click below
click below
Normal Size Small Size show me how
CH 4 SCI
| Term | Definition |
|---|---|
| homeostasis | The condition in which an organisms internal environment is kept stable in spite of changes in the external environment. |
| adaptation | An inherited behavior or physical charateristic that helps an organisms 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 minor 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. |
| athropod | 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 | A internal skeleton structural support system within 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 chordates back just below the nerve cord |
| vertebra | The bones that make up the backbone of an organism. In humans one of the 26 bones that make up the backbones. |
| 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. |
| fish | A vertebrate whose body temperature is determined by the temperature of its environment and that lives in the water and has fins. |
| cartilage | A connective tissue that is more flexible than bone and that protects the ends of the bones and keeps them from rubbing together. |
| amphibian | A vertebrate whose body temperature is determined by the temperature of its environment and that lives its early life in water and its adult life on land. |
| reptile | A vertebrate whose temperature is determined by the temperature of its environment that has lungs and scaly skin and that lays eggs on land. |
| bird | A vertebrate whose body temperature is regulated by its internal heat lays eggs and has feathers and four chambered heart. |
| mammal | A vertebrate whose body temperature is regulated by its internal heat and that has skin covered with hair or fur and glands that produce milk to feed its young. |
| mammary gland | An organ in female mammals that produces milk for the mammals young. |
| monotreme | A mammal that lays eggs |
| marsupial | A mammal whose young are born at an early stage of development and which usually continue to develop in pouch on their mothers body. |
| placental mammals | A mammal that develops inside its mothers body until its body systems can function independently. |
| placenta | An organ in most pregnant mammals including humans that links the mother and the developing embryo and allows for the passage of materials between them. |