PHYLOGENY: (Greek: phulo "tribe" + geny "birth") The sequence of events in the evolutionary development of a species or other taxonomic group. (See ONTOGENY) (MP)
PHYLUM: (Greek: phulon "race") The second highest level of taxonomic classification of organisms below the kingdom, and containing one or more classes. For example Phylum Arthropodia (including insects and crustaceans) or Phylum Chordata (including all vertebrates). (See KINGDOM, SPECIES, TAXONOMY) (MP)
PHYSICAL MAP: A map of the locations of identifiable landmarks on DNA (e.g., restriction enzyme cutting sites, genes, RFLP markers), regardless of inheritance. Distance is measured in base pairs. For the human genome, the lowest-resolution physical map is the banding patterns of the 24 different chromosomes; the highest-resolution map would be the complete nucleotide sequence of the chromosomes. (DM)
PHYSICAL POLLUTION: See POLLUTION.
PHYSICAL PROCESS SUSTAINABILITY: See SUSTAINABLE MANAGEMENT.
PHYSICAL RESTRAINT: Use of a device for the purpose of preventing an individual from moving all or part of the body. (DM)
PHYSICIAN: (Greek: physis 'nature'). A health professional who has completed a Doctor of Medicine (M.D.) degree. Interestingly, the ancients saw the physical laws (physikos meaning natural) of the universe and the work of physicians inseparably interconnected. From our perspective, reflecting on the ancient thesis of the unity of all things, we are again confronting modern physics. Thus, physician and physics can be seen as a metaphor - the body that must be healed is united with the immensity of the cosmos of which it is a part. (See PHYSICS, PLACEBOS). (IP)
PHYSICS: (Greek: physikos "natural") The scientific study of matter and energy, their interrelations and the physical properties of the universe. Physics is based on mathematics and its natural laws, forces and processes are fundamental to the other sciences. Branches of physics include mechanics, thermodynamics, optics, acoustics, electromagnetism, nuclear physics, particle physics, solid-state physics, astrophysics and quantum mechanics. (See CHEMISTRY) (MP)
PHYSIOLOGICAL ECOLOGY:See ECOPHYSIOLOGY.
PI: The fascinating number denoted by the Greek letter π (pi), 22 divided by 7, or 3.14159… and on to an infinite number of significant digits in a sequence of seemingly random numbers; but multiply 2pi by radius of a circle to get circumference, multiply pi by radius squared to get area. An example of chaos, and of simple rules embedded in complexity. (See CHAOS, COMPLEXITY, STATISTICS) (MP)
PIDGIN: A pidgin is a mixed tongue which develops between neighbors or trading partners speaking different languages, for example 'pidgin English'. A creole is a pidgin which has matured to become a localized mother tongue. Pidgins have limited grammar and vocabulary resulting from their makeshift origin, but are creatively adaptive expressions never to be stereotyped as the result of 'primitive' thought processes. (See ARTIFICIAL LANGUAGES, LINGUA FRANCA) (MP)
PILOT STUDY: An initial study carried on a small sample, to explore the subject and identify requirements for design of the main study or experiment. (See BASELINE MONITORING, EXPERIMENT, EXPLORATORY RESEARCH, SCOPING) (MP)
PLACEBOS: Biologically inactive substances used for their psychological effect in patient care or as control agents in research. The word placebo is Latin for 'I will please', and refers to any procedure administered solely to gratify a patient's desire for treatment. Since the therapy is scientifically ineffective, its efficacy is realized by self-governance or reliance on an authority figure (doctor, spiritual healer, Shaman) for getting well. Therefore, an alternative meaning of placebo has to do with the way in which a patient 'pleases' by involving the doctor (or surrogate) as the therapeutic agent in the process of getting well. The placebo effect, as measured in a variety of modern studies, has been estimated to range from 21% to a remarkable 58%, depending on the disease, the placebo, and the way the study was executed. (See CLINICAL TRIALS, PHYSICIAN). (DM+IP).
PLACENTAL MAMMAL: See EUTHERIAN MAMMAL.
