| A | B |
|---|
| Biosphere | all parts of the planet inhabited by living things; sum of all Earth's ecosystems |
| ecosystem | community of living things plus the nonliving features of the environment that support them |
| Biome | major type of terrestrial ecosystem that covers a large region of Earth |
| Community | all the organisms living in an area |
| Population | group of individuals of the same species living in a particular area at the same time |
| Organism | living thing |
| Organ System | unit of multiple organs that together perform a vital body function |
| Organ | unit consisting of several tissues that together perform a specific task |
| Tissue | cooperating unit of many similar cells that perform a specific function |
| Molecule | two or more atoms held together by covalent bonds |
| Elements | pure substance that cannot be broken down into other substances by chemical or physical means |
| Atoms | smallest particles of elements |
| Cell | basic unit of living matter; separated from its environment by a plasma membrane |
| Unicellular | consisting of a single cell |
| Multicellular | consisting of many cells |
| Prokaryotic Cell | cell lacking a nucleus and most other organelles |
| Eukaryotic Cell | cell with a nucleus (surrounded by its own membrane) and other internal organelles |
| DNA | molecule responsible for inheritance; nucleic acid that contains the sugar deoxyribose |
| Gene | unit of inherited information in DNA |
| Amino Acids | monomer that makes up proteins; contains carboxyl and amino functional groups |
| Domains | broadest category used to classify life forms (archaea, bacteria, eukarya) |
| Archaea | domain of prokaryotic organisms that are biochemically and genetically distinct from bacteria |
| Bacteria | domain of prokaryotic organisms that are biochemically and genetically distinct from archaea |
| Eukarya | domain of eukaryotic organisms subdivided into four kingdoms (protista, fungi, plantae, and animalia) |
| Kingdoms | subgroups of domains |
| Monera | kingdom of prokaryotic organisms in old five-kingdom classification scheme |
| Photosynthesis | process by which plants use the sun's energy to convert water and carbon dioxide into sugars |
| Cellular Respiration | chemical process that uses oxygen to convert chemical energy stored in organic molecules into ATP (adenosine triphosphate) |
| Producer | organism that makes its own food (autotroph) and produces organic molecules that serve as food for other organisms in its ecosystem |
| Consumer | organism that obtains food by eating producers (autotrophs) or other consumers |
| Homeostasis | internal stability or "steady state" maintained by the body |
| Adaptation | inherited characteristic, improves an organism's ability to survive & reproduce in a particular environment |
| Natural Selection | process by which individuals with inherited characteristics well-suited to the environment leave more offspring than do other individuals |
| Evolution | gen-to-gen change in proportion of different inherited genes in a population that accounts for all changes that have transformed life over an immense time |
