Apologia Biology (3rd edition) Module 13

invertebrate

animal that lacks a backbone

vertebrate

animals that possess a backbone

Chordata

The phylum of the animal kingdom that includes vertebrates.

symmetry

having the same shape, size, and position on both sides of a dividing line

Spherical symmetry

An organism possesses spherical symmetry if it can be cut into two identical halves by any cut that runs through the organism's center

radial symmetry

An organism possesses radial symmetry if it can be cut into two identical halves by any longitudinal cut through its center

bilateral symmetry

An organism possesses bilateral symmetry if it can only be cut into two identical halves by a single longitudinal cut along its center which divides it into right and left halves.

Cephalization

concentration of sense organs and nerves in the head of an animal

Anterior

head region

Posterior

tail end

Porifera

the phylum of sponges

asymmetrical

no symmetry

Epidermis

An outer layer of cells designed to provide protection

endodermis

an inner layer of cells

Mesenchyme

The jellylike substance that separates the epidermis from the inner cells in a sponge

Spicules

small, spike shaped particles of calcium carbonate or silicon dioxide that make up the skeleton of some sponges

Spongin

tough web of protein that make ups the skeleton of some sponges.

Choanocytes (collar cells)

flagellated cells that push water through a sponge

Amoebocytes

Cells that move using pseudopods and perform different functions in different animals

Gemmule

A cluster of cells encased in a hard, spicule-reinforced shell

polyp

The sessile, tubular form of a cnidarian with a mouth and tentacles at one end and a basal disk at the other

Medusa

A free-swimming cnidarian with a bell-shaped body and tentacles

Epithelium

Animal tissue consisting of one or more layers of cells that have only one free surface, because the other surface adheres to a membrane or other substance

Mesoglea

The jellylike substance that separates the epithelial cells in a cnidarian

Nematocysts

Small capsules that contain a toxin which is injected into prey or predators

gastrovascular cavity

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

hydra

An organism that exists in the polyp stage only

Testes

organs that produces sperm

Ovaries

Organs that produce eggs

Corals

Cnidaria

planula

the free-swimming, ciliated larva of a cnidarian

Annelida

phylum of segmented worms

segmented worms

Phylum Annelida

Clitellum

Band of thickened, specialized segments in annelids that secretes a mucus ring into which eggs and sperm are released

anus

A muscular opening at the end of the rectum through which waste material is eliminated from the body

Setae

Bristle-like structures that help segmented worms move

circular layer of smooth muscle

fibers in circumference of organ; contraction --> constricts lumen, elongates organ

longitudinal layer of smooth muscle

fibers parallel to long axis of organ; contraction dilates and shortens

complete digestive tract

digestive system that has two openings, a mouth and an anus, that are at opposite ends of a continuous tube

pharynx (earthworm)

where a mixture of soil and organic matter eaten by the earthworm enters

crop (earthworm)

stores food

gizzard (earthworm)

grinds up the food (mixed with sand)

digestive system

nephridia

organs that remove metabolic wastes from an animal's body

nephridiopore

External opening on each somite from which wastes are secreted

closed circulatory system

A system in which blood stays in vessels designed to transport food and other necessary substances throughout a creature's body

dorsal blood vessel (earthworm)

one of the main blood vessels on a worm

ventral blood vessel (earthworm)

the other main blood vessel on a worm

aortic arches (earthworm)

contracts to push blood around

circulatory system

Cuticle (earthworm)

moist layer covering the epidermis

nervous system

A system of sensitive cells that respond to stimuli such as sound, touch, and taste

ganglia (earthworm)

Masses of nerve cell bodies

hermaphrodite

possessing both the male ad female reproductive organs

seminal vesicles

Sperm of earthworm stored here

Oviducts

Eggs of earthworm stored here

slime tube

place where two earthworms attach to each other to exchange sperm

seminal receptacles

receive sperm from another worm

radioles

tentacles from a trumpet-shaped tube used to catch food

Platyhelminthes

Phylum of flatworms

Regeneration

The ability to regrow a missing part of the body

Trichinosis

infection caused by the roundworm Trichinella spiralis

Gastropods

A mollusk with a single shell or no shell.

Bivalves

have a hinged, two-part shell and include clams, oysters, and scallops.

Cephlapods

Quick, head-footed mollusks with arms and tentacles

open circulatory system

a system in which blood is pumped through vessels into various chambers or body cavities where it comes in direct contact with cells, tissues, and organs

Mantle

A sheath of tissue that encloses the vital organs of a mollusk, makes the mollusk's shell, and performs respiration

shell

A tough, multilayered structure secreted by the mantle, generally used for protection, but sometimes for body support

Visceral hump

A hump that contains a mollusk's heart, digestive, and excretory organs

foot

A muscular organ that is used for locomotion and takes a variety of forms depending on the animal

Radula (Mollusca)

an organ covered with teeth that mollusks use to scrape food into their mouths

Univalve

An organism with a single shell

pelecypods (bivalves)

have 2 shells