Based on molecular evidence, we know life evolved from one common ancestor around three billion years ago. From then, evolution progressed slowly to begin with; in the last billion years we see very rapid diversification of life forms on Earth as multiple components clicked into place, including multicellularity, or multiple cells coming together to form one organism. Against this backdrop, all insects share a relationship with each other: they have a certain body plan, cellular functions, and genetically encoded features (many have six legs, for instance), with the information of how these features form encoded in their genome.

Butterflies share many evolutionary features with insects. Butterflies are also specialized moths, the two separating from their sister group of insects 150 to 200 million years ago. Thereafter, moths themselves evolved significantly before butterflies emerged as a separate group about 85 million years ago, around when dinosaurs went extinct.

All the characteristics butterflies have, including much more acute vision compared to moths (who rely more on smell), grew thereon; visual cues are extremely important for butterflies, which explains why many are so attractive. Their appealing colours evolved to help them either evade predators or attract mates, with dark colours developing to help butterflies maintain body temperature, being cold-blooded.

Some species developed fascinating traits. Aposematism is a combination of two features: one is a defence against predators, like a chemical cover, with some butterflies being toxic to birds, spiders and the like; these caterpillars feed on toxic plants that are difficult, if not deadly, for predators to digest. Being protected thus is an internal property; but butterflies with toxins then developed bright wing patterns to show predators they are dangerous, signaling the risk they bear.