This eventual process of speciation by natural selection is illustrated by a sketch drawn by Darwin in his personal notebook nearly 20 years before the Origin of Species was published (Figure 1).

Speciation is the process by which a single species gives rise to two daughter species, which are genetically distinct and eventually unable to interbreed. Speciation can occur as a result of ...

The biological equivalent is "allopatric speciation," an evolutionary process in which one species divides into two because the original homogenous population has become separated and both groups ...

The more we discover about our species' family tree, the harder it becomes to pinpoint when exactly Homo sapiens emerged, ...

This hypothesis predicts that the fossil record at any one site is unlikely to record the process of speciation. If a site records that the ancestral species lived there, the new species would ...

But according to a study published this week in Nature, new species can arise arbitrarily and without provocation, challenging the widely held notion that physical isolation and selection are the ...