Insect Fossil The fossils of insects provide a distinctive look into the past, while many are drawn to large fossils like dinosaur bones and mammoths, there is much to learn from creepy crawlies. Insect fossils are much more abundant and diverse and provide much needed information on climate change through the millennium. An example being Griffinflies, an extinct relative of dragonflies that could grow a wingspan of more than 2 feet wide. This was caused by the higher oxygen content in the earth's atmosphere, close to 35% as opposed to the 21% oxygen our atmosphere is made of today.