Chapter 1: Exploring Life Flashcards
Archaea
One of two prokaryotic domains of life, the other being Bacteria.
Bacteria
One of two prokaryotic domains of life, the other being Archaea.
biosphere
The entire portion of Earth inhabited by life; the sum of all the planet’s ecosystems.
cell
A basic unit of living matter separated from its environment by a plasma membrane; the fundamental structural unit of life.
community
An assemblage of all the organisms living together and potentially interacting in a particular area.
controlled experiment
A component of the process of science whereby a scientist carries out two parallel tests, an experimental test and a control test. The experimental test differs from the control by one factor, the variable.
domain
A taxonomic category above the kingdom level. The three domains of life are Archaea, Bacteria, and Eukarya.
ecosystem
All the organisms in a given area, along with the nonliving (abiotic) factors with which they interact; a biological community and its physical environment.
emergent properties
New properties that emerge 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 that has a membrane-enclosed nucleus and other membrane-enclosed organelles. All organisms except bacteria and archaea are composed of eukaryotic cells.
evolution
Descent with modification; the idea that living species are descendants of ancestral species that were different from present-day ones; also the genetic changes in a population over generations.
gene
A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses). Most of the genes of a eukaryote are located in its chromosomal DNA; a few are carried by the DNA of mitochondria and chloroplasts.
hypothesis
(plural, hypotheses) A tentative explanation a scientist proposes for a specific phenomenon that has been observed.
molecule
A group of two or more atoms held together by covalent bonds.
natural selection
A process in which organisms with certain inherited characteristics are more likely to survive and reproduce than are organisms with other characteristics.
organ
A structure consisting of several tissues adapted as a group to perform specific functions.
organ system
A group of organs that work together in performing vital body functions.
organelle
A membrane-enclosed structure with a specialized function within a cell.
organism
An individual living thing, such as a bacterium, fungus, protist, plant, or animal.
population
A group of individuals belonging to one species and living in the same geographic area.
producer
An organism that makes organic food molecules from CO2, H2O, and other inorganic raw materials: a plant, alga, or autotrophic bacterium.
prokaryotic cell
A type of cell lacking a membrane-enclosed nucleus and other membrane-enclosed organelles; found only in the domains Bacteria and Archaea.
systems biology
An approach to studying biology that aims to model the dynamic behavior of whole biological systems.
technology
The practical application of scientific knowledge.
theory
A widely accepted explanatory idea that is broad in scope and supported by a large body of evidence.
tissue
An integrated group of cells with a common function, structure, or both.
