Download Darwin called his idea “natural selection”

Natural Selection
Darwin called his idea “natural selection”. By this he meant that if small variations in
a living organism’s characteristics occur from generation to the next, an organism
with an advantageous characteristic, such as running faster or better hunting skills,
will be at an advantage over others and will be more likely to survive. For example,
sickle-cell anaemia is a distressing and incurable genetic illness (you cannot catch it)
caused by red blood vessels being misshapen. It is very common in some parts of the
world. What is interesting is that, originally, it came from a part of the world where
malaria is endemic, and sickle cell anaemia gives the person suffering from it
resistance to catching malaria. In other words, there was an advantage to having it in
the area from where the illness originates.
Darwin himself wrote:
“If variations useful to any organic being ever do occur, assuredly individuals thus
characterised will have the best chance of being preserved in the struggle for life; and
for the strong principle of inheritance, these will tend to produce offspring similarly
characterised. This principle of preservation, or the survival of the fittest, I have called
Natural selection.” (Darwin, The Origin of Species)
Endemic: Usually used to refer to a disease which is always present in a particular
community or area (e.g. one could say that malaria is endemic in sub-Saharan Africa)