G
G20 (Group of 20): a forum for the European Union and 19 countries: Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the United Kingdom, and the United States. As Spain is a permanent guest, the G20 is actually G21.
G protein (aka guanine nucleotide-binding protein): a protein family that acts as a molecular switch inside cells.
G-quadruplex: a guanine-rich 4-stranded DNA structure, squarish in shape.
GABA (gamma-Aminobutyric acid): a neurotransmitter which is inhibitory in humans.
Gaia: a theory by English environmentalist James Lovelock that Earth acts as “a single physiological system.”
“Evolution is a tightly coupled dance, with life and the material environment as partners. From the dance emerges the entity Gaia.” ~ James Lovelock
galactic web: the interconnection of galaxies via gravitational and energetic filaments.
galactose (C6H12O6): a sugar which is a constituent of lactose, less soluble and less sweet than glucose.
galago (aka bushbaby): a small, slow-moving nocturnal prosimian native to continental Africa.
galangal: a plant with a more potent rhizome than ginger, used as a spice in Asia.
Galápagos Islands: an archipelago of 18 large and 3 small volcanic islands in the Pacific Ocean near the equator, 972 km west of Ecuador.
Galápagos marine iguana: a marine iguana found only on the Galápagos Islands, capable of diving 9 meters to graze on algae and seaweed.
galaxy: via a massive black hole, a gravitationally bound cluster of star systems and stellar remnants, swirling in an interstellar mixture of gas and dust.
Galilean relativity (aka Galilean invariance): a 1632 hypothesis by Galileo Galilei that the laws of motion are the same in all inertial frames.
gall: an outgrowth on the surface of organisms. Commonly used for abnormal plant growths invoked by various parasites, including bacteria, fungi, and insects.
gallbladder: a vertebrate muscular organ that stores bile from the liver.
gallfly (aka gall wasp): a small wasp of ~1,300 species of wasps, named after the galls they induce on plants for larval development. The larvae of most gall wasps develop in plant galls which they induce. Oak is the wood of choice for many gall wasps.
Gallionella: an aquatic iron-oxidizing bacterium.
gambler’s fallacy: the tendency to see chance as self-correcting.
game theory: the study of strategic interaction between rational decision-makers; specifically, theorization of outcomes and dynamics in situations involving parties with conflicting interests. Modern game theory was developed in the early 1940s and further evolved in the 1950s. Compare decision theory.
gamete: a cell or cell nucleus that undergoes sexual fusion to form a zygote. In animals, gametes are eggs and sperm cells. Plant germ cells produce ovules and pollen.
gametangia: an organ or cell in which gametes are produced.
gametophyte: the haploid, gamete-producing phase of plants and algae that undergo alternation of generations; the prothallus in ferns, and the embryo sac in angiosperms. Compare sporophyte.
gamma ray: electromagnetic radiation above 10 exahertz (>1019 Hz); extremely high energy/frequency radiation.
ganglion: a cluster of nerve cells.
gannet: a large seabird in the Morus genus that hunts by diving into the sea from height. Gannets can dive from 30 meters up, achieving speeds of 100 km/h as they strike the water. This lets them catch fish much deeper than other diving birds.
Ganymede: Jupiter’s largest moon, and the largest in the solar system. Ganymede is the 9th-largest body in the solar system, and the largest without an atmosphere to speak of.
garlic (Allium sativum): the bulb of a plant in the onion genus.
gas: a fluid that may be airborne.
gasoline (aka petrol (British English)): a colorless liquid derived from petroleum.
gastric emptying: the process of the stomach emptying its contents into the duodenum of the small intestine for further digestion and nutrient absorption.
gastric juice: digestive fluid formed in the stomach, comprising potassium chloride, sodium chloride, and hydrochloric acid (~0.5%).
gastrointestinal tract: the human organ system employed in consuming and digesting food, providing nutrients to the body, and expelling inedible wastes.
gastropod: a slug or snail.
Gatorade: a “sports” drink concocted by a team of chemists in 1965 at the University of Florida (which has the alligator as its mascot). Gatorade was designed to replace body fluids lost during hot, sweaty physical exertion. Any perceived aid from Gatorade owes to the placebo effect. Further, no gators have been aided by the drink, and so continue their decline in swamps throughout the American south, despite being the ostensibly esteemed state reptile in Florida, Louisiana, and Mississippi. The American alligator is commercially “harvested” for its meat and skin.
gauge boson: a quantum force carrier.
Gaul: a region of western Europe inhabited by Celtic tribes during the Iron Age, including modern-day France, Belgium, Luxembourg, most of Switzerland, and parts of northern Italy. Gaul was ruled by the Romans 103 BCE to 486 CE, when it fell to the Franks, becoming Francia.
gaydar: the ability through mutual gaze for homosexuals to discern sexual preference.
Gaza: one of the oldest cities in the world; first settled 5 tya, during the Bronze Age. Now a dilapidated Palestinian city, Gaza is on Mediterranean coast.
gazelle: an antelope of 13 species in the genus Gazella.
gazing: one person looking at another. Compare eye contact.
