Bio Ch 23

a body plan in which only a single plane through the central axis will divide the body into mirror-image halves

asexual reproduction by the growth of a miniature copy, or bud, of the adult animal on the body of the parent; the bud breaks off to begin independent existence

concentration of sensory organs and nervous tissue in the anterior (head) portion of the body

a type of circulatory system, found in certain worms and vertebrates, in which the blood is always confined within the heart and vessels

in animals, a space or cavity, lined with tissue derived from mesoderm, that separates the body wall from the inner organs

a type of eye, found in many arthropods, that is composed of numerous independent subunits called ommatidia; each ommatidium contributes a piece of a mosaic-like image perceived by the animal

an animal with a mode of embryonic development in which the coelom is derived from outpocketings of the gut; characteristic of echinoderms and chordates

the outermost embryonic tissue layer, which gives rise to structures such as hair, the epidermis of the skin, and the nervous system

the innermost embryonic tissue layer, which gives rise to structures such as the lining of the digestive and respiratory tracts

a rigid internal skeleton with flexible joints that allow for movement

a rigid external skeleton that supports the body, protects the internal organs, and has flexible joints that allow for movement

a cluster of neurons

a cavity within the bodies of certain invertebrates in which a fluid called hemolymph bathes tissues directly; part of an open circulatory system

an organism that possesses both male and female sexual organs; some hermaphroditic animals can fertilize themselves; others must exchange sex cells with a mate

in invertebrate animals, a body structure in which fluid-filled compartments provide support for the body and change shape when acted on by muscles, which alters the animal's body shape and position, or causes the animal to move

an animal that lacks a vertebral column

an immature form of an animal that subsequently undergoes metamorphosis into its adult form; includes the caterpillars of moths and butterflies, the maggots of flies, and the tadpoles of frogs and toads

the middle embryonic tissue layer, lying between the endoderm and ectoderm, and normally the last to develop; gives rise to structures such as muscles, the skeleton, the circulatory system, and the kidneys

in animals with indirect development, a radical change in body form from larva to sexually mature adult, as seen in amphibians (e.g. tadpole to frog) and insects (e.g. caterpillar to butterfly)

to shed an external body covering, such as an exoskeleton, skin, feathers, or fur

a major nervous pathway consisting of a cord of nervous tissue extending lengthwise through the body, paired in many invertebrates and unpaired in chordates

a type of circulatory system found in some invertebrates, such as arthropods and most mollusks, that includes an open space (the hemocoel) in which blood directly bathes body tissues

an organism that lives in or on a larger organism (its host) harming the host but usually not killing it immediately

an animal with a mode of embryonic development in which the coelom is derived from splits in the mesoderm; characteristic of arthropods, annelids, and mollusks

in animals, a "false coelom;" that is, a space or cavity, partially but not fully lined with tissue derived from mesoderm, that separates the body wall from the inner organs; found in roundworms

a developmental stage in some insect species in which the organism stops moving and feeding and may be encased in a cocoon; occurs between the larval and the adult phases

a body plan in which any plane along a central axis will divide the body into approximately mirror-image halves. Cnidarians and many adult echinoderms exhibit this.

an animal body plan in which the body is divided into repeated, typically similar units

a group of (normally similar) cells that together carry out a specific function; a tissue may also include extracellular material produced by its cells

an animal that has a vertebral column