Biology

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, deoxyribonucleic 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.

4. 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.