The most basic definition of an insect is a small air-breathing arthropod. Insects have three pairs of legs (six legs total) and three body regions--head, thorax, and abdomen. Entomologists, scientists who study insects, would also add that insects have antennae and external mouthparts. As a group (class Insecta), insects are considered the largest group of organisms on earth. Scientists have found and named more than one million species of insects, not to mention the ones that have not been named or discovered yet.
Because they belong to the phylum arthropods within the Animal Kingdom, all insects have exoskeletons or hard outer skeletons that protect and support an organism's body. The "Insect Fear Film Festival" featured two movies on scorpions and ancient trilobites. These creepy crawlers are not considered insects, but science fiction movies make their own definitions. Insects only have six legs while scorpions have eight legs and trilobites had many more. Yet other classes of arthropods include: Arachnida (spiders), Crustacea (crabs), and Myriapoda (millipedes and centipedes). Thus, the film features on scorpions and trilobites were actually quite appropriate because they are found in the same phylum as insects.
While they do have exoskeletons, insects do not have backbones. They are the only invertebrates that are capable of flight. Insects also have incredible vision. Some have thousands of lenses in their eyes, which is called a composite eye. As a result, their field of vision is much wider than that of most organisms.
Insects exist in nearly all types of environments. However, only a small portion can survive in water. Most insects are found in soil, leaf litter, or in rotting logs. Along with this, insects can either be diurnal (active during the day) or nocturnal (active during the night), or a combination of the both. For more information on insects, see:
No comments:
Post a Comment