| Adaptation | Production overy many generations of organisms that are better suited to their environment. Also used to refer to a trait that helps organisms adjust to particular environmental stresses. |
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acid rain |
increases in the acidity (lowering of the pH) of precipitation resulting from air pollution |
| Active transport | Movement of a substance across a membrane from a region of lower concentration to a region of higher concentration. Metabolic energy (ATP) must be used to drive this process. |
| Allele frequency | The relative proportions of an allele in a population. |
| Alleles | An alternate form of a gene found at the same position (locus) on homologous chromosomes. A diploid organism has two alleles, either the same or different, for each trait. |
| Alternation of generation cycle | A type of sexual life cycle in which there are multicellular forms in both the diploid and haploid phases of the cycle. All organisms in the Plantae Kingdom have this type of life cycle as well as a few select alga species. |
| Amino acid | Monomeric building blocks of protein. Each contains an amino group and carboxyl group and one of twenty different R groups attached to a central carbon. |
| Anatomy | The study of the internal arrangement of cells and tissues within an organ or organism. |
| Angiosperms | The flowering plants. Seeds are borne within a vessel called the fruit. The most successful of the plant groups. |
| Artificial selection | Human being are the agent of selection that fosters the differential reproduction of variants of the plant. Features selected are those than benefit humans and not necessarily the plant. |
| Asexual reproduction | A type of reproduction that does not require two parents. An individual can undergo asexual |
| Atom | The smallest particle of an element that retains all the properties of the element. |
| ATP | Adenosine triphosphate: this molecule is the energy currency of the cell; it is needed to run cellular activities. |
| Autotrophs | Organisms that can manufacture organic molecules from simple inorganic compounds using light or chemical energy. |
| Bacterial fission | The asexual division of a bacterial cell into two similar cells. Bacterial cell replication does not involve mitosis. |
| Biennial | A plant that takes two growing seasons to complete its life cycle |
| Binomial | The scientific name of an organism consisting of a genus name and a specific epithet. |
| Binomial system of nomenclature | A system of naming organisms by combining the genus name and the species epithet. System was originated by Carolus Linnaenus. |
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biodiversity |
biological diversity; indication of the number and abundance of biological species in a certain area |
| Biological classification | Arrangement of organisms into categories based upon relatedness. |
| Biological control | Control of pest organisms using a biological organism or a product derived from a biological organisms. |
| Bioremediation | A method of removing toxic pollutants from the environment by using organisms that break down the toxic compounds. Bacteria are able to do this because of their unique metabolism. |
| Biosphere | The sum of all of the living organisms on Earth; that portion of the earth that is inhabitated by living organisms. |
| Biotechnology | The commercial use of living organisms or their components for the benefit of humankind. Often the benefits are in food production and in the area of human health. |
| Blade | The flat part of the leaf |
| Bond | Force that holds atoms together in a molecule. |
| Breed true | When an individual is self fertilized, the offspring are identical to one another and to the parent for the given trait. The cause of breeding true is the presence of identical alleles (homozygous) for the trait. |
| Bryophytes | A group of spore-producing novascular plants that includes the mosses and liverworts. |
| Buds | The undeveloped tips of stems that contains the apical meristem and leaf primoridia |
| Bulbs | A fleshy underground structure that contains a short stem and fleshy leaves. |
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caliche |
an impervious layer of calcium carbonate in soil: common to the southwestern U.S.; also called hardpan |
| Carbohydrate | Organic molecules that contain carbon, hydrogen, and oxygen with the ratio of hydrogen to carbon of 2 to 1. |
| Carrier protein | A protein, located across a membrane, that binds to specific substances and ferrys them across the membrane. ATP energy is required for carrier proteins activity.. Energy must be expended to change the shape of the protein. |
| Cell | The basic structural and functional unit of life. |
| Cell cycle | The series of events that occurs during the division of a cell |
| Cell division | Process whereby a single cell is duplicated. In eukaryotic cells this involves DNA replication, nuclear division and cytoplasmic division. |
| Cell theory | The theory that has as the following basic postulates: a cell is the basic structural unit of life; that all organisms are composed of one or more cells; and cells arise from preexisting cells. |
| Cell wall | Rigid, supportive structure that is found outside of the plasma membrane in cells of algae, bacteria, fungi, and plants. Serves a protective function for the living cell within. |
| Cellular specialization | Variations in the structure of cells that allow it to carry out specific functions. |
| Cellulose microfibril | Strand of cellulose molecules bonded together by hydrogen bonds. Cellulose microfibrils are embedded in polysaccharide and proteins to form plant cell walls. |
| Channel protein | A protein, located across a membrane, that makes a channel or pore through which specific molecules can diffuse. |
| Chemical reaction | A process whereby starting compounds or atoms (reactants) are chemically transformed into new compounds (the products). |
| Chemically reactive | A substance that is able to undergo chemical reactions. |
| chlorophyll | Green pigments found in plant cells and algae that are needed for photosynthesis. |
| Chloroplast | Double membrane bound organelle found in plant cells that carry out the process of photosynthesis, making sugars from carbon dioxide and water using energy of sunlight. |
| Chromosome | Linear strands of DNA would around proteins that are found in the nucleus of eukaryotic cells. Chromosomes are visible in the light microscope during meiosis and mitosis. |
| Classification | Arrangement of objects into groups or categories based upon established criteria. |
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clay |
mineral soil particles less than 0.002 mm in diameter |
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climax communities |
the final stage of a successional process |
| Coevolution | The mutual interaction of two different species in such a way as to reciprocally influence the evolution of each other. |
| Cohesion | The forces that hold like molecules together. Forces most often are hydrogen bonds that form between polar molecules. In water movement, cohesion is responsible for movement of water up the xylem en masse (as a column instead of individual molecules. |
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commensalism |
type of symbiosis in which one individual benefits from the association and the other individual is not affected |
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community |
all the organisms inhabiting and interacting in a common environment |
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competition |
interaction between members of a community to obtain resource that are required and are in limited supply |
| Complex tissue | A group of cells of dissimilair cell types that work together to carry out a specific function |
| Compost | Partially decomposed organic matter improves the soil structure and aeration. |
| Compound | A substance composed of more than one element that has unique chemical properties. |
| Concentration | The number of molecules in a particulare volume. If the volume is the same but there are more molecules in that volume than the other, we say that the solution is more concentrated. |
| Conidia (sing. Conidium) | Naked, asexual spores that are produced on the tips of hyphae in one group of the higher fungi. |
| Conjugation | In bacteria it is the transfer of DNA from one bacterial cell to another by way of a temporary tubular connection. |
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conservation |
efforts to slow down the rate of ecosystem damage and destruction and preserve biodiversity |
| Control | Part of a scientific experiment in which the independent variable is not altered or is maintained at a standard value. Used for comparison with the experimental group. |
| Controlled experiment | An experiment in which all factors except one remain constant. |
| Convergent evolution | Independent evolution of similarities in appearance and/or physiology as a result of exposure to similar selective pressures. |
| Cork | The outer layer of bark of a woody plant |
| Cork cambium | A lateral meristem (area of dividing cells) that produces cells that make up cork |
| Cortex | Ground tissue that occurs between the epidermis and vascular system in roots and stems |
| Cotyledons | The seed leaf of a plant embryo; often contains stored food for developing seedling |
| Covalent bond | A type of bond formed when electrons are shared between two atoms. Two atoms may share one (single), two (double), or three (triple) pairs of electrons depending upon the atom. |
| Cuticle | A waxy covering on the outside of the epidermis of leaves and stems |
| Cytokinins | A plant hormone involved in many processes including cell division and shoot growth |
| Cytoplasm | The matrix of the cell consisting of a semifluid (viscous) solution in which enzymes and substances are dissolved and in which particulates are suspended. In prokaryotic cells the particulates are ribosomes and in eukaryotic cells the particulates include ribosomes and membrane-bound organelles. |
| Cytoplasmic streaming | The circular flow of cytoplasm which distributes substances or organelles throughout the cell. |
| Cytoskeleton | A network of protein filaments (microtubules, microfilaments, and intermediate filaments) that serve as a scaffolding for the cell and for movement of substances and organelles within the cell. |
| Cytosol | The semifluid substance of the cell in which substances dissolved. |