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Definition
| An animal that lacks a body cavity entirely |
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Definition
| refers to the bottom side of a radial animal |
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Definition
| refers to the head of the animal |
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Definition
| a cavity formed by the embryo during gastrulation that will become the organism's digestive tract |
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Definition
| bilaterally symmetric animals, which means they can be divided along a vertical plane at the midline to creat two halves |
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Definition
| the embryo at the stage when it forms an outer epithelial layer and an inner cavity |
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Definition
| the opening of the archenteron to the outside |
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Definition
| the localization of sensory structures at the anterior end of the body |
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Definition
| a succession of rapid cell divisions with no significant growth that produces a hollow sphere of cells called a blastula |
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Definition
| a fluid-filled body cavity in an animal |
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Definition
| an animal with a true coelom |
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Definition
| a characteristic of proteostome development in which the fate of each embryonic cell is determined very early |
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Definition
| an animal exhibiting radial cleavage; includes echinoderms and vertebrates |
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Definition
| having two distinct germ layers ectoderm and endoderm but no mesoderm |
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Definition
| refers to the upper side of an animal |
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Definition
| the periodic shedding and re-formation of the exoskeleton |
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Definition
| a clade that encompasses primarily the arthropods and the nematodes |
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Definition
| an outer layer of cells that covers the surface of the embryo and differentiates into the epidermis and the nervous system |
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Definition
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Definition
| in deuterostomes, a pattern of development in which a layer of mesoderm cells form outpockets that bud off from the developing gut to form the coelom |
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Definition
| a subgroup of animals having more than one type of tissue and, for the most part, different types of organs |
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Definition
| a process in which an area in the blastula invaginates and folds inward, creating different embryonic cell layers called germ layers |
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Definition
| genes involved in patterning the body axis |
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Definition
| a fluid-filled body cavity surrounded by muscles that gives support and shape to the body of organisms |
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Term
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Definition
| a characteristic of deuterostome development in which each cell produced by early cleavage retains the ability to develop into a complete embry |
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Definition
| a horseshoe-shaped crown of tentacles used for feeding |
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Definition
| a clade that encompasses the annelids, molusks, and several other phyla; they are distinguished by two morphological features--the lophophore, and the trochophore larva |
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Definition
| the collective term for animals |
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Term
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Definition
| the middle germ layer formed during gastulation |
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Definition
| refers to the top side of a radial animal |
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Definition
| a subgroup of animals that are not generally thought to possess specialized tissue types or organs, although they may have several distinct types of cells; the one phylum in this group is the Porifera (sponges) |
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Definition
| refers to the tail of an animal |
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Definition
| an animal that exhibits spiral cleavage; includes mollusks, annelid worms, and arthropods |
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Definition
| a coelom that is not completely lined by tissue derived from mesoderm |
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Definition
| an animal with a pseudocoelom |
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Definition
| radially symmetric animals, which means they can be divided equally by a longitudinal plane passing through the central axis; includes cnidarians and ctenophores |
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Term
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Definition
| a mechanism of development in which the cleavage planes are either parallel or perpindicular to the vertical axis of the egg |
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Term
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Definition
| in protostomes, a pattern of development in which a solid mass of mesoderm cells split to form the cavity that becomes the coelom |
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Definition
| a mechanism of development in which the planes of cell cleavage are oblique to the axis of the embryo |
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Definition
| having three distinct germ layers, endoderm, ectoderm, and mesoderm |
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Definition
| a distinct larval stage of many of the phyla |
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Definition
| refers to the lower side of an animal |
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Definition
| a mobile cells within a sponge's mesohyl that absorbs food from choanocytes, digests it, and carries the nutrients to the other cells |
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Definition
| a muscular sac at the base of each tube foot of a crustacean that stores water |
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Definition
| in echinoderms, the ability to intentionally detach a body part, such as a limb, that will later regenerate |
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Definition
| a hard protective fold in a crustacean |
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Definition
| in flatworms, a paired structure that receives input from photoreceptors in eyespots and sensory cells |
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Definition
| a phenomenon that results from chemical reactions that give off light rather than heat |
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Definition
| the fused head and thorax structure in species of the class Arachnida |
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Definition
| a specialized cell of sponges that functions to trap and eat small particles |
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Term
| closed circulatory system |
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Definition
| a system in which blood and interstitial fluid are separate by blood vessel walls, and they differ in their components and chemical composition |
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Definition
| on the surface of a cnidocyte, a hairlike trigger that detects stimuli |
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Definition
| a characteristic feature of cnidarians; a stinging cell that functions in defense or the capture of prey |
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Definition
| an insoluble fibrous protein of the extracellular matrix of a tissue |
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Definition
| a change in body form in the majority of insects, consisting of four stages: egg, larva, pupa, and adult |
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Definition
| the ciliated crown of members of members of phylum Rotifera |
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Definition
| a waxy surface coating that helps to reduce water loss from a plant surface. Also a nonliving cover that serves to both support and protect an animal |
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Definition
