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As the abstract of this article claims,
Madagascar was one of the last landmasses to be reached by people… Madagascar was settled approximately 1200 years ago by a very small group of women (approx. 30), most of Indonesian descent (approx. 93%).
So is Madagascar the most-recently settled landmass in the world?
(I do not know what a good definition of "settle" is, but I might suggest this: Multiple generations living and reproducing continuously. This is to exclude places like Antarctica.)
New Zealand is usually credited to be the last significant area on Earth to have been colonized by human beings in the sense of the question; as the first settlers seem to have arrived in the late 1200CE. By contrast, there are signs of human settlements on Madagascar dating from the beginning of the common era and records of trade with the island dating from around 700CE, so half a millennia before anyone stepped foot on New-Zealand (and indeed, even Iceland seems to have been colonized much later than Madagascar).
The Stone Age began about 2.6 million years ago, when researchers found the earliest evidence of humans using stone tools, and lasted until about 3,300 B.C. when the Bronze Age began. It is typically broken into three distinct periods: the Paleolithic Period, Mesolithic Period and Neolithic Period.
Did you know? Humans weren’t the first to make or use stone tools. Some 3.3 million years ago, an ancient species that lived on the shores of Lake Turkana in Kenya earned that distinction – a full 700,000 years before the earliest members of the Homo genus emerged.
Some experts believe the use of stone tools may have developed even earlier in our primate ancestors, since some modern apes, including bonobos, can also use stone tools to get food.
Stone artifacts tell anthropologists a lot about early humans, including how they made things, how they lived and how human behavior evolved over time.
New Study Refutes Theory of How Humans Populated North America
Archaeological studies have found that human colonization of North America by the so-called Clovis culture dates back more than 13,000 years ago, and recent archaeological evidence suggests that people could have been on the continent 14,700 years ago𠅊nd possibly even several millennia before that. The conventional thought has been that the first migrants who populated the North American continent arrived across an ancient land bridge from Asia once the enormous Cordilleran and Laurentide ice sheets receded to produce a passable corridor nearly 1,000 miles long that emerged east of the Rocky Mountains in present-day Canada.
Map outlining the opening of the human migration routes in North America. (Credit: Mikkel Winther Pedersen)
Evolutionary geneticist Eske Willerslev, however, believed there was one aspect of the conventional theory that required further investigation. “What nobody has looked at is when the corridor became biologically viable,” says Willerslev, director of the Center for GeoGenetics at the University of Copenhagen. “When could they actually have survived the long and difficult journey through it?”
A pioneer in the study of ancient DNA who led the first successful sequencing of an ancient human genome, Willerslev specializes in extracting ancient plant and mammal DNA from sediments to reconstruct ancient history. According to a recent profile in the New York Times, “Willerslev and his colleagues have published a series of studies that have fundamentally changed how we think about human history,” and a new study published in the journal Nature co-authored by Willerslev may lead to a rethinking of how Ice-Age humans first arrived in North America.
The study’s international team of researchers travelled in the dead of winter to the Peace River basin in western Canada, a spot that based on geological evidence was among the last segments along the 1,000-mile corridor to become free of ice and passable. At this crucial chokepoint along the migration path the research team took nine sediment cores from the bottoms of British Columbia’s Charlie Lake and Alberta’s Spring Lake, remnants of a glacial lake that formed as the Laurentide Ice Sheet began to retreat between 15,000 and 13,500 years ago.
Illustration of North America and Greenland with areas covered in ice highlighted in red, land bridge in purple, c. 15,000 years ago. (Credit: Dorling Kindersley / Getty Images)
After examining radiocarbon dates, pollen, macro-fossils and DNA from the lake sediment cores, the researchers found that the corridor’s chokepoint was not 𠇋iologically viable” to have sustained humans on the arduous journey until 12,600 years agonturies after people were known to have been in North America. Willerslev’s team found that until that time the bottleneck area lacked the basic necessities for survival, such as wood for fuel and tools and game animals to be killed for sustenance by hunter-gatherers.
From the core samples, the researchers discovered that steppe vegetation first began to appear in the region 12,600 years ago followed quickly by the arrival of animals such as bison, wooly mammoths, jackrabbits and voles. Around 11,500 years ago there was a transition to a more densely populated landscape with trees, fish such as pike and perch and animals including moose and elk.
9 Humans Have Persistent Chronic Illness
The prison planet theory suggests that most human beings, even those of us who are extremely healthy, suffer from chronic &ldquoillnesses,&rdquo albeit ones that are trivial when isolated.  Think about it&mdashwhen was the last time you felt truly &ldquogood?&rdquo No little niggles or twitches. No headache, or hay fever, or any manner of small annoyances that are barely significant enough to mention but seemingly plague each one of us.
Perhaps we should also look at humans&rsquo reaction to the Sun, one of the main keys to our existence. Many other animals can sit out in the sunlight all day long with no effect to their health (generally speaking). However, humans will be sunburned within hours, while long-term exposure can sometimes result in a variety of skin cancers. We also squint our eyes in reaction to the Sun, unlike other animals. Even the fact that we have only a tiny auditory frequency range and can only see a very tiny sliver of the electromagnetic spectrum could be indicators of a home planet other than Earth.
The Conservation of Races
The American Negro has always felt an intense personal interest in discussions as to the origins and destinies of races: primarily because back of most discussions of race with which he is familiar, have lurked certain assumptions as to his natural abilities, as to his political , intellectual and moral status, which he felt were wrong. He has, consequently, been led to deprecate and minimize race distinctions, to believe intensely that out of one blood God created all nations, and to speak of human brotherhood as though it were the possibility of an already dawning to-morrow.
Nevertheless, in our calmer moments we must acknowledge that human beings are divided into races that in this country the two most extreme types of the world’s races have met, and the resulting problem as to the future relations of these types is not only of intense and living interest to us, but forms an epoch in the history of mankind.
It is necessary, therefore, in planning our movements, in guiding our future development, that at times we rise above the pressing, but smaller questions of separate schools and cars, wage-discrimination and lynch law, to survey the whole questions of race in human philosophy and to lay, on a basis of broad knowledge and careful insight, those large lines of policy and higher ideals which may form our guiding lines and boundaries in the practical difficulties of every day. For it is certain that all human striving must recognize the hard limits of natural law, and that any striving, no matter how intense and earnest, which is against the constitution of the world, is vain. The question, then, which we must seriously consider is this: What is the real meaning of Race what has, in the past, been the law of race development, and what lessons has the past history of race development to teach the rising Negro people?
When we thus come to inquire into the essential difference of races we find it hard to come at once to any definite conclusion. Many criteria of race differences have in the past been proposed, as color, hair, cranial measurements and language. And manifestly, in each of these respects, human beings differ widely. They vary in color, for instance, from the marble-like pallor of the Scandinavian to the rich, dark brown of the Zulu, passing by the creamy Slav, the yellow Chinese, the light brown Sicilian and the brown Egyptian. Men vary, too, in the texture of hair from the obstinately straight hair of the Chinese to the obstinately tufted and frizzled hair of the Bushman. In measurement of heads, again, men vary from the broad-headed Tartar to the medium-headed European and the narrow-headed Hottentot or, again in language, from the highly- inflected Roman tongue to the monosyllabic Chinese. All these physical characteristics are patent enough, and if they agreed with each other it would be very easy to classify mankind. Unfortunately for scientists, however, these criteria of race are most exasperatingly intermingled. Color does not agree with texture of hair, for many of the dark races have straight hair nor does color agree with the breadth of the head, for the yellow Tartar has a broader head than the German nor, again, has the science of language as yet succeeded in clearing up the relative authority of these various and contradictory criteria. The final word of science, so far, is that we have at least two, perhaps three, great families of human beings–the whites and Negroes, possibly the yellow race. That other races have arisen from the intermingling of the blood of these two. This broad division of the world’s races which men like Huxley and Raetzel have introduced as more nearly true than the old five-race scheme of Blumenbach, is nothing more than an acknowledgment that, so far as purely physical characteristics are concerned, the differences between men do not explain all the differences of their history. It declares, as Darwin himself said, that great as is the physical unlikeness of the various races of men their likenesses are greater, and upon this rests the whole scientific doctrine of Human Brotherhood.
Although the wonderful developments of human history teach that the grosser physical differences of color, hair and bone go but a short way toward explaining the different roles which groups of men have played in Human Progress, yet there are differences–subtle, delicate and elusive, though they may be– which have silently but definitely separated men into groups. While these subtle forces have generally followed the natural cleavage of common blood, descent and physical peculiarities, they have at other times swept across and ignored these. At all times, however, they have divided human beings into races, which, while they perhaps transcend scientific definition, nevertheless, are clearly defined to the eye of the Historian and Sociologist.
If this be true, then the history of the world is the history, not of individuals, but of groups, not of nations, but of races, and he who ignores or seeks to override the race idea in human history ignores and overrides the central thought of all history. What, then, is a race? It is a vast family of human beings, generally of common blood and language, always of common history, traditions and impulses, who are both voluntarily and involuntarily striving together for the accomplishment of certain more or less vividly conceived ideals of life.
Turning to real history, there can be no doubt, first, as to the widespread, nay, universal, prevalence of the race idea, the race spirit, the race ideal, and as to its efficiency as the vastest and most ingenious invention of human progress. We, who have been reared and trained under the individualistic philosophy of the Declaration of Independence and the laisser-faire philosophy of Adam Smith, are loath to see and loath to acknowledge this patent fact of human history. We see the Pharaohs, Caesars, Toussaints and Napoleons of history and forget the vast races of which they were but epitomized expressions. We are apt to think in our American impatience, that while it may have been true in the past that closed race groups made history, that here in conglomerate America NOUS AVONS CHANGER TOUT CELA–we have changed all that, and have no need of this ancient instrument of progress. This assumption of which the Negro people are especially fond, can not be established by a careful consideration of history.
