Biology 2

Araneae

"spiders;" an order in Class Arachnida; 35,000 speciesorder of arachnida, class of chelicerata: Chelicerae with terminal fang, spinnerets.

Chilopoda

"thorned foot" (centipede). Pair of antenna on head. Three pairs of appendages modified as mouth parts, jawlike mandibles. One pair of walking legs per segment. Predators, poison claws.

Acari

"ticks and mites;" an order in Class Arachnida; cephalothorax and abdomen completely fused,Order of chelicerata. Most have fused head, abdomen, & thorax

cuticle

(1) A waxy covering on the surface of stems and leaves that acts as an adaptation that prevents desiccation in terrestrial plants. (2) The exoskeleton of an arthropod, consisting of layers of protein and chitin that are variously modified for different functions. (3) A tough coat that covers the body of a nematode.

Polychaeta

(Annelida, Class) Mostly marine segmented worms. Well-developed head; each segment usually has parapodia with setae; tube-dwelling and free-living.

Metamerism

(Annelids), that is their coelom is divided into a series of segments by septa (except leaches). Each segment is called metamere. (earthworms)

suspension feeders

(a sub-group of suspension feeders) are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, some fish and sharks, and baleen whales. Some birds, such as flamingos, are also filter feeders. Filter feeders can play an important role in clarifying water.

Bivalvia

(common name bivalves) is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells. The class was known for some time as Pelecypoda, which is a reference to the soft parts of the animal, whereas the name Bivalvia simply describes the shell, which has two valves. Other names which have been used for this class include Lamellibranchia (referring to the plate-like gill elements, see ctenidium), Acephala (they have no head), and Bivalva (two valves).

Mantle

(zoology) a protective layer of epidermis in mollusks or brachiopods that secretes a substance forming the shell

trocophore

-larval stage-free-swimming, ciliated to propel through water***-suggest mollusks and annelids share common ancestor

Ectoderm

..., One of the three primary (embryonic) germ layers formed during gastrulation. Ectoderm ultimately forms external structures such as the skin, hair, nails, and inner linings of the mouth and anus, as well as the entire nervous system.

Platyhelminthes (1)

1. Symmetry bilateral. Three germ layers (triploblastic). Body usually flattened dorsoventrally. No true segmentation. 2. Epidermis soft and ciliated(turbelaria), or covered with cuticule and with external suckers or hooks, or both for connection to host (Trematoda, Cestoda). 3. Digestive system incomplete (a mouth but no anus) and usually much branched. None in Acoela or Cestoda. 4. Muscle layers well developed. No body cavity. Spaces between internal organs filled by loose parenchyma. 5. No skeletal, ciculatory or respiratory systems. Excretory system with many flame cells connected to excretory ducts (protonephridia).

Sporocyst

2nd larval stage in flukeswhich develop in the molluscan host, a saclike larval stage in the life cycle of some trematodes, which develops from a miracidium and produces several rediae

Platyhelminthes (2)

6. The nervous system is a pair of anterior ganglia or a nerve ring connected to 1 - 3 pairs of longitudinal nerve chords with transverse commissures. 7. The sexes are usually united (monoecious). Reproductive system of each sex with gonads, ducts, and accessory organs. Fertilization occurs internally. The eggs are microscopic, each enclosed with several yolk cells in a shell. The development in its life cycle is either direct (some Turbellaria and monogenetic Trematoda) or with one or more larval stages (digenetic Trematoda and some Turbellaria and Cestoda). Asexual in some species.flatworms (tapeworms, planarians, flukes); bilateral symmetry; central nervous system

Rhynchocoel

A cavity that holds the inverted proboscis in nemertinean worms.

Cnidocytes/nematocytes

A cnidocyte, cnidoblast, or nematocyte is a type of venomous cell unique to the phylum Cnidaria (corals, sea anemones, hydrae, jellyfish, etc.). The cnidocyte cell provides a means for them to catch prey and defend themselves from predators. Despite being morphologically simple, lacking a skeleton and usually being sessile, cnidarians prey on fish and crustaceans. A cnidocyte fires a structure that contains the toxin, from a characteristic sub-cellular organelle called a cnidocyst (also known as a cnida or nematocyst). This is responsible for the stings delivered by jellyfish.

