Chapter 9 Science Vocabulary

Homeostasis

Condition in which an organism's internal environment remains stable in spite of changes externally in the environment

Adaptation

Inherited behavior or physical characteristic that helps organisms survive and reproduce

Vertebrate

An animal with a backbone

Invertebrate

An animal without a backbone

Tissue

A group of similar cells that perform a specific function

Organ

Body structure composed of varied tissues that all work together

Radial symmetry

Body plan that any number of imaginary lines passing through a central point divide the animal into identical images

Bilateral symmetry

Body plan that one imaginary line divides the body into identical images (with a left and right side)

Cnidarian

A radially symmetrical invertebrate that uses stinging cells to catch food and defend itself

Mollusk

Invertebrate with a soft, unsegmented body (protected with hard shell)

Arthropod

Invertebrate with a segmented body, external skeleton, and jointed appendages

Exoskeleton

External skeleton; tough, waterproof outer coat that protects, supports, and prevents evaporation

Echinoderm

Radially symmetrical marine invertebrate with internal skeleton (endoskeleton) and fluid-filled tube system

Endoskeleton

Internal skeleton; structural support system inside animal

Chordate

Animal with a notochord, nerve cord, and throat pouches at one point

Notochord

Flexible rod supporting chordate's back (below nerve cord)

Vertebrae

Bones making up backbone (26 in human body)

Ectotherm

Animal whose body temperature is decided by temperature of its surroundings

Endotherm

Animal whose body temperature is decided by internal heat produced by it

Fish

Vertebrate, ectotherm, and lives in the water with fins

Cartilage

Flexible connective tissue that protects bones from rubbing together

Amphibian

Vertebrate, ectotherm, and lives childhood in water, and adulthood on land

Reptile

Vertebrate, ectotherm, with lungs, scaly skin, and lays eggs on land

Bird

Vertebrate, endotherm, lays eggs, has 4 chambered heart, and has feathers

Mammal

Vertebrate, endotherm, with milk-producing glands, and skin with hair/fur

Mammary gland

Organ in female mammal that makes milk for kids

Monotreme

Mammal that lays eggs

Marsupial

Mammal whose young develop in mother's pouch and are born at early development

Placental mammal

Mammal that develops in mom until ready to function independently

Placenta

Organ in pregnant mammals that connects mom with developing embryo, so they can pass materials