Chapter 1: Evolution, the Themes of Biology, and Scientific Inquiry

Archaea

One of two prokaryotic domains, the other being Bacteria.

Bacteria

One of two prokaryotic domains, the other being Archaea.

bioinformatics

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

biology

The scientific study of life.

climate change

A directional change in temperature, precipitation, or other aspect of the global climate that lasts for three decades or more.

consumer

An organism that feeds on producers, other consumers, or nonliving organic material.

controlled experiment

An experiment designed to compare an experimental group with a control group; ideally, the two groups differ only in the factor being tested.

data

Recorded observations.

deductive reasoning

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

dependent variable

A factor whose value is measured during an experiment or other test to see whether it is influenced by changes in another factor (the independent variable).

DNA (deoxyribonucleic acid)

A nucleic acid molecule, usually a double-stranded helix, in which each polynucleotide strand consists 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.

emergent properties

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

Eukarya

The domain that includes all eukaryotic organisms.

eukaryotic cell

A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with eukaryotic cells (protists, plants, fungi, and animals) are called eukaryotes.

evolution

Descent with modification; the process by which species accumulate differences from their ancestors as they adapt to different environments over time; also defined as a change in the genetic composition of a population from generation to generation.

experiment

A scientific test. Often carried out under controlled conditions that involve manipulating one factor in a system in order to see the effects of changing that factor.

feedback regulation

The regulation of a process by its output or end product.

gene

A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses).

gene expression

The process by which information encoded in DNA directs the synthesis of proteins or, in some cases, RNAs that are not translated into proteins and instead function as RNAs.

genome

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.

genomics

The systematic study of whole sets of genes (or other DNA) and their interactions within a species, as well as genome comparisons between species.

hypothesis

A testable explanation for a set of observations based on the available data and guided by inductive reasoning. A hypothesis is narrower in scope than a theory.

independent variable

A factor whose value is manipulated or changed during an experiment to reveal possible effects on another factor (the dependent variable).

inductive reasoning

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

inquiry

The search for information and explanation, often focusing on specific questions.

model organism

A particular species chosen for research into broad biological principles because it is representative of a larger group and usually easy to grow in a lab.

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

producer

An organism that produces organic compounds from CO2 by harnessing light energy (in photosynthesis) or by oxidizing inorganic chemicals (in chemosynthetic reactions carried out by some prokaryotes).

prokaryotic cell

A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with prokaryotic cells (bacteria and archaea) are called prokaryotes.

proteome

The entire set of proteins expressed by a given cell, tissue, or organism.

proteomics

The systematic study of sets of proteins and their properties, including their abundance, chemical modifications, and interactions.

science

An approach to understanding the natural world.

systems biology

An approach to studying biology that aims to model the dynamic behavior of whole biological systems based on a study of the interactions among the system's parts.

technology

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

theory

An explanation that is broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence.

variable

A factor that varies in an experiment.