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In insects, the second body region, between the head and thorax. It is the region where the legs and wings are attached.
Industry:Biology
A group of cells with a specific function in the body of an organism. Lung tissue, vascular tissues, and muscle tissue are all kinds of tissues found in some animals. Tissues are usually composed of nearly identical cells, and are often organized into larger units called organs.
Industry:Biology
An animal with four limbs that evolved from a common fish ancestor during the Devonian Period (~365 million years ago). Tetrapods include amphibians, reptiles, birds, and mammals. Though "tetrapod" literally translates to "four-footed," many animals in this group have limbs adapted for different modes of transportation. Humans walk upright on two legs; the legs of whales, dolphins, and other marine mammals have evolved into fins and flippers; and snakes have lost their legs all together. Tetrapods are generally thought of as terrestrial animals, but some, like dolphins and whales, have returned to marine habitats.
Industry:Biology
Appendages which are flexible, because they have no rigid skeleton. Cnidarians and molluscs are two kinds of orgnaisms which may have tentacles.
Industry:Biology
The last segment of the abdomen in many arthropods. May be flat and paddlelike, buttonlike, or long and spiny, as in the horseshoe crabs.
Industry:Biology
A vertebrate distinguished by a skull with one pair of openings in the sidebehind the eyes, e.g., mammals and their close relatives.
Industry:Biology
In insects and some other terrestrial arthropods, a small opening through which air is taken into the tracheae. Insects have several spiracles, arranged along the sides of the abdomen.
Industry:Biology
Crystalline or mineral deposits found in sponges, sea cucumbers, or urochordates. They are structural components in many sponges, and may serve a protective function in other organisms.
Industry:Biology
Support structure in animals, against which the force of muscles acts. Vertebrates have a skeleton of bone or cartilage; arthropods have one made of chitin; while many other invertebrates use a hydrostatic skeleton, which is merely an incompressible fluid-filled region of their body.
Industry:Biology
