Insects are hexapod invertebrates belonging to the class Insecta within the phylum Arthropoda. They are defined by a unique combination of characteristics: a three-part body plan (head, thorax, abdomen), three pairs of jointed legs, one or two pairs of wings (in most adults), and a chitinous exoskeleton. Insects exhibit incredible diversity, with over a million described species, and they play vital roles in ecosystems as pollinators, decomposers, and food sources.
- Three-part body: head, thorax, abdomen
- Six legs (three pairs) attached to thorax
- Most have wings in adult stage
- Exoskeleton made of chitin
- Immense diversity: over 1 million species
- Crucial ecological roles: pollination, decomposition, food chain