PLAGUE: Bobonic plague killed between 17 and 28 million during the years 1347 to 1350, i.e. one third of Europe. Japanese attempted to use it as a biological weapon on Chinese during World War II with the loss of some human lives on both sides. (JA)
PLANCK, MAX: (1858-1947). German Physicist. Planck's work on the laws of thermodynamics and black body radiation moved him away from classical Newtonian principles, opening up the way for original innovative thinking. In 1900 Planck proposed the quantum theory for which he received, in 1918, the Nobel Prize for physics. (See CLASSICAL MECHANICS, EINSTEIN, NEWTON, QUANTUM THEORY). (IP)
PLANKTON: The collection of organisms that float in the water; planktonic organisms float or swim more slowly than typical currents. (RW)
PLANNED OBSOLESCENCE: Integral features of a product known by the manufacturer to wear out or become superfluous, ensuring regular return custom for replacements or updates. This is typical for computer and software technology which supersedes itself at a fast rate. Planned obsolescence and in-built redundancy protect commercial values only at the expense of both environmental and social values. (See CONSPICUOUS CONSUMPTION, WASTE) (MP)
PLANT BREEDING: The development of plants with certain desirable characteristics, such as disease resistance. (DM)
PLANT VARIETY: Cultivated plants that are clearly distinguishable from others by one or more characteristics, and that when reproduced retain those distinguishing characteristics. (DM)
PLANT VARIETY PROTECTION: Patent-like protection for certain sexually produced plants. Plant variety protection is granted by many countries, and applies within those countries. It only applies if the holder ensures a reasonable commercial supply of that variety to all who want it. (DM)
PLANTAE: Plantae are the plants, one of the five taxonomic kingdoms along with Animalia, Fungi, Protista and Monera. Plants are autotrophic organisms with chloroplasts which manufacture energy directly from the sun through photosynthesis. They have rigid cell walls and reproduce on a variation of the alternating diploid sporophyte and haploid gametophyte life-cycle model, with increasing emphasis on the sporophyte stage through evolution. Members of the kingdom Plantae include algae (green, red, bluegreen, macro-algae), bryophytes (mosses, liverworts), ferns, tracheophytes (vascular plants) and Spermopsida (seed plants; gymnosperms and angiosperms). Plant communities form the basis of habitat structure and ecological energy procurement, and include phytoplankton, seaweeds, seagrasses, mangroves, deciduous forest, sclerophyll forest, coniferous forest and tropical rainforest. (See ALGAE, ANGIOSPERM, AUTOTROPHS, CONIFEROUS FOREST, DECIDUOUS FOREST, EUTROPHICATION, GYMNOSPERM, HABITAT, MANGROVE FOREST, PERMACULTURE, PHOTOSYNTHESIS, PLANT VARIETY, POLYCULTURE, REFORESTATION, SEAGRASS, SCLEROPHYLL FOREST, TREE PLANTING, TROPICAL RAINFOREST) (MP)
PLASMID: An extrachromosomal, circular piece of DNA found in the cytoplasm and capable of replicating and segregating independently of the host chromosome. See vector. Found in cytoplasm of bacteria and in some eukaryotes. R-plasmids are those that carry gene for drug resistance and Col - plasmids that carry the gene for producing a protein, known as Colicins, conjugal plasmids transfer their properties to other members of the population, non-conjugal are non transmissible in nature. (DM, JA)
PLASTIC SURGERY: See COSMETIC SURGERY.
PLATO (428-7 - 348-7 BC): Pupil of Socrates and teacher of Aristotle, Plato is famous for his many literary-philosophical dialogues in which Socrates is given the central role. He believed that this world is a not-very-good copy of the world of forms or ideas, where the true archetypes of things exist. In his Republic, he advocated a rather regimented society in which people would be educated to live ethical ways of life, and to perform functions according to their class. Karl Popper, in his Open Society and its Enemies depicted Plato's Republic as the model of the closed society.
