Origin of species
The creation of species is is one of several key "creation" questions which form the core of many mythologies and for which science has begun to provide likely answers only fairly recently.
Vast amounts of evidence point to the idea that the life presently on Earth evolved by common descent from simpler forms over hundreds of millions of years by a process of natural selection.
This idea was controversial when first proposed by Charles Darwin in his 1859 book On the Origin of Species but ultimately was overwhelmingly accepted by the scientific community due to ever-increasing bodies of confirming evidence across multiple disciplines and the lack of any viable alternative explanation.
Most mythologies seem to presume that species were created more or less in their present-day forms, so the question of the creation of species is subsumed into the question of the creation of life.
Despite the now-overwhelming evidence, evolution by natural selection nonetheless continues to be opposed by religious groups who advance alternative theories proposing that most species were created in essentially their present forms by a supernatural force or entity of some kind, most commonly referred to as "God". Where these beliefs flatly contradict the available evidence, they are known as creationism.
Some versions of creationism have been carefully vetted, removing references to the Bible or God, in order to avoid running afoul of the separation of church and state mandated by the US Constitution and thence to permit their use in US public schools. Intelligent design, the best known of these attempts to insert religious mythology into educational curricula under the heading of "science", avoids (often crudely) any mention of religion or the supernatural while using scientific-sounding (but thoroughly refuted) arguments against evolution by natural selection as its primary justification.