Biology Chapter 1 Terms

Front 1

a trait that increases the ability of an individual to survive and reproduce compared to individuals without the trait. ion

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adaptation

Front 2

the smallest particle of an element that retains the properties of the element.

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atom

Front 3

“self-feeder”; normally, a photosynthetic organism; a producer.

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autotroph

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a scientific naming system by which each organism is given a two-word name corresponding to its genus and species

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binomial system

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the total number of species within an ecosystem and the resulting complexity of interactions among them.

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biodiversity

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the smallest unit of life, consisting, at a minimum, of an outer membrane that encloses a watery medium containing organic molecules, including genetic material composed of DNA.

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cell

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the scientific theory stating that all living things are composed of one or more cells.

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cell theory

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a single DNA double helix together with proteins that help to organize the DNA.

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chromosome

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all the interacting populations within an ecosystem.

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community

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in the scientific method, the decision about the validity of a hypothesis on the basis of experimental evidence.

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conclusion

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that portion of an experiment in which all possible variables are held constant; in contrast to the “experimental” portion, in which a particular variable is altered.

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control

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the material contained within the plasma membrane of a cell, exclusive of the nucleus.

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cytoplasm

Front 13

the process of generating hypotheses about how a specific experiment or observation will turn out.

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deductive reasoning

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a molecule composed of deoxyribose nucleotides; contains the genetic information of all living cells.

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deoxyribonucleic acid

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the broadest category for classifying organisms; organisms are classified into three domains: Bacteria, Archaea, and Eukarya.

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domain

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a substance that cannot be broken down, or converted, to a simpler substance by ordinary chemical means.

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element

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the capacity to do work.

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energy

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referring to cells of organisms of the domain Eukarya (plants, animals, fungi, and protists). ------------- cells have genetic material enclosed within a membrane-bound nucleus and contain other membrane-bound organelles.

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eukaryotic

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the descent of modern organisms with modification from preexisting life-forms; strictly speaking, any change in the proportions of different genotypes in a population from one generation to the next.

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evolution

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in the scientific method, the testing of a hypothesis by carefully controlled observations, leading to a conclusion.

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experiment

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the unit of heredity; a segment of DNA located at a particular place on a chromosome that encodes the information for the amino acid sequence of a protein, and hence particular traits.

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gene

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literally, “other-feeder”; an organism that eats other organisms; a consumer.

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heterotroph

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the maintenance of a relatively constant environment required for the optimal functioning of cells, maintained by the coordinated activity of numerous regulatory mechanisms, including the respiratory, endocrine, circulatory, and excretory systems.

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homeostasis

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in the scientific method, a supposition based on previous observations that is offered as an explanation for the observed phenomenon and is used as the basis for further observations, or experiments.

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hypothesis

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the process of creating a generalization based on many specific observations that support the generalization, coupled with an absence of observations that contradict it.

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inductive reasoning

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the second broadest taxonomic category, contained within a domain and consisting of related phyla or divisions.

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kingdom

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a particle composed of one or more atoms held together by chemical bonds; the smallest particle of a compound that displays all the properties of that compound.

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molecule

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many-celled; most members of the kingdoms Fungi, Plantae, and Animalia are multicellular, with intimate cooperation among cells.

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multicellular

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a change in the base sequence of DNA in a gene; normally refers to a genetic change significant enough to alter the appearance or function of the organism.

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mutation

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the scientific principle that natural events occur as a result of preceding natural causes.

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natural causality

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the unequal survival and reproduction of organisms due to environmental forces, resulting in the preservation of favorable adaptations. Usually, natural selection refers specifically to differential survival and reproduction on the basis of genetic differences among individuals.

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natural selection

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the membrane-bound organelle of eukaryotic cells that contains the cell’s genetic material

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nucleus (cellular)

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a substance acquired from the environment and needed for the survival, growth, and development of an organism.

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nutrient

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in the scientific method, the noting of a specific phenomenon, leading to the formulation of a hypothesis.

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observation

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a structure (such as the liver, kidney, or skin) composed of two or more distinct tissue types that function together.

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organ

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a structure, found in the cytoplasm of eukaryotic cells, that performs a specific function; sometimes refers specifically to membrane-bound structures, such as the nucleus or endoplasmic reticulum.

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organelle

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describing a molecule that contains both carbon and hydrogen.

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organic/organic molecule

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an individual living thing.

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organism

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two or more organs that work together to perform a specific function; for example, the digestive system.

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organ system

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the complete series of chemical reactions in which the energy of light is used to synthesize high-energy organic molecules, normally carbohydrates, from low-energy inorganic molecules, normally carbon dioxide and water.

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photosynthesis

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the outer membrane of a cell, composed of a bilayer of phospholipids in which proteins are embedded.

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plasma membrane

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all the members of a particular species within an ecosystem, found in the same time and place and actually or potentially interbreeding.

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population

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in the scientific method, a “thought experiment” based on a hypothesis, in which the experimenter reasons about the outcome of an experimental manipulation, and then uses this reasoning to design a scientific experiment.

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prediction

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referring to cells of the domains Bacteria or Archaea. ------------ cells have genetic material that is not enclosed in a membrane-bound nucleus; they also lack other membrane-bound organelles.

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prokaryotic

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a rigorous procedure for making observations of specific phenomena and searching for the order underlying those phenomena.

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scientific method

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a general explanation of natural phenomena developed through extensive and reproducible observations; more general and reliable than a hypothesis.

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scientific theory

Front 47

the basic unit of taxonomic classification, consisting of a population or series of populations of closely related and similar organisms. In sexually reproducing organisms, a species can be defined as a population or series of populations of organisms that interbreed freely with one another under natural conditions but that do not interbreed with members of other species.

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species

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a group of (normally similar) cells that together carry out a specific function; for example, muscle; may include extracellular material produced by its cells.

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tissue

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single-celled; most members of the domains Bacteria and Archaea and the kingdom Protista are unicellular.

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unicellular

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a factor in a scientific experiment that is deliberately manipulated in order to test a hypothesis.

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variable