Objects appear to be different colours because they absorb some wavelengths and reflect others. A green flower absorbs all coloured light wavelengths except for green which it reflects. Photoreception is the general scientific term used to describe the biological responses of organisms to light. Photosynthesis is the specific method by which green plants utilise light energy to transform water and carbon dioxide into their necessary carbohydrate sustenance. In animals rods and cones are the names given to the two different types of photoreceptor cells in the retina which affect visual perception.
Rods primarily influence visual perception when the light intensity is low or dim.
Cones are responsible for the differentiation of colour in many animals in conditions of greater light intensity. Many insects have good colour vision whereas dogs and other mammals have limited colour vision and probably see in yellows and blues. Many insects can see into the ultraviolet spectrum which the unaided human eye can not. Many flowers emit patterns of ultraviolet light which are visible to insects but not to humans. Flowers which are pollinated by insects tend to have flowers with white, yellow, orange or blue flowers.