. And things that are found together, at the same depth and location, in undisturbed earth, might have been "deposited" at the same time. But the fossil record is tentative. We say that, on the basis of the limited information that we have available to us at this moment in time, it looks as if thus and such is so. But if new evidence is found tomorrow, we might revise our opinion. So it is not fixed, but ever-changing.

Paleontologists (the study of ancient things) notice that most of the fossils of early human-like creatures or ape-human like creatures have thus far been found in Africa. This suggests that the human species first arose in Africa. Paleontologists and paleo-anthropologists ask, for example, if the human species arose in Asia why have we not found many ancient fossils in Asia, and why are the oldest human-like fossils found (to date) mostly from Africa? Homo erectus fossils in Asia are much more recent than the African fossils.

E. DNA

Vincent Sarich and Allan Wilson studied the DNA of humans, chimps and other animals. They compared the reaction of human antibodies to animal DNA. This reaction shows up in a test tube as "milkiness." The more "milky" the reaction, the stronger the bonding between the DNA of the different species. They found that the albumin or protein reaction of monkeys and humans was 80%. The reaction with baboon DNA was higher. The reaction to an Asian ape called a gibbon was 88%. The reaction with orangutan DNA was 92%. The DNA of humans and African apes (gorillas, which do NOT have tails) was about 97% similar. The reaction with chimpanzees suggested that human and chimp DNA are about 98 or 99% similar. Sarich and Wilson hypothesized that the greater the DNA reaction, the closer the relationship, and the more recently that the species diverged from a common ancestor. They concluded that humans and chimps diverged from a common ancestor 5-7 million years ago. (See John Pfieffer, "Current research cats new light on human origins," Science, 1980).

F. THE FOSSIL RECORD

1. A GREAT VARIETY OF FOSSIL TYPES (BONES OF OUR ANCESTORS)

See Boyce Rensberger "Bones of Our Ancestors," Science, April 1984, pp. 29-39.

To summarize, scientists are aware of a startling variety of fossils. They suspect that these hominids (members of the human family) or pre-hominds are relatives to one another. But they are not yet sure how they relate to each other. Who is the great grandfather?. Who is the grandfather, or father? Who is a cousin or nephew? We do not know. The sequence is not direct or linear.

Early pre-hominids include 1a) Ramapithecus, found in India and widely dispersed, and 1b) Sivapithecus found in China. They both lived between 17 million and 8 million years ago. A specimen of Sivapithecus dates from 8 million years ago. Sivapithecus resembles an orangutan, or Asian ape. It might be a common ancestor, or it might not be. WE DO NOT KNOW.

1c. In 1924 Dr. Raymond Dart, and Australian, and professor of anatomy at the University of Witwatersrand in South Africa, obtained a fossil that had been found at a limestone quarry at Taung. It was called the Taung child. Its scientific name, in Latin, was Australopithecus africanus. Australopitchecus is derived from a Latin word and a Greek word. In Latin, Australis means south or southern. In Greek, pithekos means ape. Thus, Australopithecus means "southern ape," abnd africanus means "from Africa or African." Thus the full name means southern ape from Africa. Subsequently other Australopithecines would be found. Most are slender or slim in build (gracile). Dart said that the fossil was more than 1 million years old, and about four feet tall, and it was bipedal. That is, it walked upright on two legs. He also said that the creature was intemermediate between chimpanzees and humans. Scholars at the time dismissed his assertions and thought he was crazy. No one could imagine an African origin for the ancestors of humans. Dart was even fired from his job, because ot religious objections to what he was saying and teaching.

