It is thought that wooden spears could have come into use as early as 5 million years ago since chimpanzees and orangutans have been observed using wooden spears and because the human – chimpanzee split is dated to around 8 million years ago. Stone tipped spears however were thought to have come into use only around 300,000 years ago during the time of the Neanderthals. But a new paper in Science finds archaeological evidence from South Africa that stone spear tips were being used around 500,000 years ago.
Archive for the ‘Evolution’ Category
Stone-tipped spears were being used for hunting 500,000 years ago
November 16, 2012What is evolutionary selection now selecting for?
November 14, 2012What are the genetic characteristics that are effectively being “selected for” today?
Evolutionary selection is a result not a cause. It is a result describing the genetic change of a population not of an individual. But all genetic change in a population comes about only through the procreation of new generations of individuals.
Evolution then is the result of the survival, success and reproduction of organisms within an environment which is changing. By environment I mean all surrounding factors whether geologic or climatic or of competition within the species or with other species. In a population of organisms the relative success of and subsequent reproduction of those better suited to the environment begets a gradual change in the characteristics of the surviving organisms. It is because of the environmental changes in the first place that there is a subsequent change in the characteristics of the organism best suited to that environment. It is this gradual change of the surviving characteristics that we call evolution and we say that the resultant, surviving characteristics have been “selected for”. If the environment did not change and if an organism was suited to its environment, the genetic make-up of the organisation would always tend back to its stable equilibrium position. Any mutational changes would provide no benefit and would just die away. Without environmental change there would be no evolution to report. Over long stretches of time and many thousands of generations, these gradual changes of environment have been sufficient to have created all the species of living things that have ever existed and to have eliminated all the non-viable species that have gone extinct.
Is human intelligence declining?
November 13, 2012There is as yet no evidence, no hard data, no way of testing his speculation but Gerald Crabtree, a genetics Professor at Stanford University, believes that human evolution no longer selects for or favours intelligence. Our intelligence may have peaked as hunter-gatherers.
He has a point.
The intricacies of modern, “civilised”, human society where “weak” members of society are cared for by others, are such that many genetic characteristics have effectively been decoupled from survival and reproduction. “Intelligence” as one such genetic charateristic is no longer something that affects survival or reproduction. In fact from the fertility rates around the world today it is already apparent that the greater the wealth (GDP) the lower the reproduction rate. I am not sure if it can be shown explicitly but I suspect that a similar relationship may apply and that the greater the “intelligence” the lower the reproduction rate.
Crabtree has published 2 papers in Trends in Genetics
- Gerald R. Crabtree. Our fragile intellect. Part I. Trends in Genetics, 2012; DOI: 10.1016/j.tig.2012.10.002
- Gerald R. Crabtree. Our fragile intellect. Part II. Trends in Genetics, 2012; DOI: 10.1016/j.tig.2012.10.003
Human intelligence and behavior require optimal functioning of a large number of genes, which requires enormous evolutionary pressures to maintain. A provocative hypothesis … suggests that we are losing our intellectual and emotional capabilities because the intricate web of genes endowing us with our brain power is particularly susceptible to mutations and that these mutations are not being selected against in our modern society.
“The development of our intellectual abilities and the optimization of thousands of intelligence genes probably occurred in relatively non-verbal, dispersed groups of peoples before our ancestors emerged from Africa,” says the papers’ author, Dr. Gerald Crabtree, of Stanford University. In this environment, intelligence was critical for survival, and there was likely to be immense selective pressure acting on the genes required for intellectual development, leading to a peak in human intelligence.
From that point, it’s likely that we began to slowly lose ground. With the development of agriculture, came urbanization, which may have weakened the power of selection to weed out mutations leading to intellectual disabilities. Based on calculations of the frequency with which deleterious mutations appear in the human genome and the assumption that 2000 to 5000 genes are required for intellectual ability, Dr. Crabtree estimates that within 3000 years (about 120 generations) we have all sustained two or more mutations harmful to our intellectual or emotional stability. Moreover, recent findings from neuroscience suggest that genes involved in brain function are uniquely susceptible to mutations. Dr. Crabtree argues that the combination of less selective pressure and the large number of easily affected genes is eroding our intellectual and emotional capabilities.
If “intelligence” is an inherited characteristic – as it seems at least partially to be – then it is only a matter of simple arithmetic that unless the “more intelligent” reproduce at a higher rate than those of “less intelligence” then the “average intelligence” of the population will inevitably decrease.
Related:
The origins of counting
November 11, 2012Before an intelligence can turn to counting it must first have some concept of numbers. When and how did our ancient ancestors first develop a concept of numbers and then start counting?
What led humans to counting and when?
… the increasing complexities of co-operation and their requirements for communication was what drove the parallel – and inter-linked – development of speech and numerology starting some 150,000 years ago.
Out of Africarabia
November 9, 2012There has been a gap of 50-65,000 years between the genetic time-line of the Out-of-Africa theory and archaeological indications of the earlier presence of anatomically modern humans outside of Africa. But the genetic evidence is now going back in time and approaching the archaeological time-line. “Out-of-Africa” is beginning to look much more like “Out-of-Africarabia”.
Out of Africarabia
Before we were apes we were sharks
June 14, 2012A new paper in Nature suggests that before we were apes we were fish and not just any old fish. The primitive fish which predates the split between sharks and bony fish, Acanthodes bronni was the common ancestor of all jawed vertebrates on Earth – including mankind, according to the paper. The split with bony fish occurred some 420 million years ago and Acanthodes bronni disappeared some 250 million years ago.
The researchers re-examined fossils of Acanthodes bronni, the best-preserved acanthodian species. They created highly detailed latex moulds of specimens revealing the inside and outside of the skull, generating a new data set for assessing cranial and jaw anatomy as well as the organizations of sensory, circulatory and respiratory systems in the species. The analysis of the sample combined with recent CT scans of skulls from early sharks and bony fishes led to the reassessment of what Acanthodes bronni tells us about the history of jawed vertebrates.
Acanthodes bronni : Wikipedia
Acanthodes and shark-like conditions in the last common ancestor of modern gnathostomes
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Sapiens + dogs >> Neanderthals
May 16, 2012Since this blog will now focus on energy, electricity, environment and climate, I shall now post my comments /views on archaeology, pre-history, anthropology, biology and matters related to the development and evolution of humans in 6,000 Generations instead:
Was dog domestication the critical advantage for Sapiens over Neanderthalensis
Though fossil evidence of domesticated dogs is very sparse and the earliest is from around 30,000 years ago, there is no certainty about when domestication actually occurred. For it to have been a critical advantage over Neanderthalensis it would have to have started with some form of regular human-canine co-operation – eventually leading to domestication – perhaps some 50,000 years ago.
The spirit of the Inquisition is alive and well
April 22, 2012The recent BBC story about the Catholic Church’s Office of the Inquisition pressurising some US nuns who are considered too liberal by the Church hierarchy got me to wondering whether our behaviour today is much different to that in medieval times.
To make the parallel to medieval times we have to substitute modern institutions. Governments and their institutions ( such as the United Nations or the IMF or the ICC) are today the equivalent of the medieval monarchs and their Catholic Church. They bless some countries and excommunicate others. They tolerate the same behaviour (for example the quest for nuclear weapons) in favoured countries and condemn it in others. They support uprisings against some of their less-favoured member countries and help suppression of rebellion in others. They enforce sanctions – even with the use of collective force – against some and ignore the same behaviour in others. And like the college of cardinals a select group of 5 nations and the 15-member Security Council makes up the holy inner circle controlling these institutions.
Controlled use of fire now dated back to at least 1 million YBP
April 3, 2012How fire came to be discovered and then brought under control by our ancestors will probably always remain a matter for speculation. There is evidence that forest fires were occurring “naturally” at least 350 million years ago when plant life colonised the land. It may have been earlier since volcanoes were active long before this but the combustible matter needed (fuel and oxygen) which volcanic eruptions could have ignited would have been plentiful only around 350 million years ago.
Many animals have learned to take advantage of the benefits of wildfires – mainly after the fire is over. Some birds of prey take advantage of fleeing insects and small animals while the fire is still raging. Carnivores search in the ashes for animals killed by the fire but still with edible remains. Herbivores gather to lick the ashes for tasty “elements” and salts. Our ancestors would have been observers and beneficiaries of the accidental “cooking” and the warmth from forest or bush fires for many millions of years.
Earthhour is not for me – It is a tale told by idiots..
March 31, 2012I shall not be trying to switch off today. But I shall not either be trying to maximise my electricity consumption in some futile gesture to protest against the even more idiotic gesture that is Earthhour. I shall be as normal as possible.
The hype around Earthhour on 31st March each year is not just irritating – it demonstrates for me the intellectual bankruptcy that is now enveloping the environmentalists and conservationists and the eco-fascists. It is a tale told by idiots and full of sound and fury and signifying – nothing.
If it was a just a meaningless gesture it would not be as bad as it is. It actually denies all that humankind has achieved and promotes a view of what the future should be which not only do I not share but is one which celebrates the lack of electricity. It condemns humankind to return to a bleak world of hunger and death and misery. That may be a future which the lack of electricity could cause but it is not a future I would choose or glorify.
This post by Ross McKitrick is pretty close to how I see things:
Earth Hour: A Dissent
by Ross McKitrick
Ross McKitrick, Professor of Economics, University of Guelph, Canada. (Photo credit: Wikipedia)
Ross McKitrick, Professor of Economics, University of Guelph, Canada. (Photo credit: Wikipedia)
In 2009 I was asked by a journalist for my thoughts on the importance of Earth Hour.
Here is my response.
I abhor Earth Hour. Abundant, cheap electricity has been the greatest source of human liberation in the 20th century. Every material social advance in the 20th century depended on the proliferation of inexpensive and reliable electricity.
Giving women the freedom to work outside the home depended on the availability of electrical appliances that free up time from domestic chores. Getting children out of menial labour and into schools depended on the same thing, as well as the ability to provide safe indoor lighting for reading.
The k2p blog 