What they eat: Plants, fruits, nectar, sap and other insects
How they reproduce: Sexually, with females laying eggs
When they evolved: At the same time as land plants, around 480 million years ago
More than half of all known animal species on Earth are insects — critters with a hard external skeleton, three pairs of jointed legs, antennae and a body divided into three segments (the head, thorax and abdomen). There are about 1.4 billion insects for every human on the planet, and their combined weight is 70 times that of all people. Insects are found on every continent and in almost every habitat type, including hot deserts, salty coastal waters and frigid mountain streams. While 97% of insects live on land, some thrive in fresh water and seawater.