1d. In 1936 another professor in South Africa, Robert Broom, found an Australopithecus africanus skull at a cave in Sterkfontein, near Johannesburg, in South Africa. Many of the early fossils were found in South Africa becaus eit is a center of mining activity (gold, diamonds). In 1938 Broom found fossils of a creature with powerful jaws and a bony crest or ridge running from back to front, along the midline fo the skull! Broom called the creature Paranthropus robustus. Leopard marks were found on the skull. Paranthropus means "parallel to man [humans]" or near or close to humans. Robustus is Latin for strong (in Italian, robusto; in English, robust)

In the 1960s these "robust" fossils were re-classified as Australopithecus robustus. However, in the last few years, scholars have tended to go back to the Paranthropus classification. Paranthropus is now regarded as a parallel line that went extinct, rather like a childless brother of our great grandfather.

1e. In 1959 Mary Leakey, the wife of the famous Louis Leakey, found a fossil in Olduvai Gorge in Tanzania. Oduvai Gorge is in a portion of the Serengeti Plain, in the Rift Valley. It is 15 and a half miles long and 328 feet deep. Louis Leakey named the fossil, that had been found by his wife, Zinjanthropus boisei.

Zinj is an Arabic word that refers to east Africa (the Arans speak of the Zinj or Zanj coast). Anthropus means man [humans]. So Zinjanthropus means "east African man." Charles Boise financed the excavation, so boisei was added to the name to honor the financial backer. The skull had pronounced cheekbones and large molars (grinding teeth). It was nicknamed "Nutcracker man," because of the impression that he could crack nuts with his bare teeth. But in the 1960s scholars re-classified the fossil as Australopithecus boisei. It was evident from  the very beginning, however, that boisei resembled the robustus fossils that Broom had found. If anything, boisei was even more "robust" than robustus (hyper-robust or super-robust). There is also a robust type called aethiopicus.

Today, scholars tend to classify boisei and robustus as Parathropus boisei and Paranthropus robustus. The theory is that they evolved teeth to eat vegetation that was very tough and stringy and required a lot of grinding and chewing, but in time that habitat may have vanished.
 

2a. AUSTRALOPITHECUS AFARENSIS

The term hominid is used to refer to members of the human family. But it is not exactly clear at what point one has a fossil that is "human" or "humanlike." At least 3.2 million years ago, but perhaps even before, Australopithecus afarensis emerged. Specimens have been found in East Africa, especially Ethiopia. The first specimen was discovered in 1974 by Donald Johanson, in the Afar region of Ethiopia. She is called "Lucy". The excavators were playing the Beatles song "Lucy in the Sky with Diamonds" when they found the fossil, so that was why they named it Lucy. She seems to have been between three and four feet tall. From 1974 to 1994 as many as 75 other specimens of afarensis have been found (See Sharon Begley, "The Three Million -Year-Old Man," Newsweek, April 11, 1994, p. 84). For many years, from 1974 until 1993, Lucy or australopithecus afarenis was the oldest pre-hominid yet discovered. Lucy herself is thought to be about 3.2 million years old, but other fossils of this species have been found that may be as old as 3.7 or 3.6 million years old. The skeleton of Lucy is at the Cleveland Museum of Natural History. The teeth of afarensis are less chimplike. Chimpanzee teeth, for instance, have three roots. Human teeth more often have two.

Australopithecus afarensis seems to have branched into several types. One type, D) australopithecus africanus, became taller and was slender. It is believed to be a more direct ancestor of modern humans. Africanus seems to have had a cranial capacity or brain size of about 485 cubic centimeters. This is a little more than a chimpanzee. Modern humans have considerably larger brains, of about 1,300-1,400 cubic centimeters (Boyce Rensberger, "Bones of Our Ancestors, Science, April 1984, p. 32). Some scholars tentatively date africanus at 3 million - 2 million years ago (p. 32).

Another branch from australopithecus afarensis may have evolved into E) australopithecus aethiopicus, and F) Australopithecus robustus. As the name implies, robustus had massive bones and jaws. Rensberger, (on p. 34), dates robustus to 2.2 million years - 1.4 million years. Robustus had enormous molars, probably for grinding plants. It appeared more apelike, with a bony crest or ridge at its forehead (p. 34).

