Tag: human evolution (page 2 of 2)

Genetic Genealogy ~ What haplogroup do you belong to?

August 23, 2014 / / 0 Comments



Dr. Spencer Wells talking about human ancestry. Photo courtesy of genographic.com

Posted by Miguel Vilar

While millions of people spent last weekend dumping buckets of ice water on their heads and documenting it on Facebook to raise money and awareness for ALS, a few us genetics geeks gathered and talked about haplogroups*  A, L and S, among others.

*Never heard of a haplogroup? Don’t worry, it’s not because you have a brain freeze. A haplogroup is a branch on the human family tree. All people belong to a haplogroup based on genetic markers carried in their cells. People belonging to the same haplogroup trace their descent to a common ancestor and a specific place where that ancestor once may have lived.
Last Saturday morning at the first International Conference for Genetic Genealogy in Chevy Chase, Maryland, Genographic Project Director and National Geographic Explorer-in-Residence Dr. Spencer Wells delivered the Keynote to an audience of 300 genetic genealogists.   He spoke about the popularity of the field and how fast consumer genetics has grown since the launch of The Genographic Project in 2005. “In 2013 the one-millionth person tested their DNA,” explained Wells, “just twelve years since the first human genome was sequenced. But this summer the two-millionth person has already tested their DNA.” The growth has been exponential, thanks in great part to the interest and promotion by those who gathered at the conference.
Dr. Wells explains the trends in genetics
Dr. Wells explains the trends in genetics. Chart courtesy of Spencer Wells
In addition to Dr. Wells, the Genographic Project was represented by Russian scientist, Dr. Oleg Balanovsky. Dr. Balanovksy talked about his efforts in mapping the world’s genetic diversity, and how his scientific partnership with the Genographic Project has informed questions like “If we are all related, where did our shared grandpas come from?”

Several leaders in the field of genetic genealogy also spoke, including Jim Bartlett, Katherine Borges, Rebekah Canada, Tim Janzen and Cece Moore. Doing his part to promote population genetics was blogger and PhD candidate Razib Kahn, who spoke about piecing together the puzzle that is ancient ancestry. Ancestry DNA was well represented by biologist Dr. Julie Granka who explained how they use DNA to help match their participants with relatives. And Dr. Joanna Mountain shared with the audience her efforts with 23andMe.
Razib Kahn talks about how we study ancestry through DNA
Razib Kahn talks about how we study ancestry through DNA. Photo by Miguel Vilar
Of the many topics discussed, it was clear that citizen science was the hot topic in this field. The public is generally more comfortable talking about their personal genomic details and a general interest in science has increased. As a result, people are encouraging friends and family to test and study their DNA. Who knows? As more people participate and find new connections and matches, genetic genealogy could become the new Facebook of science!

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How many people have ever lived on earth?

August 20, 2014 / / 0 Comments





blog.world-mysteries.com

Assuming that we start counting from about 50,000 B.C., the time when modern Homo sapiens appeared on the earth (and not from 700,000 B.C. when the ancestors of Homo sapiens appeared, or several million years ago when hominids were present), taking into account that all population data are a rough estimate, and assuming a constant growth rate applied to each period up to modern times, it has been estimated that a total of approximately 106 billion people have been born since the dawn of the human race, making the population currently alive roughly 6% of all people who have ever lived on planet Earth. Others have estimated the number of human beings who have ever lived to be anywhere from 45 billion to 125 billion, with most estimates falling into the range of 90 to 110 billion humans.

YearPopulation
50,000 B.C.2
8000 B.C.5,000,000
1 A.D.300,000,000
1200450,000,000
1650500,000,000
1750795,000,000
18501,265,000,000
19001,656,000,000
19502,516,000,000
19955,760,000,000
20026,215,000,000
Number who have ever been born106,456,367,669
World population in mid-20026,215,000,000
Percent of those ever born who are living in 20025.8
The above estimate shows  that about 5.8 percent of all people ever born are alive today.  
That’s actually a fairly large percentage when you think about it. Source: Population 
Reference Bureau estimates.


Number of people who have ever lived

Estimates of  “the total number of people who have ever lived” published in the first decade of the 21st century range approximately from 100 to 115 billion.