Nauplius

A distinct planktonic larval stage seen in many crustaceans., larval form with three pairs of appendages and a single median eye, occurring usually as the first stage of development after leaving the egg.

Medusa

A free-floating, oftemumbrella shaped body form found in cnidarian animals, such as jellyfish.

tracheal system

A gas exchange system of branched, chitin-lined tubes that infiltrate the body and carry oxygen directly to cells in insects.

Mesoglea

A layer of gelatinous material that lies between the epidermis and gastrodermis in cnidarian and ctenophores. In bilateral animals, a third body layer, the mesoderm, forms between endoderm and ectoderm, and forms the muscles of most eumetazoans.

Protostome

A member of one of two distinct evolutionary lines of coelomates, consisting of the annelids, mollusks, and arthropods, and characterized by spiral, determinate cleavage, schizocoelous formation of the coelom, and development of the mouth from the blastopore.

metamorphosis

A process in which an animal's body undergoes dramatic changes in form during its life cycle, change of form; Ex. metamorphosis of caterpillar to butterfly.

spermatophores

A specialized container filled with sperm which is transferred, in a variety of ways, to the female; many arthropods, including insects, scorpions, mites, and copepods, transfer sperm indirectly to the female using spermatophores.

malpighian tubules

An excretory organ that is unique to insects, empties into digestive tract and removes nitrogenous wastes from the hemolymph, also plays a role in osmoregulation, Found in insects and terrestrial arthropods.

Coelomates

Animals where the body cavity is completely lined with the mesoderm; covers the outside of the digestive system; ex=earthworms.

Eumetazoa

Animals with true tissues, Members of the subkingdom that includes all animals except sponges.

Parapodia

Appendages found in some annelids from which bristle-like structures (chaetae) extend. , characteristic of Phylum Annelidia; appendages used for swimming, crawling, and burrowing

Polyp

Are cylindrical and are usaully found attached to a firm substrate. They may be solitary ofr colonial. In a polyp. the body opening, which acts both as a mouth and anus. faces away from the substrate on whcih the animal is growing, and therefore often faces upward. Many polyps build a chitinous or calcaeous (calcium carbonate) external or internal skeleton, or both. Only a few polyps are free living.

ampulla

At the base of each tube foot is a muscular sac, which contains fluid. When the ampulla contracts. the fluid is prevented from entering the radial canal by a one-way valve and is forced into the tube foot, thus extending it.

halteres

Balancing structures (not wings) on the dorsal metathoracic segment., insects typically have two pairs of wings; however, in certain groups, such as the flies the second pairs is modified into small knobs or balancing organs.

Arachnida

Class. Spiders. Two Body Segments (cephalothorax and the abdomen)2 body segments=cephalothorax and abdomen with **6 pairs (12) appendages: chelicerae-pincers or fangs (1 pair), pedipalps- sensing (1 pair), 4 pairs of walking legs

Clonorchis sinensis

Diseases: clonorchiasis Characteristics: trematode (liver fluke) Life cycle: humans ingest undercooked fish containing encysted larvae (metacercariae); immature flukes enter biliary duct, become adults, and release eggs that are passed in feces; eggs are eaten by snails, hatch and form miracidia. Encyst under scales of fish and eaten by humans Transmission: eating raw or undercooked freshwater fish Epidemiology:

Intestinal Roundworms

Enterobius vermicularis (pinworm) Ascaris lumbricoides (giant roundworm) Trichnella spiralis Strongyloides stercoralis Ancylostoma, Necator americanus (hookworms)

Torsion

Gastropoda (snails, slugs, nudibranchs, abalone), the mantle cavity and anus are moved from the posterior to the anterior

Coiling

Gastropoda (snails, slugs, nudibranchs, abalone), the spiral winding of the shell

Chitons

Group of Molluscs, known as polyplacophora, Marine, shell with 8 plates,foot used for locomotion, radula, no head.

choanoflagellates

Have one flagellum, a collar made of microtubules that filters water for food. Free living, usually sessile. Often colonial in a jelly like matrix, free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals.