A similar variation is called Australopithecus boisei. Robustus and boisei seem to have been contemporary with one another, and both seem to have come to a dead end. They are like brothers or cousins of africanus. Aethiopicus, Robustus and boisei had massive molars and thick jaw bones. Apparently their teeth were adapted for a specialized diet of thick tough vegetable matter, which they crushed with their grinding teeth. In contrast, africanus had smaller teeth, and seems to have had a more generalized diet, more like an omnivore that opportunistically took advantage of whatever was available to eat, whether fruits, vegetables, leaves, insects, scavenging of animals that were already dead, etc. Because our teeth and the teeth of later hominds are more like those of africanus, paleo-anthropologists infer that we are more closely related to africanus than to aethiopicus, robustus or boisei. Our body build is also more similar to the slender africanus.

2b. THE LAETOLI FOOTPRINTS

In 1978 Paul Abell, who was working on a team directed by Mary Leakey, found foot prints preserved in volcanic ash, at Laetoli, in Tanzania. The volcanic ash then hardened, like wet cement hardens. The ash has been dated to 3.8 million -3.6 million years ago. The footprints are clearly bipedal. The to footprints appear to have been made by three individuals, and are presumed to be of Australopithecus. The prints of other animals, such as rhinos and ostriches, were found at the same location. It seems that the creatures walked across slightly wet soil, and then the volcanic ash covered it and preserved it.

3. RAMIDUS

Sources: Malcolm Ritter, AP, "Humanity's oldest relative discovered at site in Ethiopia," Burlington County (NJ) Times, September 1994, p. C2, and AP, "Ape-man fossil found in Ethiopia." Phila. Daily News, 1994, p. 36. In December 1992 and spring 1993 fossils were discovered in Ethiopia, by Gen Suwa of the University of Tokyo and Tim White of U.C. Berkeley. They discovered parts of the skeletons of 17 individuals. These were teeth, parts of skulls, lower jaws and a left arm. The discovery was made only 45 miles south of where Lucy had been found, near the towns of Aramis and Harar in Ethiopia. In the language of the local Afar tribesmen, ramid means root, as in origin or source. So initially the archaeologists called these fossils Australopithecus ramidus. The fossils were found in sediments 4.4 million years old, which is older than Lucy (3.5-3.2 million Before the Present). Lucy now became the next to the oldest fossil found thus far, although this too would change. Ramidus was more chimp like than Lucy, about 4 feet tall, and 65 pounds. It was bipedal. Since then, the fossil has been re-classified asArdipithecus ramidus. It is now believed ramidus is an older, different species from Lucy and australopithecus afarensis. It is more primitive and chimplike, but perhaps ancestral to Australopithecus.

4) BIPEDALITY

For many decades, paleo-anthropologists have debated about the cause of bidepedality, that is to say WHY hominids first stood upright on two legs. Through the 1950s, 1960s and 1970s, it was believed bipedality evolved in a grassland environment, as the short prehominid creatures had to stand upright to be able to see over the tall grass. Grass in the savanna can be three or four or five feet high. The see-over-the-grass-in-the-savanna theory was so widespread it is difficult to attribute it to any one author.

Interestingly, evidence suggests Ramidus lived in a wooded environment, not a grassland or savanna environment. Fossil evidence from the plants and animals found at the stratum of the earth where ramidus lived shows that it was a woodland, and there were aquatic plants and animals. The region did not turn into savanna until 1 million years after ramidus was already walking upright. Therefore a change from a forest/woodland environment to a savanna environment could NOT have been the cause of ramidus walking upright, because Ethiopia did not become a savanna or arid region until 1 million years AFTER ramidus. The future cannot cause the past. The layers of the earth that correspond to 1 million years after ramidus shows very little evidence of plants, trees, fruits, aquatic plants and animals, so this is how scientists conclude that the climate was drier and more grasslike in that time period. In the ramidus layer there are remains of animals that eat fruits from trees. In later layers are the remains of grazing animals that eat grass.

