| A | B |
| commensalism | the symbiotic relationship in which one organism benefits and the other is unaffected |
| consumer | an organism that eats producers or other organisms for energy |
| decomposer | an organism that gets energy by breaking down th remains of dead organisms or animal wastes and consuming or absorbing the nutrients |
| extinction | describes a species of organism that has died out completely |
| food web | a complex diagram representing the many energy pathways in a real ecosystem |
| fossils | the physical evidence of an organism, such as remains or imprints, preserved by geologic processes |
| mutualism | a symbiotic relationship in which both organisms benefit |
| parasitism | a symbiotic relationship in which one organism benefits and the other is harmed |
| producer | organisms that make their own food, usually by using the energy from sunlight to make sugar |
| relative age | determining the age of a rock or fossil by its placement with other rocks and fossils |
| sedimentary rocks | rock formed in distinct layers by the hardening of sediment |
| wave | a disturbance that transmits energy through matter or space |
| wavelength | the distance between one point on a wave and the corrresponding point on an adjacent wave in a series of waves |
| tides | daily movements of ocean warter that change the level of the ocean's surface |
| seasons | one of the divisions of the year that is determined by the position of the Earth in its orbit around the sun |
| relative age | the age of an object determined by comparing it with objects around it in the geologic column |
| refraction | the bending of a wave as it passes at an angle from one medium to another |
| reflection | the bouncing back of a wave after it strikes a barrier or an object |
| nuclear power | power produced by a nuclear reactor |
| heat flow | the transfer of thermal energy from an object of higher temperature to an object of lower temperature |
| frequency | the number of waves produced in a given amount of time |
| forms of energy | different categories of energy including thermal, chemical , electrical, sound, light, and nuclear |
| energy transformations | the change of energy from one form to another |
| lunar eclipse | an event in which the shadow of the Earth falls on the moon |
| solar eclipse | an event in whilch the shadow of the moon falls on the Earth's surface |
| amplitude | the maximum distaance a wave vibrates from its rest position |
| classification | the systematic arrangement of living things into categories |