Complete metamorphosis

Insect development consisting of four stages: egg, larva, pupa, and adult, type of insect development in which the larvae look and act nothing like their parents and also feed in completely different ways

Incomplete metamorphosis

Insect development consisting of three stages: egg, nymph, and adult, A type of development in certain insects, such as grasshoppers, in which the larvae resemble adults but are smaller and have different body proportions. The animal goes through a series of molts, each time looking more like an adult, until it reaches full size

Arthropoda

Insects, arachnids, crustaceans; segmented bodies; paired, jointed legs; chitinous exoskeleton; open circulatory system; dorsal heart, Shrimp (Crustacea), spider (Arachnida), bee (insecta) , centipede (Chilopoda)

Bilateria

Members of the branch of eumetazoans possessing bilateral symmetry., A member of a major lineage of animals (Bilateria) that are bilaterally symmetrical at some point in their life cycle, have three embryonic germ layers, and have a coelom. All protostomes and deuterostomes are bilaterians., bilaterally symmetric animals, which means they can be divided along a verticasl plane at the midline to create two halves

Mollusca

Motile organisms with soft bodies and hard shells. Are the first protostomes and the first coelomates (with spiral, determinate cleavage). Include gastropods, bivalves, cephalopods. E.g. octopuses, squids, snails, clams.

Visceral mass

One of the three main parts of a mollusk, it contains most of the internal organs above the head; the heart and organs of digestions, excretion, and reproduction.

Deuterostome

One of two coelomate divisions (the other is the protostomes) characterized by a radial cleavage pattern during early development, indeterminate cleavage, and the development of the blastopore into the anus. This group includes the echinoderms and the chordates.

Heterotrophs

Organisms that depend on other organisms for their food

Anterior

Pertaining to the front, or head, of a bilaterally symmetrical animal.

Rotifera

Phylum: small organisms with sessile, colonial, and planktonic forms. most freshwater.Rotifers; tiny filter feeders; pseudocoelomates; complete digestive tract, , bilaterally symmetrical, unsegmented, pseudocoelomates with a ciliated crown...ex..rotifers

radial canals

Portions of water vascular system emanating from the ring canal and leading into each arm of the sea star

Triploblastic

Possessing three germ layers: the endoderm, mesoderm, and ectoderm. Most eumetazoa are triploblastic., platyhelminthes, nematoda, mollusca, annelida, arthropoda, echinodermata, Roundworms (Nematoda), Flatworms (Platyhelminthes), Rotifers tissue layers

prostomium

Small projection that hangs over the mouth that is used as a sensory device in a worm

Spicules

Small, needlelike structures in sponges made of calcium carbonate, silica or a tough fibrous protein called spongin.

chromatophores (2)

Some species can rapidly change colour through mechanisms that translocate pigment and reorient reflective plates within chromatophores. This process, often used as a type of camouflage, is called physiological colour change. Cephalopods such as octopus have complex chromatophore organs controlled by muscles to achieve this, while vertebrates such as chameleons generate a similar effect by cell signaling. Such signals can be hormones or neurotransmitters and may be initiated by changes in mood, temperature, stress or visible changes in local environment.

Chelicerata

Subphylum of Arthropoda that includes Class Merostomata -horseshoe crabs, Class Arachnida - spiders, scorpions, ticks, mites, harvestmen, Class Pycnogonida - sea spiders.subphylum of arthropods including merostomatans, related to trilobites and eurypterids

Ecdysozoa

Supergroup of protostomes; characterized by periodic molting of their exoskeleton. Include the roundworms and arthropods., Division of Protostomes. Animals that molt (nematodes, arthropods)

Schistosoma

TAPEWORM. Snails are hosts. Goes up through skin. Causes granulomas, fibrosis, portal hypertension and splenomegaly. Cause SQUAMOUS CARCINOMA OF BLADDER.