By 1994 it began to appear that prehominids began to stand upright even while they still lived in wooded or forest environments, even before they wandered out onto the grasslands. The presumption is that prehominids, like chimpanzees, spent some of their time in the trees. Typically chimpanzees forage on the ground during the day but construct nests of leaves in the trees at night, where they are safer from predators such as leopards.

For decades, paleontologists theorized that an increase in brain size preceded, or led to, bipedality and the use of the hands. Ramidus had a small chimplike brain, but appears to already have been bipedal. It now seems that bipedality, or walking upright on two legs, came first. Bipedality preceded the increase in brain size and the development of a big brain.

Another popular belief was that hominids stood upright because it freed the hands and enabled them to use tools or weapons. These things may result from bipedality, but seem not to have been the cause.

5. OWEN LOVEJOY'S THEORY OF BIPEDALITY

In the article "Out of Africa, a Missing Link," by Sharon Begley (Newsweek, October 3, 1994, p. 56), anatomist Owen Lovejoy of Kent State University in Ohio discusses this further. Lovejoy has argued since 1981 that prehumans did NOT begin to stand up to see over the high grass of the savanna, or to use weapons. Instead, he believes that prehominids began to stand upright because it was necessary to stand upright in order to carry their babies. He suggests that prehominid infants were much like human infants, nearly helpless. The chimpanzee infant holds on to its mother's fur. The infant clings to the mother's fur while it is upside down under the mother. Later it rides on the back of its parent, like a human rides a horse. But human infants cannot hold on. Their parents have to carry them. Further, humans have no fur for the baby to cling to anyway. Lovejoy believes females began to stand upright because this freed their arms. They could hold or carry the infant in one hand and still move about on their legs, or carry food in the other hand. We know, for example, that among baboons, females forage for food while carrying the baby with one limb. Older adolescent children are left in the care of relatives. But female baboons take their infants with them when they hunt or forage for food. In a similar way, chimp mothers need to carry the infant in one arm while using the other arm and walking upright. Thus, the theory is that bipedality bestowed an evolutionary advantage. It allows a more successful adaptation for a species with helpless young. For the pre-hominid, parents who walk upright would be better caregivers because they can carry the baby and also procure and carry food.

And, Lovejoy speculates, females may have preferred to mate with males who also stood upright, rather than those who did not stand upright. A male who stands upright is more helpful to the female and more useful than one who does not or cannot. A male who walks upright can bring, or carry, some food back. If he is down on all fours, what can he bring back for the female? Who needs that? And sometimes he can even hold the baby while the female is busy. Thus, males who stood upright would be preferred or selected as mates, and their genes would be passed on to the next generation. Males who did not or could not stand upright, and didn't bring any food back, would be passed over as mates, and fewer of their genes would be passed on. This would be natural selection or mate selection that favors bipedality. Bipedality preceded big-brainedness, and preceded the stage where pre-hominids moved from the safety of the forests out onto the open savanna.

6. KEVIN HUNT: GET THE FOOD

In my heart-of-hearts I like Lovejoy's theory, but he is probably wrong. In 1996 Kevin Hunt put forward the arboreal feeding hypothesis. He noted that studies of chimpanzees show that although they can stand upright on two legs, and sometimes do, when they stand up on two legs most of the time they are propped up by a branch of a tree, and most of the time they are reaching for food such as fruits or leaves in the trees. He believes that hominids, like chimps, began to stand upright for the simple, mundane reason of reaching food in their forest, woodland, arboreal environment. Hence the arboreal posture thesis. This may also be why chimps and early species such as ramidus had short legs, but long arms. Getting food is even more basic and essential than holding the baby.