We find upon the world’s stage today eight distinctly differentiated races, in the sense in which History tells us the word must be used. They are, the Slavs of eastern Europe, the Teutons of middle Europe, the English of Great Britain and America, the Romance nations of Southern and Western Europe, the Negroes of Africa and America, the Semitic people of Western Asia and Northern Africa, the Hindoos of Central Asia and the Mongolians of Eastern Asia. There are, of course, other minor race groups, as the American Indians, the Esquimaux and the South Sea Islanders these larger races, too, are far from homogeneous the Slav includes the Czech, the Magyar, the Pole and the Russian the Teuton includes the German, the Scandinavian and the Dutch the English include the Scotch, the Irish and the conglomerate American. Under Romance nations the widely-differing Frenchman, Italian, Sicilian and Spaniard are comprehended. The term Negro is, perhaps, the most indefinite of all, combining the Mulattoes and Zamboes of America and the Egyptians, Bantus and Bushmen of Africa. Among the Hindoos are traces of widely differing nations, while the great Chinese, Tartar, Corean and Japanese families fall under the one designation–Mongolian.
The question now is: What is the real distinction between these nations? Is it the physical differences of blood, color and cranial measurements? Certainly we must all acknowledge that physical differences play a great part, and that, with wide exceptions and qualifications, these eight great races of to-day follow the cleavage of physical race distinctions the English and Teuton represent the white variety of mankind the Mongolian, the yellow the Negroes, the black. Between these are many crosses and mixtures, where Mongolian and Teuton have blended into the Slav, and other mixtures have produced the Romance nations and the Semites. But while race differences have followed mainly physical race lines, yet no mere physical distinctions would really define or explain the deeper differences–the cohesiveness and continuity of these groups. The deeper differences are spiritual, psychical, differences– undoubtedly based on the physical, but infinitely transcending them. The forces that bind together the Teuton nations are, then, first, their race identity and common blood secondly, and more important, a common history, common laws and religion, similar habits of thought and a conscious striving together for certain ideals of life. The whole process which has brought about these race differentiations has been a growth, and the great characteristic of this growth has been the differentiation of spiritual and mental differences between great races of mankind and the integration of physical differences.
The age of nomadic tribes of closely related individuals represents the maximum of physical differences. They were practically vast families, and there were as many groups as families. As the families came together to form cities the physical differences lessened, purity of blood was replaced by the requirement of domicile, and all who lived within the city bounds became gradually to be regarded as members of the group i.e., there was a slight and slow breaking down of physical barriers. This, however, was accompanied by an increase of the spiritual and social differences between cities. This city became husbandmen, this, merchants, another warriors, and so on. The IDEALS OF LIFE for which the different cities struggled were different. When at last cities began to coalesce into nations there was another breaking down of barriers which separated groups of men. The larger and broader differences of color, hair and physical proportions were not by any means ignored, but myriads of minor differences disappeared, and the sociological and historical races of men began to approximate the present division of races as indicated by physical researches. At the same time the spiritual and physical differences of race groups which constituted the nations became deep and decisive. The English nation stood for constitutional liberty and commercial freedom the German nation for science and philosophy the Romance nations stood for literature and art, and the other race groups are striving, each in its own way, to develop for civilization its particular message, it particular ideal, which shall help to guide the world nearer and nearer that perfection of human life for which we all long, that “one far off Divine event.”
This has been the function of race differences up to the present time. What shall be its function in the future? Manifestly some of the great races of today–particularly the Negro race–have not as yet given to civilization the full spiritual message which they are capable of giving. I will not say that the Negro-race has yet given no message to the world, for it is still a mooted question among scientists as to just how far Egyptian civilization was Negro in its origin if it was not wholly Negro, it was certainly very closely allied. Be that as it may, however, the fact still remains that the full, complete Negro message of the whole Negro race has not as yet been given to the world: that the messages and ideal of the yellow race have not been completed, and that the striving of the mighty Slavs has but begun. The question is, then: How shall this message be delivered how shall these various ideals be realized? The answer is plain: By the development of these race groups, not as individuals, but as races. For the development of Japanese genius, Japanese literature and art, Japanese spirit, only Japanese, bound and welded together, Japanese inspired by one vast ideal, can work out in its fullness the wonderful message which Japan has for the nations of the earth. For the development of Negro genius, of Negro literature and art, of Negro spirit, only Negroes bound and welded together, Negroes inspired by one vast ideal, can work out in its fullness that great message we have for humanity. We cannot reverse history we are subject to the same natural laws as other races, and if the Negro is ever to be a factor in the world’s history–if among the gaily-colored banners that deck the broad ramparts of civilizations is to hang one uncompromising black, then it must be placed there by black hands, fashioned by black heads and hallowed by the travail of 200,000,000 black hearts beating in one glad song of jubilee.
For this reason, the advance guard of the Negro people–the 8,000,000 people of Negro blood in the United States of America– must soon come to realize that if they are to take their just place in the van of Pan-Negroism, then their destiny is NOT absorption by the white Americans. That if in America it is to be proven for the first time in the modern world that not only Negroes are capable of evolving individual men like Toussaint, the Saviour, but are a nation stored with wonderful possibilities of culture, then their destiny is not a servile imitation of Anglo-Saxon culture, but a stalwart originality which shall unswervingly follow Negro ideals.
It may, however, be objected here that the situation of our race in America renders this attitude impossible that our sole hope of salvation lies in our being able to lose our race identity in the commingled blood of the nation and that any other course would merely increase the friction of races which we call race prejudice, and against which we have so long and so earnestly fought.
Here, then, is the dilemma, and it is a puzzling one, I admit. No Negro who has given earnest thought to the situation of his people in America has failed, at some time in life, to find himself at these cross-roads has failed to ask himself at some time: What, after all, am I? Am I an American or am I a Negro? Can I be both? Or is it my duty to cease to be a Negro as soon as possible and be an American? If I strive as a Negro, am I not perpetuating the very cleft that threatens and separates Black and White America? Is not my only possible practical aim the subduction of all that is Negro in me to the American? Does my black blood place upon me any more obligation to assert my nationality than German, or Irish or Italian blood would?
It is such incessant self-questioning and the hesitation that arises from it, that is making the present period a time of vacillation and contradiction for the American Negro combined race action is stifled, race responsibility is shirked, race enterprises languish, and the best blood, the best talent, the best energy of the Negro people cannot be marshalled to do the bidding of the race. They stand back to make room for every rascal and demagogue who chooses to cloak his selfish deviltry under the veil of race pride.
Is this right? Is it rational? Is it good policy? Have we in America a distinct mission as a race–a distinct sphere of action and an opportunity for race development, or is self-obliteration the highest end to which Negro blood dare aspire?
If we carefully consider what race prejudice really is, we find it, historically, to be nothing but the friction between different groups of people it is the difference in aim, in feeling, in ideals of two different races if, now, this difference exists touching territory, laws, language, or even religion, it is manifest that these people cannot live in the same territory without fatal collision but if, on the other hand, there is substantial agreement in laws, language and religion if there is a satisfactory adjustment of economic life, then there is no reason why, in the same country and on the same street, two or three great national ideals might not thrive and develop, that men of different races might not strive together for their race ideals as well, perhaps even better, than in isolation. Here, it seems to me, is the reading of the riddle that puzzles so many of us. We are Americans, not only by birth and by citizenship, but by our political ideals, our language, our religion. Farther than that, our Americanism does not go. At that point, we are Negroes, members of a vast historic race that from the very dawn of creation has slept, but half awakening in the dark forests of its African fatherland. We are the first fruits of this new nation, the harbinger of that black to-morrow which is yet destined to soften the whiteness of the Teutonic to-day. We are that people whose subtle sense of song has given America its only American music, its only American fairy tales, its only touch of pathos and humor amid its mad money-getting plutocracy. As such, it is our duty to conserve our physical powers, our intellectual endowments, our spiritual ideals as a race we must strive by race organization, by race solidarity, by race unity to the realization of that broader humanity which freely recognizes differences in men, but sternly deprecates inequality in their opportunities of development.
For the accomplishment of these ends we need race organizations: Negro colleges, Negro newspapers, Negro business organizations, a Negro school of literature and art, and an intellectual clearing house, for all these products of the Negro mind, which we may call a Negro Academy. Not only is all this necessary for positive advance, it is absolutely imperative for negative defense. Let us not deceive ourselves at our situation in this country. Weighted with a heritage of moral iniquity from our past history, hard pressed in the economic world by foreign immigrants and native prejudice, hated here, despised there and pitied everywhere our one haven of refuge is ourselves, and but one means of advance, our own belief in our great destiny, our own implicit trust in our ability and worth. There is no power under God’s high heaven that can stop the advance of eight thousand thousand honest, earnest, inspired and united people. But–and here is the rub–they MUST be honest, fearlessly criticising their own faults, zealously correcting them they must be EARNEST. No people that laughs at itself, and ridicules itself, and wishes to God it was anything but itself ever wrote its name in history it MUST be inspired with the Divine faith of our black mothers, that out of the blood and dust of battle will march a victorious host, a mighty nation, a peculiar people, to speak to the nations of earth a Divine truth that shall make them free. And such a people must be united not merely united for the organized theft of political spoils, not united to disgrace religion with whoremongers and ward-heelers not united merely to protest and pass resolutions, but united to stop the ravages of consumption among the Negro people, united to keep black boys from loafing, gambling and crime united to guard the purity of black women and to reduce the vast army of black prostitutes that is today marching to hell and united in serious organizations, to determine by careful conference and thoughtful interchange of opinion the broad lines of policy and action for the American Negro.
