Ch 29 - Introduction to Invertebrates

acoelomate

A solid-bodied animal lacking a cavity between the gut and outer body wall.

Animalia

Kingdom of the most complex organisms; multi-cellular, heterotrophic, lack rigid cell walls, mobile, tissues in internal organs, sensory organs, nervous system

asymmetrical

not being the same on both sides.

bilateral symmetry

body plan in which only a single, imaginary line can divide the body into two equal halves; characteristic of worms, arthropods, and chordates

cephalization

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

cestode

ribbon-like flatworms that are parasitic in the intestines of humans and other vertebrates

cnidarian

radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures / uses stinging cells to capture food and defend itself

coelom

a cavity in the mesoderm of an embryo that gives rise in humans to the pleural cavity and pericardial cavity and peritoneal cavity

coelomate

An animal that possesses a true coelom (a body cavity lined by tissue completely derived from mesoderm).

comb jelly

biradially symmetrical hermaphroditic solitary marine animals resembling jellyfishes having for locomotion eight rows of cilia arranged like teeth in a comb, Member of phylum Ctenophora; free-swimming marine invertebrates.

cyst

a small anatomically normal sac or bladderlike structure (especially one containing fluid)

dueterostome

An evolutionary line that are characterized by radial, indeterminate cleavage and development of the anus from the blastopore

dimorphic

undergoing two different adult morphologies, has both sessile (polyps) and motile (medusa) stages

elephantiasis

a condition in which the limbs become extremely swollen and the skin hardens and thickens, happens when a large amount of filarial worms block lymphatic vessels

flatworms

A group of often parasitical worms that have bilateral symmetry, a one opening digestive system, and the beginnings of a brain; tapeworm, Phylum Platyhelminthes

gastrovascular cavity

digestive chamber with a single opening, in which cnidarians, flatworms, and echinoderms digest food

heartworm disease

disease of dogs, cats, ferrets. mosquitoes are key to disease transmission. affects all areas of the US

hermaphroditic

possessing both the male and the female reproductive organs

hydra

small tubular solitary freshwater hydrozoan polyp

invertebrate

any animal lacking a backbone or notochord

medusa

one of two forms that coelenterates take: is the free-swimming sexual stage in the life cycle of a coelenterate and has a gelatinous umbrella-shaped body and tentacles

mesoglea

in cnidarians, the jellylike material located between the ectoderm and the endoderm

nematocyst

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.

nerve net

in cnidarians, a network of nerve cells that lacks a central control; impulses pass in any or all directions to produce a generalized response

Obelia

a Hydrozoan, we looked at preserved colonies, includes both polyp and medusa stages on the colony (nutritive polyps called hydranths and reproductive polyps called gonangia

polyp

one of two forms that coelenterates take e.g. a hydra or coral: usually sedentary and has a hollow cylindrical body usually with a ring of tentacles around the mouth

proglottid

Detachable section of a tapeworm that contains muscles, nerves, flame cells, and reproductive organs

protostome

Animal whose mouth is formed from its blastopore

pseudocoelomate

An animal whose body cavity is lined by tissue derived from mesoderm and endoderm.

radial symmetry

body plan in which body parts repeat around the center of the body; characteristic of sea anemones and sea stars

ribbon worm

soft unsegmented marine worms that have a threadlike proboscis and the ability to stretch and contract

rotifer

a member of the phylum which consists of small, aquatic invertebrates whose ring of cilia around the mouth makes the animal look like a spinning wheel

roundworm

member of a group of cylindrical invertebrates with pointed heads and tapered tails

schistosomiasis

a disease that is caused by a parasitic blood fluke and that affects the skin, intestines, liver, vascular system, or other organs

scolex

knob-like, anterior end of tapeworm, having hooks and suckers that attach to the host's intestinal lining

segmentation

Division of an animal body along its length into a series of repeated parts

sessile

describes an organism that remains attached to a surface for its entire life and does not move

sessile filter feeder

animal that stays in one place and consumes small food particles from the water

spicule

needle of silica or calcium carbonate in the skeleton of some sponges

sponge

primitive multicellular marine animal whose porous body is supported by a fibrous skeletal framework

spongin

a fibrous protein that contains sulfur and composes the fibers of the skeleton of some sponges

trematode

parasitic flatworms having external suckers for attaching to a host

trichinosis

disease causd by roundworms resulted in eating uncooked meat

tube-within-a-tube body plan

body with a digestive tract that has both a mouth and an anus

turbellarian

flatworm with three tissue layers, acoelomate, no unique characters, inhabit freshwater streams and ponds, oceans and moist terrestrial environments

vertebrate

animals having a bony or cartilaginous skeleton with a segmented spinal column and a large brain enclosed in a skull or cranium