7) AUSTRALOPITHECUS ANAMENSIS

But as time passes, more and more fossils are discovered, older fossils--which pushes the dates back even further. On August 28, 1995 Geoffrey Cowley and Amy Salzhauer published an article in the Science section of Newsweek, (p. 64) entitled "Humankind's First Steps." The article relates that in August 1994 Meave Leakey, the wife of RichardLeakey, (son of Mary and Richard Leakey) announced the discovery of Australopithecus anamensis, near Lake Turkana in Kenya. In the language of the Turkana tribe or ethnic group, near Lake Turkana, anam means lake. So the fossil found near lake Turkana is called anamensis, "from the lake region." Anamensis is more like afarenis, but older, at 4.2 million years.Anamensis lived in a forested or woodland environment, and was bipedal. Anamensis now occupies the place held by Lucy from 1974 to 1992. For a few years Anamensis was the oldest known fossil in what is thought to be the line of ancestry to humans. Ramidus was older, but so primitive that it was more like a chimpanzee, and not considered an Australopithecus.

8) ANAMENSIS AND BIPEDALITY.

The afarensis, ramidus and anamensis fossils shed light on another debate. For many decades scientists believed that a bigger brain led to bipedality. Afarensis, Anamensis and Ramidus suggest otherwise. Anamensis is 4.2 million years ago. It had a small brain. But it was already bipedal. The fossils suggest that prehominids developed bipedality first, and their brains only got larger later on. Tim White of Berkeley and Craig Freibel of Rutgers insist that Anamensis lived in a woodland environment, not yet on the savanna. Let me add that gorillas, chimps and humans have opposable thumbs. This is what allows us to grasp objects with our hands, and create and use tools and weapons. Bipedality frees the hands. Chimps and gorilla also have opposable toes. They can use their toes the way we use our thumbs. But Freibel's analysis of Anamensis shows that it had leg bones (tibia) that allow it to place all of its weight on its legs while standing upright, rather than bending its knee as a chimp would. And it did not have muscles on its feet to sustain an opposable toe. Anamensis walked upright. (See Tom Ewing, "A Handful of Dust," Rutgers Magazine, Spring 1996, pp. 32-37 and 45.

9) AUSTRALOPITHECUS BAHR-EL-GHAZALI

In (1996) French scientists discovered an Australopithecus jawbone in Chad, now close to the Sahara Desert. It is near the Bahr El Ghazal River and province in Sudan. Therefore the fossil is named Australopithecus bahrelghazali, after the location where it was found. It is tentatively dated at 3-3.5 million years ago. It is also significant because up until now all of the Australopithecus afarensis fossils have been found in East Africa (Ethiopia, Kenya and Tanzania) or in South Africa. This is the first Australopithecus fossil found toward central and west Africa. It is the westernmost find yet. This suggests that Australopithecus may have had a wider range than was previously known. For all we know, one day Australopitehcus fossils might be found under the Sahara. (See Amy Barrett, AP, "Discovery of new human ancestor throws scientists for a loop," Houston Chronicle, May 21, 1996, p. 12A.

10. ANCIENT APE-MAN UNCOVERED, 3.5 MILLION YEAR OLD FOSSIL in AFRICA (see abcnews.go.com/science/) 3/30/99

In March 1999 the South African Journal of Science reported the discovery of a fossil of Australopithecus at Sterkfontein Cave, near Krugersdorp, near Witwatersrand, which is near Johannesburg. It was found in December 1998. It appears to be a well preserved specimen of Australopithecus africanus, at about 3.6 or 3.5 million years old. Almost the entire skeleton is intact, and it was preserved in limestone. The article "S. Africans report key find of ape-man skeleton" (CNN, Dec. 9, 1998) also discusses this find, which was about four feet tall.