| an internal skeleton composed of calcareous plates overlaid by a thin skin |
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Definition
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Definition
| a tunicate structure used to expel water |
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Definition
| an external skeleton that surrounds and protects most of the body surface |
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Definition
| a cell that exists primarily to maintain osmotic balance between the flatworm's body and surrounding fluids |
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Definition
| a muscular structure in mollusks usually used for movement |
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Definition
| a body cavity with a single opening to the outside |
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Definition
| a very large axon in the ventral nerve chord that facillitates high-speed nerve conduction and rapid responses to stimuli |
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Definition
| specialized filamentous mollusk organs that are rich in blood vessels |
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Definition
| an individual that can produce both sperm and eggs |
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Definition
| a gradual change in body form in some insects that has three stages: egg, nymph, and adult |
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Definition
| a tunicate structure used to draw water through the mouth |
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Definition
| a stage of growth in a young insect |
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Definition
| an animal without a backbone, a category that makes up more than 95% of all animal species |
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Definition
| a sieve-like plate on the surface of a crustacean |
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Definition
| a structure in the insect excretory system that involves a series of narrow, extensive tubes that arises from the midgut and extends into the surrounding hemolymph |
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Definition
| a fold of skin draped over the visceral mass of a mollusk that secretes a shell in those species that form shells |
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Definition
| the chamber in a mollusk mantle that houses delicate gills |
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Definition
| the circular muscular pharynx in the mouth of rotifers |
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Definition
| a gelatinous substance that connects the two germ layers in the Radiata |
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Definition
| mollusk organs that discharge into the mantle cavity |
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Definition
| a gelatinous, protein-rich matrix in between the choanocytes and the epithelial cells of a sponge |
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Definition
| the first larval stage in a crustacean |
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Definition
| in a cnidarian, a powerful capsule with an inverted coiled and barbed thread that functions to immobilize small prey so they can be passed to the mouth and ingested |
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Definition
| the smooth, iridescent lining of the shells of oysters, mussels, abalone, and other mollusks |
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Term
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Definition
| the simplest nervous system found in the cnidarians. no single group of neurons controls all the others; instead, the neurons connect to each other in a network that can be activated all at once. |
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Definition
| a single flexible rod that lies between the digestive tract and the nerve cord in the chordate |
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Definition
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Definition
| an independent visual unit that functions as a separate photoreceptor capable of forming an independent image |
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Definition
| a system in which the vessels open into the animal's body cavity |
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Definition
| a large opening at the top of a sponge |
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Definition
| fleshy, footlike structures in the polychaetes that are pushed into the substrate to provide traction during movement |
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Definition
| an asexual process in which offspring develops from an unfertilized egg |
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Definition
| glands in the foot of a rotifer that secretes a sticky substance that aids in attachment to the substrate |
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Definition
| a narrow, waistlike point of attachment in a spider body |
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Definition
| in a crustacean, the spines and jawlike pincers that cover the skeleton and deter the settling of animals such as barnacles |
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Definition
| in spiders, a pair of appendages that have various sensory, predatory, or reproductive functions |
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Definition
| a filter-feeding device in primitive chordates |
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Definition
| the coiled tongue of a butterfly or moth, which can be uncoiled, enabling it to drink nectar from flowers |
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Definition
| the simplest filtration mchanism for cleansing the blood, used by flatworms |
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Definition
| a unique, protrusible, tonguelike organ in a mollusk that has many teeth and is used to eat plants, scrape food particles off rocks, or bore into shells of other species and tear flesh |
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Definition
| a structure in the water vascular system of crustaceans |
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Definition
| the structure that seals off the old and new chambers of a nautilus |
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Definition
| in annelids, the chitinous bristles on each segment |
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Definition
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Definition
| a sharp, piercing organ in the mouth of a nematode |
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Definition
| a spider's abdominal silk gland |
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Definition
| a pore in the body of a terrestrial species |
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Definition
| a central cavity in the body of a sponge |
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Definition
| a tough protein that lends skeletal support to a sponge |
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Definition
| an abdominal appendage in a crustacean to provide movement |
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Definition
| the fusion of body segments into functional units |
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Definition
| in terrestrial species, a series of finely branched air tubes called tracheae that leads into the body from pores called spiracles |
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Definition
| crustacean structures that function in movement, gas exchange, and feeding |
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Definition
| a nonliving structure that encloses a tunicate, made of a protein and a cellulose-like material called tunicin |
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Definition
| a free-swimming larva that has a rudimentary foot, shell, and mantle |
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Definition
| a structure in mollusks containing the internal organs that rests atop the foot |
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Definition
| a network of canals in a crustacean powered by hydraulic power, that is, by water pressure generated by the contraction of muscles that enables the extension and contraction of the tube feet, allowing echinoderms to move slowly |
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Definition
| a nonliving case that houses a bryozoan |
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Definition
| an extraembryonic membrane in the amniotic egg that serves as a disposal sac for metabolic wastes |
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Definition
| an innermost extraembryonic membrane in the amniotic egg; it protects the developing embryo in a fluid-filled sac called the amniotic cavity |
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