This, is the reason for being which the American Negro Academy has. It aims at once to be the epitome and expression of the intellect of the black-blooded people of America, the exponent of the race ideals of one of the world’s great races. As such, the Academy must, if successful, be
(a). Representative in character.
(b). Impartial in conduct.
(c). Firm in leadership.
It must be representative in character not in that it represents all interests or all factions, but in that it seeks to comprise something of the BEST thought, the most unselfish striving and the highest ideals. There are scattered in forgotten nooks and corners throughout the land, Negroes of some considerable training, of high minds, and high motives, who are unknown to their fellows, who exert far too little influence. These the Negro Academy should strive to bring into touch with each other and to give them a common mouthpiece.
The Academy should be impartial in conduct while it aims to exalt the people it should aim to do so by truth–not by lies, by honesty–not by flattery. It should continually impress the fact upon the Negro people that they must not expect to have things done for them–they MUST DO FOR THEMSELVES that they have on their hands a vast work of self-reformation to do, and that a little less complaint and whining, and a little more dogged work and manly striving would do us more credit and benefit than a thousand Force or Civil Rights bills.
Finally, the American Negro Academy must point out a practical path of advance to the Negro people there lie before every Negro today hundreds of questions of policy and right which must be settled and which each one settles now, not in accordance with any rule, but by impulse or individual preference for instance: What should be the attitude of Negroes toward the educational qualification for voters? What should be our attitude toward separate schools? How should we meet discriminations on railways and in hotels? Such questions need not so much specific answers for each part as a general expression of policy, and nobody should be better fitted to announce such a policy than a representative honest Negro Academy.
All this, however, must come in time after careful organization and long conference. The immediate work before us should be practical and have direct bearing upon the situation of the Negro. The historical work of collecting the laws of the United States and of the various States of the Union with regard to the Negro is a work of such magnitude and importance that no body but one like this could think of undertaking it. If we could accomplish that one task we would justify our existence.
In the field of Sociology an appalling work lies before us. First, we must unflinchingly and bravely face the truth, not with apologies, but with solemn earnestness. The Negro Academy ought to sound a note of warning that would echo in every black cabin in the land: UNLESS WE CONQUER OUR PRESENT VICES THEY WILL CONQUER US we are diseased, we are developing criminal tendencies, and an alarmingly large percentage of our men and women are sexually impure. The Negro Academy should stand and proclaim this over the housetops, crying with Garrison: I WILL NOT EQUIVOCATE, I WILL NOT RETREAT A SINGLE INCH, AND I WILL BE HEARD. The Academy should seek to gather about it the talented, unselfish men, the pure and noble-minded women, to fight an army of devils that disgraces our manhood and our womanhood. There does not stand today upon God’s earth a race more capable in muscle, in intellect, in morals, than the American Negro, if he will bend his energies in the right direction if he will Burst his birth’s invidious bar And grasp the skirts of happy chance, And breast the blow of circumstance, And grapple with his evil star.
In science and morals, I have indicated two fields of work for the Academy. Finally, in practical policy, I wish to suggest the following ACADEMY CREED:
1. We believe that the Negro people, as a race, have a contribution to make to civilization and humanity, which no other race can make.
2. We believe it the duty of the Americans of Negro descent, as a body, to maintain their race identity until this mission of the Negro people is accomplished, and the ideal of human brotherhood has become a practical possibility.
3. We believe that, unless modern civilization is a failure, it is entirely feasible and practicable for two races in such essential political, economic and religious harmony as the white and colored people in America, to develop side by side in peace and mutual happiness, the peculiar contribution which each has to make to the culture of their common country.
4. As a means to this end we advocate, not such social equality between these races as would disregard human likes and dislikes, but such a social equilibrium as would, throughout all the complicated relations of life, give due and just consideration to culture, ability, and moral worth, whether they be found under white or black skins.
5. We believe that the first and greatest step toward the settlement of the present friction between the races–commonly called the Negro Problem-lies in the correction of the immorality, crime and laziness among the Negroes themselves, which still remains as a heritage from slavery. We believe that only earnest and long continued efforts on our own part can cure these social ills.
6. We believe that the second great step toward a better adjustment of the relations between races, should be a more impartial selection of ability in the economic and intellectual world, and a greater respect for personal liberty and worth, regardless of race. We believe that only earnest efforts on the part of the white people of this country will bring much needed reform in these matters.
7. On the basis of the foregoing declaration, and firmly believing in our high destiny, we, as American Negroes, are resolved to strive in every honorable way for the realization of the best and highest aims, for the development of strong manhood and pure womanhood, and for the rearing of a race ideal in America and Africa, to the glory of God and the uplifting of the Negro people.
Kupe, Toitehuatahi and Turi
According to many tribal narratives, Kupe was the first Pacific explorer to discover the islands of New Zealand. Stories about his exploration on his canoe, the Matawhaorua or Matahorua, differ from region to region but often feature a fight with a great wheke (octopus). Many New Zealand place names, preserved by later generations of Māori people, recall his journey.
Cliff Whiting, for the New Zealand Geographic Board, Crown Copyright reserved.
Toitehuatahi (Toi), another early visitor from Hawaiki (the traditional Māori place of origin), is an important ancestor for many Māori people.
One of the captains remembered as voyaging to New Zealand was Turi, the captain of the Aotea canoe. Stories of Turi and Kupe are intertwined throughout the Pacific. Tradition says that Turi followed Kupe’s instructions when sailing from Hawaiki to New Zealand via Raoul Island in the Kermadecs. The canoe made landfall in Waitematā Harbour, then travelled down the west coast of the North Island from Aotea Harbour, named after the canoe, to Pātea in Taranaki, where he and his people settled many places on this coast are named for events that occurred during this journey.
Cliff Whiting, for the New Zealand Geographic Board, Crown Copyright reserved.
Turi, the captain of the Aotea canoe.
In geochronology, time is generally measured in mya (million years ago), each unit representing the period of approximately 1,000,000 years in the past. The history of Earth is divided into four great eons, starting 4,540 mya with the formation of the planet. Each eon saw the most significant changes in Earth's composition, climate and life. Each eon is subsequently divided into eras, which in turn are divided into periods, which are further divided into epochs.
|Hadean||4,540–4,000||The Earth is formed out of debris around the solar protoplanetary disk. There is no life. Temperatures are extremely hot, with frequent volcanic activity and hellish-looking environments (hence the eon's name, which comes from Hades). The atmosphere is nebular. Possible early oceans or bodies of liquid water. The Moon is formed around this time probably due to a protoplanet's collision into Earth.|
|Archean||4,000–2,500||Prokaryote life, the first form of life, emerges at the very beginning of this eon, in a process known as abiogenesis. The continents of Ur, Vaalbara and Kenorland may have existed around this time. The atmosphere is composed of volcanic and greenhouse gases.|
|Proterozoic||2,500–541||The name of this eon means "early life". Eukaryotes, a more complex form of life, emerge, including some forms of multicellular organisms. Bacteria begin producing oxygen, shaping the third and current of Earth's atmospheres. Plants, later animals and possibly earlier forms of fungi form around this time. The early and late phases of this eon may have undergone "Snowball Earth" periods, in which all of the planet suffered below-zero temperatures. The early continents of Columbia, Rodinia and Pannotia, in that order, may have existed in this eon.|
|Phanerozoic||541–present||Complex life, including vertebrates, begin to dominate the Earth's ocean in a process known as the Cambrian explosion. Pangaea forms and later dissolves into Laurasia and Gondwana, which in turn dissolve into the current continents. Gradually, life expands to land and familiar forms of plants, animals and fungi begin appearing, including annelids, insects and reptiles, hence the eon's name, which means "visible life". Several mass extinctions occur, among which birds, the descendants of non-avian dinosaurs, and more recently mammals emerge. Modern animals—including humans—evolve at the most recent phases of this eon.|
The history of the Earth can be organized chronologically according to the geologic time scale, which is split into intervals based on stratigraphic analysis.   The following five timelines show the geologic time scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. Therefore, the second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in the third timeline, the most recent period is expanded in the fourth timeline, and the most recent epoch is expanded in the fifth timeline.
The standard model for the formation of the Solar System (including the Earth) is the solar nebula hypothesis.  In this model, the Solar System formed from a large, rotating cloud of interstellar dust and gas called the solar nebula. It was composed of hydrogen and helium created shortly after the Big Bang 13.8 Ga (billion years ago) and heavier elements ejected by supernovae. About 4.5 Ga, the nebula began a contraction that may have been triggered by the shock wave from a nearby supernova.  A shock wave would have also made the nebula rotate. As the cloud began to accelerate, its angular momentum, gravity, and inertia flattened it into a protoplanetary disk perpendicular to its axis of rotation. Small perturbations due to collisions and the angular momentum of other large debris created the means by which kilometer-sized protoplanets began to form, orbiting the nebular center. 
The center of the nebula, not having much angular momentum, collapsed rapidly, the compression heating it until nuclear fusion of hydrogen into helium began. After more contraction, a T Tauri star ignited and evolved into the Sun. Meanwhile, in the outer part of the nebula gravity caused matter to condense around density perturbations and dust particles, and the rest of the protoplanetary disk began separating into rings. In a process known as runaway accretion, successively larger fragments of dust and debris clumped together to form planets.  Earth formed in this manner about 4.54 billion years ago (with an uncertainty of 1%)     and was largely completed within 10–20 million years.  The solar wind of the newly formed T Tauri star cleared out most of the material in the disk that had not already condensed into larger bodies. The same process is expected to produce accretion disks around virtually all newly forming stars in the universe, some of which yield planets. 
