Answer:
Never changed.
Step-by-step explanation:
Before Darwin's theories, scientists thought that species never changed. This concept was commonly known as the doctrine of "fixity of species," which posited that species were immutable and remained unchanged since their creation. According to this belief, species were considered to be fixed entities with no potential for an evolutionary change or adaptation to their environment. This view was deeply entrenched in the prevailing scientific and religious beliefs of the time, and it was not until Darwin's groundbreaking work on natural selection and the theory of evolution that this long-held notion was challenged and replaced with the understanding that species do indeed change over time through the process of natural selection and other mechanisms of evolution.