Chapter 1: Exploring Life

Question 1

Archaea

Answer 1

One of two prokaryotic domains of life, the other being Bacteria.

Question 2

Bacteria

Answer 2

One of two prokaryotic domains of life, the other being Archaea.

Question 3

biosphere

Answer 3

The entire portion of Earth inhabited by life; the sum of all the planet’s ecosystems.

Question 4

cell

Answer 4

A basic unit of living matter separated from its environment by a plasma membrane; the fundamental structural unit of life.

Question 5

community

Answer 5

An assemblage of all the organisms living together and potentially interacting in a particular area.

Question 6

controlled experiment

Answer 6

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.

Question 7

domain

Answer 7

A taxonomic category above the kingdom level. The three domains of life are Archaea, Bacteria, and Eukarya.

Question 8

ecosystem

Answer 8

All the organisms in a given area, along with the nonliving (abiotic) factors with which they interact; a biological community and its physical environment.

Question 9

emergent properties

Answer 9

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

Question 10

Eukarya

Answer 10

The domain that includes all eukaryotic organisms.

Question 11

eukaryotic cell

Answer 11

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.

Question 12

evolution

Answer 12

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.

Question 13

gene

Answer 13

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.

Question 14

hypothesis

Answer 14

(plural, hypotheses) A tentative explanation a scientist proposes for a specific phenomenon that has been observed.

Question 15

molecule

Answer 15

A group of two or more atoms held together by covalent bonds.

Question 16

natural selection

Answer 16

A process in which organisms with certain inherited characteristics are more likely to survive and reproduce than are organisms with other characteristics.

Question 17

organ

Answer 17

A structure consisting of several tissues adapted as a group to perform specific functions.

Question 18

organ system

Answer 18

A group of organs that work together in performing vital body functions.

Question 19

organelle

Answer 19

A membrane-enclosed structure with a specialized function within a cell.

Question 20

organism

Answer 20

An individual living thing, such as a bacterium, fungus, protist, plant, or animal.

Question 21

population

Answer 21

A group of individuals belonging to one species and living in the same geographic area.

Question 22

producer

Answer 22

An organism that makes organic food molecules from CO2, H2O, and other inorganic raw materials: a plant, alga, or autotrophic bacterium.

Question 23

prokaryotic cell

Answer 23

A type of cell lacking a membrane-enclosed nucleus and other membrane-enclosed organelles; found only in the domains Bacteria and Archaea.

Question 24

systems biology

Answer 24

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

Question 25

technology

Answer 25

The practical application of scientific knowledge.

Question 26

theory

Answer 26

A widely accepted explanatory idea that is broad in scope and supported by a large body of evidence.

Question 27

tissue

Answer 27

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