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The first insects were landbound, but about 400 million years ago in the Devonian period one lineage of insects evolved flight, the first animals to do so. [1] The oldest insect fossil has been proposed to be Rhyniognatha hirsti , estimated to be 400 million years old, but the insect identity of the fossil has been contested. [ 3 ]
Insects breathe air through a system of paired openings along their sides, connected to small tubes that take air directly to the tissues. The blood therefore does not carry oxygen; it is only partly contained in vessels, and some circulates in an open hemocoel. Insect vision is mainly through their compound eyes, with additional small ocelli.
Flies are insects of the order Diptera, the name being derived from the Greek δι- di-"two", and πτερόν pteron "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced mechanosensory organs known as halteres , which act as high-speed sensors of rotational movement and allow ...
They are soft-bodied beetles commonly called fireflies, lightning bugs, or glowworms for their conspicuous production of light, mainly during twilight, to attract mates. [5] Light production in the Lampyridae is thought to have originated as a warning signal that the larvae were distasteful.
Bed bugs are parasitic insects from the genus Cimex, who are micropredators that feed on blood, usually at night. [7] Their bites can result in a number of health impacts, including skin rashes, psychological effects, and allergic symptoms. [5] Bed bug bites may lead to skin changes ranging from small areas of redness to prominent blisters.
An insect uses its digestive system to extract nutrients and other substances from the food it consumes. [3]Most of this food is ingested in the form of macromolecules and other complex substances (such as proteins, polysaccharides, fats, and nucleic acids) which must be broken down by catabolic reactions into smaller molecules (i.e. amino acids, simple sugars, etc.) before being used by cells ...
Insects do not have lungs; oxygen and other gases, such as carbon dioxide, pass through their exoskeleton via tiny valves called spiracles. Insects also lack closed blood vessels ; instead, they have a long, thin, perforated tube along the top of the body (called the "dorsal aorta") that functions like a heart, and pumps haemolymph toward the ...
Insects are the only group of invertebrates that have evolved wings and flight. Insects first flew in the Carboniferous, some 300 to 350 million years ago, making them the first animals to evolve flight. Wings may have evolved from appendages on the sides of existing limbs, which already had nerves, joints, and muscles used for other purposes.