Over the entrance to Plato's academic was a warning that people who had not studied mathematics were not welcome to enter. This was long before the days in which academic learning was separated into humanities and sciences, and in which people could become "professional philosophers" without having studied mathematics or the sciences. Bioethics, which raises ethical and spiritual questions as a consequence of studies in mathematics and the sciences, is a return to the interdisciplinary philosophical tradition for which Plato's Academy stood. (FL)
PLEASURE: (Old French: plaisir "to please") An enjoyable sensation or emotion which arouses delight or happiness. Common positive sources of pleasure include love, friendships, recreation, relaxation, productivity, personal and financial success and security. However, some religious philosophy has been interpreted to condemn pleasure-seeking in an attempt to avoid greed, excess, selfishness and self-indulgence. Certain means of satisfying the human drive for pleasure have associated costs and ethical boundaries, for example inappropriate or overconsumed resources, material possessions, food, drink, drugs, sex, money, trivial amusements, theft, revenge or other harmful behaviours. A sense of balance must be developed and avenues for pleasure-seeking must be bounded by our ethics and the consequences of our actions. (See HAPPINESS, JOY). (MP)
PLEBISCITE:A referendum to allow people to vote directly on an issue or policy of relevance to their lives. (See REFERENDUM) (MP)
PLEIOTROPIC EFFECT: The production of several unrelated changes in the characteristics of a cell or organism by a single genetic change. (DM)
PLURIPOTENT: Cells capable of differentiation into any type of organs or cell type. (See STEM CELL). (JA)
PLUTONIUM (PU): (Planet Pluto). A highly toxic synthetic waste product of nuclear power plants. Plutonium, discovered in 1940, is a transuranic metallic element which is produced by the collision of a neutron with uranium; thus, it is formed in uranium fuel rods in nuclear reactors. Plutonium is itself an extremely efficient source of nuclear energy so it can be extracted from used fuel rods for re-use in a different type of nuclear reactor. The process whereby more nuclear fuel is produced than is used is called 'breeding' and the reactors employed are known as 'fast-breeder reactors'. Plutonium was used in the assembly of early nuclear weapons. (See ATOM BOMB, NEUTRON BOMB). (IP).
PO: A word coined by Edward de Bono as a lateral-thinking tool to counter-force the ‘No’ of logical thinking. ‘Po’ is somewhere between yes and no, implying the non-judgmental creation of new patterns of thought and dismantling of old patterns, exploring lateral ideas before testing them again against rationality. It has some of the feel of possibility, hypothesis suppose and potent, but rather opens up spaces ‘outside of reason’, a ‘holiday from the usual conventions of logic’, therefore more in the spirit of poetry. Po has not been the most successful of memes, but still has an intangible persuasiveness. (See LATERAL THINKING) (MP)
POACHING: Poaching is unauthorized hunting or capture of animals, for example illegal fishing, hunting outside the appropriate season, or taking wildlife from private property or National Parks. Large amounts of illegal African ivory, skins and other animal products have been ceremoniously destroyed in the war against poaching. In some countries, poaching of charismatic and threatened species is crime enough for rangers to have a shoot-first policy for poachers. Regulatory and consumer action must be maintained against products containing animal parts, for example Asian tiger, rhino and seahorse 'aphrodisiacs'. (See HUNTING) (MP)
POISON: (Latin potio 'drink'). Any substance that when ingested, inhaled or absorbed into the body in small amounts destroys life or injures health. Poisons may act by rapid action or become damaging after repeated exposure. Clinically poisons are categorized into those that respond to specific treatments and those for which there are no specific treatments available. (See POISON HEMLOCK, TERATOGEN, TOXIN). (IP)
POISON HEMLOCK: Conjum maculatum is a biennial plant found in wastelands and moist soils in the eastern US and on the Pacific coast. It has large, compound umbels of small, white flowers that appear from June to August. Poison hemlock contains an alkaloid toxin that makes it a dangerously poisonous plant that has sometimes been used for sedation and analgesia. In classical times it was a standard method of executing convicted criminals - Socrates being the best known of its victims. Unintentional poisoning has taken place when the seeds were mistaken for anise, the leaves for parsley and the roots for parsnip. Legend tells us that even blowing a whistle made from the hollow stem can cause fatal poisoning. (See BUSH MEDICINE, HERBALISM, POISON, SOCRATES, TOXICOLOGY). (IP)
POLICY ANALYSIS: Indicates that the document contains substantive argumentation concerning moral and/or public policy. (DM)
POLITICAL ACTIVITY: Actions by individual citizens or by interest groups, designed to influence government policies. (DM)
POLITICAL CORRECTNESS: See DEBATE.
POLITICAL REFUGEES: See REFUGEES.