Diploblastic

Term for animals with just two germ layers - the ectoderm and endoderm. Include Cnidarians and comb jellies.

Cephalopoda

The class Cephalopoda, which means "head foot", are mollusks and therefore related to bivalves (scallops, oysters, clams), gastropods (snails and slugs), scaphopoda (tusk shells), and polyplacophorans (chitons). Some mollusks, such as bivalves, don't even have a head, much less something large enough to be called a brain! Yet cephalopods have well-developed senses and large brains. Most mollusks are protected by a hard external shell and many of them are not very mobile. Although nautilus has an external shell, the trend in cephalopods is to internalize and reduce the shell. The shell in cuttlefish, is internal and is called the cuttlebone, which is sold in many pet shops to supply calcium to birds. Squid also have a reduced internal shell called a pen. Octopuses lack a shell altogether. (triploblastic, radula, mantle, eucoelomate).

glochidia

The glochidium (plural glochidia) is a special microscopic larval stage of larger freshwater mussels, aquatic bivalve mollusks in the families Unionidae and Margaritiferidae, the river mussels and European freshwater pearl mussels. This larva form has hooks, which enable it to attach itself to fish (for example to the gills of a fish host species) for a period of time before it detaches and falls to the substrate and takes on the typical form of a juvenile mussel. Since a fish is active and free-swimming, this process helps distribute the mussel species to potential areas of habitat that it could not reach any other way.

Endoderm

The innermost of the three primary germ layers in animal embryos; lines the archenteron and gives rise to the liver, pancreas, lungs, and the lining of the digestive tract, membranelike tissue lining the digestive tract

Mesoderm

The middle primary germ layer of an early embryo that develops into the notochord, the lining of the coelom, muscles, skeleton, gonads, kidneys, and most of the circulatory system, The middle embryonic germ layer, lying between the ectoderm and the endoderm, from which connective tissue, muscle, bone, and the urogenital and circulatory systems develop.

Insecta

This is a class that is under the subphylum Uniramia that contains more species than any group of animals. It have a three-part body with a segmented body, jointed appendages, and an exoskeleton., class with insects such as bees, ants, grasshoppers, butterflies

septa

Walls between cells with pores to allow cytoplasm to flow divides fungal cells yet allows cytoplasm to flow (exchange materials because no vascular tissue)

Peristaltic movement

Waves of contraction and relaxation that propel food down the alimentary canal. this also coensides with movement. (earthworms)

Corona

a ciliated corona on the head of a rotifers head that creates a current of water to bring food particles to their mastax.

Lophotrochozoa

a clade that encompasses the annelids, mollusks, and several other phyla, they are distinguished by two morphological features, the lophophore, a crown of tentacles used for feeding,and the trochophore larva, a distinct larval stage, Main group of protostomes; widely diverse. Includes the flatworms, rotifers, annelids, and molluscs.

Oligochaeta

a class of terrestrial and freshwater annelid worms with many segments, but few setae per segment; have a clitellum, but lack parapodia and a differentiated head region; mostly monoecious, with permanent gonads and direct development

Zygote

a fertilized egg, produced by the joining of a sperm and an egg

Mesohyl

a gelatinous, protein rich matrix in between the choanocytes and epithelial cells of a sponge

Hox gene

a group of homeotic genes clustered together that determine the head to tail identity of body parts in animals. All hox genes contain the homeobox DNA sequence.

fat body

a mass of fatty tissue in insects, used as an energy source during hibernation and metamorphosis a similar tissue mass in amphibians and reptiles

Hookworms

a type of parasite that usually enters the body through bare feet and moves thorugh the body to the small intestines where they attach themselves with a series of hooks around their mouths.

