Arthropod

An invertebrate animal of the phylum Arthropoda, characterized by a segmented body, jointed appendages, and an external skeleton made chiefly of chitin.

Chitin: A structural polysaccharide found in arthropod exoskeletons and fungal cell walls. It forms a major structural component of the arthropod cuticle.
Insect: A six-legged arthropod whose body is organized into head, thorax, and abdomen. Insects are the most species-rich arthropod group.
Arthropod locomotion: Movement by arthropods using jointed limbs, body muscles, or specialized appendages. Jointed appendages convert muscle action into walking, swimming, and other movement.
Cambrian explosion: A geologically brief interval in the early Cambrian when animal diversity and fossil visibility rose sharply. Many major arthropod lineages appear in the fossil record during this interval.
Pollination: The transfer of pollen from an anther to a plant's receptive stigma. Insects and other arthropods pollinate many flowering plants.
Exoskeleton: A structural covering on an animal's exterior that supports and protects its body. Arthropods rely on an external skeleton rather than an internal bony framework.
Arachnid: An arthropod group that includes spiders, scorpions, mites, and ticks. Arachnids illustrate a major lineage with four pairs of walking legs.
Arthropod molting: The process by which an arthropod sheds its old cuticle and forms a larger one. Molting temporarily leaves the animal soft and vulnerable while it expands.
Burgess Shale: A fossil deposit in British Columbia preserving diverse Cambrian animals and soft tissues. Its fossils preserve early arthropods and reveal forms absent from later ecosystems.
Biological pest control: The use of organisms to suppress populations of pests. Predatory and parasitic arthropods can reduce crop pests.

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