An estimate of the total number of people who have ever lived was prepared by Carl Haub of the Population Reference Bureau in 1995 and subsequently updated in 2002; the updated figure was approximately 106 billion. Haub characterized this figure as an estimate that required “selecting population sizes for different points from antiquity to the present and applying assumed birth rates to each period”. Given an estimated global population of 6.2 billion in 2002, it could be inferred that about 6% of all people who had ever existed were alive in 2002.
In the 1970s it was a popular belief that 75% of all the people who had ever lived were alive in the 1970s, which would have put the total number of people who ever lived as of the 1970s as less than the number of people alive today. This view was eventually debunked.
The number is difficult to estimate for the following reasons:
* The set of specific characteristics that define a human is a matter of definition, and it is open to debate which members of early Homo sapiens and earlier or related species of Homo to include. See in this regard also Sorites paradox. Even if the scientific community reached wide consensus regarding which characteristics distinguished human beings, it would be nearly impossible to pinpoint the time of their first appearance to even the nearest millennium because the fossil record is simply too sparse. However, the limited size of population in early times compared to its recent size makes this source of uncertainty of limited importance.
* Robust statistical data only exist for the last two or three centuries. Until the late 18th century, few governments had ever performed an accurate census. In many early attempts, such as Ancient Egypt and in the Persian Empire the focus was on counting merely a subset of the people for purposes of taxation or military service.[108] All claims of population sizes preceding the 18th century are estimates, and thus the margin of error for the total number of humans who have ever lived should be in the billions, or even tens of billions of people.
* A critical item for the estimation is life expectancy. Using a figure of twenty years and the population estimates above, one can compute about fifty-eight billion. Using a figure of forty yields half of that. Life expectancy varies greatly when taking into account children who died within the first year of birth, a number very difficult to estimate for earlier times. Haub states that “life expectancy at birth probably averaged only about ten years for most of human history”[106] His estimates for infant mortality suggest that around 40% of those who have ever lived did not survive beyond one year. [ Source: http://en.wikipedia.org/wiki/World_population ]

Estimated world population at various dates (in millions)

Source: http://en.wikipedia.org/wiki/World_population

YearWorld(in millions)
70,000 BC< 0.015
10,000 BC1
9000 BC3
8000 BC5
7000 BC7
6000 BC10
5000 BC15
4000 BC20
3000 BC25
2000 BC35
1000 BC50
500 BC100
AD 1200
AD 1000310
AD 1750791
AD 1800978
AD 18501,262
AD 19001,650
AD 19502,519
AD 19552,756
AD 19602,982
AD 19653,335
AD 19703,692
AD 19754,068
AD 19804,435
AD 19854,831
AD 19905,263
AD 19955,674
AD 20006,070
AD 20056,454
Jul. 1, 20086,707

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Several Paleolithic Cultures Flourished In North Africa before Sumer

August 19, 2014 / / 0 Comments


African-Tool-Diversity
(Courtesy The British Museum)


OXFORD, ENGLAND—A new study of Paleolithic stone tools from 17 sites in North Africa shows that between 130,000 and 75,000 years ago, there were at least four separate populations in the region, each with its own distinctive cultural traits, reports phys.org. Researchers led by University of Oxford visiting scholar Eleanor Scerii made 300,000 measurements on stone tools and combined the data with enviromental reconstuctions of prehistoric North Africa to analyze how modern human populations dispersed across the Sahara using ancient rivers and streams that no longer exist. "This is the first time that scientists have identified that early modern humans at the cusp of dispersal out of Africa were grouped in separate, isolated and local populations," says Scerii. "Our picture of modern human demography around 100,000 years ago is that there were a number of populations, varying in size and degree of genetic contact, distributed over a wide geographical area." According to Scerii, the team's work supports the theory that modern humans left Africa before 60,000-50,000 years ago.

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Scientific proof human race was created by aliens

August 13, 2014 / / 0 Comments

ufosightingshotspot.blogspot.com A group of researchers worked for 13 years at the Human Genome Project (Project completed in 2003) indicate that they made an astonishing scientific discovery: They believe so-called 97% non-coding sequences in human...

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