sodium amytal test: anesthetize one hemisphere and check for language function dichotic listening test: report more digits heard by dominant half functional brain imaging: fMRI or PET used to see which half is active when performing a language test
The process of change by which new species develop from preexisting species over time? The process by which species change over time is evolution. The process by which new species develop from preexisting species over time is evolution.
According to this definition, proposed by the evolutionary biologist Ernst Mayr in the mid-20th century, species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups.