RE: THE AFRICAN HERITAGE IN HUMAN BIOLOGICAL HISTORY::
“It was during the Archean Eon (a very early period of Earth’s history comprising 43% of our planet’s history and encompassing Earth’s first 2,000 million years and during the PROTEROZOIC ERA that distinct types of microorganisms existed and during the 20th century found in a rock formation IN ZAMBIA, IN AFRICA.
These pioneers of life on earth may have founded the lineage that many eons later led to both plants and animals, including humans.” The scenario is reasonably well defined.
6 billion years ago:
“the Earth originated about 4.6 billion years ago, and by about 4 billion years ago its surface had become cool enough to make life possible.
“By 3.8 billion years ago, rivers were eroding mountains and carrying sediment to valleys and flood plains, forming the first sedimentary rocks. These strata are completely devoid of life.
“The oldest known fossil cells are from the FIG TREE CHERT OF SOUTH AFRICA and are about 3.5 billion years old. (p. 175)
“Paleontologist Elso Barghoorn has found deposits in the fig tree chert of South Africa containing concentrated masses of thick-walled cells about 3.5 billion years old. [G. Ledyard Stebbins, Darwin To DNA: Molecules To Humanity, [Stebbins 1982: 189]
[Note: It was also indicated that:
“THE FIRST CONVINCING EVIDENCE OF PRECAMBRIAN ANIMAL LIFE CAME IN 1930 WITH THE FINDING BY THE GERMAN PALEONTOLOGIST G. GURICH OF TRACES OF FOSSILIZED MULTICELLULAR ORGANISMS IN LATE PROTEROZOIC ROCKS FROM NAMIBIA IN AFRICA.
It was cited in “The oldest eukaryotic cells,” by Gonzalo Vidal in Scientific American, February 1984, volume 250, no. 2.]
Also in 1947 the Australian geologist r. C. Sprigg discovered numerous imprints of primitive aquatic animals – including jellyfish, various kinds of worms and possibly sponges – in the sandstone beds of the Ediacara Jills in South Australia; at the time the rocks were believed to date from the early Cambrian period, but subsequent studies showed that they too belonged to the late Proterozoic.
“Since then similar animal fossils have been found in sedimentary rocks of comparable age in Britain, Canada, Sweden and the U.S.S.R. The discovery of these Ediacarian= fossils pushed the oldest record of MULTICELLULAR LIFE back to about 670 million years ago. Except for the equivocal STROMATOLITES, however, no trace of earlier Precambrian life forms was found until the 1950s.
“The existence of Precambrian microbial life was first established in 1954 by Elso S. Barghoorn of Harvard University and Stanley A. Tyler of the University of Wisconsin, on the basis of their study of microscopic bodies in stromatolitic rocks from the gunflint iron formation in Southern Ontario. Radioactive dating of minerals in the rocks showed they were formed about two billion years ago.
“… The most important step in the uncovering of early Precambrian life had been taken. From this point on the investigation of fossil microorganisms was to lead to a veritable flood of published reports on findings in Precambrian deposits throughout the world.
Comparable studies of precambrian and early paleozoic microfossils were undertaken at the same time by Boris V. Timofeev of the Academy of Sciences of the U.S.S.R., and a similar deluge of publications followed his pioneering work.
” … The American line followed the original hypothesis of Charles Doolittle Walcott, who first ascribed a biological origin to STROMATOLITES at the beginning of the twentieth century. [Gonzalo Vidal 1984: 48]
Professor g. Ledyard Stebbins indicated:
“Until recently, the fossil record of early animal evolution was almost blank, but significant clues are now available.
The oldest recognizable remains:
“The oldest recognizable remains are fossilized worm burrows about 1 billion years old – 400 million years younger than the oldest single-celled eukaryotes.
“A trace fossils of this kind are not common in rocks older than the Ediacara formation of Australia, which is between 680 million and 580 million years old, where paleontologist m. F. Glaessner found remains of several kinds of worms and jellyfishes (medusae) but no indications of more complex life. Slightly younger rocks contain minute fragments of the external skeletons of larger MULTICELLULAR ANIMALS, the nature of which cannot be determined.
[Note: In “The Oldest Eukaryotic Cells,” by Gonzalo Vidal (it was indicated:
“All higher organisms are composed of eukaryotic, or nucleated, cells. A review of the fossil record indicates that the eukaryotes originally evolved in the form of unicellular plankton some 1.4 billion years ago” cited in Scientific American, February 1984, volume 250, no. 2.]
“At the beginning of the cambrian period – about 570 million years ago – external skeletons appear that definitely belong to many living phyla.
“At the turn of the century, geologists and paleontologists accumulated data on all the world’s strata … These investigations were followed by a flood of new discoveries about radioactivity. Physicists discovered that such elements as uranium and strontium, and mixtures of potassium and argon, decay at regular, measurable rates. The technique of RADIOMETRIC DATING that emerged from these discoveries is now standardized to such a degree that geologists and physicists agree almost unanimously about the results obtained.
“RADIOMETRIC DATING tells us that the earth is about 4 billion years old, and that the first living cells may have appeared more than 3 billion years ago, that organisms having cellular nuclei, chromosomes,and possibly the ability to reproduce sexually evolved between 1 billion and 1.4 billion years ago, and that primitive jellyfishes, worms, seaweeds, and other many-celled organisms first appeared between 600 and 700 million years ago.
“most physicists, chemists, and biological evolutionists agree that the evolution of organic molecules began about 4 billion years ago. The first living cell appeared about 3.5 billion years ago, and the first simple many-celled animal appeared roughly 600 million years ago.
“FROM OCEAN TO LAND – SIX HUNDRED MILLION YEARS AGO … THE EARTH’S LANDMASSES WERE JOINED TOGETHER AS A SUPERCONTINENT:
John Reader, The Rise of Life: The First 3.5 Billion Years (Alfred A. Knopf: New York), 1986
The move of ocean life to land:
“With regard to the move of ocean life to land that occurred over 600 million years ago when there were the matching Atlantic coastlines of Africa and South America.
Professor Reader stated:
“Everyone at some time or another has been struck by the matching Atlantic coastlines of Africa and South America. Six hundred million years ago the Earth’s landmasses were joined together as a SUPERCONTINENT straddled diagonally across the Equator, centered on what is now the Atlantic basin.”