GDP (gross domestic product): a distorted monetary measure of the value of all final goods and services produced in an economy for some period (usually yearly or quarterly). GDP measures are wildly off, as they fail to measure much economic activity. (gross domestic product): a distorted monetary measure of the value of all final goods and services produced in an economy for some period (usually yearly or quarterly). GDP measures are wildly off, as they fail to measure much economic activity.
gecko: a group of lizards fond of warm climate. Geckos are unique among lizards for their gregarious vocalizations. There are 1,500 gecko species: the most speciose of lizards.
geitonogamy: pollination of one flower by pollen of a different flower on the same plant.
gemeinshaft (intimate community): a society of interlaced interpersonal bonds, such as in village life. Contrast gesellschaft. Compare mechanical solidarity, organic solidarity.
gender: designation of female or male of a species. See sex.
generalized other (sociology): an individual’s internalized impression of norms and expectations; coined by George Mead.
gene: the idea that nucleic acids provide instructions for producing an organic molecule, typically a protein. Genes do not exist; they are merely a construal. The actuality of genetics is more intricate than supposed by matterist geneticists, as heritable bioproduct information is stored energetically, with organic molecules as illusory material substrates. See egene.
gene conversion: a recombination transfer between DNA sequences.
gene expression: employment of a gene; the conceptual process by which genetic information is used to synthesize a bioproduct.
gene mapping: the process of determining the locus for a specific biological trait.
gene product: the biochemical material resulting from gene expression. A protein is the typical gene product, though RNA is also a gene product.
gene regulation: control of gene expression, including stifling gene expression.
General Electric (GE) (1892–): American multinational conglomerate corporation descended from Thomas Edison’s electricity-related companies, with an abysmal record of polluting wherever it sets down.
General Motors (GM) (1908–): America car maker that began as a holding company for American industrialist William Durant. Durant had been a leading manufacturer of horse-drawn vehicles before his foray into cars.
general relativity: a geometric physical theory that treats gravity as a property of spacetime, based upon the mass of objects; proposed by Albert Einstein in 1915. Gravity distorts 4d spacetime extra-dimensionally under general relativity.
General Strike of 1926: a nationwide strike throughout Britain 4–13 May 1926.
generalist (ecology): a species with considerable tolerances to environmental changes. Contrast specialist.
generation (physics): a division for fermions, based on mass. Only 1st-generation fermions make up everyday matter. 2nd- and 3rd-generation fermions rapidly decay.
genetic code: the conceptual rulebook by which information is encoded in genetic material.
genetic drift (aka allelic drift): a difference in genome between species in a hereditary lineage.
genetic epistemology: the study of knowledge acquisition during organism development.
genetic mutation: a change in a DNA sequence.
genetic recombination: the process of transferring broken-off molecules of nucleic acid to a different DNA sequence.
genetically modified organism (GMO): an organism with its genome modified by humans. Genetic modification (GM, aka genetic engineering (GE)) is exemplary of human tendency to use technology on a broad scale before understanding its actual benefits and risks. In the case of GM crops, there have been no benefits to food quantity or quality, but numerous risks to human health while more intensely degrading the environment.
genetics: the study of heredity and variation in life forms at the molecular level. The 4 major subdisciplines of genetics are transmission genetics (heredity), molecular genetics (chemistry), population genetics (traits in populations), and epigenetics (influences of living on inheritance).
genitalia (aka genitals): a sex organ.
genius: extraordinary intellectual acumen.
genome: the (idea of the) entire set of genes within an organism. Like genes, a genome is merely a concept, not phenomenal.
genophore: a package of DNA in a prokaryote’s nucleoid. Compare chromosome.
genotype: the energetic constitution of an organism, as artifactually represented by genome. The gen in genotype refers to genesis (not genetics).
genus (plural: genera): a category of organisms, more generic than species.
geodetic effect: the curvature of spacetime caused by an orbiting body, such as a planet around a star.
geodynamic: relating to dynamic processes or forces within Earth.
geoglyph: a large (>4 meters) design or motif formed on the ground using durable landscape elements, typically clastic rocks.
geographic harmonic (aka geoharmonic): the energetic resonance of a biome (affecting biota).
geoid: the geometric figure formed by an imaginary surface that coincides with mean sea level and its extension through continents.
geology: the science of the solid matter that comprises Earth, especially in the crust.
geometry: the branch of mathematics concerned with the properties of elements that remain invariant under certain transformations.
geophagy: eating soil or rock.
geophyte: a plant that employs an underground energy storage organ.
Georgism: an economic philosophy holding that the natural resources should be belong equally to everyone in a community, but that the value people add belongs to them. Named after its proponent, Henry George.
geosphere: within Earth, including the crust and mantle. Compare pedosphere.
geosmin (C12H22O): an organic compound with the scent of rich earth, produced by Streptomyces soil bacteria. Geosmin gives beets their earthy taste. Geosmin contributes to the scent in the air when rain falls after a dry spell, or when soil is disturbed.
Geranium (aka cranesbills): a genus of 422 species of flowering plants.
germ: see pathogen.
germ layer: a primary layer of cells during embryogenesis.
germ plasm theory: a theory espoused by August Weismann that the only carriers of inheritance are germ cells (eggs and sperm).
German cockroach (Blattella germanica): a small cockroach, tan to almost black colored. The German cockroach can barely fly. Omnivorous scavengers, German cockroaches are ubiquitous throughout much of the human world, where they are considered an especially persistent domestic pest. Though known as the “German” cockroach in English-speaking countries, the Germans call it the “Russian roach.”
German Hansa (aka Hanseatic League): a defensive confederation of merchant guilds and market towns that dominated sea trade in the northern Europe from the 13th–17th centuries.
German idealism (aka post-Kantian idealism): a philosophical movement that emerged in Germany in the 1780s and lasted until the 1840s. The most famous in the movement were Kant, Fichte, and Hegel. The root of this idealism is the recognition that properties in Nature are solely the product of perception, not inherent in the objects themselves.
German Peasants’ War (1524–1525): a widespread revolt in German-speaking areas of central Europe, provoked by popular desire for political influence and greater liberty, as contrasted to the serfdom suffered. The aristocracy ended the revolt with a bloodbath, slaughtering ~100,000 of the 300,000 uppity, poorly armed farmers and peasants.
Germany: a nation in northern central western Europe that has shaped European politics since the fall of the western Roman Empire. Germany has 82.2 million people (2018).
germinate: to begin growth or development.
germline: the line (sequence) of gene cells within the gene set that may be passed to offspring.
germline cell: the line (sequence) of cells that may be passed to offspring. Contrast soma.
gerrymander (US): the dividing of an electoral district so as to give one political party majority power while concentrating the voting strength of other parties in as few districts as possible, so as to give them as little power as possible.
gesellschaft (impersonal association): a society of differentiated tasks and possibly cultures, such as in industrialized nations. Contrast gemeinshaft. Compare organic solidarity, mechanical solidarity.
gestalt: (viewing) the whole being as greater than the sum of the parts involved; organization and organized activity with a coherence greater than can be attributed by summation of employed components. See synergy.
Gestalt psychology (aka gestaltism): a school of psychology with the central principle that the mind naturally creates a worldview through self-organizing tendencies.
Gestalt therapy: a school of psychological treatment emphasizing personal responsibility and in living within the context of the present moment; founded by Fritz Perls, Laura Perls, and Paul Goodman in the 1940s.
GeV (giga-electron volt): a unit of energy equal to a thousand million (109) electron volts (eV).
ghrelin: a peptide produced by cells in the gastrointestinal tract which regulates the sensation of hunger and is instrumental in energy distribution and use. See leptin.
ghost: the confused soul of a dead being that haunts its previous existence.
ghost crab: a crab common on tropical and subtropical beaches, named for its nocturnality and generally pale coloration. Ghost crabs have one claw larger than the other, thick and elongated eyestalks, and a boxy body.
ghost field: a field that affects the mass of a boson via interactions with other bosons and fermions. Ghost fields are necessary to maintain mathematical consistency in quantum physics’ Standard Model. Ghost fields are conventionally construed solely as a mathematical device, and considered nonexistent, despite their being the origin of virtual particles, which are presumed to exist.
giant siphonophore (Praya dubia): a deep-sea siphonophore, with a body length of 40–50 meters; native to the Atlantic Ocean, between the Gulf of Mexico and Europe.
gibberellin: a plant hormone that regulates growth.
Giffen good: a good that violates the law of demand, in that either that people consume more as the price rises, or vice versa; named after Robert Giffen.
gigabyte (GB): 230 (1,073,741,824) bytes (= 1,0243). Storage drive manufacturers cheat, and call a GB a billion bytes (1,000,000,000).
gill: a respiratory organ common to aquatic animals. All fish have gills to dissolve the oxygen in water and excrete CO2. Some aquatic creatures, such as hermit crabs, have gills that allow atmospheric respiration as long as they stay moist.
ginger: a flowering plant in the Zingiber genus, with 244 named species, native to Southeast Asia. The rhizome of Z. officinale (garden ginger) is most commonly used as a spice. Each ginger species has a distinct culinary use. Ginger has also been used in traditional medicines.
ginkgo: a long-lived large tree, sometimes reaching 50 meters. Ginkgo have unique fan-shaped leaves.
giraffe: an African even-toed ungulate ruminant with an exceedingly long neck, making it the tallest living terrestrial animal.
Gitterwelt: a lattice world imagined by Werner Heisenberg in 1930. Gitterwelt exists in specific crystalline structures.
glacial period (aka glaciation): a period of glaciers, typically thousands of years, within an ice age, marked by colder temperatures and glacial advances. By contrast, interglacials are periods of warmer climate within an ice age. The last glacial period ended 15,000 years ago. The present epoch, the Holocene, is the current interglacial.
glaciation: the process of glacier formation.
gland: a group of cells in an animal that synthesizes substances for release inside or on the body.
glass: an amorphous (non-crystalline) solid.
glass transition: a temperature associated with phase transition from glass to liquid. The glass transition temperature is always lower than the melting temperature.
glasswort: an annual halophyte.
GlaxoSmithKline: large British drug maker, formed through multiple mergers of companies to dominate the industry.
glia: the predominant cell type in animal brains. Neurons (nerve cells) support glial cells via their interfaces outside the brain.
gliding bacterium: a bacterium that moves under its own power, without a flagellum. Gliding is typical in cyanobacteria, myxobacteria, and cytophaga-flavobacteria.
gliogenesis: the generation of glia cells.
globin: a family of heme-containing globular proteins involved in binding and/or transporting oxygen.
glomerulus (plural: glomeruli): a small, intertwined mass (as of capillaries, nerve fibers, or organisms).
Glorious Revolution (1688): the overthrow of King James II of England by Dutch stadtholder William of Orange, who was invited by English Parliamentarians to dispose of the king. England’s ruling class was Anglican. Parliament had the dire concern that continued rule of James, a Catholic, could lead to a Roman Catholic dynasty aligned with France. This would, it was feared, eviscerate Parliament’s power. William’s invasion of England led to his ascending of the English throne as William III of England, jointly with his wife, Mary II of England, in accordance with the 1689 Bill of Rights, which was an act of Parliament that set the limits of monarchial rule.
glowworm: the larva of a firefly.
glucagon: a peptide hormone which elevates blood glucose level.
glucocorticoid: a corticosteroid that regulates glucose metabolism. The most important human glucocorticoid is cortisol.
glucose (C6H12O6): a simple sugar used in glycolysis to form ATP.
glucosinolate: an organic compound containing sulfur and nitrogen, derived from glucose and an amino acid. Glucosinolate is toxic to animals at high doses. Some insects, including specialized sawflies and aphids, sequester glucosinolates to render themselves inedible.
gluon: the boson that porters the strong force.
glutamate: a non-essential amino acid that acts as a neurotransmitter.
gluten: a protein found in wheat and related grains, to which a small percentage of people are intolerant of or allergic to.
glycan (aka glycosyl group): ostensibly a synonym for polysaccharide, but commonly used to refer to the carbohydrate bonded to a protein or other glycoconjugate.
glycocalyx: an extracellular glycoprotein produced by some bacteria, epithelia, and other cells.
glycerol: a simple alcohol compound, comprising 3 hydroxyl groups (3 molecules of hydrogen and oxygen).
glycocalyx: extracellular polymeric material comprised of glycoproteins. See extracellular matrix.
glycoconjugate: a carbohydrate covalently bonded to another chemical species, including peptides, proteins, and lipids.
glycogen: a carbohydrate made from glucose, employed for energy storage in fungi and animals. Compare starch.
glycolipid: a lipid with an attached carbohydrate. Glycolipids provide energy and act as markers for cellular recognition.
glycolysis: a metabolic pathway of 10 reactions that results in free energy; often used to form ATP.
glycoprotein: a protein containing a carbohydrate (glycan) attached to a polypeptide side chain.
glycoside: a sugar bound to another functional group (moiety) via covalent bond.
glycosidic bond: a covalent bond joining a carbohydrate to another group.
glycosylation: the process of adding a carbohydrate (glycosyl group) to another functional group (a glycosyl acceptor). Glycosylation typically refers to adding a glycosyl group (glycan) to a protein to form a glycoprotein.
glymphatic system: the waste clearance system in vertebrates’ brains; coined by Maiken Nedergaard.
glyphosate (C3H8NO5P): an herbicide marketed by Monsanto under the trade name Roundup®.
GMO: an artificially genetically modified organism.
gnetophyte: a group of gymnosperms which differs from others by having the water-transport vessel elements found in flowering plants.
Gnetum: a genus of gymnospermous tropical trees, shrubs, and lianas which may have been the first plants to be insect pollinated.
Gnosticism: various ancient religions whose adherents forsook the material world in favor of spiritualism. Christianity is conceptually Gnostic.
go (Chinese: 围棋; Japanese: 囲碁): a strategy board game invented in China 2,500–4,000 years ago.
goat: an even-toed bovid, closely related to sheep.
goby: a fish in one of the most specious families of fish (Gobiidae), with more than 2,000 species in over 200 genera.
God: the myth of an immortal supreme being who is omniscient and typically omnipotent, albeit often inexplicably reserved in exercising such power in moral ways comprehensible to mere mortals. The concept of God is object orientation run amok: one of many delusions construed by believing in what is conceived as contrasted to actuality, and what reasonably may be inferred from known facts.
Gödel’s incompleteness theorems: 2 mathematical logic theorems about the inherent limits of any mathematical system, published by Kurt Gödel in 1931. The 1st theorem states that all truths about the arithmetic of natural numbers cannot be proven. The 2nd theorem, extending from the 1st, shows that a mathematical system cannot demonstrate its own consistency.
In 1921, David Hilbert proposed a solution to a known crisis in mathematics. Early attempts to formalize the foundations of math had been found to have inconsistencies and paradoxes. Hilbert’s proposal was to ground all existing theories to a finite, complete set of axioms, and then prove that these axioms are consistent. Hilbert’s program, as it came to be known, went swimmingly well until Gödel drowned it with his incompleteness theorems.
Godetia: flowering plants, mostly annuals, in the genus Clarkia; native to western North America, except for single species that resides in Chile, commonly called Sangre de toro, Inutil, and Huasita (Clarkia tenella).
Golan Heights: an 1,800 km2 geographic region between Israel and Syria.
gold (Au): the element with the atomic number 79; a dense, malleable, and ductile metal that is a bright reddish-yellow (golden) in hue. Gold is one of the least reactive elements.
Gold Standard Act of 1900: a US federal law establishing the gold standard: gold as the sole metal for redeeming paper money.
Goldbach’s conjecture: the as-yet unproven assertion that every even number greater than 2 can be expressed as the sum of 2 primes.
golden algae (aka chrysophytes): a group of algae found mostly in fresh water. Though a green algae, the name derives from the golden sheen given by accessory pigments. The designation is sometimes applied to the species Prymnesium parvum.
golden angle (geometry): 137.508°; derived by applying the golden ratio (j) to the circumference of a circle; golden angle (ƒ) = 1 / j2.
golden hamster (aka Syrian hamster, Mesocricetus auratus): a hamster endemic to arid areas of northern Syria and southern Turkey.
golden ratio (j; aka golden mean, golden section): the ratio (a+b)/a = a/b, where the ratio of the sum of 2 integers (a+b) to the larger integer (a) is equal to the ratio of the larger integer (a) to the smaller integer (b). The golden ratio has fascinated the mathematically-inclined since the time of the ancient Greeks. In the book Elements (~300 BCE), Euclid gave the first-recorded definition of the golden ratio.
goldenrod: an angiosperm in the Solidago genus, with 100–200 species; most are herbaceous and found in North America.
Goldilocks (aka The Story of the Three Bears): a fairy tale in which an intrusive little girl pilfers porridge from homebody bears.
Goldman Sachs (1869–): American multinational investment bank.
Goldstone mode: spontaneous breakdown of continuous symmetry. Named after Jeffrey Goldstone.
Golgi body (aka Golgi complex, Golgi): an organelle comprising a stack of membranes that works in concert with the endoplasmic reticulum to package proteins inside a cell before shipping the proteins off to their intended destination. Discovered by Camillo Golgi in 1898 while investigating the human nervous system.
gomphothere: a family of elephant-like animals that lived 12–0.7 mya, before being hunted to extinction by humans.
gonad: a reproductive gland that produces the gametes (sex cells) and sex hormones of an organism. The male gonad (testicle) produces sperm. The female gonad (ovary) produces eggs. Both gametes are haploid germ cells.
Gondwana (510–200 mya): a supercontinent prior to Pangea (300 mya); later becoming the southernmost of 2 supercontinents (Laurasia to the north) 200 mya. Gondwana was the progenitor of the landmasses in today’s southern hemisphere: Antarctica; Australia; the Arabian Peninsula and Indian subcontinent, both now part of the northern hemisphere; Madagascar, Africa; and South America.
gonopod: a specialized appendage that various arthropods use in reproduction or egg-laying. In males, gonopods facilitate sperm transfer.
good (economics): an item of commerce. The term insinuates the goodness of materialism.
Google: an American technology corporation that feeds on Internet traffic with its advertising service.
goose (plural: geese): a large waterfowl. Some other birds have “goose” as part of their names. Distantly related birds include the generally larger swans and smaller ducks.
gorilla: a large, ground-dwelling ape that lives in the African forest, in the genus Gorilla, with 2 species: one in the mountains, the other in lowlands.
gossamer-winged butterfly: a small (typically <5 cm), brightly colored butterfly in the Lycaenidae family, with over 6,000 species worldwide.
gossip: talk about the personal affairs of others.
gourd (aka cucurbit): a flowering vine in the Cucurbitaceae family, with ~965 species in ~95 genera. Squash, pumpkin, cucumber, and watermelon are exemplary gourds.
government: a group which has the power to make and enforce laws for an area or country. See state.
GPa (gigapascal): pascal (Pa) is a standard unit of pressure. Geophysicists use gigapascal (GPa) for tectonic stresses with the Earth. Herein, GPa is used for intense pressures related to superconductivity.
GPS (global positioning system): a satellite-based navigation system.
gracile: a slender bodily build.
grade (biological classification): a taxon designating a level of morphological or physiological complexity. Compare clade.
grade (biology): similarity between 2 organisms.
grain (food): small, hard, dry seed harvested for animal consumption.
grain of salt: an English idiom meaning skeptical reception, or to not take literally.
Gram staining: a technique using dyes to classify bacteria.
Hans Christian Gram and Carl Friedländer worked together in Berlin’s city morgue. In 1882, they devised a technique of staining lung tissue to look for bacteria. Gram’s 1884 published report noted that the typhus bacillus did not retain the stain, rendering it Gram-negative.
Whether a bacterium holds a purple dye determines whether it is Gram-positive or Gram-negative. Stain retention is based upon a bacterium’s cell wall.
Murein (aka peptidoglycan) is a polymer of amino acids and sugars, in a mesh as part a bacterium’s cell wall, giving the wall rigidity and structural strength.
Gram-positive bacteria have a thick (20–80 nm) cell wall, mostly made of murein (50–90%). Gram-negative bacteria have a much thinner (7–8 nm) cell wall; only 10% peptidoglycan.
Instead of much murein, Gram-negative bacteria have an extra layer of lipopolysaccharide. This lipid layer does not contribute strength but does act as a selective barrier that keeps unwanted large molecules away from the plasma membrane. Both wall types have their advantages.
In contrast to bacterial cell wall constructions, archaeal cell walls lack a peptidoglycan component. Thus, they are immune to antibiotics that interfere with bacterial cell wall synthesis. Drugs that inhibit ribosomes and protein synthesis in bacteria have no effect on archaeans.
Crystal violet is the blue-violet triarylmethane ((C6H5)3CH) dye used in the 1st step of Gram staining, which is a 4-step process. The dye is a topical antiseptic, with antibacterial, antifungal, and anthelmintic (anti-parasitic) properties.
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The Gram staining process:
1) Apply crystal violet (the primary stain) to a heat-fixed smear of bacteria on a slide. Heat-fixing affixes the bacteria to the slide, at the cost of killing some.
2) Add a mordant (Gram’s iodine) that binds to the stain and traps it within bacterial cells.
3) Decolorize with a quick rinse in alcohol (CH3CH2OH) or acetone (((CH3)2CO).
4) Counterstain with safranin (C20H19ClN4), a red dye.
After decolorization, a Gram-positive bacterium holds its purple, while a Gram-negative does not. Applying safranin gives Gram-negative bacteria a pink or reddish hue.
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Gram staining does not always work. Some bacteria yield a Gram-variable pattern after Gram staining: a mix of pink and purple cells. This may reflect cell division in some of the Gram-positive bacteria, at a time when cell walls are sensitive to breakage.
Some bacteria are Gram-indeterminate, as they don’t respond to Gram staining. This includes various Gram-variable bacteria, as well as acid-fast bacteria, which resist the decolorization step. Mycobacterium, the genus which include tuberculosis, are acid-fast.
Further, the age of the culture may influence the results of a Gram stain.
grammar: the overarching rules for proper use of language, including semantics, syntax, punctuation, and spelling.
Grande Coupure (33.9 mya): the mass extinction event that delineates the Eocene and Oligocene epochs in the Paleogene period. Marine and aquatic fauna were hardest hit, with a major turnover in European animal species 33.5 mya. The Grande Coupure occurred during global cooling, not obviously linked with any catastrophic geological event, though likely during extended volcanic activity.
grand jury: a legal body empowered to investigate accusation of criminal conduct and determine whether charges should be brought.
grandmother hypothesis: the surmise by George Williams in 1957 that menopause evolved so that grandmothers could help rear offspring of a succeeding generation.
granellare: a base from which a xenophyophore builds a shell-like stercomare.
granite: a coarse-grained igneous rock, at least 20% quartz by volume.
granivore: a specialized seed eater.
granulocyte: a white blood cell that has granules in its cytoplasm.
grape: the fruiting berry of the woody vine in the Vitus genus.
grapheme: the smallest unit (such as a letter) of a writing system.
graphical user interface (GUI): a computer software user interface relying upon images that may be selected with a pointing device to activate various functionality.
graphite: a crystalline, semimetal form (allotrope) of carbon. Graphite is a native element mineral, and a form of coal.
grass: a large, versatile, ubiquitous monocot that grows on all continents, in the family Poaceae. Grasses have small flowers and sheathing leaves covering hollow stems. They include cereals and bamboo, but not other plants commonly called grasses, such as seagrasses, rushes, and sedges (though rushes and sedges are related to grass).
grass snake (aka ringed snake, water snake, Natrix natrix): a Eurasian nonvenomous snake that lives near water, feeding almost exclusively on amphibians.
grasshopper: a predominantly tropical, ground-dwelling, herbivorous insect with powerful hind legs for leaping; extant for 250 MYA, now with 11,000 known species. { Spokes 3 }
grasshopper: a predominantly tropical, ground-dwelling insect with powerful hind legs for leaping; extant for 250 million years, now with 11,000 known species. Grasshoppers are herbivorous. Only 1 is monophagous. The others have various dietary preferences (polyphagous). Many grasshoppers maintain a rounded diet: eating from different plant species every day. To distinguish from crickets and katydids, grasshoppers are sometimes called short-horned. Species that change color and aggregate in huge populations are called locusts. { Spokes 2 }
graviton: the hypothetical boson of gravity.
gravitropism: plant movement in response to gravity.
gravity: an entropic spacetime distortion caused by mass. Generally considered one of the 4 fundamental forces, though that is something of a misconception, as the other 3 interactions – strong, weak, and electromagnetism – are significant to subatomic particles, whereas gravity is not.
gray matter: (the appearance of) neuronal clusters in the brain, as contrasted to glia cell concentrations (white matter).
Great American Interchange: the period of intercontinental species migration between North and South America 3 mya. See Nearctic and Neotropic.
Great Depression (1929–1939): the longest and most severe economic downturn experienced in the industrialized world prior to the 21st century. The financial shock that sparked the depression originated in the United States. Its contagion quickly spread to Europe.
great desert skink (aka Kintore’s egernia, Liopholis kintorei): a medium-sized skink native to western Australia. Adults may grow to ~19 cm. The great desert skink is unusual in building elaborate underground mansions for its family, and that males are mostly monogamous.
Great Dying (252 mya): Earth’s most severe mass extinction event, at the Permian–Triassic (P–T) boundary.
Great Famine (1315–1317): a famine in Europe–extending east to Russia and south to Italy–that killed millions and ended the economic growth period of the 11th–13th centuries. The Great Famine was of only of magnitude and duration. Famines were frequent in medieval Europe. Cool temperatures and incessant rain in the spring of 1315 resulted in widespread crop failures, leading to famine. Historically high population levels and the ineffectiveness of medieval governments contributed to the crisis. Continuing cold, wet weather prolonged the famine. Starvation abated in the summer of 1317 as the weather returned to its pre-famine pattern.
