Cleavage leads to this multicellular stage, which in many animals takes the form of a hollow ball.
Process during which the layers of embryonic tissues that will develop into adult body parts are produced.
Sexually immature form of an animal that is morphologically distinct from the adult, usually eating different food and even living in a different habitat than the adult.
A developmental transformation that turns the animal into a juvenile that resembles an adult, but is not yet sexually mature.
A wave of animal diversification that occurred 535-525 million years ago, during the Cambrian period of the Paleozoic era.
Particular set of morphological and developmental traits, integrated into a functional whole- the living animal.
Evolutionary trend in whih sensory equipment is concentrated at the anterior end, including a central nervous system ("brain") in the head.
The germ layer covering the surface of the embryo, gives rise to the outer covering of the animal and, in some phyla, to the central nervous system.
The innermost germ layer, lines the pouch that forms during gastrulation (the archenteron) and gives rise to the lining of the digestive tract (or cavity) and organs such as the liver and lungs of vertebrates.
Layer present in all bilaterally symmetrical animals, which fills much of the space between the ectoderm and the endoderm.
A fluid or air-filled pace between the digestive tract and the outer body wall found in most triploblastic animals.
Animals having "true" coeloms, formed from tissue derived from mesoderm. The inner and outer layers of tissue that surround the cavity connect and form structures that suspend internal organs.
Some triploblastic animals have a body cavity that is formed from mesoderm and endoderm.
Planes of division are diagonal to the vertical axis of the embryo; smaller cells are centered over the grooves between larger, underlying cells.
Rigidly casts ("determines") the developmental fate of each embryonic cell very clearly.
Cleavage planes are lateral to the vertical axis of the embryo; the tiers of the cells are aligned one direction above the other.
Each cell produced by the early cleavage divisions retain the capacity to develop into a complete embryo.
Animals that capture food particles suspended in the water that passes through their body, which in some species resembles s sac perforated with pores.
Collar cells lining the interior of the spongocoel, they are flagellated and engulf bacteria and other food particles by phagocytosis.
Cylindrical forms that adhere to the substrate by the aboral end of their body (the end opposite the mouth) and extend their tentacles, waiting for prey.
Resembles a flattened, mouth-down version of the polyp that moves freely in the water by a combination of passive drifting and contractions of its bell-shaped body.
Specialized cnidae that contain a stinging thread that can penetrate the body wall of the cnidarain's prey.
Networks of tubules with ciliated structures called flame bulbs that pull fluid through branched ducts opening to the outside.
Lamp Shell, superficially resemble clams and other hinged-shelled molluscs, but the two halves of the brachiopod shell are dorsal and ventral, rather than lateral, as in clams.
A fold of tissue that drapes over the visceral mass and secretes a shell (if one is present).
Water-filled chamber found in many molluscs, which houses the gills, anus, and excretory pores.
In gastropods, a developmental process in which the visceral mass rotates up to 180°, causing the animal's anus and mantle cavity to be positioned above its head.
Open Circulatory system
Fluid called hemolymph is propelled by a heart through short arteries snd then into spaces called sinuses surrounding the tissues and organs.
One of the four major lineages of arthropods consisting of sea spiders, horseshoe crabs, scorpions, ticks, mites, and spiders
Named for the claw-like feeding appendages claaed chelicerae, which serve as pincers or fangs. Anterior Cephalothorax and a posterior abdomen. lacking antennae, with simple eyes.
One of the four major lineages of arthropods including insects and their wingless, six-legged relatives
One of the four major lineages of arthropods including crabs, lobsters, shrimps, barnacles, and many others
Bulf of modern chelicerates; Cephalothorax has six appendages, the chelicerae; a pair of appendages called pediapalps that function in sensing, feeding, or reproduction, and four pairs of walking legs. Spiders, ticks, mites.
In most spiders, gas exchange is carried out by stacked platelike structures contained in an internal chamber.
The young (nymphs) resemble adults but are maller, have different body proportion, and lack wings. nymph undergoes a series of molts, each time looking more like an adult, reaching sexually maturity with the final molt.
One of the largest groups of crustaceans, which includes terrestrial, fresh-water, and marine species, including pill bugs or wood lice.
Water Vascular system
A network of hydraulic canals branching into extensions called tube feet that function in locomotion and feeding.
Phylum Chordata that contains the vertebrates; Bilateral animals, within bilateria, they belong to the clade of animals known as Deuterostomia
In chordate embryos, one fo the grooves that separate a series of pouches along the sides of of the pharynx and may develop into a pharyngeal slit.
In chordates embryos, one of the slits that form from the pharyngeal clefts and communicate to the outside, later developing into gill slits in many vertebrates.
The most basal group of living chordates, which get their name from their bladelike shape.
Feature unique to cranates, collection of cells that appears near the dorsal margins of the closing neural tube in an embryo.
Lateral Line System
Characteristic of aquatic gnasthostomes in which organs form a row along each side of the body and are sensitive to vibrations in the surrounding water.
Cartilage fish; have a skeleton composed predominately of cartilage, though often impregnated with calcium.
Sharks, Rays and their relatives.
Young develop within the uterus and obtain nourishment from the mother's blood through a yolk sac placenta, by absorbing a nutritious fluid produced by the uterus, or by eating other eggs.
Vertebrates; clade gnasthostomes; have an ossified (bony) endoskeleton with a matrix of calcium phosphate.
Contains four specialized membranes; the amnion, the chorion, the yolk sac, and the allantois.
Clade includes tuataras, lizards, snakes, turtles, crocodillians, and birds, along with a number of extinct froups, such as plesiosaurs and icthyosaurs.
Ancient reptile clade; derived characters pair of holes on each side of the skull, behind the eye socket; muscles pass through these holes and attach to the jaw, controlling jaw movement.
Member of an amniote clade distinguished by a single hole on each side of the skull. Synapsids include mammals.
Found only in Australia and New Guinea and are represented by one species of platypus and four species of echnidnas (spiny anteaters). Lay eggs, have hair, produce milk, but they lack nipples. Milk is secreted byl glands on the belly of the mother. After hatching, the baby sucks the milk from the mother's fur.
The lining of the uterus and the extraembryonic structure in which nutrients diffuse into the embryo from the mother' blood.
Can touch the ventral surface (fingerprint side) of the tip of all four fingers with the ventral surface of the thumb of the same hand.`