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Due to the high levels of mortality and morbidity caused by malaria—especially the P. falciparum species—it has placed the greatest selective pressure on the human genome in recent history.
However, after a period with no new mutations, the genetic variation at these sites is eliminated due to genetic drift. Natural selection reduces genetic variation by eliminating maladapted individuals, and consequently the mutations that caused the maladaptation. At the same time, new mutations occur, resulting in a mutation–selection ...
An unusual effect of the Northridge earthquake was an outbreak of coccidioidomycosis (Valley fever) in Ventura County. This respiratory disease is caused by inhaling airborne spores of the fungus. The 203 cases reported, of which three resulted in fatalities, constituted roughly 10 times the normal rate in the initial eight weeks.
Recent human evolution refers to evolutionary adaptation, sexual and natural selection, and genetic drift within Homo sapiens populations, since their separation and dispersal in the Middle Paleolithic about 50,000 years ago. Contrary to popular belief, not only are humans still evolving, their evolution since the dawn of agriculture is faster ...
Kettlewell's experiment was a biological experiment in the mid-1950s to study the evolutionary mechanism of industrial melanism in the peppered moth (Biston betularia). [1][2] It was executed by Bernard Kettlewell, working as a research fellow in the Department of Zoology, University of Oxford. He was investigating the cause of the appearance of dark-coloured moth since Industrial Revolution ...
Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within lineages. [1][2][3] Charles Darwin was the first to describe the role of natural selection in ...
Disruptive selection is a specific type of natural selection that actively selects against the intermediate in a population, favoring both extremes of the spectrum. Disruptive selection is inferred to oftentimes lead to sympatric speciation through a phyletic gradualism mode of evolution.
Lactase persistence is a textbook example of natural selection in humans: it has been reported to present stronger selection pressure than any other known human gene. [24] However, the specific reasons as to why lactase persistence confers a selective advantage "remain open to speculation". [41]