Homo sapiens have been around for 250,000 years - surely long enough to have become fully evolved?
It was thought that the dramatic extension of life spans during the 20th century eliminated natural selection, but new evidence shows that to be false.
Will selection always be natural, or could postmodern also mean posthuman?
Professor Christopher Dye is based at the World Health Organization, where he evaluates epidemiological and economic trends for tuberculosis, malaria, and other infectious diseases, measures the impact of control programs, and presents the findings to governments, scientists, and the media.
Professor Dye holds a BA from the University of York and a DPhil from the University of Oxford and has taught at Cambridge University, Imperial College and the London School of Hygiene and Tropical Medicine. He was elected a fellow of the Academy of Medical Sciences in 2008.
His work in epidemiology is described in more than 200 scientific papers, and he is currently a member of the editorial board of science.
Evolution of modern human beings from extinct nonhuman and humanlike forms. Genetic evidence points to an evolutionary divergence between the lineages of humans and the great apes on the African continent 85 million years ago (mya). The earliest fossils considered to be remains of hominins (members of the human lineage) date to at least 4 mya in Africa; they include the genus Australopithecus and other forms. The next major evolutionary stage, Homo habilis, inhabited sub-Saharan Africa about 21.5 mya. Homo habilis appears to have been supplanted by a taller and more humanlike species, Homo erectus, which lived from c. 1,700,000 to 200,000 years ago, gradually migrating into Asia and parts of Europe. Between c. 600,000 and 200,000 years ago, Homo heidelbergensis, sometimes called archaic Homo sapiens, lived in Africa, Europe, and perhaps parts of Asia. Having features resembling those of both H. erectus and modern humans, H. heidelbergensis may have been an ancestor of modern humans and also of the Neanderthals (H. neanderthalensis), who inhabited Europe and western Asia from c. 200,000 to 28,000 years ago. Fully modern humans (H. sapiens) seem to have emerged in Africa only c. 150,000 years ago, perhaps having descended directly from H. erectus or from an intermediate species such as H. heidelbergensis.
• Modern medicine is accelerating the evolution, differing and brooding the gene-base in the short and medium time-scale. And therefore increasing the survival-rate of random mutations in the long time scale. Further more medicine is´nt going on every were and kills blindly out of ignorance every day. So the "old concept" still goes on and is accelerated as well. Chemical compounds and radiation in the food, water and air overcompensates for the medical advances by far.
• Smokers don´t burn out as easily as non smokers (it´s a meditative break to smoke).
• Steve Jones is stuck in the meet. Love and social skills are the most important factors now, than some physical primeval ability.
• (09) Brain-size is increased by caesarean births.
• (10) Toxoplasmos is an important factor. (parasite from cats)
• (11) Better example of present cyborg implants are: scull vibrating hearing aids and of cause the pacemaker.
Evolution is partially a byproduct of sexual reproduction. Creating as many variations of traits as you can while still retaining enough similarity to combine to realize a new combination of traits makes the species more adaptable in order to withstand the worlds body stressors such as disease and environmental tolerance. It is why sexual reproduction is so successful.
Cultural norms and stereotypes will continue to cause an influence on sexual selection: hence evolution. Our bodies will also adapt to better handle the toxins we now breath, the 3 dimensional space we interact with and medical treatments as these all have an influence on us before a sexual reproductive age and could influence sexual selection even if advances in medicine eliminate casualties from those forces.
The modern cultural pressure to start having children later is an expression of our recognition of the power of neoteny (the retention of juvenile traits into adulthood) as a distinguishing feature of humans over other mammals. If we restrict our breeding to those of us who retain fertility longer, then we'll be selecting for a population which is ready to start to select for a couple of desirable traits. One will be to introduce a pressure towards staying healthier longer, in particular to shift the start of the cancer slope rightwards. The other perceived advantage will be the opportunity to slow our development and grow larger brains before we reach maturity.
On the wisdom teeth issue, the ready availability of dental treatment (for children in the UK it is high quality and free) removes a natural pressure to retain our previous form, or to adopt an alternate solution like evolving smaller teeth or not developing wisdom teeth at all. So the cause may be environmental (by food and by dentistry) but if we lost the dentistry then we'd be left with an evolutionary solution. I suggest we don't though. Toothache is a horrible way to fall out of the gene pool.
Professor Dye's lecture brings up the concept of evolution of biological organisms, we'll call them germs, and what has now become a problem that these germs have become resistant to the the antibiotics now in use. This in it's self is more than enough evidence that evolution is ongoing even today. For those that didn't catch it, this is basically how it came to be. Germs infect the body, a environment, and are killed off with penicillin, a introduction of a adverse condition, but some survive which reproduce offspring with resistance, in other words the species have adapted to their new environment. This is how it works from the smallest organisms to the largest though the adverse conditions may very.
He brought up that Steve Jones thinking is that by and large men have the same number of children as they always have. Though this is true in many parts of the world, those in the developed nations tend to have less children. The factors in this is because of the cost, the cost being nurturing and preparation for adult life in a advanced society, and the survival of more of these children, thus a population growth slowdown, thus adapting to a conditional environment. Of course, the introduction of birth control also plays a factor, but this coexist with the need for fewer births because more of these children survive into adulthood, and thus fewer births are required to sustain the population, but then again, this is adapting to a condition or environment.
Of course, this seems to have more to do with social or cultural adaption rather than actual physical adaption.
In the last several thousand years we have possibly become more thin with bigger brains, though I am not in complete agreement with this being that, at least in the United States and Europe, obesity has become almost a norm, if not a actual health problem as eluded to in one of the diagrams, but with that aside, due to less physical work and more brain work, we have evolved a a bit physically, although I find that the general population as a whole is just as gullible and naïve as ever, as recent propaganda for politics and conflict has shown,
I tend to favor R. Dawkins's description of evolution as “No purpose...nothings but blind pitiless indifference” being that if a species should die out, another would take it's place as though nothing had happened. It might have some importance to us only because we might know about it.
I could also agree with Stephen Jay Gould's statement that “There's been no biological change in humans in 40,000 years”, though I think that it might actually be a longer period since the Homo sapien come into being around 130,000 years ago and though we may be a bit less robust now than then, we are basically the same. I don't know if the Homo sapien evolved as a subspecies from another hominid or came into being totally independent from other hominids, not even after watching this clip can I say that we will evolve or devolve but I would suggest that we will become taller and thiner over time if the current trends and environment continue but should we be subject to a catastrophic occurrence, such as a large meteor strike, global warming or biological pandemic the surviving population would go through some changes in the next 40,000 years.