Final answer:
Paper chromatography separates pigments or chemicals by exploiting their differing affinities to the stationary and mobile phases, resulting in a physical separation based on chemical properties.
Step-by-step explanation:
Paper chromatography is a technique used to separate pigments such as those in a black dot or to separate chemicals from a mixture. This separation occurs because different components of the mixture have different affinities for the stationary phase (the paper) and the mobile phase (the solvent).
As the solvent moves through the paper, components that have a greater solubility in the mobile phase will move further up the paper, while those with a stronger attraction to the stationary phase will move less. This results in a physical separation of the pigments or chemicals based on their differing chemical properties. In the study of photosynthetic organisms, paper chromatography can be used alongside spectrophotometers to identify the various pigments based on their absorption of specific wavelengths of light, a crucial aspect in understanding an organism's photosynthetic properties.