11a). THE FIRST BUTCHER

In May 1999 news came of the discovery of a new fossil in Ethiopia, called Australopithecus garhi. It was in the Awash Valley, the same part of Ethiopia that Lucy and Ramidus were found. The word garhi means "surprise" in the language of the Afar tribesmen. Garhi is more primitive than early humans, but more modern than the Australopithecines previously encountered. It dates about 2.5 million years ago, so it is younger than Lucy. What was surprising about garhi is that tools are found with him, and there is clear evidence that it used knives to fillet or slice meat from bones. There is the impression of forethought, which is to say that he thought far enough ahead and planned far enough ahead to bring his tools with him to be able to fillet the meat once he got it. Garhi could have been a scavenger, but the point is he went out looking for something to eat and to slice up, and took his tools with him so that he could cut it once he found it. If you slice open the bone you can eat the marrow, which is rich in protein.

Also, garhi's leg bones are long, which is to say he is getting taller. And this precedes the shortening of the forearm by 1 million years. In other words, our ancestors got taller from longer leg bones before our arms got shorter. Recall that chimps and gorillas have long arms, so long that they drag their knuckles on the ground. (See Michael, Lemonick, "The First Butcher," Time, May 3, 1999, 68-69.

11b. Tugenensis
But as time goes on, and scientists discover (unearth) new fossils, they find older adn older fossils. In 2000 a team of French and Kenyan paleontologists found fissilized remains in the Tugen Hills, in the Baringo district, in the Rift Valley. The bones belong to at least five individuals, and are dated at 6 million years BP. The fossils have been called Millennium Man (see "In Kenya, scientists find fossils of man's earliest ancestor," CNN.com, Dec. 4, 2000; posted by Reuters). The scientific name is Orrorin tugenensis.

11c. And in July 2002, a team of French researchers reported the discovery of a skull, jawbone and teeth of pre-hominids, in the Djurab portion of the Sahara Desert, in northern Chad, believed to be between 6 and 7 million years old. The fossils are from a new species called Sahelanthropus tchadensis. This is Sahel man from tchad. (In French, the country that we call Chad is called Tchad). The local Goran residents call the fossils "Toumaii" after the name given to children born before the dry season. Toumaii mans "hope of life." To date, these are the oldest pre-hominid fossils yet found. But it is only a matter of time before even older fossils are found. They just have not been unearthed YET.

Homo sapiens 35,000 yrs ago

Neanderthal 100,000-35,000

Homo erectus robustus, boisei
1.9 million A. aethiopicus

Homo habilis
2 million

Australopithecus
garhi
(2.5 m)

A. africanus
(3.5-3.5m)

A. afarensis (3.6-3.2 m) (overlap)
females, 4 feet, 75 lbs
males, 5 feet, 100 lbs

A. anamensis (4.2 million) [last common ancestor?]

Ardipithecus ramidus 4 feet tall
(4.5 or 4.4 m) 65 lbs

Millennium Man (6 million yrs BP) Orrorin tugenensis

Sahelanthropus tchadensis (6-7 yrs BP)

G. "TRUE" HOMINIDS

Next to emerge was 1. homo habilis, or toolmaker man, perhaps 2 million years ago. This was the first species to he called "homo," which is Latin for man (human). Habilis is more humanlike than apelike. There is not a great deal of difference between africanus and homo erectus. Some paleontologists think homo habilis is just late africanus. However, habilis seems to have a larger brain, about 500-800 cubic centimeters. Habilis made crude, flaked stone tools (p. 34). Wherever we find habilis, we find his tools. Habilis and erectus sometimes overlap in time. There are many different names of habilis, such as rudolfensis (from Lake Rudolf), heidelburgiensis, ergaster (Ethiopia).

2. HOMO ERECTUS

By 1.9 million years ago homo erectus emerged. Erectus seems to be a direct descendant of habilis. Erectus seems to be the first species of hominids to have travelled out of Africa. Erectus had a brain capacity of at least 900 cubic centimeters, and some even had 1200 cubic centimeters. One specimen of erectus, found in China, is called Peking man. Another, found on the island of Java, in Indonesia, is called Java man.