Great Lakes: large freshwater lakes in northeastern North America, covering 244,106 km2.
Great Oxidation Event (aka Great Oxygenation Event, GOE) (beginning 2.45 BYA): biologically induced augmentation of dioxygen (O2) into Earth’s atmosphere. Cyanobacteria begat the ‘event’ via photosynthesis on a massive scale. The first oxygen-generating organisms arose long before, 3.4 BYA. The onset of Earth’s oxidation was neither an “event” nor “great.” The initial oxidation was only a few parts per million of O2. Atmospheric oxygen did not begin a serious upswing until 850 MYA.
Great Pacific garbage patch (aka Pacific trash vortex): a massive gyral concentration of plastic marine debris in the north central Pacific Ocean, located roughly from 135°W to 155°W and 35°N to 42°N.
Great Recession (2009): a sharp, severe worldwide economic downturn caused by financial speculation, especially in real estate. While official statistics define the recession as global for only a single year, the recession in many countries begin in 2008 and lasted into 2011 or later.
great reed warbler (Acrocephalus arundinaceus): a Eurasian passerine that is the largest of the European warblers.
Great Rift Valley: a geographic trench in East Africa, best known for fossils found of early hominids. The Great Rift Valley runs from Afar Triple Junction: 3 plates – the Nubian, Somalian, and Arabian – that intersect where the Gulf of Aden and the Red Sea meet, to central Mozambique.
great tit (Parus major): a small, common passerine resident in woodlands throughout North Africa, the Middle East, Eugreater hooked squid (Onykia ingens): a deep-water subAntarctic squid. Females are twice as long as males.
greater hooked squid (Onykia ingens): a deep-water subAntarctic squid. Females are twice as long as males.
grebe: a freshwater diving bird of 6 genera and 22 species in the Podicipediformes order. Grebes live in temperate biomes around the world.
greed: insensible desire.
Greek Dark Ages (aka Homeric Age) (12th to 9th century BCE): the period of Greek history from the end of the Mycenaean palatial civilization to beginning of the Greek poleis (city-states). Compare Dark Ages.
green anole (aka Carolina anole, American anole, red-throated anole, Anolis carolinensis): a small- to medium-sized arboreal lizard with a slender body. Males are 15% larger than females. Though related to iguanas, the green anole can change colors in a chameleon-like manner.
green darner (aka common green darner, Anax junius): a large, abundant migrating dragonfly, named for its resemblance to a darning needle. The green darner is native to North America, the Caribbean, Tahiti, and East Asia.
green iguana (aka American iguana, Iguana iguana): a large, arboreal iguana native to the Caribbean, and Central and South America.
Green Party of the United States (GPUS) (2001–): American left-wing party favoring social equity, democracy, and environmentalism.
green scale (aka coffee scale, Coccus viridis): a soft scale insect endemic to Brazil, but now found worldwide. The green scale is considered a major pest by coffee growers.
green tree frog: a common name for several distinct green tree frogs.
greeneye: a deep-sea marine fish in tropical and temperate waters, with 18 species in 2 genera.
greenhouse: an enclosed area, usually with much glass to let abundant sunlight in, in which a desired temperature range is maintained. Greenhouses are used to cultivate tender plants or grow them out of season.
greenhouse (climate): see hothouse.
greenhouse effect: the process by which radiation from the atmosphere warms a planet’s surface.
greenhouse gas: an atmospheric gas that has a warming effect on a planet’s surface from shedding heat energy absorbed via infrared radiation. The primary greenhouse gases in Earth’s atmosphere are carbon dioxide, methane, nitrous oxide, and ozone. Water vapor acts as a greenhouse gas.
Greenland shark (aka gurry shark, gray shark, Somniosus microcephalus): a large shark endemic to the frigid waters of the North Atlantic and Arctic oceans. Greenland sharks are also adapted to being comfortable at great depths.
gregarious: highly social.
greigite (Fe3S4): an iron sulfide mineral, found in clays and hydrothermal veins. One commonly found impurity in greigite is nitrogen. ( FeNi)S clusters are somewhat common in enzymes, while the cubic Fe4S4 unit of greigite is employed by proteins for metabolism.
Grenada: an island country in the southeastern Caribbean Sea, northeast of Venezuela. Grenada is a leading exporter of the spices nutmeg and mace.
grooming: the practice of keeping the body clean by removing foreign objects from the fur. Grooming plays a major role in primate social relations.
grosbeak: a seed-eating passerine with a pronounced beak.
gross domestic product: see GDP.
Grotthuss mechanism: the process of a proton moving through the hydrogen bond network of water molecules or other hydrogen-bonded liquids via the formation and concomitant cleavage of covalent bonds of neighboring molecules. Proposed by Theodor Grotthuss in 1806; an astonishing theory at the time, as the water molecule was thought to be HO, not H2O, and ions were not understood.
ground meristem: the primary meristem that produces various ground tissues, used for structural support, leaf energy production, and would repair.
ground state: the lowest energy state of a quantum-mechanical system.
ground tissue: plant tissue that manufactures and stores nutrients.
groundwater: water within the crust, the upper surface of which forms the water table.
group (sociology): an association of people with some degree of affinity bonding.
group selection: the unsubstantiated hypothesis that evolution acts at the level of the group, not individuals; developed by Charles Darwin. See kin selection.
