Vocabulary Review
Ch 32 – Intro to
Animals

A multicellular, heterotrophic organism that lacks cell walls and that is usually characterized by movement and sexual reproduction; a member of
Kingdom Animalia
Animal

An animal that has a backbone; includes mammals, birds, reptiles, amphibians, and fish
Vertebrate

An animal that does not have a backbone
Invertebrate

The evolutionary adaptation of a cell, organ, organism, or population for a particular function or environment
Specialization

The process of taking in food
Ingestion

The cell that results from the fusion of gametes; a fertilized egg
Zygote

The structural and functional specialization of cells during an organism’s development
Differentiation

An animal that at some stage in its life cycle has a dorsal nerve, a notochord, and pharyngeal pouches; examples include mammals, birds, reptiles, amphibians, fish, and some marine lower forms
Chordate

In the embryos of all chordates and in many adult chordates, a firm, flexible rod of tissue that is located in the dorsal part of the body
Notochord

A neural tube dorsal to the notochord
Dorsal nerve cord

One of the lateral sac that branch from the pharynx of chordate embryos and that may open to the outside as gill slits in adult fishes and invertebrate chordates
Pharyngeal pouch

A body arrangement in which parts that lie on opposite sides of a central line are identical
Symmetry

A body plan in which the parts of an animal’s body are organized in a circle around a central axis
Radial symmetry

Lying on or near the back
Dorsal

The lower or abdominal part of an organism
Ventral

The front part of a body or structure
Anterior

In animals with bilateral symmetry, refers to the end of the body that is opposite the head; rear
Posterior

A condition in which two equal halves of a body mirror each other
Bilateral symmetry

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

One of the layers of tissue that develop in the embryos of all animals except sponges
Germ layer

The division of the body of an organism into a series of similar parts
Segmentation

A hard, external, supporting structure that develops from the ectoderm
Exoskeleton

In aquatic animals, a respiratory structure that consists of many blood vessels surrounded by a membrane that allows for gas exchange
Gill

A type of circulatory system in which the circulatory fluid is not contained entirely within vessels; a heart pumps fluid through vessels that empty into spaces called sinuses
Open circulatory system

A circulatory system in which the heart circulates blood through a network of vessels that form a closed loop; the blood does not leave the blood vessels, and materials diffuse across the walls of the vessels
Closed circulatory system

An organism that has both male and female reproductive organs
Hermaphrodite

An independent and immature form of an organism that is morphologically different from the adult form
Larva

An internal skeleton made of bone and cartilage
Endoskeleton

One of the 33 bones in the spinal column
(backbone)
Vertebra

The outer, protective covering of a body, a body part, an ovule, or a sporangium
Integument

The central organ of the respiratory system in which oxygen from the air is exchanged with carbon dioxide from the blood
Lung

One of the organs that filter water and wastes from the blood, excrete products as urine, and regulate the concentration of certain substances in the blood
Kidney

A compound that improves the quality of the soil to produce plants
Fertilization

In biological development, a series of cell divisions that occur immediately after an egg is fertilized
Cleavage

The stage of an embryo before gastrulation
Blastula

The transformation of the blastula into the gastrula or the formation of the embryonic germ layers
Gastrulation

The embryo in the stage of development after the blastula; contains the embryonic germ layers
Gastrula

The primitive gastric cavity of an embryo
Archenteron

An opening that develops in the blastula
Blastopore

The outermost of the three germ layers of an embryo that develops into the epidermis and epidermal tissues, the nervous system, external sense organs, and the mucous membranes lining the mouth and anus
Ectoderm

An animal that can generate body heat through metabolism and can maintain a constant body temperature despite temperature changes in the animal’s environment
Endoderm

In an embryo, the middle layer of cells that gives rise to muscles, blood, and various systems
Mesoderm

An animal that lacks a coelom, or body cavity
Acoelomate

The type of body cavity, derived from the blastocoel and referred to as a “false body cavity,” that forms between the mesoderm and the endoderm in rotifers and roundworms
Pseudocoelom

A body cavity that is completely lined by mesoderm and that contains the internal organs of an animal
Coelom

An organism whose embryonic blastopore develops into the mouth, whose coelom arises by schizocoely, and whose embryo has determinate cleavage
Protostome

An organism whose embryonic blastopore develops into an anus, whereas its mouth develops from a second opening at the opposite end of the archenteron; usually characterized by an embryo that undergoes indeterminate, radial cleavage
Deuterostome

The method of coelom formation in protostomes in which the embryonic mesoderm splits into two layers
Schizocoely

In deuterostomes, the method of coelom formation in which the embryonic mesoderm develops from pouches within the archenteron
Enterocoely