Chapter 17, BJU Biology 5th Edition

arthropod

A member of the phylum Arthropoda, including chelicerates (spiders, scorpions, ticks, etc.), crustaceans, and insects.

chitin

An organic substance, derived from glucose, found in the cell walls of fungi and the exoskeletons of invertebrates.

molting

The periodic shedding of an exoskeleton, scales, feathers, or fur. In arthropods, the organism will then secrete a new exoskeleton that quickly hardens (exoskeletons are not living tissue and do not grow with the organism).

compound eye

An eye that is composed of many individual lenses set at angles to create a mosaic image.

thorax

The body region between the head and the abdomen (b. in picture).

abdomen

A body region posterior to the thorax (often called the tail--c. in the picture).

cephalothorax

A body region in some arthropods consisting of a fused head and thorax.

antenna

An elongated, movable sensory appendage on the head of many invertebrates that provides information regarding taste, smell, and touch.

chelicera (pl. chelicerae)

The clawlike appendages for grabbing and immobilizing prey of animals in the subphylum Chelicerata (These have one or two body sections and include mites, ticks, scorpions, horshoe crabs, and arachnids).

pedipalp

One of the second pair of arachnid appendages used for sensory perception, eating, and mating.

malpighian tubule

One of numerous threadlike tubules that extracts wastes from the blood and empties them into the intestine.

book lung

A plate-like respiratory structure found on arachnids that allows air to enter their bodies and go straight into tissues (does not have to enter a respiratory system). Aquatic chelicerates have book gills.

spinneret

An organ in spiders and some insects that produces a silk filament made from a protein manufactured at the tip of the abdomen.

carapace

The portion of the exoskeleton that covers the cephalothorax in some crustaceans.

swimmeret

One of the small flipper-like appendages extending from the abdomen on some crustaceans that is used for swimming and reproduction.

walking leg

An appendage on a crustacean used for locomotion/movement.

cheliped

A crustacean walking leg bearing a small claw at its end.

mandible

A chewing mouth part found in insects and some other arthropods for crushing food.

green gland

one of a pair of glands with excretory functions in some crustaceans near the base of the large antennae

ecosystem engineers

species that dramatically alter their environment

keystone species

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

trachea

A branching tubule that transfers air directly to the tissues of insects. These may connect to book lungs and open to the outside through spiracles.

spiracle

One of the small pores in an insect's body that open into the trachea and allows air to enter the insect. (Insecticides may clog these to kill the insect).

crop

stores food

Gizzard

grinds food

pheromone

A chemical released by an animal that influences the behavior of another animal of the same species.

ovipositor

A pointed organ in some female invertebrates that digs a nest hole and deposits eggs

metamorphosis

A change in shape or form as an animal undergoes in its development from egg to adult.

incomplete metamorphosis

A type of insect development in which eggs hatch into nymphs that look like little adults and mature into adults.

nymph

One of the stages in the incomplete metamorphosis of an insect; looks like a small adult.

complete metamorphosis

A common form of insect development that normally includes four stages: egg, larva, pupa, adult.

pupa

The resting or inactive stage of development during complete metamorphosis in an insect.