2a) Turkana Boy

In October 1984 Sharon Begley wrote "Unearthing a V.I.P. fossil," with Mary Hager, in Newsweek (Oct. 29, 1984, p. 133). The article describes the Turkana boy fossil, found at Lake Turkana, in the Rift Valley, in Kenya, in 1984. A nearby river is called Nariokotome. So this fossil is also called Nariokatome boy. It was found by Kamoya Kimeu of Kenya, a member of an archaeological team led by Richard Leakey, son of Louis and Mary Leakey, and Alan Walker of John Hopkins University. It is one of the most complete skeletons of homo erectus ever found. It is the skeleton of a boy, about age 12, who was 5 and a half feet tall. It is estimated that as an adult he might have grown to be six feet tall. More recent analysis by Alan Walker in 1996 suggests that the boy was 9 rather than 12 years old, and had a cranial capacity of 880 cubic centimeters. Homo erectus learned to control fire, and used sharpened, tools (See John R. Alden, review of The Wisdom of the Bones, by Alan Walker and Pat Shipman, in Phila. Inquirer, May 5, 1996, p. K10.

2b. (See John Noble Wilford, "A Jawbone Could Smite Ideas About Prehumans," New York Times, Feb. 3, 1992

Continuing discoveries are pushing back the age of Homo erectus. They also show that erectus seems to have travelled prodigiously, and very quickly. In 1991 a homo erectus fossil was found in former Soviet Georgia, in the Caucasus Mountains. It might be as old as 1.6 million years old. If so, erectus spread amazingly fast

2c. The article "An Ancient Wanderlust" (Sharon Begley, Newsweek, Nov. 27, 1995) describes what might be a species similar to habilis, at the Longgupo Caves, in Sichuan, China, dated at 1.9 million years. This raises new questions. There are also fossils from Spain dated at 1.6 million years. All of this generates new questions, but gives few answers. The family tree keeps getting more complicated as new relatives appear.

2d. "ANCIENT EXODUS" (Michael Lemonick, Time)

It seems that Homo erectus evolved 2 million years ago, and there is evidence that Homo. erectus lived in Indonesia 1.8 million years Before the Present (BP). A Homo. erectus fossil from Dmanisi in the Republic of Georgia, formerly part of the Soviet Union, is dated at 1.7 million years B.P.

It seems that H. erectus was not merely a scavenger, but an active hunter who followed game animals. Erectus is also bigger than habilis.

2e. "NEW LIGHT ON HUMAN ORIGINS," Rutgers Focus, March 26, 1999, p. 2

Prof. Eugene Harris of Rutgers, suggests that there may have been a split in the hominid population of Homo erectus about 200,000 years ago and two groups developed or evolved in parallel to one another. There could have been some development of Homo erectus outside of Africa. The question then becomes, what happened to the descendents of Homo erectus in Asia, and why does it seem that genetically most if not all humans alive today are descended from Africans?

H. THE DEBATE ABOUT NEANDERTHAL

The species Homo sapiens appears perhaps as early as 400,000 years ago, though some prefer a more conservative date of 250,000 years ago. It is possible that some of the earlier Homo erectus blended into it. For decades scientists have quarreled over Homo sapiens neanderthalis, or "neanderthal" for short. The first skeleton was found in the Neander River Valley, in Germany, in 1856. Subsequently it was realized that some bones found before 1856 were Neanderthal too, but at the time no one realized it. Two articles that discuss all of this are "Finding the Missing Link" (Newsweek, July 8, 1991, p. 49) and Sharon Begley, "The Caveman Convention," (Newsweek, May 27, 1996, p. 61). Traditionally Neanderthals have been depicted as strong and brutish. Their bones are certainly thicker than those of modern humans, and they are described as having the build of a linebacker. They also had a massive brow ridge over their eyes at the front of the skull. They are our image of the caveman. But they did bury their dead, and evidently cared for the sick and lame. The debate was over whether or not Neanderthal evolved into Cro-Magnon, or if Cro-Magnon is a different and more recent species. In the last few years the view has shifted.