POLITICS: Actions by government officials or bodies in the development of public policy. (DM)
POLLUTANT Any chemical/solid/liquid/gaseous substance/suspended particulate matter released into the environment and are present in such concentrations that may cause or induce deleterious environmental condition or to organisms or tend to be injurious to human beings. Any substance that is categorized as wastes specified by a competent authority and included in a Schedule appended to a specific rule/government order. (JA)
POLLUTION: Any undesirable change in the physical, chemical or biological characteristics of air, land and water with a possibility to harm organisms/human beings/cultural assets/industrial process/living conditions. Physical pollution include noise (undesirable sound) pollution, genetic pollution include man made alteration in the gene sequence that may go out of control at a later stage; cultural pollution include undesirable social change. Introduction by humans, directly or indirectly, of substances or energy into the environment (including air, water, soil etc.). Often resulting in such deleterious effects as harm to living resources, hazards to human health, hindrance to activities including agriculture, fishing, impairment of quality for use of water and reduction of amenities (See GESAMP). (JA)
POLLY: Transgenic cloned sheep, produced from a cell line of genetically modified foetal cell culture by Roslin Institute and PPL-Therapeutics, expressing a human protein in its milk. (JA)
POLYCHLORINATED BIPHENYLS OR PCBs are synthetic, chemically stable industrial compounds used 1. as hydraulic fluids, flame retardants, dielectric fluids for capacitors and transformers 2. As organochlorine insecticides methoxychlor, kepone and DDT, as well as a number of closely related chlorinated hydrocarbons such as chlordane, dieldrin, endin and heptachlor used in aerial crop spraying, and numerous other products. PCBs are in a class collectively known as "hormone disruptors" because they mimic naturally-occurring steroid hormones such as estrogens and testosterone, and interfere with thyroid and adrenal gland metabolism. They resist the body’s natural detoxification processes so accumulate in the body’s fat deposits (see Biomagnification) and have been documented to seriously affect fertility and development; particularly in wildlife where many species have been pushed into extinction, and may also be an important factor in rising infertility rates in humans (see DDT, SYNTHETIC HORMONE DISRUPTORS). (IP)
POLYCULTURE: (Greek: polys "many" + Latin: cultura "cultivation") The agricultural cultivation of a range of intermingled mixed crops. This diversity allows for stability in the face of environmental change, and enables the cohabitation of a wider biodiversity of native species. (See MONOCULTURE, PERMACULTURE) (MP)
POLYGAMY [Gr. poly: many + gamos: marriage] a breeding system in which an individual acquires more than one mate. In polyandry, a female mates with more than one male, in polygyny, a male mates with more than one female. (IP)
POLYGENIC DISORDERS: Genetic disorders resulting from the combined action of alleles of more than one gene (e.g., heart disease, diabetes, and some cancers). Although such disorders are inherited, they depend on the simultaneous presence of several alleles, thus the hereditary patterns are usually more complex than those of single-gene disorders. Compare single gene disorders. (DM)
POLYMERASE: An enzyme that assembles a number of similar or identical subunits into a macromolecule (e.g. DNA polymerase and RNA polymerase). (DM)
POLYMERASE CHAIN REACTION (PCR) - a technique for the rapid amplification of a specific nucleic acid sequence contained in a stretch of DNA. (DM)
POLYMORPHISM: Difference in DNA sequence among individuals. Genetic variations occurring in more than 1 percent of a population would be considered useful polymorphisms for genetic linkage analysis. Compare MUTATION. (DM)
POLYPLOID: Having a chromosome number that is greater than two of the monoploid number. Polyploid oysters were among the first non-naturally occurring, non-human, multicellular, living organisms to be declared patentable subject matter. Multiple chromosome sets in the nucleus are common in plants, but rare in animals. Eg. Triplid, teraploids. (DM, JA)
POMOLOGY: Science of growing fruits (JA)
POPPER, Sir Karl Raimund: (1902-1994) Born in Austria. One of the most famous philosophers of science of the 20th Century. Popper rejected inductive 'proof' in science and emphasized that scientific ideas must be falsifiable. (RW)
POPs:See PERSISTENT ORGANIC POLLUTANTS.
