T
T cell: a lymphocyte of the adaptive immune system that kills or assists killing pathogens. Compare B cell.
taboo: a behavior contrary to mores.
tachyon: a hypothetical particle with imaginary mass that always travels faster than light.
tactile corpuscle (aka Meissner’s corpuscle): a nerve cell that acts as a touch mechanoreceptor.
taiga (aka boreal forest): a biome characterized by coniferous forest. Taiga is the Earth’s largest land biome, comprising 29% of the world’s forest cover.
tailings: residue separated during preparation of a product, typically mined ores or grown grains.
taily weed (Ochradenus baccatus): a perennial plant that grows to a meter, with a woody base and many fleshy smooth branches; native to north Africa and the Middle East. Taily weed produces small berries year-round.
Takata (1933–): Japanese automotive parts manufacturer.
talapoin: an arboreal monkey found in swamp forests of central Africa; the smallest Old World monkey. Talapoins live in troops of 50–100.
talent: a special aptitude.
Taliban: an Islamic fundamentalist political movement in Afghanistan, noted for its strict interpretation of Islamic law and brutalization of women.
talionic: the retaliation principle of “an eye for an eye”; from the Latin lex talionis (law of the talion). The English term talion refers to retaliation authorized by law, where the punishment corresponds in kind and degree to the injury.
talisman: an object with symbolic engravings intended to act as a charm for good fortune or to avert evil.
Talmud: an ancient compendium of Jewish ethics and law, philosophy, history, customs, and lore, with the 1st portion compiled 200 ce.
“The Talmud is a conglomerate of law, legend, and philosophy, a blend of unique logic and shrewd pragmatism, of history and science, anecdotes, and humor. It is a collection of paradoxes: its framework is orderly and logical, every word and term subjected to meticulous editing, completed centuries after the actual work of composition came to an end; yet it is still based on free association, on a harnessing together of diverse ideas reminiscent of the modern stream-of-consciousness novel.” ~ Talmudic scholar Adin Steinsaltz
tamarin: a squirrel-sized arboreal South American monkey.
Tamarixia radiata: a parasitic wasp that lays its eggs on jumping plant lice.
tandem running: a teaching method in some ant species, using recruitment to lead nestmates to food, or to facilitate quorum-sensing. During a tandem run, the follower maintains contact with the leader by frequent feedback touches of the antennae between the 2.
Tang Dynasty (618–907): an imperial dynasty in China, generally regarded as a high point in Chinese civilization, in being a golden age of cosmopolitan culture, notably literature, poetry, and painting. The 1st half of Tang rule was a time of stability. After an attempted usurpation (the An Lushan Rebellion), Tang central authority declined. Woodblock printing developed, and Buddhism had its initial influence on Chinese culture during the Tang Dynasty.
tangle web spider (Anelosimus octavius): a South American orb-weaving spider that spins a platform web when under the influence of the parasitoid wasp Polysphincta gutfreundi.
Tanimbar corella (aka Goffin’s cockatoo, Goffin’s corella, Cacatua goffini): a small white cockatoo endemic to the islands of the Tanimbar archipelago in Indonesia.
tank plant: a rainforest species of bromeliad that clings to trees.
tannin: an astringent, bitter plant polyphenolic compound.
tantalum (Ta): the element with atomic number 73; a hard, blue-gray, lustrous transition metal that is extremely corrosion-resistant.
tanycyte: a specialized ependymocyte that provides communication between cerebrospinal fluid and the central nervous system.
Tao (Chinese philosophy and religion): the order of Nature; may also be considered a synonym for Ĉonsciousness. See logos.
Taoism: a Chinese religious tradition emphasizing living in harmony with Nature and the ineffable Tao. Taoism dates at least to the 4th century BCE, and to the legendary Lao Tzu.
tapeworm: an obligate endoparasite of the animal gut.
tapioca: starch extracted from the tuber of a cassava plant.
taproot: a large, long, somewhat straight root.
taqlid: an Islamic term for conforming to accepted religious law, and thereby stifling innovation via conservatism; a stricture increasingly enforced from the 16th century on.
tarantula: a group of often large and hairy spiders. Some are arboreal, others ground dwellers.
tardigrade (aka water bear): a hardy, 0.5-mm-long, aquatic animal of over 1,150 species, found in most ecosystems.
tariff: a governmental tax on imports or exports.