The proto-Earth grew by accretion until its interior was hot enough to melt the heavy, siderophile metals. Having higher densities than the silicates, these metals sank. This so-called iron catastrophe resulted in the separation of a primitive mantle and a (metallic) core only 10 million years after the Earth began to form, producing the layered structure of Earth and setting up the formation of Earth's magnetic field.  J.A. Jacobs  was the first to suggest that Earth's inner core—a solid center distinct from the liquid outer core—is freezing and growing out of the liquid outer core due to the gradual cooling of Earth's interior (about 100 degrees Celsius per billion years  ).
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga.  : 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga,    soon after the formation of the Earth's crust and the Earth itself. The giant impact hypothesis for the Moon's formation states that shortly after formation of an initial crust, the proto-Earth was impacted by a smaller protoplanet, which ejected part of the mantle and crust into space and created the Moon.   
From crater counts on other celestial bodies, it is inferred that a period of intense meteorite impacts, called the Late Heavy Bombardment, began about 4.1 Ga, and concluded around 3.8 Ga, at the end of the Hadean.  In addition, volcanism was severe due to the large heat flow and geothermal gradient.  Nevertheless, detrital zircon crystals dated to 4.4 Ga show evidence of having undergone contact with liquid water, suggesting that the Earth already had oceans or seas at that time. 
By the beginning of the Archean, the Earth had cooled significantly. Present life forms could not have survived at Earth's surface, because the Archean atmosphere lacked oxygen hence had no ozone layer to block ultraviolet light. Nevertheless, it is believed that primordial life began to evolve by the early Archean, with candidate fossils dated to around 3.5 Ga.  Some scientists even speculate that life could have begun during the early Hadean, as far back as 4.4 Ga, surviving the possible Late Heavy Bombardment period in hydrothermal vents below the Earth's surface. 
Formation of the Moon
Earth's only natural satellite, the Moon, is larger relative to its planet than any other satellite in the Solar System. [nb 1] During the Apollo program, rocks from the Moon's surface were brought to Earth. Radiometric dating of these rocks shows that the Moon is 4.53 ± 0.01 billion years old,  formed at least 30 million years after the Solar System.  New evidence suggests the Moon formed even later, 4.48 ± 0.02 Ga, or 70–110 million years after the start of the Solar System. 
Theories for the formation of the Moon must explain its late formation as well as the following facts. First, the Moon has a low density (3.3 times that of water, compared to 5.5 for the Earth  ) and a small metallic core. Second, there is virtually no water or other volatiles on the Moon. Third, the Earth and Moon have the same oxygen isotopic signature (relative abundance of the oxygen isotopes). Of the theories proposed to account for these phenomena, one is widely accepted: The giant impact hypothesis proposes that the Moon originated after a body the size of Mars (sometimes named Theia  ) struck the proto-Earth a glancing blow.  : 256  
The collision released about 100 million times more energy than the more recent Chicxulub impact that is believed to have caused the extinction of the non-avian dinosaurs. It was enough to vaporize some of the Earth's outer layers and melt both bodies.   : 256 A portion of the mantle material was ejected into orbit around the Earth. The giant impact hypothesis predicts that the Moon was depleted of metallic material,  explaining its abnormal composition.  The ejecta in orbit around the Earth could have condensed into a single body within a couple of weeks. Under the influence of its own gravity, the ejected material became a more spherical body: the Moon. 
Mantle convection, the process that drives plate tectonics, is a result of heat flow from the Earth's interior to the Earth's surface.  : 2 It involves the creation of rigid tectonic plates at mid-oceanic ridges. These plates are destroyed by subduction into the mantle at subduction zones. During the early Archean (about 3.0 Ga) the mantle was much hotter than today, probably around 1,600 °C (2,910 °F),  : 82 so convection in the mantle was faster. Although a process similar to present-day plate tectonics did occur, this would have gone faster too. It is likely that during the Hadean and Archean, subduction zones were more common, and therefore tectonic plates were smaller.  : 258 
The initial crust, formed when the Earth's surface first solidified, totally disappeared from a combination of this fast Hadean plate tectonics and the intense impacts of the Late Heavy Bombardment. However, it is thought that it was basaltic in composition, like today's oceanic crust, because little crustal differentiation had yet taken place.  : 258 The first larger pieces of continental crust, which is a product of differentiation of lighter elements during partial melting in the lower crust, appeared at the end of the Hadean, about 4.0 Ga. What is left of these first small continents are called cratons. These pieces of late Hadean and early Archean crust form the cores around which today's continents grew. 
The oldest rocks on Earth are found in the North American craton of Canada. They are tonalites from about 4.0 Ga. They show traces of metamorphism by high temperature, but also sedimentary grains that have been rounded by erosion during transport by water, showing that rivers and seas existed then.  Cratons consist primarily of two alternating types of terranes. The first are so-called greenstone belts, consisting of low-grade metamorphosed sedimentary rocks. These "greenstones" are similar to the sediments today found in oceanic trenches, above subduction zones. For this reason, greenstones are sometimes seen as evidence for subduction during the Archean. The second type is a complex of felsic magmatic rocks. These rocks are mostly tonalite, trondhjemite or granodiorite, types of rock similar in composition to granite (hence such terranes are called TTG-terranes). TTG-complexes are seen as the relicts of the first continental crust, formed by partial melting in basalt.  : Chapter 5
Oceans and atmosphere
Earth is often described as having had three atmospheres. The first atmosphere, captured from the solar nebula, was composed of light (atmophile) elements from the solar nebula, mostly hydrogen and helium. A combination of the solar wind and Earth's heat would have driven off this atmosphere, as a result of which the atmosphere is now depleted of these elements compared to cosmic abundances.  After the impact which created the Moon, the molten Earth released volatile gases and later more gases were released by volcanoes, completing a second atmosphere rich in greenhouse gases but poor in oxygen.  : 256 Finally, the third atmosphere, rich in oxygen, emerged when bacteria began to produce oxygen about 2.8 Ga.  : 83–84, 116–117
In early models for the formation of the atmosphere and ocean, the second atmosphere was formed by outgassing of volatiles from the Earth's interior. Now it is considered likely that many of the volatiles were delivered during accretion by a process known as impact degassing in which incoming bodies vaporize on impact. The ocean and atmosphere would, therefore, have started to form even as the Earth formed.  The new atmosphere probably contained water vapor, carbon dioxide, nitrogen, and smaller amounts of other gases. 
Planetesimals at a distance of 1 astronomical unit (AU), the distance of the Earth from the Sun, probably did not contribute any water to the Earth because the solar nebula was too hot for ice to form and the hydration of rocks by water vapor would have taken too long.   The water must have been supplied by meteorites from the outer asteroid belt and some large planetary embryos from beyond 2.5 AU.   Comets may also have contributed. Though most comets are today in orbits farther away from the Sun than Neptune, computer simulations show that they were originally far more common in the inner parts of the Solar System.  : 130–132
As the Earth cooled, clouds formed. Rain created the oceans. Recent evidence suggests the oceans may have begun forming as early as 4.4 Ga.  By the start of the Archean eon, they already covered much of the Earth. This early formation has been difficult to explain because of a problem known as the faint young Sun paradox. Stars are known to get brighter as they age, and at the time of its formation the Sun would have been emitting only 70% of its current power. Thus, the Sun has become 30% brighter in the last 4.5 billion years.  Many models indicate that the Earth would have been covered in ice.   A likely solution is that there was enough carbon dioxide and methane to produce a greenhouse effect. The carbon dioxide would have been produced by volcanoes and the methane by early microbes. Another greenhouse gas, ammonia, would have been ejected by volcanos but quickly destroyed by ultraviolet radiation.  : 83
Origin of life
One of the reasons for interest in the early atmosphere and ocean is that they form the conditions under which life first arose. There are many models, but little consensus, on how life emerged from non-living chemicals chemical systems created in the laboratory fall well short of the minimum complexity for a living organism.  
The first step in the emergence of life may have been chemical reactions that produced many of the simpler organic compounds, including nucleobases and amino acids, that are the building blocks of life. An experiment in 1953 by Stanley Miller and Harold Urey showed that such molecules could form in an atmosphere of water, methane, ammonia and hydrogen with the aid of sparks to mimic the effect of lightning.  Although atmospheric composition was probably different from that used by Miller and Urey, later experiments with more realistic compositions also managed to synthesize organic molecules.  Computer simulations show that extraterrestrial organic molecules could have formed in the protoplanetary disk before the formation of the Earth. 
Additional complexity could have been reached from at least three possible starting points: self-replication, an organism's ability to produce offspring that are similar to itself metabolism, its ability to feed and repair itself and external cell membranes, which allow food to enter and waste products to leave, but exclude unwanted substances. 
Replication first: RNA world
Even the simplest members of the three modern domains of life use DNA to record their "recipes" and a complex array of RNA and protein molecules to "read" these instructions and use them for growth, maintenance, and self-replication.
The discovery that a kind of RNA molecule called a ribozyme can catalyze both its own replication and the construction of proteins led to the hypothesis that earlier life-forms were based entirely on RNA.  They could have formed an RNA world in which there were individuals but no species, as mutations and horizontal gene transfers would have meant that the offspring in each generation were quite likely to have different genomes from those that their parents started with.  RNA would later have been replaced by DNA, which is more stable and therefore can build longer genomes, expanding the range of capabilities a single organism can have.  Ribozymes remain as the main components of ribosomes, the "protein factories" of modern cells. 
Although short, self-replicating RNA molecules have been artificially produced in laboratories,  doubts have been raised about whether natural non-biological synthesis of RNA is possible.    The earliest ribozymes may have been formed of simpler nucleic acids such as PNA, TNA or GNA, which would have been replaced later by RNA.   Other pre-RNA replicators have been posited, including crystals  : 150 and even quantum systems. 
In 2003 it was proposed that porous metal sulfide precipitates would assist RNA synthesis at about 100 °C (212 °F) and at ocean-bottom pressures near hydrothermal vents. In this hypothesis, the proto-cells would be confined in the pores of the metal substrate until the later development of lipid membranes. 