POPULATION: Strictly a collection of individuals within a SPECIES (q.v.) that forms an interbreeding group. However, the term is often used simply to mean a number of individuals within a species found in a common area. People also talk about world human population size, which probably reached six billion (6 x 109) in the year 2000 at which time is was increasing by about 80 million a year. (MR)
POPULATION CONTROL: Regulation of the growth and distribution of people in a country or region. (DM)
POPULATION DENSITY: The number of individuals of a species per unit of land area occupied by that species, for example people per square kilometre. The measure should exclude land unsuitable for habitation, such as rugged mountains, deserts or other inappropriate habitats. (See POPULATION DISTRIBUTION) (MP)
POPULATION DISTRIBUTION:The location, range and extent of occupation of a population or species. The arrangement of a population may be measured by its extent of occurrence, which is the area within the boundary encompassing all known or inferred sites of occurrence, excluding vagrant individuals. It may also be more accurately measured using the area of occupancy, which is the sum of appropriately sized grid squares occupied by the species, thereby excluding unsuitable habitat within its extent of occurrence. (See POPULATION, POPULATION DENSITY) (MP)
POPULATION EXPLOSION: In most species the number of individuals in a POPULATION (q.v.) can increase rapidly, i.e. undergo a 'population explosion' at times when there is an excess of food and other factors necessary for successful reproduction. (See EXPONENTIAL) (MR)
POPULATION LIMITS: See LIMITING FACTOR, LIMITS TO GROWTH.
PORNOGRAPHY: lascivious art or literature. The Greek word porne or harlot first appeared in the 7th Century BC and is derived from the ancient verb pernimi to sell (Greek porne whore + graphein write/draw). (IP)
POSITIVE DISCRIMINATION: See AFFIRMATIVE ACTION.
POSITIVE EUGENICS: The achievement of systematic or planned genetic changes to improve individuals or their offspring. (DM)
POSITIVE FEEDBACK: See FEEDBACK.
POSITIVISM The form of positivism best known today is Logical Positivism, a philosophy developed by a group called the Vienna Circle, who met regularly in Vienna from the 1920's until they fled the Nazis in the late 1930's. Their philosophy is presented in a readable form in A.J. Ayer's clear and classic book, Language, Truth and Logic. The Logical Positivists sought to rid our language of nonsensical talk, which they believed derived from religion and fanatic ideologies. In fact the movement may have been at least in part a reaction against the ideologies of nationalism, fascism, and Nazism, which were prevalent in Europe at that time. They decreed that a statement is meaningful if, and only if, it is either analytic or empirically verifiable. By "analytic" is meant a statement, which can be proved to be true by the methods of logic or mathematics. By "empirically verifiable" is meant provable or falsifiable, by direct sense observation, or by the methods of laboratory science. It should be noted that a false statement, like "The Eiffel Tower is in Tokyo", is just as meaningful as a true one. Statements, which are neither analytic nor empirically verifiable, were called: "Strictly speaking, nonsense." Statements of religion, spiritualism, etc, were deemed nonsensical by the Logical Positivists. So were statements of ethics. The statement: "This is red", is meaningful because red is an observable property. But the statement: "This is bad" is not meaningful because bad is not an observable property. We can observe a murder, for example. And we might observe all sorts of colours, smells, sounds, etc. But bad is not one of the things, which we observe. (The reasoning was taken from David Hume) But although the positivists believed that statements of ethics have no meaning, they allowed that they have a use. Their use was in expressing emotions. This was called the "emotivist" theory of ethics.
Since ethical statements were considered meaningless, it became no longer acceptable in some circles for philosophers to say anything about what is good and what is bad. The job of philosophers became to "analyse" what other people say when they make ethical statements. In professional language, philosophers stopped engaging in ethics,and started to engage in metaethics. The distinction is the forerunner of Macer's discussions of prescriptive and descriptive bioethics. (FL)
POSITIVITY: Positivity is an expression of enthusiasm, optimism, good cheer, acceptance, tolerance and love. Most things have elements of both good and bad, people have strengths and weaknesses, there are pros and cons to every decision or change - positivity is a general focus on the good aspects. Experimental studies have looked at the beneficial effects of positivity on the longevity of relationships. Using an index of positive and negative comments made during a single 15-minute discussion of an issue of dispute between newly-weds, a study successfully predicted over 90% of marriage breakups over a ten year period. Positive thinking also has benefits to health, business and self-perception. So don’t worry, be happy, look on the bright side of life, see the glass half full, notice the good in people. (MP)