Arthropods and Echinoderms

Science

The hard outer covering that protects some animals, like spiders

Exoskeleton

The hard outer covering that protects some animals, like spiders. Exoskeleton. An exoskeleton is a tough external shell that supports and protects an animal's body.

A structure that grows out of the body of an arthropod, like a leg or wing

Appendage

A structure that grows out of the body of an arthropod, like a leg or wing. Appendage. In Science, an appendage is a body part that extends from the main body, such as a leg, wing, or antenna.

An arthropod’s respiratory organ, with folded walls arranged like pages in a book

Book lung

An arthropods respiratory organ, with folded walls arranged like pages in a book. Book lung. A book lung is a breathing organ in some arachnids, like spiders, that looks like stacked pages and helps them exchange gases with the environment.

A fused head and thorax found in some arthropods

Cephalothorax

A fused head and thorax found in some arthropods. Cephalothorax. In some arthropods like spiders and crabs, the cephalothorax is a body part where the head and chest are combined into one section.

A fused head and thorax found in some arthropods the mouthpart adapted for biting and chewing food, in most arthropods

Mandible

A fused head and thorax found in some arthropods the mouthpart adapted for biting and chewing food, in most arthropods. Mandible. A mandible is the jaw or jawbone, particularly in arthropods, used for biting and chewing food.

An excretory tube located in the abdomen of most insects and arthropods

Malpighian tubule

An excretory tube located in the abdomen of most insects and arthropods. Malpighian tubule. Malpighian tubules help insects remove waste from their bodies by filtering out unwanted substances from their blood.

The shedding and replacement of an exoskeleton, skin or feathers

Molting

The shedding and replacement of an exoskeleton, skin or feathers. Molting. Molting is when animals shed their outer layer like skin or feathers to grow or renew them.

A chemical released by an animal, that affects the behavior of other animals of the same species

Pheromone

A chemical released by an animal, that affects the behavior of other animals of the same species. Pheromone. Pheromones are natural chemicals that animals release to send signals to others, like attracting mates or marking territory.

A small hole in an insect’s thorax or abdomen for air to enter and leave

Spiracle

A small hole in an insects thorax or abdomen for air to enter and leave. Spiracle. A spiracle is an opening on an insect's body that helps it breathe.

One of the hollow tubes that transport air through the body in terrestrial arthropods

Tracheal tube

One of the hollow tubes that transport air through the body in terrestrial arthropods. Tracheal tubes are small airways in insects that help them breathe by delivering oxygen directly to their tissues.

Changes in form as an animal becomes an adult

Metamorphosis

Changes in form as an animal becomes an adult. Metamorphosis. Metamorphosis is the process where an animal undergoes significant physical changes during its life cycle, like a caterpillar turning into a butterfly.

An immature form of an insect that resembles the adult in form and function

Nymph

An immature form of an insect that resembles the adult in form and function. Nymph. In simple terms, a nymph is a young insect that looks similar to its adult form but is not fully developed.

The second pair of appendages in arachnids, used for sensing and for holding prey

Pedipalp

The second pair of appendages in arachnids, used for sensing and for holding prey, is called a pedipalp. In simple terms, a pedipalp is a specialized limb in spiders and scorpions that helps them sense their environment and catch food.

The third stage of complete metamorphosis, between larva and adult insect

Pupa

The third stage of complete metamorphosis, between larva and adult insect, is called pupa. A pupa is a life stage in which an insect transforms inside a protective casing before becoming an adult.

The silk-producing glands of a spider

Spinneret

The silk-producing glands of a spider. Spinneret. A spinneret is a special organ in spiders that they use to produce and release silk threads.

An arthropod’s hind section, it contains reproductive and digestive organs

Abdomen

An arthropods hind section, it contains reproductive and digestive organs. Abdomen. In simple terms, the abdomen is the part of an animal's body where digestion and reproduction happen.

An arthropod’s midsection, behind its head, it may have legs and wings attached

Thorax

An arthropods midsection, behind its head, it may have legs and wings attached. Thorax. The thorax is the middle part of an insect's body where the legs and wings are connected.

One of a pair of appendages that act as pincers or fangs, in Chelicerata like sea spiders

Chelicerae

One of a pair of appendages that act as pincers or fangs, in Chelicerata like sea spiders. Chelicerae are mouthparts used for feeding or defense in certain arthropods, like spiders and scorpions.

A group of individuals in an insect society that performs specialized tasks

Caste

A group of individuals in an insect society that performs specialized tasks. Caste. In science, a caste is a group within a social species that has a specific role, such as workers or soldiers in ants or bees.

Sieve-like structure that filters particles from an echinoderm’s water vascular system

Madreporite

Sieve-like structure that filters particles from an echinoderms water vascular system. Madreporite. The madreporite is a small, porous plate on the surface of echinoderms that acts like a filter to manage water flow into their water vascular system.

Hollow tubes that end in suction cups, echinoderms use them to move and collect food

Tube feet

Hollow tubes that end in suction cups, echinoderms use them to move and collect food. Tube feet are small, flexible appendages used by sea stars and sea urchins to help them move and gather food.

A system of fluid-filled tubes in echinoderms like starfish

Water vascular system

A system of fluid-filled tubes in echinoderms like starfish. Water vascular system. It is a network of tubes in sea creatures like starfish that helps them move and feed using water pressure.

The paired openings located in the pharynx, behind the mouth of a chordate embryo

Pharyngeal pouch

The paired openings located in the pharynx, behind the mouth of a chordate embryo. Pharyngeal pouches are small pockets that develop in embryos and can become parts of the face, neck, or throat.

A flexible, rod-like structure that runs along the upper part of a chordate’s body

Notochord

A flexible, rod-like structure that runs along the upper part of a chordates body. Notochord. The notochord is a supportive structure found in embryos that helps in the development of the spinal column in vertebrates.

An animal that has a tail, nerve cord, notochord, and throat slits at some point in its life

Chordate

An animal that has a tail, nerve cord, notochord, and throat slits at some point in its life. Chordate. A chordate is an animal with a backbone or spine, like humans, fish, and birds.

An invertebrate with an exoskeleton, jointed legs, and segmented body, like any insect, spider, crab etc

Arthropod

An invertebrate with an exoskeleton, jointed legs, and segmented body, like any insect, spider, crab etc. arthropod. Arthropods are animals with a hard outer shell and jointed limbs.

Tough polysaccharide that makes up insect exoskeletons and fungi cell walls

Chitin

Tough polysaccharide that makes up insect exoskeletons and fungi cell walls. Chitin. Chitin is a natural material that forms protective shells in insects and supports fungi structure.

The shell of a turtle or tortoise, or the plate that covers the head of a crustacean

Carapace

The shell of a turtle or tortoise, or the plate that covers the head of a crustacean. Carapace. In science, a carapace is a hard protective outer covering found on certain animals, like turtles and crustaceans.

Metamorphosis with 3 stages, where the young and the adults look alike

Incomplete metamorphosis

Metamorphosis with 3 stages, where the young and the adults look alike. Incomplete metamorphosis. Incomplete metamorphosis is when an insect changes form in three stages egg, nymph, and adult, and the young nymphs resemble the adults.

Metamorphosis with 4 stages, where the young and the adults look very different

Complete metamorphosis

Metamorphosis with 4 stages, where the young and the adults look very different. Complete metamorphosis. Complete metamorphosis is when an insect undergoes four distinct stages egg, larva, pupa, and adult, each looking different from the others.