Metabolism first: iron–sulfur world
Another long-standing hypothesis is that the first life was composed of protein molecules. Amino acids, the building blocks of proteins, are easily synthesized in plausible prebiotic conditions, as are small peptides (polymers of amino acids) that make good catalysts.  : 295–297 A series of experiments starting in 1997 showed that amino acids and peptides could form in the presence of carbon monoxide and hydrogen sulfide with iron sulfide and nickel sulfide as catalysts. Most of the steps in their assembly required temperatures of about 100 °C (212 °F) and moderate pressures, although one stage required 250 °C (482 °F) and a pressure equivalent to that found under 7 kilometers (4.3 mi) of rock. Hence, self-sustaining synthesis of proteins could have occurred near hydrothermal vents. 
A difficulty with the metabolism-first scenario is finding a way for organisms to evolve. Without the ability to replicate as individuals, aggregates of molecules would have "compositional genomes" (counts of molecular species in the aggregate) as the target of natural selection. However, a recent model shows that such a system is unable to evolve in response to natural selection. 
Membranes first: Lipid world
It has been suggested that double-walled "bubbles" of lipids like those that form the external membranes of cells may have been an essential first step.  Experiments that simulated the conditions of the early Earth have reported the formation of lipids, and these can spontaneously form liposomes, double-walled "bubbles", and then reproduce themselves. Although they are not intrinsically information-carriers as nucleic acids are, they would be subject to natural selection for longevity and reproduction. Nucleic acids such as RNA might then have formed more easily within the liposomes than they would have outside. 
The clay theory
Some clays, notably montmorillonite, have properties that make them plausible accelerators for the emergence of an RNA world: they grow by self-replication of their crystalline pattern, are subject to an analog of natural selection (as the clay "species" that grows fastest in a particular environment rapidly becomes dominant), and can catalyze the formation of RNA molecules.  Although this idea has not become the scientific consensus, it still has active supporters.  : 150–158 
Research in 2003 reported that montmorillonite could also accelerate the conversion of fatty acids into "bubbles", and that the bubbles could encapsulate RNA attached to the clay. Bubbles can then grow by absorbing additional lipids and dividing. The formation of the earliest cells may have been aided by similar processes. 
A similar hypothesis presents self-replicating iron-rich clays as the progenitors of nucleotides, lipids and amino acids. 
Last universal common ancestor
It is believed that of this multiplicity of protocells, only one line survived. Current phylogenetic evidence suggests that the last universal ancestor (LUA) lived during the early Archean eon, perhaps 3.5 Ga or earlier.   This LUA cell is the ancestor of all life on Earth today. It was probably a prokaryote, possessing a cell membrane and probably ribosomes, but lacking a nucleus or membrane-bound organelles such as mitochondria or chloroplasts. Like modern cells, it used DNA as its genetic code, RNA for information transfer and protein synthesis, and enzymes to catalyze reactions. Some scientists believe that instead of a single organism being the last universal common ancestor, there were populations of organisms exchanging genes by lateral gene transfer. 
The Proterozoic eon lasted from 2.5 Ga to 542 Ma (million years) ago.  : 130 In this time span, cratons grew into continents with modern sizes. The change to an oxygen-rich atmosphere was a crucial development. Life developed from prokaryotes into eukaryotes and multicellular forms. The Proterozoic saw a couple of severe ice ages called snowball Earths. After the last Snowball Earth about 600 Ma, the evolution of life on Earth accelerated. About 580 Ma, the Ediacaran biota formed the prelude for the Cambrian Explosion. [ citation needed ]
The earliest cells absorbed energy and food from the surrounding environment. They used fermentation, the breakdown of more complex compounds into less complex compounds with less energy, and used the energy so liberated to grow and reproduce. Fermentation can only occur in an anaerobic (oxygen-free) environment. The evolution of photosynthesis made it possible for cells to derive energy from the Sun.  : 377
Most of the life that covers the surface of the Earth depends directly or indirectly on photosynthesis. The most common form, oxygenic photosynthesis, turns carbon dioxide, water, and sunlight into food. It captures the energy of sunlight in energy-rich molecules such as ATP, which then provide the energy to make sugars. To supply the electrons in the circuit, hydrogen is stripped from water, leaving oxygen as a waste product.  Some organisms, including purple bacteria and green sulfur bacteria, use an anoxygenic form of photosynthesis that uses alternatives to hydrogen stripped from water as electron donors examples are hydrogen sulfide, sulfur and iron. Such extremophile organisms are restricted to otherwise inhospitable environments such as hot springs and hydrothermal vents.  : 379–382 
The simpler anoxygenic form arose about 3.8 Ga, not long after the appearance of life. The timing of oxygenic photosynthesis is more controversial it had certainly appeared by about 2.4 Ga, but some researchers put it back as far as 3.2 Ga.  The latter "probably increased global productivity by at least two or three orders of magnitude".   Among the oldest remnants of oxygen-producing lifeforms are fossil stromatolites.   
At first, the released oxygen was bound up with limestone, iron, and other minerals. The oxidized iron appears as red layers in geological strata called banded iron formations that formed in abundance during the Siderian period (between 2500 Ma and 2300 Ma).  : 133 When most of the exposed readily reacting minerals were oxidized, oxygen finally began to accumulate in the atmosphere. Though each cell only produced a minute amount of oxygen, the combined metabolism of many cells over a vast time transformed Earth's atmosphere to its current state. This was Earth's third atmosphere.  : 50–51  : 83–84, 116–117
Some oxygen was stimulated by solar ultraviolet radiation to form ozone, which collected in a layer near the upper part of the atmosphere. The ozone layer absorbed, and still absorbs, a significant amount of the ultraviolet radiation that once had passed through the atmosphere. It allowed cells to colonize the surface of the ocean and eventually the land: without the ozone layer, ultraviolet radiation bombarding land and sea would have caused unsustainable levels of mutation in exposed cells.   : 219–220
Photosynthesis had another major impact. Oxygen was toxic much life on Earth probably died out as its levels rose in what is known as the oxygen catastrophe. Resistant forms survived and thrived, and some developed the ability to use oxygen to increase their metabolism and obtain more energy from the same food. 
The natural evolution of the Sun made it progressively more luminous during the Archean and Proterozoic eons the Sun's luminosity increases 6% every billion years.  : 165 As a result, the Earth began to receive more heat from the Sun in the Proterozoic eon. However, the Earth did not get warmer. Instead, the geological record suggests it cooled dramatically during the early Proterozoic. Glacial deposits found in South Africa date back to 2.2 Ga, at which time, based on paleomagnetic evidence, they must have been located near the equator. Thus, this glaciation, known as the Huronian glaciation, may have been global. Some scientists suggest this was so severe that the Earth was frozen over from the poles to the equator, a hypothesis called Snowball Earth. 
The Huronian ice age might have been caused by the increased oxygen concentration in the atmosphere, which caused the decrease of methane (CH4) in the atmosphere. Methane is a strong greenhouse gas, but with oxygen it reacts to form CO2, a less effective greenhouse gas.  : 172 When free oxygen became available in the atmosphere, the concentration of methane could have decreased dramatically, enough to counter the effect of the increasing heat flow from the Sun. 
However, the term Snowball Earth is more commonly used to describe later extreme ice ages during the Cryogenian period. There were four periods, each lasting about 10 million years, between 750 and 580 million years ago, when the earth is thought to have been covered with ice apart from the highest mountains, and average temperatures were about −50 °C (−58 °F).  The snowball may have been partly due to the location of the supercontinent Rodinia straddling the Equator. Carbon dioxide combines with rain to weather rocks to form carbonic acid, which is then washed out to sea, thus extracting the greenhouse gas from the atmosphere. When the continents are near the poles, the advance of ice covers the rocks, slowing the reduction in carbon dioxide, but in the Cryogenian the weathering of Rodinia was able to continue unchecked until the ice advanced to the tropics. The process may have finally been reversed by the emission of carbon dioxide from volcanoes or the destabilization of methane gas hydrates. According to the alternative Slushball Earth theory, even at the height of the ice ages there was still open water at the Equator.  
Emergence of eukaryotes
Modern taxonomy classifies life into three domains. The time of their origin is uncertain. The Bacteria domain probably first split off from the other forms of life (sometimes called Neomura), but this supposition is controversial. Soon after this, by 2 Ga,  the Neomura split into the Archaea and the Eukarya. Eukaryotic cells (Eukarya) are larger and more complex than prokaryotic cells (Bacteria and Archaea), and the origin of that complexity is only now becoming known. [ citation needed ] The earliest fossils possessing features typical of fungi date to the Paleoproterozoic era, some 2.4 ago these multicellular benthic organisms had filamentous structures capable of anastomosis. 
Around this time, the first proto-mitochondrion was formed. A bacterial cell related to today's Rickettsia,  which had evolved to metabolize oxygen, entered a larger prokaryotic cell, which lacked that capability. Perhaps the large cell attempted to digest the smaller one but failed (possibly due to the evolution of prey defenses). The smaller cell may have tried to parasitize the larger one. In any case, the smaller cell survived inside the larger cell. Using oxygen, it metabolized the larger cell's waste products and derived more energy. Part of this excess energy was returned to the host. The smaller cell replicated inside the larger one. Soon, a stable symbiosis developed between the large cell and the smaller cells inside it. Over time, the host cell acquired some genes from the smaller cells, and the two kinds became dependent on each other: the larger cell could not survive without the energy produced by the smaller ones, and these, in turn, could not survive without the raw materials provided by the larger cell. The whole cell is now considered a single organism, and the smaller cells are classified as organelles called mitochondria. 