“If one man in a tribe invented a new snare or weapon, the tribe would increase in number, spread, and supplant other tribes. In a tribe thus rendered more numerous there would always be a rather better chance of the birth of other superior and inventive members.” ~ Charles Darwin
groupthink: the praxis of approaching and dealing with issues via consensus, characterized by a strong streak of conformity, and lack of individual initiative and creativity.
grouse: a heavily built herbivorous bird that inhabits temperate and subarctic biomes in the northern hemisphere.
guanine (G) (C5H5N5O): a nucleobase of DNA and RNA. Guanine is complementary to cytosine. Guanine has a variety of biological employment, notably for reflective optical effects in the skin of fish for camouflage, and in the eyes of deep-sea fish, and some reptiles, such as crocodiles.
Guardian, The (1821–): a British national newspaper, known until 1959 as the Manchester Guardian.
guenon: an arboreal forest-dwelling monkey in the Cercopithecus genus, endemic to sub-Saharan Africa; characterized by bold markings of white and/or bright color. Guenons live in nuclear families of 1 adult male and 2 or 3 adult females, along with youngsters.
guild (botany): a group of plants interlinked through a common mycorrhizal network.
guile (noun): deceitful cunning; stratagem; trick.
guilt: an emotion of self-reproach. Compare shame.
Guinea baboon(aka western baboon, red baboon, Papio papio): the smallest species of baboon, endemic to a small range in westernmost Africa, inhabiting dry forests, gallery forests, steppes, and savannas. The Guinea baboon is diurnal and terrestrial, though it sleeps in trees at night for safety. The number of suitable trees for sleeping limits its group size and range. Troops are up to 200 members. Guinea baboons are highly communicative. Socially a troop comprises a complex multilevel society. Unlike other baboons, adult male Guineas are tolerant and cooperative, forming social bonds with other males regardless of kin relation.
Guinness Book of World Records, The: a reference book of world records; both human achievements and extremes in the natural world. The book itself holds its own world record as the best-selling copyrighted book series of all time. The book is one of those most frequently stolen books from American public libraries.
Gulf Stream: a swift, powerful, and warm Atlantic Ocean current that runs from the Gulf of Mexico up the Atlantic seaboard to Newfoundland before crossing to the west coast of Europe; named by Benjamin Franklin.
gull (aka seagull): a medium-to-large assertive seabird that is an opportunistic eater.
gullible: easily deceived, duped, or cheated.
guņa: a quality (thread) of being according to Hindu philosophy. The 3 guņas are sattva (goodness, harmony, construction), rajas (passion, activity), and tamas (chaos, discord, destruction).
Gunter’s quadrant: an instrument for solving many common problems associated with spheres, such as taking the altitude of an object in degrees and figuring the hour of the day.
Gunter’s rule: a large engraved plane scale that helped answer navigational and trigonometry questions, aided by a pair of compasses.
guppy (aka million fish, rainbow fish, Poecilia reticulate): a freshwater tropical fish native to northeast South America.
Gupta Empire (India): the 2nd successful attempt to create an empire in India, after the Mauryan Empire (322–185 BCE).
guru: a realized teacher.
gustation: the act or faculty of taste.
gymnosperm: a group of seed-producing plants, including conifers, cycads, ginkgo, and gnetophytes.
gut (aka alimentary canal, alimentary tract): the tube by which food is transferred to digestion organs in most animals, including humans. Commonly used to refer to the digestive tract. An example of convergent evolution, the gut independently evolved twice.
gut flora (aka gut microbiota): the microbial colonies in the digestive tract that break down food for absorption by the host body.
gymnema (aka cowplant, gurmari, Gymnema sylvestre): an herb native to the tropical forests of southern and central India and Sri Lanka that suppresses the taste of sweet.
gymnosperm: a seed-producing plant that arose in the early Carboniferous, 340 mya. Gymnosperm include conifers (e.g., pine, fir), cycads, ginkgo, and gnetophytes. { Spokes 3 }
gyne: the primary reproductive caste in social insects (ants, bees, wasps, termites). Whereas the typical female worker is sterile, gynes are destined to become queens. A colony with a single queen is monogyne (e.g., honeybees), whereas a colony with multiple queens (e.g., ants) is polygyne.
gynoecium: the female part of a flower that produces ovules which develop into fruit and seeds.
gynogenesis: asexual reproduction related to parthenogenesis, but with the requirement that an egg be stimulated by presence of sperm – without incorporating the sperm’s genetic material – in order to develop.
gynosome: the penis of a female booklice.
gypsy moth: a moth found in Europe, Africa and North America. Gypsy moth larvae eat the leaves of over 300 different trees.
gypsum (sulfate dihydrate (CaSO4·2H2)): a soft sulfate mineral used as fertilizer, and the main constituent in plaster, blackboard chalk, and wallboard. Alabaster, a fine-grained light variety of gypsum, was used for sculpture by many ancient cultures, and in medieval England.
gyre: a conceptual framework treating a physical system as a dynamic vortex. A gyre is characterized by its structure, qualities, thermodynamics, and interactions. See tensor.
gyroid: an infinitely connected triply periodic minimal surface, discovered by Alan Schoen in 1970. A gyroid separates space into 2 oppositely congruent labyrinths of passages.