1. NEANDERTHAL AND CRO-MAGNON

Anatomically modern humans, or Homo sapiens sapiens (wise man) dates from more than 30,000 years ago. Some early samples have been found in Africa and Europe.

J. REBECCA CANN

Rebecca Cann believes that variations or mutations in the mitochondrial DNA, which is inherited exclusively from the mother, occur at a steady rate. The more variation that a population has in its mtDNA, the older it is presumed to be because it takes a long time for these variations to arise. The fewer variations, the younger a population is assumed to be. Cann argues that the population which has the greatest variation in its mtDNA is the !Kung people of the Kalahari region in Namibia, in southwest Africa. They are one of the Khoisan groups that speak a language with many click sounds. All human beings on earth share a segment of mtDNA from people in Africa. The common link in all of our mtDNA is African. And mtDNA is inherited. The reason we all have it is because we share a remote common ancestry. Cann believes the Kung and Africans are the oldest population, and other populations descended from it and evolved from it as humans spread out of Africa. Not everyone agrees with her findings, but the oldest known fossils come from Africa, and to date we have not found anything remotely similar to a human being outside of Africa before 2 million years ago, while ramidus dates from 4.4 million and anamensis from 4.2 million.

It is also important to understand that the genetic mutations or variations discussed in this context are changes in the genes in the egg cell that get passed on to the next generation.

K. STANLEY AMBROSE, VOLCANIC WINTER, 1998

In 1998 Stanley Ambrose introduced a stunning new discovery. His exploration of supervolcanoes and Ice Ages showed that there was a volcanic winter about 71,000 years ago, when Mt. Toba erupted in Sumatra, in Indonesia. He thinks it precipitated an Ice Age that lasted perhaps 10,000 years, to 60,000 years ago, and wiped out most of the humans in Asia and Europe as a cloud of volcanic ash swirled around the earth. The prevailing westerly winds would have blown the dust cloud east to Australia and across the Pacific to North and South America, and then to Europe and Africa. The strong jet stream in the northern hemisphere would have had a severe impact on Europe, and glaciation in Europe would have doomed populations there. The one group that survived was people in Africa, closer to the equator, where it was warmest. Indeed, scientists have found ash from the Toba eruption in India and the Middle East, attesting to the tremendous impact of the eruption. After that Ice Age receded, 60,000 years ago, the migration of Africans out of Africa led to the rise of an Australasian population (in India and Southeast Asia and Australia) and a northern Eurasian population in Europe and Central Asia. Ambrose believes that the real reason most humans are 99% alike genetically is because we are actually descended from a small group of Africans who migrated out of Africa only 70,000 years ago and re-populated the earth. If Homo erectus has live doutside of Africa for nearly 2 million years, there should be far greater genetic diversity in human populations after 2 million years. But human beings are about 99% genetically alike. Ambrose suspects that most of the Neanderthal and homo erectus populations outside of Africa prior to 70,000 years ago were wiped out in the volcanic winter precipitated by the Toba explosion. Thus, although Homo erectus lived outside of Africa from 1.9 million years ago to the Toba explosion, in the explosion and the resulting Ice Age the non-African populations died out. By an accident of natural history, the non-African populations may have perished. In effect, the African survivor populations replaced earlier human populations outside of Africa that died out in the volcanic winter. This theory is the state of the art theory these days, only five years old. It is too early to know whether he is right or not. Stay tuned. If he is correct, it supports Stephen J. Gould's theory of catastrophism. See Stanley H. Ambrose, 1998, "Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans," Journal of Human Evolution, 35:115-118.

Other research suggests that of the 20 genetic lineages that have been identified, three seem to possess a genetic mutation in the mitochondria that allow a person's body to metabolize nutrition into energy more efficiently in very cold weather. These three lineages possess the mutation, and live in northerly Asia and North America (Native Americans). If this observation is correct, it would explain why so few groups lived in the harsh arctic climate of Asia (Siberia) and North America and why these particular groups were able to do so when others were not.