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Chapter4 Lessons1-4
Vocab
Question | Answer |
---|---|
homeostasis | The condition in which an organism's internal environment is kept stable in spite of changes in the external environment . |
adaptation | An inherited behavior or physical characteristic that helps an organism survive and reproduce in its environment. |
vertebrate | An animal WITH a backbone. |
invertebrate | An animal WITHOUT a backbone. |
tissue | A group of similar cells that perform a specific function. |
organ | A body structure that is composed of different kinds of tissues that work together . |
radial symmetry | A body plan in which any number of imaginary lines that all pass through a central point divide the animal into two mirror images. |
bilateral symmetry | A body plan in which a single imaginary line divides the body into left and right sides that are mirror images of each other. |
cnidarian | A radially symmetrical invertebrate that uses stinging cells to capture food and defend itself. |
mollusk | An invertebrate with a soft, unsegmented body; most are protected by a hard outer shell. |
arthropod | An invertebrate that has an external skeleton, a segmented body, and jointed appendages. |
exoskeleton | External skeleton; a tough, waterproof outer covering that protects, supports, and helps prevent evaporation of water from the body of many invertebrates. |
echinoderm | A radially symmetrical marine invertebrate that has an internal skeleton and a system of fluid-filled tubes. |
endoskeleton | An internal skeleton; structural support system within the body of an animal. |
chordate | An animal that has a notochord, a nerve cord and throat pouches at some point in its life. |
notochord | A flexible rod that supports a chordate's back just below the nerve chord. |
vertebra | A stack of many small bones called vertebrae. A single one of these bones is a vertebra. |
ectotherm | An animal whose body temperature is determined by the temperature of its environment. |
endotherm | An animal whose body temperature is regulated by the internal heat the animal produces. |