A similar event occurred with photosynthetic cyanobacteria  entering large heterotrophic cells and becoming chloroplasts.  : 60–61  : 536–539 Probably as a result of these changes, a line of cells capable of photosynthesis split off from the other eukaryotes more than 1 billion years ago. There were probably several such inclusion events. Besides the well-established endosymbiotic theory of the cellular origin of mitochondria and chloroplasts, there are theories that cells led to peroxisomes, spirochetes led to cilia and flagella, and that perhaps a DNA virus led to the cell nucleus,   though none of them are widely accepted. 
Archaeans, bacteria, and eukaryotes continued to diversify and to become more complex and better adapted to their environments. Each domain repeatedly split into multiple lineages, although little is known about the history of the archaea and bacteria. Around 1.1 Ga, the supercontinent Rodinia was assembling.   The plant, animal, and fungi lines had split, though they still existed as solitary cells. Some of these lived in colonies, and gradually a division of labor began to take place for instance, cells on the periphery might have started to assume different roles from those in the interior. Although the division between a colony with specialized cells and a multicellular organism is not always clear, around 1 billion years ago  , the first multicellular plants emerged, probably green algae.  Possibly by around 900 Ma  : 488 true multicellularity had also evolved in animals. [ citation needed ]
At first, it probably resembled today's sponges, which have totipotent cells that allow a disrupted organism to reassemble itself.  : 483–487 As the division of labor was completed in all lines of multicellular organisms, cells became more specialized and more dependent on each other isolated cells would die. [ citation needed ]
Supercontinents in the Proterozoic
Reconstructions of tectonic plate movement in the past 250 million years (the Cenozoic and Mesozoic eras) can be made reliably using fitting of continental margins, ocean floor magnetic anomalies and paleomagnetic poles. No ocean crust dates back further than that, so earlier reconstructions are more difficult. Paleomagnetic poles are supplemented by geologic evidence such as orogenic belts, which mark the edges of ancient plates, and past distributions of flora and fauna. The further back in time, the scarcer and harder to interpret the data get and the more uncertain the reconstructions.  : 370
Throughout the history of the Earth, there have been times when continents collided and formed a supercontinent, which later broke up into new continents. About 1000 to 830 Ma, most continental mass was united in the supercontinent Rodinia.  : 370  Rodinia may have been preceded by Early-Middle Proterozoic continents called Nuna and Columbia.  : 374  
After the break-up of Rodinia about 800 Ma, the continents may have formed another short-lived supercontinent around 550 Ma. The hypothetical supercontinent is sometimes referred to as Pannotia or Vendia.  : 321–322 The evidence for it is a phase of continental collision known as the Pan-African orogeny, which joined the continental masses of current-day Africa, South America, Antarctica and Australia. The existence of Pannotia depends on the timing of the rifting between Gondwana (which included most of the landmass now in the Southern Hemisphere, as well as the Arabian Peninsula and the Indian subcontinent) and Laurentia (roughly equivalent to current-day North America).  : 374 It is at least certain that by the end of the Proterozoic eon, most of the continental mass lay united in a position around the south pole. 
Late Proterozoic climate and life
The end of the Proterozoic saw at least two Snowball Earths, so severe that the surface of the oceans may have been completely frozen. This happened about 716.5 and 635 Ma, in the Cryogenian period.  The intensity and mechanism of both glaciations are still under investigation and harder to explain than the early Proterozoic Snowball Earth.  Most paleoclimatologists think the cold episodes were linked to the formation of the supercontinent Rodinia.  Because Rodinia was centered on the equator, rates of chemical weathering increased and carbon dioxide (CO2) was taken from the atmosphere. Because CO2 is an important greenhouse gas, climates cooled globally. [ citation needed ] In the same way, during the Snowball Earths most of the continental surface was covered with permafrost, which decreased chemical weathering again, leading to the end of the glaciations. An alternative hypothesis is that enough carbon dioxide escaped through volcanic outgassing that the resulting greenhouse effect raised global temperatures.  Increased volcanic activity resulted from the break-up of Rodinia at about the same time. [ citation needed ]
The Cryogenian period was followed by the Ediacaran period, which was characterized by a rapid development of new multicellular lifeforms.  Whether there is a connection between the end of the severe ice ages and the increase in diversity of life is not clear, but it does not seem coincidental. The new forms of life, called Ediacara biota, were larger and more diverse than ever. Though the taxonomy of most Ediacaran life forms is unclear, some were ancestors of groups of modern life.  Important developments were the origin of muscular and neural cells. None of the Ediacaran fossils had hard body parts like skeletons. These first appear after the boundary between the Proterozoic and Phanerozoic eons or Ediacaran and Cambrian periods. [ citation needed ]
The Phanerozoic is the current eon on Earth, which started approximately 542 million years ago. It consists of three eras: The Paleozoic, Mesozoic, and Cenozoic,  and is the time when multi-cellular life greatly diversified into almost all the organisms known today. 
The Paleozoic ("old life") era was the first and longest era of the Phanerozoic eon, lasting from 542 to 251 Ma.  During the Paleozoic, many modern groups of life came into existence. Life colonized the land, first plants, then animals. Two major extinctions occurred. The continents formed at the break-up of Pannotia and Rodinia at the end of the Proterozoic slowly moved together again, forming the supercontinent Pangaea in the late Paleozoic. [ citation needed ]
The Mesozoic ("middle life") era lasted from 251 Ma to 66 Ma.  It is subdivided into the Triassic, Jurassic, and Cretaceous periods. The era began with the Permian–Triassic extinction event, the most severe extinction event in the fossil record 95% of the species on Earth died out.  It ended with the Cretaceous–Paleogene extinction event that wiped out the dinosaurs. [ citation needed ] .
The Cenozoic ("new life") era began at 66 Ma,  and is subdivided into the Paleogene, Neogene, and Quaternary periods. These three periods are further split into seven subdivisions, with the Paleogene composed of The Paleocene, Eocene, and Oligocene, the Neogene divided into the Miocene, Pliocene, and the Quaternary composed of the Pleistocene, and Holocene.  Mammals, birds, amphibians, crocodilians, turtles, and lepidosaurs survived the Cretaceous–Paleogene extinction event that killed off the non-avian dinosaurs and many other forms of life, and this is the era during which they diversified into their modern forms. [ citation needed ]
Tectonics, paleogeography and climate
At the end of the Proterozoic, the supercontinent Pannotia had broken apart into the smaller continents Laurentia, Baltica, Siberia and Gondwana.  During periods when continents move apart, more oceanic crust is formed by volcanic activity. Because young volcanic crust is relatively hotter and less dense than old oceanic crust, the ocean floors rise during such periods. This causes the sea level to rise. Therefore, in the first half of the Paleozoic, large areas of the continents were below sea level. [ citation needed ]
Early Paleozoic climates were warmer than today, but the end of the Ordovician saw a short ice age during which glaciers covered the south pole, where the huge continent Gondwana was situated. Traces of glaciation from this period are only found on former Gondwana. During the Late Ordovician ice age, a few mass extinctions took place, in which many brachiopods, trilobites, Bryozoa and corals disappeared. These marine species could probably not contend with the decreasing temperature of the sea water. 
The continents Laurentia and Baltica collided between 450 and 400 Ma, during the Caledonian Orogeny, to form Laurussia (also known as Euramerica).  Traces of the mountain belt this collision caused can be found in Scandinavia, Scotland, and the northern Appalachians. In the Devonian period (416–359 Ma)  Gondwana and Siberia began to move towards Laurussia. The collision of Siberia with Laurussia caused the Uralian Orogeny, the collision of Gondwana with Laurussia is called the Variscan or Hercynian Orogeny in Europe or the Alleghenian Orogeny in North America. The latter phase took place during the Carboniferous period (359–299 Ma)  and resulted in the formation of the last supercontinent, Pangaea. 
By 180 Ma, Pangaea broke up into Laurasia and Gondwana. [ citation needed ]
The rate of the evolution of life as recorded by fossils accelerated in the Cambrian period (542–488 Ma).  The sudden emergence of many new species, phyla, and forms in this period is called the Cambrian Explosion. The biological fomenting in the Cambrian Explosion was unprecedented before and since that time.  : 229 Whereas the Ediacaran life forms appear yet primitive and not easy to put in any modern group, at the end of the Cambrian most modern phyla were already present. The development of hard body parts such as shells, skeletons or exoskeletons in animals like molluscs, echinoderms, crinoids and arthropods (a well-known group of arthropods from the lower Paleozoic are the trilobites) made the preservation and fossilization of such life forms easier than those of their Proterozoic ancestors. For this reason, much more is known about life in and after the Cambrian than about that of older periods. Some of these Cambrian groups appear complex but are seemingly quite different from modern life examples are Anomalocaris and Haikouichthys. More recently, however, these seem to have found a place in modern classification. [ citation needed ]
During the Cambrian, the first vertebrate animals, among them the first fishes, had appeared.  : 357 A creature that could have been the ancestor of the fishes, or was probably closely related to it, was Pikaia. It had a primitive notochord, a structure that could have developed into a vertebral column later. The first fishes with jaws (Gnathostomata) appeared during the next geological period, the Ordovician. The colonisation of new niches resulted in massive body sizes. In this way, fishes with increasing sizes evolved during the early Paleozoic, such as the titanic placoderm Dunkleosteus, which could grow 7 meters (23 ft) long. [ citation needed ]
The diversity of life forms did not increase greatly because of a series of mass extinctions that define widespread biostratigraphic units called biomeres.  After each extinction pulse, the continental shelf regions were repopulated by similar life forms that may have been evolving slowly elsewhere.  By the late Cambrian, the trilobites had reached their greatest diversity and dominated nearly all fossil assemblages.  : 34
Colonization of land
Oxygen accumulation from photosynthesis resulted in the formation of an ozone layer that absorbed much of the Sun's ultraviolet radiation, meaning unicellular organisms that reached land were less likely to die, and prokaryotes began to multiply and become better adapted to survival out of the water. Prokaryote lineages  had probably colonized the land as early as 2.6 Ga  even before the origin of the eukaryotes. For a long time, the land remained barren of multicellular organisms. The supercontinent Pannotia formed around 600 Ma and then broke apart a short 50 million years later.  Fish, the earliest vertebrates, evolved in the oceans around 530 Ma.  : 354 A major extinction event occurred near the end of the Cambrian period,  which ended 488 Ma. 