Pseudocoelomates

an animal whose body cavity is lined by tissue derived from mesoderm and endoderm,( Roundworms)

lyme disease

an infection caused by a bacteria carried by deer ticks and transmitted to humans by the bite of an infected tick; symptoms vary but may include a rash at the site of the bite and flu like symptoms such as fever, headache, joint pain, and fatigue (INFECTED TICK OR MOSQUITO)

Herbivores

an organism that eats only plants.

Acoelomates

animals, such as flatworms, that do not have a body cavity, Without coelom

Biramous

appendages that fork into two parts at the base; two parts can look exactly the same or be completely different; can also be internal/external (gills and walking legs in crayfish); members of Class Crustacea (arthropod limb that spreads into two)

Rediae

are larval or immature stage flukes as described in the life cycle of Fasciola hepatica and Schistosoma. They form within the sac-like sporocyst that developes from a miracidium after it enters a water snail. They undergo asexual reproduction to form cercariae.

chromatophores (1)

are pigment-containing and light-reflecting cells found in amphibians, fish, reptiles, crustaceans, and cephalopods. They are largely responsible for generating skin and eye colour in cold-blooded animals and are generated in the neural crest during embryonic development. Mature chromatophores are grouped into subclasses based on their colour (more properly "hue") under white light: xanthophores (yellow), erythrophores (red), iridophores (reflective / iridescent), leucophores (white), melanophores (black/brown) and cyanophores (blue). The term can also refer to coloured, membrane associated vesicles found in some forms of photosynthetic bacteria.

Cercariae

are tadpole like larvae that are free swimming larval stages of trematodes the final stage of fluke development occuring in the first intermediate host(snail); has body and tail for mobility

Posterior

at or near the hind end in quadrupeds or toward the spine in primates

clitellum

band of thickened, specialized segments in annelids that secretes a mucus ring into which eggs and sperm are released, in leeches and earthworms, a thick depression of the body wall that functions in reproduction.

Coelom

body cavity that forms between the mesoderm and endoderm, found in nematodds

cephalothorax

body part of Arachnids and Crustaceans where head and thorax are fused together,The anterior part of an arthropod body, consisting of a head and other body segments fused together

Ostia

by beating their flagella, choanocytes draw water into the sponge through numerous pores

ossicles

calcified plates that make up echinoderm endoskeleton

flame cells

characteristic of Phylum Platyhelminthes; very primitive kidney whose job is to maintain the animal's water balance and excretion,Specialized cells that remove excess water from the body by forming a network of tubes that empties into the outside environment through tiny pores.

Cestoda

class of flatworms; all are parasitic; endoparasites in intestine; bud long chains of proglottids; tapeworms; eg. Taenia, Group of Platyhelminthes, parasite of vertebrates, scolex attaches to host, proglottids produce eggs and break after fertilization, no head or digestive system, life cycles with one or more intermediate hosts.

Trematoda

class of flatworms; all are parasitic; parasites in blood or digestive system; up to 5 developmental stages in 2 or more hosts; parasitic liver and blood flukes; eg. Clonorchis

Turbellaria

class of flatworms; planarians; ventral mouth; locomotion by creeping on cilia and mucous; free living, mostly aquatic; eg. Dugesia, Bipalium, class of platyhelminthes ex flatworms - mostly free living (nonparasitic) ;commonly known as planarians - ciliated, so thin lack specialized organs, carnivores;

Polyplacophora

class of mollusca called chiton, has 8 overlapping dorsal (top) plates, clings to rocks water edge with suction cup foot, head reduced

Gastrula

double-walled stage of the embryo resulting from invagination of the blastula, An embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm.

Auricles

ear-like projections on a flatworm that are sensitive to chemicals and touch

Metacercariae

encysted form of the fluke life cycle. Occurs on water plants or in the second intermediate hosts, such as fish, crabs, or crayfish. The infective stage for humans.

