Biology Midterm
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60 terms
Terms | Definitions |
|---|---|
 population | a group of individuals belonging to one species and living in the same geographic area |
| natural selection | a process in which organisms with certain inherited characteristics are more likely to survive and reproduce than organisms with other characteristics |
| theory of evolution | the change over time of populations into different forms from a common ancestor |
| common ancestor | the shared ancestor of new, different species |
| adaptation | an inherited characteristic that enhances us organism's ability to survive and reproduce in a particular environment |
| extinction | the irrevocable loss of species |
| ecology | the scientific study of how organisms interact with their environments |
| abiotic factor | a nonliving component of an ecosystem such as water, air or temperature |
| biotic factor | a living component of an environment |
| ecosystem | all the organisms in a given area, along with the nonliving factors with which they interact; a biological community and physical environment |
| niche | the status of an organism within its environment and community |
| symbiosis | a close association between organisms of two or more species |
| competition | the struggle between organisms to survive in a habitat with limited resources |
| mutualism | an interspecific relationship in which both partners benefit |
| predation | an interaction between two species in which one species, the predator, eats the other, the pray |
| herbivory | consumption of plant parts or algae by an animal |
| parasitism | the relation between two different kinds of organisms in which one receives benefits from the other by causing damage to it |
| autotroph | an organism that makes its own food by photosynthesis, thereby sustaining itself without eating other organisms |
| photosynthesis | the process by which plants, autotrophic protists, and some bacteria use light energy to make sugars and other organic food molecules from carbon dioxide and water |
| heterotroph | an organism that cannot make its own food and must obtain them from consuming organisms or their organic products |
| herbivore | organism that obtains energy by eating only plants |
| carnivore | organism that obtains energy by eating animals |
| omnivore | organism that obtains energy by eating both plants and animals |
| food chain | a sequence of food transfers from producers through one to four levels of consumers in an ecosystem |
| food web | a network of interconnecting food chains |
| 10% rule | only 10% of energy in each organism is taken in by the predator when eaten; other 90% is lost |
| respiration | carbon in the form of carbon dioxide gas being emitted by living organisms on the planet when they make energy |
| combustion | burning of gas, wood, oil, etc. by humans to make electrical energy which emits large quantities of CO2 into the atmosphere |
| erosion | weather such as rain erodes phosphorus from rocks to be used by plants |
| proton | a subatomic particle with a single positive electrical charge; found in the nucleus of an atom |
| electron | a subatomic particle with a single negative electrical charge; one or more electrons move around the nucleus of an atom |
| valence shell | The outermost energy shell of an atom, containing the valence electrons |
| shells | the orbits of electrons around the nucleus |
| molecule | a group of two or more atoms held together by covalent bonds |
| ion | an atom that has gained or lost one or more electrons, thus acquiring a charge |
| covalent bond | an attraction between atoms that share one or more pairs of outer-shell electrons (valence electrons) |
| hydrophobic | "water-fearing" |
| hydrophilic | "water-loving" |
| hydrogen bond | a weak chemical bond formed when the partially positive hydrogen atom is attracted to the partially negative atom |
| cohesion | the binding together of like molecules, often by hydrogen bonds |
| adhesion | the attraction between different kinds of molecules |
| surface tension | a measure of how difficult it is to stretch or break the surface of a liquid; water has a high surface tension because the hydrogen bonding of surface molecules |
| pH scale | a measure of the relative acidity of a solution, ranging in value from 0 (most acidic) to 14 (most basic); pH = potential hydrogen, refers to the concentration of hydrogen ions |
| prokaryotic cell | a type of cell lacking a membrane-enclosed nucleus and other membrane-enclosed organelles; found only in bacteria and archaea |
| eukaryotic cell | a type of cell that has a membrane-enclosed nucleus and other membrane-enclosed organelles; all organisms except bacteria and archaea have these |
| organelle | a membrane-enclosed cell structure with a specialized function within a cell |
| cytoplasm | everything inside a cell between the plasma membrane and the nucleus; consists of a semifluid medium and organelles |
| cell wall | a protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists; protects cell and helps maintain its shape |
| chloroplast | an organelle found in plants and photosynthesis protists that absorbs sunlight and uses it to drive the synthesis of organic molecules from carbon dioxide |
| nucleus | 1) an atom's central core, containing protons and neutrons 2) the genetic control center of a eukaryotic cell |
| diffusion | the spontaneous tendency of a substance to move down its concentration gradient from where it is more concentrated to where it is less concentrated |
| osmosis | the diffusion of water across a selective permeable barrier |
| hypertonic solution | in comparing two solutions, the one with the greater concentration of solutes; cells in such a solution will lose water to their surroundings |
| hypotonic solution | in comparing two solutions, the one with the lower concentration of solutes; cells in such a solution will take up water from their surroundings |
| isotonic solution | a solution having the same solute concentration as another solution, thus having no effect on passage of water in or out of the cell |
| photosynthesis equation | 6CO2 + 6H2O → C6H12O6 + 6O2 |
| cellular respiration equation | C6H12O6 + 6O2 → 6CO2 + 6H2O |
| oxidization | the loss of electrons from a substance involved in a redox reaction |
| carbohydrate | molecules consisting of simple single-monomer sugars (monosaccharides), two-monomer sugars (disaccharides), and other multiunit sugars (polysaccharides) |
| dehydration reaction | a chemical process in which two molecules become covalently bonded to each other with the removal of a water molecule |
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