3rd June 2017
Human evolution is SPEEDING UP RAPIDLY, and no, it has not come to an end
A friend said that human evolution has come to an end since selection pressures are no longer relevant.
Let’s look at the facts. It is evident that human evolution is rapidly speeding up.
1) More mutations than ever before: Because human population is much larger than ever before (from a mere 5000 or so 75,000 years ago), therefore there are vastly more mutations in the species than ever before. Numbers matter. Mutations led to “races”, with slight changes in biology over the past 100,000 years. These variations are likely to further increase.
2) Fitness: Selection pressures kill off or otherwise disable those genes (through infertility) that are not well adapted to the environment. These pressures have led to the evolution of lactose tolerant genes in cow herders, plague tolerant genes in most Europeans, and malaria tolerant genes in most Africans. Selection pressures
continue unabated in most parts of the world (mostly in the Third World – India, Africa, China) where hundreds of millions of people die from disease. The survivors are more likely to have protective mutations. Pressures of climate cannot be removed, either.
3) Sexual selection: In a crowded world, not everyone gets a chance to reproduce. The genes of those not found suitable are weeded out. Likewise, certain genes that promote desirable traits (e.g. IQ, “beauty” – often affected by fashion) are in demand. The human brain is probably the most affected by this – since smarter people are more in demand.
Note that all dogs are a kind of wolf that’s been super-rapidly bred by humans – in just a few thousand years. Likewise. one would expect various “breeds” of humans to evolve through sexual selection.
4) Cultural selection: Some cultures weed out those who don’t “obey”. I suspect that if North Korean genes are analysed, the children may now have subservenient genes, with those who had independent genes being slaughtered. So also in many “hardcore” Islamic societies. In addition, in those societies, the ultra-stupids are regularly weeded out through suicide bombing.
A few articles/ videos to clarify this. Click the links on red – these are articles.
Study shows humans are evolving faster than previously thought
At least 7% of human genes have undergone recent evolution. Some of the changes included the emergence of fair skin and blue eyes in northern Europe, greater resistance to malaria in some African populations and the appearance of a gene that allows lactose to be digested.
Fastest-evolving human gene linked to brain boost
They identified the rapidly evolving region of DNA – called human accelerated region 1 (HAR1)
Humans are still evolving—and we can watch it happen
Two studies presented at the Biology of Genomes meeting here last week show how our genomes have changed over centuries or decades, charting how since Roman times the British have evolved to be taller and fairer, and how just in the last generation the effect of a gene that favors cigarette smoking has dwindled in some groups. the human genome quickly responds to new conditions in subtle but meaningful ways, she says.
Our brain size is rapidly changing
The gene Microcephalin (MCPH1) regulates brain size and has evolved under strong positive selection in the human evolutionary lineage. We show that one genetic variant of Microcephalin in modern humans, which arose È37,000 years ago, increased in frequency too rapidly to be compatible with neutral drift. This indicates that it has spread under strong positive selection [Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans – Science, 9 SEPTEMBER 2005]
And so on. Search google.
A couple of videos: