Introduction to biology, general educational information.

Unifying Principles of Modern Biology.  There are three:

        A.  All Organisms Are Made Up of Cells.  In 1838, a German botanist, M. Schleiden demonstrated plant cells.  In 1839, zoologist T. Schwann demonstrated animal cells.  In 1858, pathologist R. Virchow said that cells only come from other cells.   In Chapter 3, we shall talk of organic molecules, and see that Amino Acids are the building
blocks of proteins for cells -- and that throughout all
nature and all forms of life, from the lowest most simple
bacteria, to humans, only 20 amino acids are used, and all
life forms use the same.  A powerful finding showing the
unity of life on Earth.

        B.  All Organisms Obey Laws of Physics and Chemistry.
Pasteur argued that there was a "vital" force in life which
gave their reactions a special form.  This was refuted as
early as 1898 by Buechner in Germany, who found that cells
have NO special "vital" reactions; indeed, the same old
chemical reactions that occurred outside of cells were the
ones occurring inside of cells.  Heredity itself, it has
since been learned, is determined by the chemical structure
of the "gene" molecules, dioxyribonucleic acid -- DNA.

C.    All Organisms Require Energy.  And follow the laws of
Thermodynamics:  

1.    Energy can change from one form to
another, but cannot be created or destroyed.  

2.   All natural events proceed in such a way that concentrations of energy tend to dissipate or become random.  A Living System is a concentration of energy, and can stay that was ONLY by the intake of additional energy, by sunlight or the chemical energy of food.  A cell is a complex of systems for the transformation of energy.  The Flow of Energy is the Essence of Life, and the entire structure of the Biosphere (chapter 55) is determined by the energy exchanges of the groups that live in it.  The hamburger you eat, for example, is a transfer of chemical energy from the cow whose meat it was, to you;  the meat, a series of protein molecules, came from an energy transfer to the cow from the plants it ate;  the plants synthesized its nutrients from converting energy from the sun.

3.  The Forms of Life.  There are about 5 million extant species.

The "Kingdoms":

          Monera:  The smallest and simplest of all organisms.
          Bacteria,           and their relatives.  One celled, "prokaryotes", 
          ("before the nucleus"), with no defined nucleus in their
          cell, and no other internal cellular structure.  Monera
          appeared on Earth about 3.5 Billion years ago, and had sole
          possession of the planet for 2 Billion years.

          Protista:  Mostly one-celled, but the cell structures
          from one form of Protista to another are very different.
          There are many different types, from simple to complex.
          Included are Algae, Amoebas, Paramecia.  They are a type
          of cell called "Eukaryotes", or "truly nucleated).  All
          types of life in all the life "kingdoms" except Monera
          are Eukaryotes.

          Fungi:  These organisms live much differently than the
          Rest of the world.  Included are Yeasts, Molds, Mushrooms.
          They live by digesting complex macromolecules into smaller
          molecules, and then absorbing them.

          Plantae:  Are many-celled organisms that collect energy
          from light.  They covert the light energy into sugars,
          proteins, and oils for use by the plant (and animals eating
          the plants).
         
          Animalia:  many-celled life-forms which depend on
          other life-forms, usually plants or animals, for their
          source of energy.  1.5 million species are represented in
          this "kingdom", 95% of which are invertebrate, with a
          million of those being insects.

          5.  The Nature of Science.

          Science is the seeking of principles of order in the
          physical universe, by gathering hypothesis;  if the hypothesis is
          confirmed by test and analysis, it graduates to a theory.
          A theory can become a principle or law.  A "hunch" becomes
          a "hypothesis" only when it is stated in such a way that
          it is Testable, by observation or experiment.  When a
          "hypothesis" of broad and basic importance has survived
          a number of independent tests, using diverse data, it may
          become a "theory".  Thus a scientific theory is one that
          has been subjected to and passed rigorous examination by
          competing scientists.  Science is a dynamic and ongoing
          process of reexamination and seeking new information.

          Science evolves, as it were.

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