Several hundred million years ago, plants (probably resembling algae) and fungi started growing at the edges of the water, and then out of it.  : 138–140 The oldest fossils of land fungi and plants date to 480–460 Ma, though molecular evidence suggests the fungi may have colonized the land as early as 1000 Ma and the plants 700 Ma.  Initially remaining close to the water's edge, mutations and variations resulted in further colonization of this new environment. The timing of the first animals to leave the oceans is not precisely known: the oldest clear evidence is of arthropods on land around 450 Ma,  perhaps thriving and becoming better adapted due to the vast food source provided by the terrestrial plants. There is also unconfirmed evidence that arthropods may have appeared on land as early as 530 Ma. 
Evolution of tetrapods
At the end of the Ordovician period, 443 Ma,  additional extinction events occurred, perhaps due to a concurrent ice age.  Around 380 to 375 Ma, the first tetrapods evolved from fish.  Fins evolved to become limbs that the first tetrapods used to lift their heads out of the water to breathe air. This would let them live in oxygen-poor water, or pursue small prey in shallow water.  They may have later ventured on land for brief periods. Eventually, some of them became so well adapted to terrestrial life that they spent their adult lives on land, although they hatched in the water and returned to lay their eggs. This was the origin of the amphibians. About 365 Ma, another period of extinction occurred, perhaps as a result of global cooling.  Plants evolved seeds, which dramatically accelerated their spread on land, around this time (by approximately 360 Ma).  
About 20 million years later (340 Ma  : 293–296 ), the amniotic egg evolved, which could be laid on land, giving a survival advantage to tetrapod embryos. This resulted in the divergence of amniotes from amphibians. Another 30 million years (310 Ma  : 254–256 ) saw the divergence of the synapsids (including mammals) from the sauropsids (including birds and reptiles). Other groups of organisms continued to evolve, and lines diverged—in fish, insects, bacteria, and so on—but less is known of the details. [ citation needed ]
After yet another, the most severe extinction of the period (251
250 Ma), around 230 Ma, dinosaurs split off from their reptilian ancestors.  The Triassic–Jurassic extinction event at 200 Ma spared many of the dinosaurs,   and they soon became dominant among the vertebrates. Though some mammalian lines began to separate during this period, existing mammals were probably small animals resembling shrews.  : 169
The boundary between avian and non-avian dinosaurs is not clear, but Archaeopteryx, traditionally considered one of the first birds, lived around 150 Ma. 
The earliest evidence for the angiosperms evolving flowers is during the Cretaceous period, some 20 million years later (132 Ma). 
The first of five great mass extinctions was the Ordovician-Silurian extinction. Its possible cause was the intense glaciation of Gondwana, which eventually led to a snowball earth. 60% of marine invertebrates became extinct and 25% of all families. [ citation needed ]
The second mass extinction was the Late Devonian extinction, probably caused by the evolution of trees, which could have led to the depletion of greenhouse gases (like CO2) or the eutrophication of water. 70% of all species became extinct. [ citation needed ]
The third mass extinction was the Permian-Triassic, or the Great Dying, event was possibly caused by some combination of the Siberian Traps volcanic event, an asteroid impact, methane hydrate gasification, sea level fluctuations, and a major anoxic event. Either the proposed Wilkes Land crater  in Antarctica or Bedout structure off the northwest coast of Australia may indicate an impact connection with the Permian-Triassic extinction. But it remains uncertain whether either these or other proposed Permian-Triassic boundary craters are either real impact craters or even contemporaneous with the Permian-Triassic extinction event. This was by far the deadliest extinction ever, with about 57% of all families and 83% of all genera killed.  
The fourth mass extinction was the Triassic-Jurassic extinction event in which almost all synapsids and archosaurs became extinct, probably due to new competition from dinosaurs. [ citation needed ]
The fifth and most recent mass extinction was the K-T extinction. In 66 Ma, a 10-kilometer (6.2 mi) asteroid struck Earth just off the Yucatán Peninsula—somewhere in the southwestern tip of then Laurasia—where the Chicxulub crater is today. This ejected vast quantities of particulate matter and vapor into the air that occluded sunlight, inhibiting photosynthesis. 75% of all life, including the non-avian dinosaurs, became extinct,  marking the end of the Cretaceous period and Mesozoic era. [ citation needed ]
Diversification of mammals
The first true mammals evolved in the shadows of dinosaurs and other large archosaurs that filled the world by the late Triassic. The first mammals were very small, and were probably nocturnal to escape predation. Mammal diversification truly began only after the Cretaceous-Paleogene extinction event.  By the early Paleocene the earth recovered from the extinction, and mammalian diversity increased. Creatures like Ambulocetus took to the oceans to eventually evolve into whales,  whereas some creatures, like primates, took to the trees.  This all changed during the mid to late Eocene when the circum-Antarctic current formed between Antarctica and Australia which disrupted weather patterns on a global scale. Grassless savanna began to predominate much of the landscape, and mammals such as Andrewsarchus rose up to become the largest known terrestrial predatory mammal ever,  and early whales like Basilosaurus took control of the seas. [ citation needed ]
The evolution of grass brought a remarkable change to the Earth's landscape, and the new open spaces created pushed mammals to get bigger and bigger. Grass started to expand in the Miocene, and the Miocene is where many modern- day mammals first appeared. Giant ungulates like Paraceratherium and Deinotherium evolved to rule the grasslands. The evolution of grass also brought primates down from the trees, and started human evolution. The first big cats evolved during this time as well.  The Tethys Sea was closed off by the collision of Africa and Europe. 
The formation of Panama was perhaps the most important geological event to occur in the last 60 million years. Atlantic and Pacific currents were closed off from each other, which caused the formation of the Gulf Stream, which made Europe warmer. The land bridge allowed the isolated creatures of South America to migrate over to North America, and vice versa.  Various species migrated south, leading to the presence in South America of llamas, the spectacled bear, kinkajous and jaguars. [ citation needed ]
Three million years ago saw the start of the Pleistocene epoch, which featured dramatic climactic changes due to the ice ages. The ice ages led to the evolution of modern man in Saharan Africa and expansion. The mega-fauna that dominated fed on grasslands that, by now, had taken over much of the subtropical world. The large amounts of water held in the ice allowed for various bodies of water to shrink and sometimes disappear such as the North Sea and the Bering Strait. It is believed by many that a huge migration took place along Beringia which is why, today, there are camels (which evolved and became extinct in North America), horses (which evolved and became extinct in North America), and Native Americans. The ending of the last ice age coincided with the expansion of man, along with a massive die out of ice age mega-fauna. This extinction is nicknamed "the Sixth Extinction".
A small African ape living around 6 Ma was the last animal whose descendants would include both modern humans and their closest relatives, the chimpanzees.  : 100–101 Only two branches of its family tree have surviving descendants. Very soon after the split, for reasons that are still unclear, apes in one branch developed the ability to walk upright.  : 95–99 Brain size increased rapidly, and by 2 Ma, the first animals classified in the genus Homo had appeared.  : 300 Of course, the line between different species or even genera is somewhat arbitrary as organisms continuously change over generations. Around the same time, the other branch split into the ancestors of the common chimpanzee and the ancestors of the bonobo as evolution continued simultaneously in all life forms.  : 100–101
The ability to control fire probably began in Homo erectus (or Homo ergaster), probably at least 790,000 years ago  but perhaps as early as 1.5 Ma.  : 67 The use and discovery of controlled fire may even predate Homo erectus. Fire was possibly used by the early Lower Paleolithic (Oldowan) hominid Homo habilis or strong australopithecines such as Paranthropus. 
It is more difficult to establish the origin of language it is unclear whether Homo erectus could speak or if that capability had not begun until Homo sapiens.  : 67 As brain size increased, babies were born earlier, before their heads grew too large to pass through the pelvis. As a result, they exhibited more plasticity, and thus possessed an increased capacity to learn and required a longer period of dependence. Social skills became more complex, language became more sophisticated, and tools became more elaborate. This contributed to further cooperation and intellectual development.  : 7 Modern humans (Homo sapiens) are believed to have originated around 200,000 years ago or earlier in Africa the oldest fossils date back to around 160,000 years ago. 