Exoskeleton

external skeleton; tough external covering that protects and supports the body of many invertebrates, A body covering, typically made of chitin, that provides support and protection

Detritivores

feed on plant and animal remains and other dead matter

Choanocytes

feeding cells (AKA collar cells); joint action of choanocyte flagella moves water through the sponge; delivers food, oxygen, gametes; carries off wastes (mostly ammonia)

Spongin

flexible, structural protein fibers in the mesoglea of most sponges

veliger

free swimming larva of most marine snails, tusk shells, and bivalves; develops from the trochophore and has the beginning of a foot, shell, and mantle

Gemmules

group of cells enclosed in tought outer coats that can remain dormant during harsh living conditions and then emerge and grow into adult sponges.Internal buds that contain amoebocytes and it is filled with food.They are surrounded by a protective coat made of organic material.

Diploblastic

having 2 germ layers: ectoderm and endoderm., 2 germ layers (ecto & endo) -Jellyfish, corals, comb jellies

Blastula

hollow ball of cells in a layer surrounding a fluid-filled space; an animal embryo after cleavage but before formation of the gastrula

ring canal

in echinoderms, a circular canal that is near the mouth and that is part of the water-vascular system

radula

in some snails and mollusks, the rasping, tonguelike organ used to drill, scrape, grate, or cut food

neuromuscular system

involves coordination of the muscles,the central nervous system and the enteric nervous system to move food along the gastrointestinal tract and to control all aspects of digestion,absorption, and elimination

Miracidium

is a free swimming, ciliated larva which emerges from the trematode egg and swims about in search for the first intermediate host (ex: snail) (The ciliated larval stage of a fluke, which develops within the ovum)

Oscula

large pores in a sponge's body wall through which water exits the body.

Myzostomids

marine animals that are parasites of echinoderms; have no body cavity and only incomplete segmentation; incorrectly allied with flatworms

Parazoa

multicellular organisms having less-specialized cells than in the Metazoa, 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).

Ctenophora

name means "comb bearer" no stinging cells, instead they have adhesive structures called colloblasts feeding organs include comb jellies Radial Symmetry 8 rows of "comb plates" ctenes fused rows of cilia, transparent, gelatinous, monecious animals. also called comb jellies or sea walnuts. (hermaphoditic)

cerebral ganglia

one of a pair of nerve cell clusters that serve as a brain at the anterior end of some inverbrates,the worm's "brain" - it responds to light, touch, chemicals, moisture, temperature, and vibrations

tube feet

one of the many small flexible fluid-filled tubes that project from the body of an echinoderm and are used in locomotion, feeding, gas exchange, and excretion

spiracles

openings on the abdomen and thorax through which air enters and waste gases leave the insect's body, small opening located along the side of the body through which air enters and leaves the body of many terrestrial arthropods

Carnivores

organisms that mainly prey upon animals., meat eaters

ecdysis

periodic shedding of the cuticle in arthropods or the outer skin in reptiles,and re-formation of the exoskeleton Shedding of out cuticular layer; molting, as in insects or crustaceans.

Ventral

pertaining to the front or anterior part of the body

Placozoa

phylum consisting of only one species Trichoplax adhaerens, which consists of a few thousand cells arranged in a double-layered plate 2 mm across; can reproduce by budding or binary fission

Chelicerae

pointed appendages which are used to grasp food, and are found in place of the chewing mandibles most other arthropods have. Additionally, some chelicerae, such as those found in spiders, are hollow and contain (or are connected to) venom glands, and are used to inject venom into prey or a (perceived) threat.(spiders)

Nemertea

proboscis worms or ribbon worms; lack a true ceolom but they have an alimentary cannal, unsegmented, dorsoventraly flattened, some cephalization, triploblastic, acoelomate, bilateral, closed circ, complete digestive system with anus

Radiata

radially symmetric animals, which means they can be divided equally by a longitudinal plane passing through the central axis, includes cnidarians and ctenophores

Echinodermata

radially symmetrical marine invertebrates include starfish and sea urchins and sea cucumbers

Cnidaria

radially symmetrical, invertebrate, coelenterates with two tissue layers & specialized stinging cells called cnidocytes that shoot out nematocysts; example: jellyfish.radially symmetrical, tentecales armed with nematocysts, vase shaped polyp form and bell shaped medusa, digestive cavity with only one opening.

