Unit 19

Front 1

Aminiotic egg

Back 1

An egg in which the developing embryo is surrounded and protected by layers of extraembryonic membranes (including the amnion) that promote gas exchange and removal of waste.

Front 2

Animalia

Back 2

The kingdom of Eukarya that is made up of animals, Multicellular heterotrophs, that have evolved specialized tissues, oragans and organ systems, body plans, and behaviors.

Front 3

Annelida

Back 3

Annelids. The eukaryotic phylum consisting of all worms with true coeloms and segmented bodies. Earthworms are the most familiar example.

Front 4

Arthropoda

Back 4

Arthropods. The largest eukaryotic phylum, consisting of animals characterized by a hard exoskeleton and jointed body parts. Arthorpods include millipedes, crustaceans, insects, and spiders.

Front 5

Bilateral symmetry

Back 5

A body arrangement in which only one plane passes vertically from the top to the bottom of the animal, dividing the body into two halves that mirror each other. Bilateral animals have distinct right and left sides, with near-identical body parts on each side.

Front 6

Blastula

Back 6

A hollow, fluid-filled sphere with a single layer of cells on the surface that forms from repeated division of a zygote.

Front 7

Cephalization

Back 7

In bilateral animals, the evolutionary trend in which structures used for eating are concentrated at the anterior end, thereby allowing the animal to look where it is going.

Front 8

Chordate

Back 8

Any of a group of animals that have a notochord, pharyngeal pouches, and a post-anal tail.

Front 9

Coelom

Back 9

A body cavity that develops within the mesoderm.

Front 10

Compound eye

Back 10

An eye, common in insects, that consists of many individual light-receiving units, each with its own lens and small cluster of photoreceptors. Honeybees use their compound eyes to see patterns of color on flowers.

Front 11

Crustacean

Back 11

Any of a group of aquatic arthropods that are especially diversified in the marine environment. Shrimp, lobster and crabs are amound the most familiar.

Front 12

Deuterostome

Back 12

Any of a group of animals, including sean stars and vertebrates, inwhich the second opening to develop in the early embryo becomes the mouth.

Front 13

Ectotherm

Back 13

An organism that relies on environmental heat for most of its heat input.

Front 14

Endotherm

Back 14

An organism that generates metabolic heat in order to warm itself, instead of depending mainly on heat gain from the environment.

Front 15

Eutherian

Back 15

Any of a group of mammals whose young are nourished inside the mother's body through the placenta and are therefore born in a reatively well-developed state. Most mammals, including humans, are eutherians.

Front 16

Exoskeleton

Back 16

An external framwork of stiff or hard material that surrounds the soft tissues of an animal.

Front 17

Gastrula

Back 17

An embryo with at least two cell layers, resulting from invagination and migration cells in the ball-like blastula.

Front 18

Homeotherm

Back 18

An endotherm that maintains a near-constant internal temperature.

Front 19

Mammary gland

Back 19

A modified sweat gland that is the most distinctive feature of mammals. Mammary glands produce a liquid rich in fat, protiens, salts and other nutritive substances that nourish the newborn.

Front 20

Marsupial

Back 20

Any of a group of mammals that protect and feed their newborns with milk in an external pocket or pouch (marsupium). Marsupials include kangaroos and opossums.

Front 21

Metamorphasis

Back 21

A dramatic developmental transformation from a reproductively immature to a reproductively mature form, involving great change in the form and function of the animal.

Front 22

Mollusca

Back 22

Mollusks. After Arthropoda, the most diverse phylum of animals, characterized by a body that has a muscular foot, a visceral mass, and a mantle. Mollusks include clams and pother bivalves.

Front 23

Molting

Back 23

Also called ecdysis. The process by which juvenile ecdyszoans (a group of protostomes) shed cuticle that encaases them.

Front 24

Monotreme

Back 24

Any of a group of mammals that have no placenta and lay eggs. The platypus and echidnas are monotremes.

Front 25

Notochord

Back 25

A structure composed of large cells that collectively form a strong but flexible bar running dorsally allong the length of an animal, providing support for the rest of the body.

Front 26

Pharyngeal pouch

Back 26

A Structure, found in the early embryo of all chordates, that first appears as a pocket of tissue on either side of the embryonic pharynx and later develops into structure such as gill slits in fishes and larval amphibians, or the larynx and trachea in mammals.

Front 27

Placenta

Back 27

Also called afterbirth. A structure found in mammals that transfers nutrients and gases from blood of the mother to the blood of the fetus developing in her uterus.

Front 28

Protostome

Back 28

Any of a group of animals, including insects, worms, and snails, in which the first opening to develop in the early embryo becomes the mouth.

Front 29

Radial symmetry

Back 29

A body arrangement in which an animal could be sliced symmetrically along any number of vertical planes passing through the center of the animal to produce body parts that are nearly identical.

Front 30

Simple eye

Back 30

A non-image-forming eye that can distinguish light from dark.

Front 31

Tetapod

Back 31

Any terrestrial vertebrate that has four limbs. Amphibians, birds, and mammals are all tetrapods.