Dragons of Eden

by Carl Sagan

  NUCLEOTIDE The fundamental building blocks of the nucleic acids (q.v.).

  OCCIPITAL LOBE Approximately, the portion of the neocortex under the back of the skull.

  OLFACTORY BULBS Components of the brain attached to the front of the forebrain, and playing an important role in the perception of smells.

  PARIETAL LOBE Approximately, the middle portion of each cerebral hemisphere of the neocortex.

  PITUITARY The “master” endocrine gland, situated in the limbic system but near the midbrain and influencing both growth and the operations of other endocrine glands.

  PLASTICITY The capability to be shaped or formed; in particular, the ability to learn from the external environment.

  PONS (also called PONS VARIOLI) The neural bridge connecting the medulla oblongata and the midbrain. It is a part of the brainstem.

  PREWIRED Computer jargon for information already in place. Also called hard-wired. The more prewiring, the less plasticity.

  PRIMARY PROCESSES Psychoanalytic term for the fundamental unconscious functions of the brain.

  PRIMATES An order (one of the taxonomic classifications) of mammals that includes lemurs, monkeys, apes, and humans.

  PROTEINS Along with the nucleic acids, the principal molecular basis of life on Earth. Proteins are made of constituent units called amino acids and are ordinarily elaborately folded and coiled. Some proteins are spherical in overall shape, while others resemble free-standing nonrepresentationalist sculpture. All enzymes, which control the rate of chemical reactions in the cell, are proteins. The synthesis and activation of enzymes are controlled by the nucleic acids.

  PSYCHOMOTOR Relating to mental control of muscular processes.

  R-COMPLEX or REPTILIAN COMPLEX The evolutionarily most ancient part of the forebrain.

  RECAPITULATION OR THE RECAPITULATION OF PHYLOGENY BYONTOGENY The apparent repetition, during the embryonic development of an individual organism, of a past evolutionary stage of the species.

  REM Rapid eye movements, particularly those which occur under the eyelids during dream sleep. Therefore, the characterization of such a sleep.

  RNA Ribonucleic acid. See Nucleic acids.

  SELECTION PRESSURE In evolutionary theory, the influence of the environment in selecting for survival and reproduction a particular set of genetic characteristics.

  SHORT-TERM MEMORY Memory retained for brief periods of time—for example, less than a day.

  SYNAPSE The junction of two neurons: the locale where an electrical impulse is transmitted from one neuron to another.

  TAXON (plural, Taxa) A group of organisms classified according to common characteristics, ranging from minor distinctions such as races and subspecies to major distinctions such as the differences between the plant and animal kingdoms.

  TEMPORAL LOBE Approximately, the portion of the neo-cortex beneath the temples of the skull.

  THALAMUS A portion of the limbic system near the center of the brain. Among other functions, it replays sensory stimuli to the neocortex.

  — — — — TOMY The cutting of an organ represented by the dashes (see, for example, Craniotomy or Lobotomy).

  TRIUNE BRAIN The idea, most recently advocated by Paul MacLean, that the forebrain comprises three separately evolved and to some degree independently functioning cognitive systems.

  ZYGOTE A fertilized egg.

  The New York Times Bestseller

  COMET

  by

  Carl Sagan and Ann Druyan

  What are these graceful visitors to our skies? We now know that they bring both life and death and teach us about our origins. In Comet, Pulitzer Prize-winning astronomer Carl Sagan and writer Ann Druyan explore the origin, nature, and future of comets, and the exotic myths and portents attached to them. Lavishly illustrated and including new material, this edition of Comet is indispensable for anyone who has ever gazed up at the heavens and wondered why.

  COMET

  by Carl Sagan and Ann Druyan

  Published by Ballantine Books.

  Available in bookstores everywhere.

  Carl Sagan and acclaimed author

  Ann Druyan show us the roots of

  the human species in

  SHADOWS OF

  FORGOTTEN

  ANCESTORS

  A thrilling account of how humans got to be the way we are, Shadows of Forgotten Ancestors begins its saga with the origin of the Earth and shows that many of our key traits-self-awareness, family ties, reason, ethics, submission to authority, and hatred for those who are different-are rooted in the deep past and illuminated by our kinship with other animals.

  SHADOWS OF FORGOTTEN

  ANCESTORS

  by Carl Sagan and

  Ann Druyan

  Published by Ballantine Books.

  Available wherever books are sold.