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.
Entire species do not evolve into new species; new species tend to evolve as isolated offshoots of existing (parent) species. In some cases, newly evolved species can end up out-competing their parent (or sibling) species, driving them to extinction, but by no means in all cases.