Biology

descent with modification; the idea that living species are descendants of ancestral species that were different from the present-day ones; also defined more narrowly as the change in the genetic composition of a population from generation to generation

the scientific study of life

new properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases

the entire portion of Earth inhabited by life; the sum of all the planet's ecosytems

all the organisms in a given area as well as the abiotic factors with which they interact; one or more communities and the physical environment around them

all the organisms that inhabit a particular area; an assemblage of populations of different species living close enough together for potential interaction

a localized group of individuals of the same species that can interbreed, producing fertile offspring

a group of organs that work together in performing vital body functions

a specialized center of body function composed of several different types of tissues

an integrated group of cells with a common function, structure, or both

any of several membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells

two or more atoms held together by covalent bonds

an approach to studying biology that aims to model the dynamic behavior of whole biological systems

• a type of cell with a membrane-enclosed nucleus and mebrane-enclosed organelles
• organisms with eukaryotic cells (protists, plants, fungi, and animals) are called eukaryotes

• a type of cell lacking a membrane-enclosed nucleus and mebrane-enclosed organelles
• organsims with prokaryotic cells (bacteria and archaea) are called prokaryotes

a double-stranded , helical nucleic acid molecule, consisting of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T); capable of being replicated and determining the inherited structure of a cell's proteins

a discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (orRNA, in some viruses)

the genetic material of an organism or virus; the complete complement of an organism's or virus's genes along with its noncoding nucleic acid sequences

the use of computers, software, and mathematical models to process and integrate biological information from large data sets

a primary mechanism of homeostasis, whereby a change in a physiological variable triggers a response that counteracts the initial change

a physiological control mechanism in which a change in a variable triggers mechanisms that amplify the change

the search for information and explanation, often focused by specific questions

the process of scientific inquiry that focuses on describing nature

record observations

a type of logic in which generalizations are based on a large number of specific observations

a tentative answer to a well-framed question, narrower in scope than a theory and subject to testing

a type of logic in which specific results are predicted from a general premise

an expirement in which an experimental group is compared with a control group that varies only in the factor being tested

an explanation that is broad in scope, generates new hypothesism and is supported by a large body of evidence

a representation of theory or process

the application of scientific knowledge for a specific purpose, often involving industry or commerce but also including uses in basic research

a substance consisting of two or more different elements combined in a fixed ratio

any substance that cannot be broken down to any other substance by chemical reactions

an element indispensible for life but required in extremely minute amounts

the smallest unit of matter that retains the properties of an element

a subatomic particle having no electrical charge (electrically neutral), with a mass of about 1.7 x 10^-24g, found in the nucleus of an atom

a subatomic particle with a single positive electrical charge, with a mass of about 1.7 x 10^-24 g, found in the nucleeus of an atom