Term | Definition |
Biology | The study of life |
Organization | A high degree of order within an organism's internal and external parts and in its interactions with the living world |
Cell | The smallest unit that can perform all of life's processes |
Unicellular | Organisms that are made up of one cell |
Multicellular | Organisms that are made up of multiple cells |
Organs | Structures that carry out specialized jobs within an organ system |
Tissues | Groups of cells that have similar abilities and that allow an organ to function |
Organelles | Tiny structures that carry out functions necessary for the cell to stay alive |
Biological molecules | Chemical components that provide physical structure and that bring about movement |
Homeostasis | The maintenance of a stable level of internal conditions even though environmental conditions are constantly changing |
Metabolism | The sum of all the chemical reactions that take in and transform energy and materials from the environment |
Cell division | The formation of two new cells from an existing cell |
Development | The process by which an organism becomes a mature adult |
Reproduction | The process by which organisms produce new organisms like themselves |
Gene | A short segment of DNA that contains the instructions for a single trait of an organism |
Domains | Three major subdivisions of living organisms |
Kingdoms | A system of grouping that divides life into six major categories |
Ecology | The branch of biology that studies organisms interacting with each other and with the environment |
Ecosystems | Communities of living species and their physical environment |
Evolution | Descent with modification or the process in which the inherited characteristics within populations change over generations, such that genetically distinct populations and new species can develop |
Natural selection | A theory that states that organisms that have certain favorable traits are better able to survive and reproduce successfully than organisms that lack these traits |
Adaptations | Traits that improve an individual's ability to survive and reproduce |
Scientific method | An organized approach of asking questions and performing experiments in order to learn how the natural world works |
Observation | The act of perceiving a natural occurrence that causes someone to pose a question |
Hypothesis | A proposed explanation for the way a particular aspect of the natural world functions |
Prediction | A statement that forecasts what would happen in a test situation if the hypothesis were true |
Experiment | Used to test a hypothesis and its predictions |
Control group | A group which provides a normal standard against which the biologist can compare results of the experimental group |
Experimental group | A group that is identical to the control group except for one factor, the independent variable |
Independent variable | The variable being manipulated or changed |
Dependent variable | The variable that is affected by the independent variable, also known as the "responding variable" |
Theory | A set of related hypotheses that are confirmed to be true many times and explains a great deal of data |
Peer review | A process where scientists who are experts in a field anonymously review and critique a research paper |
Compound light microscope | A microscope that shines light through a specimen and has two lenses to magnify an image |
Eyepiece (ocular lens) | The part of the microscope that magnifies an image, usually 10 times |
Objective lens | A lens which enlarges the image of the specimen, located directly above the specimen |
Stage | A platform that supports a slide holding the specimen |
Light source | A light bulb that provides light for viewing the image |
Magnification | The increase of an object's apparent size |
Nosepiece | The structure that holds the set of objective lenses |
Resolution | The power to show details clearly in an image |
Scanning electron microscope (SEM) | An electron microscope that passes a beam of electrons over a specimen's surface. This provides a detailed image of the specimen's surface that may be magnified up to 100,000 times |
Transmission electron microscope (TEM) | An electron microscope that transmits a beam of electrons through a very thinly sliced specimen. This results in an image of the specimen's internal structures and can magnify up to 200,000 times. |
Metric system | A single, standard system used by scientists; it is a decimal system and based on powers of 10 |
Base units | Units that describe length, mass, time, and other quantities |