Dorsal

relating to the back of an animal; Ex. dorsal fin, Pertaining to the top of an animal with radial or bilateral symmetry.

pedipalps

second pair of appendages, modified for sensory functions and manipulating prey,in spiders, a pair of appendages that have various sensory, predatory, or reproductive functions, pair of mouthparts in chelicerates that are usually modified to grab prey (arachnids)

Annelida

segmented worms ex: eathworm

proglottids

series of body segments of a tapeworm, each has a complete set of male and female reproductive organs, each can make 100,000 eggs, (4000 eggs per month).

Nerve Net

simple nervous system that has no brain or spinal cord but consists of neurons that receive sensory information and connect directly to other neurons that move muscles

Acoela

simple pharynx, no permanent gut cavity, mouth/pharynx leads to solid cellular entodermal mass, flatworms simple nervous system,Cephalization, bilateral symmetry, triploblastic (stem cells) Separate lineage from Platylemninthes, diverging before mail bilaterian clades.

madreporite

sleve like structure through which the water vascular system of an echinoderm opens to the outside

Nematocysts

small capsules that contain a toxin which is injected into prey or predators, In a cnidocyte of a cnidarian, a specialized capsule-like organelle containing a coiled thread that when discharged can penetrate the body wall of the prey.

Gastropoda

snails, slugs, nudibranchs, abalone.a. Largest and most diverse class (40,000 species). b.Most have heads with pair of tentacles with eyes at end.

Porifera

sponges; sessile animals that lack true tissues; suspension feeders, trap particles that pass through the interal channels of their bodies, (sponges) simplest of all animals, no tissues, no organs; thick sack of cells with pores, canals, chambers; live in one place (sessile) in h20 (water); filter feeders; super regenerators; often asymetrical

Crustacea

subphylum of arthropoda; crabs, lobsters, crayfish, and shrimp, barnacles, shrimp, and pill bugs.

Zooxanthellae

symbiotic unicellular dinophytes found in corals, sea anemones, mollusks and several other types of marine animals, photosynthetic algae which gives corals food in exchange for protection and light access

Water vascular system

system of internal tubes in echinoderms that carries out essential functions such as feeding, respiration, circulation, and movement, A network of hydraulic canals unique to echinoderms that branches into extensions called tube feet, which function in locomotion, feeding, and gas exchange.

Planula

the ciliated, free-swimming planktonic larva of cnidarians that settles to the bottom and metamorphoses into a juvenile, a ciliated larva developed by the blastula. (ciliated larva developed by the blastula)

Mastax

the circular muscular pharynx in the mouth of rotifers, a muscular organ that breaks down food into smaller particles (roundworms), "jaws"

Cephalization

the concentration of nerve tissue and sensory organs at the anterior end of an organism

Metamerism

the division of the body into identical subunits called segments, Segmented body part arrangements like the earthworm

Ocelli

the simple eye of many insects; located on the vertex of the head and next to the compound eyes; sensitive to light which helps the insect keep track of day and night.

Morula

the solid mass of cells resulting from the cleavage of the ovum before the formation of a blastula.

Filarial Worms

threadlike worms that live in the blood and lymph vessels of birds and mammals;transmitted through bitting insects;large numbers of these may block the passage of fluids within the lymph vessels which causes elephantiasis.

setae

tiny bristles that help segmented worms move by anchoring their bodies in the soil so each segment can move the animal along

Nematoda

unsegmented worms: roundworms, Soil dwellers with pseudocoeloms. Complete digestive tract that extends from mouth → anus. Some are parasites.Round worms (hookworm, trichina, free-living soil nematodes); has endo, meso, ectoderm; no circulatory system; has nerve cords and an anterior nerve ring