A dichotomous key usually uses an organisms physical characteristics, such as: -Certain limbs (Wings, legs, horns, etc.) -Certain skins. (Scales, feathers, fur, etc.) and other things. That's the best I can describe it, so I hope it helps.
Dichotomous key may be defined as the method of identification in which the organisms are divided into two groups. The key is generally represented in the flow chart and in the descriptive representation.
The immature characteristics are used in the preparation of the dichotomous key. The color, size and the behavior pattern between the different group of organisms are used. The limb numbers, reproduction methods and strategy can be used as a characteristics in the dichotomous key.