The first humans to show signs of spirituality are the Neanderthals (usually classified as a separate species with no surviving descendants) they buried their dead, often with no sign of food or tools.  : 17 However, evidence of more sophisticated beliefs, such as the early Cro-Magnon cave paintings (probably with magical or religious significance)  : 17–19 did not appear until 32,000 years ago.  Cro-Magnons also left behind stone figurines such as Venus of Willendorf, probably also signifying religious belief.  : 17–19 By 11,000 years ago, Homo sapiens had reached the southern tip of South America, the last of the uninhabited continents (except for Antarctica, which remained undiscovered until 1820 AD).  Tool use and communication continued to improve, and interpersonal relationships became more intricate. [ citation needed ]
Throughout more than 90% of its history, Homo sapiens lived in small bands as nomadic hunter-gatherers.  : 8 As language became more complex, the ability to remember and communicate information resulted, according to a theory proposed by Richard Dawkins, in a new replicator: the meme.  Ideas could be exchanged quickly and passed down the generations. Cultural evolution quickly outpaced biological evolution, and history proper began. Between 8500 and 7000 BC, humans in the Fertile Crescent in the Middle East began the systematic husbandry of plants and animals: agriculture.  This spread to neighboring regions, and developed independently elsewhere, until most Homo sapiens lived sedentary lives in permanent settlements as farmers. Not all societies abandoned nomadism, especially those in isolated areas of the globe poor in domesticable plant species, such as Australia.  However, among those civilizations that did adopt agriculture, the relative stability and increased productivity provided by farming allowed the population to expand. [ citation needed ]
Agriculture had a major impact humans began to affect the environment as never before. Surplus food allowed a priestly or governing class to arise, followed by increasing division of labor. This led to Earth's first civilization at Sumer in the Middle East, between 4000 and 3000 BC.  : 15 Additional civilizations quickly arose in ancient Egypt, at the Indus River valley and in China. The invention of writing enabled complex societies to arise: record-keeping and libraries served as a storehouse of knowledge and increased the cultural transmission of information. Humans no longer had to spend all their time working for survival, enabling the first specialized occupations (e.g. craftsmen, merchants, priests, etc.). Curiosity and education drove the pursuit of knowledge and wisdom, and various disciplines, including science (in a primitive form), arose. This in turn led to the emergence of increasingly larger and more complex civilizations, such as the first empires, which at times traded with one another, or fought for territory and resources.
By around 500 BC, there were advanced civilizations in the Middle East, Iran, India, China, and Greece, at times expanding, at times entering into decline.  : 3 In 221 BC, China became a single polity that would grow to spread its culture throughout East Asia, and it has remained the most populous nation in the world. During this period, famous Hindu texts known as vedas came in existence in Indus valley civilization. This civilization developed in warfare, arts, science, mathematics and in architect. [ citation needed ] The fundamentals of Western civilization were largely shaped in Ancient Greece, with the world's first democratic government and major advances in philosophy, science. Ancient Rome in law, government, and engineering.  The Roman Empire was Christianized by Emperor Constantine in the early 4th century and declined by the end of the 5th. Beginning with the 7th century, Christianization of Europe began. In 610, Islam was founded and quickly became the dominant religion in Western Asia. The House of Wisdom was established in Abbasid-era Baghdad, Iraq.  It is considered to have been a major intellectual center during the Islamic Golden Age, where Muslim scholars in Baghdad and Cairo flourished from the ninth to the thirteenth centuries until the Mongol sack of Baghdad in 1258 AD. In 1054 AD the Great Schism between the Roman Catholic Church and the Eastern Orthodox Church led to the prominent cultural differences between Western and Eastern Europe. [ citation needed ]
In the 14th century, the Renaissance began in Italy with advances in religion, art, and science.  : 317–319 At that time the Christian Church as a political entity lost much of its power. In 1492, Christopher Columbus reached the Americas, initiating great changes to the new world. European civilization began to change beginning in 1500, leading to the scientific and industrial revolutions. That continent began to exert political and cultural dominance over human societies around the world, a time known as the Colonial era (also see Age of Discovery).  : 295–299 In the 18th century a cultural movement known as the Age of Enlightenment further shaped the mentality of Europe and contributed to its secularization. From 1914 to 1918 and 1939 to 1945, nations around the world were embroiled in world wars. Established following World War I, the League of Nations was a first step in establishing international institutions to settle disputes peacefully. After failing to prevent World War II, mankind's bloodiest conflict, it was replaced by the United Nations. After the war, many new states were formed, declaring or being granted independence in a period of decolonization. The democratic capitalist United States and the socialist Soviet Union became the world's dominant superpowers for a time, and they held an ideological, often-violent rivalry known as the Cold War until the dissolution of the latter. In 1992, several European nations joined in the European Union. As transportation and communication improved, the economies and political affairs of nations around the world have become increasingly intertwined. This globalization has often produced both conflict and cooperation. [ citation needed ]
Change has continued at a rapid pace from the mid-1940s to today. Technological developments include nuclear weapons, computers, genetic engineering, and nanotechnology. Economic globalization, spurred by advances in communication and transportation technology, has influenced everyday life in many parts of the world. Cultural and institutional forms such as democracy, capitalism, and environmentalism have increased influence. Major concerns and problems such as disease, war, poverty, violent radicalism, and recently, human-caused climate change have risen as the world population increases. [ citation needed ]
In 1957, the Soviet Union launched the first artificial satellite into orbit and, soon afterward, Yuri Gagarin became the first human in space. Neil Armstrong, an American, was the first to set foot on another astronomical object, the Moon. Unmanned probes have been sent to all the known planets in the Solar System, with some (such as the two Voyager spacecraft) having left the Solar System. Five space agencies, representing over fifteen countries,  have worked together to build the International Space Station. Aboard it, there has been a continuous human presence in space since 2000.  The World Wide Web became a part of everyday life in the 1990s, and since then has become an indispensable source of information in the developed world. [ citation needed ]
These factions of Sirian rebels used advanced technology to change the orbit of their planet, and to catch a ride on the trajectory of our Sun, this planet is known today as Nibiru. They decided to strike out on their own and dominate and rule other cultures, other planets, adopting the war like behaviors and attitude of their previous Reptilian overlords. They created a new race of bodies which is called Nephilim with the support of some factions of the Elohim and reptilians supporting this race of giants.
The Sirians (Sirius B) were hosting the second cycle of seeding the Human Race on the earth, and in retaliation to their power and control over the earth evolution, the ancient Annunaki adopted their new relatives from Niburu. They demanded from the Sirians that their races have place to evolve on the earth as equal placement to the human beings, because they did not have the ability to evolve with source creator. This was a hidden deception as they were not interested in equality or evolution on the earth, but that the giant Nephilim could be controlled easily and directly by them off planet. Thus, they would get more power and control on the surface over the planet earth resources (such as mining for gold and minerals), as well as make humans the slave race to serve the reptilian genetic based races and their projects and agendas.
During the end of 2nd Seeding the Annunaki started breeding with Humans and a race called NEPHILIM was created. This was not agreed upon to genetically tamper with the human race and the Higher factions of the Lyran-Elohim council would not continue to let this race walk on or be on the Earth. They considered it violation which angered the Annunaki because other extraterrestrial races were being allowed to introduce genetic material into the earth, as the "grand experiment". This created a Conflict and another War broke out. This created the war with the Annunaki and other Annunaki sympathizers,such as the Dracs and Sirian Annunaki Hybrids. The War ended this seeding attempt and we reorganized for the next Evolutionary Round. Since then, the planet endured the Luciferian Rebellion 22,000 years ago and Luciferian Covenant which was organized by these rebel faction offshoots and their reptilian hybrids to have full control over the earth and program humans to be their slaves.
New Fossil Discovery Rewrites History of First Human Beings
Late last month, we reported on how new fossil finds had changed what were thought to be settled questions about the last common ancestor between chimpanzees and humans. Now, we’ve got news of another major upset to the known human timeline and our own appearance on planet Earth.
Previously, the earliest fossil remains of anatomically modern humans (AMH) were found in Ethiopia and dated to
200,000 years ago. Many other AMH fossils have been found in the same areas of Africa, and the scientific consensus has been that these finds represented the first appearance of modern humans. This single origin hypothesis isn’t the only theory for how humanity first emerged and then spread across the continent and planet, but it’s been the most common argument for a number of years. These new finds, located in Morocco, challenge the existing narrative. It was believed that humanity spread across Africa for over a hundred thousand years before traveling to new continents roughly 70,000 years ago.
This new work is from a site named Jebel Irhoud, where excavations have been ongoing for decades. Part of what sets them apart is that the research team isn’t working from just one skull or bone fragments from a single individual, but a group of five separate people. Dr. Hublin and his colleagues used a technique known as thermoluminescence, a technique that measures the accumulated radiation dose of objects that have previously been heated or exposed to sunlight to measure how old they are. The degree of luminescence is proportional to the radiation dose absorbed by the material in question.
In this case, the dating method established that flint blades buried at the site had been burned, probably through exposure to cooking fires, roughly 300,000 years ago. The skulls the expedition found were in the same rock layer as the flint blades, which strongly implies they date to roughly the same time period.
One of the interesting differences between early and modern humans (both of which are classified as homo sapiens sapiens) is that while they looked nearly identical to us, their brains were shaped differently. It’s proven difficult to find a comparison image of brain size, but this slide does show the subtle difference in skull shape between early and modern man.
Both our skulls and our brains have become rounder over the millennia, possibly driven by an enlarged parietal lobe and cerebellum compared with the earliest examples of modern humans. How and if this changed how humans think is unknown. The humans who lived at Jebel Irhoud could start fires and craft spears. The flint that they used for their weapon tips wasn’t local to the area, but came from a site some 20 miles south of Jebel Irhoud. This suggests that early humans knew how to find resources and utilize them even when said resources were scattered rather than grouped in a single location. That’s significant in and of itself, particularly for remains as unusual as these.
The argument advanced by Dr. Gunz and Dr. Hublin is that human beings didn’t evolve at a single location or even one specific place. “What we think is before 300,000 years ago, there was a dispersal of our species — or at least the most primitive version of our species — throughout Africa,” Hublin told Nature. Around this time, the Sahara was green and filled with lakes and rivers. Animals that roamed the East African savanna, including gazelles, wildebeest and lions, also lived near Jebel Irhoud, suggesting that these environments were once linked.”
So how do these finds, assuming they prove to be accurately dated and to belong to our own species, change our understanding of human evolution? They suggest, at minimum, that homo sapiens sapiens was around much earlier than we previously thought it was. Whether our species evolved in a single specific location or more generally across the continent is still unclear. And not every scientist agrees with Gunz and Hublin that the Jebel Irhoud bones are clear evidence for AMHs more than 100,000 years before they were previously thought to have emerged.