Dark skin is a naturally occurring human skin color that is rich in eumelanin pigments and having a dark color. People with relatively dark skin are referred to as brown, and those with very dark skin are often referred to as black, although this usage can be ambiguous in some countries where it is
also used to specifically refer to different ethnic groups or populations. The evolution of dark skin is believed to have begun around 1.2 million years ago in light-skinned early hominid species after they moved from the equatorial rainforest to the sunny savannas. In the heat of the savannas, better cooling mechanisms were required, which were achieved through the loss of body hair and development of more efficient perspiration.
Charles Robert Darwin (12 February 1809-19 April 1882) was an English naturalist, geologist and biologist. He is best known for his contributions to the science of evolution. He established that all species of life have descended over time from common ancestors and, in a joint publication with
Alfred Russel Wallace, introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding.
A Speakers' Corner is an area where open-air public speaking, debate, and discussion are allowed. The original and most noted is in the north-east corner of Hyde Park in London, England. Speakers here may talk on any subject, as long as the police consider their speeches lawful, although this right
is not restricted to Speakers' Corner only. Contrary to popular belief, there is no immunity from the law, nor are any subjects proscribed, but in practice the police intervene only when they receive a complaint. Speakers' Corner is often held up to demonstrate freedom of speech, as anyone can turn up unannounced and talk on almost any subject, although always at the risk of being heckled by regulars.
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting
it with artificial selection, which is intentional, whereas natural selection is not. Variation exists within all populations of organisms.
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