A succession of mitotic cell divisions without cell growth between the divisions.
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.
Resulting developmental stage of gastrulation.
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.
Fossils of soft-bodied Eukaryotes, named for the Ediacara Hills of Australia.
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.
Type of symmetry found in a flowerpot.
Ex: Sea Anemone
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.
Animals that have only two germ layers.
Layer present in all bilaterally symmetrical animals, which fills much of the space between the ectoderm and the endoderm.
Having three germ layers.
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.
Triploblastic animals lacking a body cavity altogether.
Spiral and determinate
Mouth develops first
Radial and indeterminate
Anus develops first
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.
An Embryo;s developing digestive tube which becomes the gut.
The indentation that during gastrulation leads to the formation of the archenteron.
A crown od ciliated tentacles that funtion in feeding.
Distinctive stage fo development for molluscs and annelids.
Animals lacking a backbone.
Animals that capture food particles suspended in the water that passes through their body, which in some species resembles s sac perforated with pores.
Pores in the central cavity of a suspension feeder.
Larger opening through which water flows out of the sponge.
Collar cells lining the interior of the spongocoel, they are flagellated and engulf bacteria and other food particles by phagocytosis.
Gelatinous region that separates two layers of sponge.
Cells that move through the moshyl and have many functions.
Each individual functions as both male and female in sexual reproduction.
The sac of a cnidarian that is the digestive compartment.
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.
Cell unique cnidarians that function in defense and prey capture.
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.
rhabditophoran; Genus Dugesia; Free-living, fresh-water species
A digestive tube with two openings, a mouth and an anus present on rotifers.
A type of asexual reproduction in which females produce only female eggs.
Greek meaning outside anus. Colonial animals that superficially resemble clumps of moss.
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 muscular foot used for movement in Coelomates like molluscs.
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.
A straplike organ used by molluscs to scrape food.
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.
Tough external coat that is shed by some animals.
Process of shedding cuticle.
Segmented body, hard exoskleleton, and jointed appendages.
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; centipedes and millipedes
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
Water Scorpions; earliest chelicerates. extinct.
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.
Jaw-like part of myriapods.
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.
Crustaceans that includes lobsters, crayfishes, crabs, and shrimps.
Planktonic crustaceans, which are the most numerous of all animals.
Slow-moving or sessile marine animals like sea stars.
Water Vascular system
A network of hydraulic canals branching into extensions called tube feet that function in locomotion and feeding.
Animals containing a back bone.
Phylum Chordata that contains the vertebrates; Bilateral animals, within bilateria, they belong to the clade of animals known as Deuterostomia
Longitudinal, flexible rod located between the digestive tube and the nerve cord.
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.
Member of the clade Urochordata, sessile marine chordates that lack a backbone.
Chordates with a head.
Feature unique to cranates, collection of cells that appears near the dorsal margins of the closing neural tube in an embryo.
Were slender, soft-bodied vertebrate with prominent eyes controlled by numerous muscles.
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.
Plate-skinned; earliest gnasthostomes
Group of jawed vertebrates that emerged at roughly the same time as placoderms.
Cartilage fish; have a skeleton composed predominately of cartilage, though often impregnated with calcium.
Sharks, Rays and their relatives.
Lay eggs that hatch outside the mother's body.
Retain the fertilized eggs in the oviduct; born after hatching in the uterus.
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.
A common chamber that ha a single opening to the outside.
Vertebrates; clade gnasthostomes; have an ossified (bony) endoskeleton with a matrix of calcium phosphate.
Protective bony flap that covers the gills of most fish.
An air sac that helps fish control their buoyancy.
Salamanders, frogs, and caecilians; tetrapods
Group of tetrapods whose extant members are the reptiles (including birds) and mammals.
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.
Animals that absorb external heat as their main source of body heat.
Capable of maintaining body temperature through metabolic activity.
Mostly large, stocky, quadrupedal herbivores.
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.
A lineage of the diapsids which include tuataras, lizards, and snakes
A lineage of diaspids that produced the crocodilians, pterosaurs, and dinosaurs.
Originated in the alte Triassic, were the first to exhibit flapping flight.
Diversified into a vast range of shapes and sizes.
Consists of ostrich, rhea, kiwi, cassowary, and emu- all flightless birds.
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.
Opossums, kangaroos, and Mole, Sugar glider, Wombat, Tasmanian devil
The lining of the uterus and the extraembryonic structure in which nutrients diffuse into the embryo from the mother' blood.
Placental mammals; Placentas are more complex than those of marsupials.
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.`
Includes monkey and apes
Study of human origins.
20 extinct species that are more closely related to humans than to chimpanzees.