Tariff Act of 1930 (aka Smoot-Hawley Tariff): a US federal law implementing protectionist trade policies via increased tariffs on imports. The Tariff Act of 1930 was an incremental pile-on to the Tariff Act of 1928, which had jacked tariffs up.
tarsier: a 10–15 cm prosimian with enormous eyes, once widespread through Asia, Europe, North America, and possibly Africa, now found only on Southeast Asian islands. Tarsiers have a distinct brain from other primates, suggesting their early, independent evolution in the lineage of primates.
tarsal (insects): the distal part of the leg, analogous to the foot.
tarsus (plural: tarsi): the end of a leg, near the foot.
taser (aka tasar): an electronic weapon designed to painfully incapacitate someone; developed by Taser International (hence the name).
Tasmanian native hen: a flightless rail native to Tasmania.
taste (aesthetics): individual aesthetic preferences.
taste (sensory): chemical perception of material in the mouth.
taste bud: a taste receptor.
tautology: repetition of an idea.
taxon (plural: taxa): a classification of organisms. Taxa either have a formal or scientific name. Scientifically termed taxa are governed by nomenclature codes: naming rules overseen by scientific organizations.
taxonomy: the classification of organisms according to their presumed natural relationships.
TCP/IP (Transmission Control Protocol / Internet Protocol): the dominant protocols for Internet traffic.
technology: the products of engineering. Technology includes techniques as well as tools.
tectonics: processes related to the movement and deformation of the Earth’s crust.
tectonic plate: a sizeable chunk of the lithosphere, including some of Earth’s crust, capable of movement.
Teddy Boy: a 1950s British subculture of young men wearing clothes inspired by the style of dandies in the Edwardian period. Savile Row tailors re-introduced this style after World War 2. There were also Teddy Girls: working-class women wearing elegant styles which rejected post-war austerity.
tegu lizard: a largish lizard native to Central and South America, occupying a variety of habitats. Tegus resemble their distant cousins, monitor lizards. The similarities represent convergent evolution. The black-and-white tegu lizard (Salvator merianae) grows to ~1.3 meter and weighs ~2 kilograms.
teleology (evolutionary biology): the obvious and well supported theory that adaptation is goal oriented.
teleology (philosophy): the doctrine that final causes (ends or purposes) exist. Socrates, Plato, and Kant argued in favor of teleology.
teleost: a class of ray-finned fish, with 26,840 extant species in 448 families.
tellurium (Te): the element with atomic number 52; a rare (on Earth), brittle, silver-white metalloid which looks like tin.
telomerase (aka terminal transferase): a ribonucleoprotein responsible for telomere maintenance. An enzymatic subunit–telomerase reverse transcriptase–endeavors to refurbish a telomere after cell division.
telomere: a protective region of repetitive nucleotide sequences at each end of a chromosome copy.
telonemia: a phylum of aquatic, microscopic, single-celled eukaryotic protists.
telophase: the stage during cell division where 2 daughter nuclei form. The outcome of telophase, after cytokinesis, is 2 daughter cells. See interphase, prophase, metaphase, anaphase.
Temnospondyli: amphibians that flourished worldwide during the Carboniferous, Permian, and Triassic periods; a few made it into the Cretaceous.
tempeh: a firm paste of soybeans fermented via a rhizopus.
temperament (psychology): consistent individual thought and behavior patterns which are biologically based and relatively independent of learning and socialization.
temperance: a social movement against drinking alcoholic beverages.
temporal lobe: one of the 4 major lobes of the cerebral cortex in the mammalian brains. The temporal lobe handles sensation, processes language, and retains image and emotional memory. See frontal lobe, parietal lobe, occipital lobe.
tennet (aka tensor network): a network of tensors.
tensor: a geometric object describing linear relations between other geometric entities (vectors, scalars, tensors). A tensor is a geometric entity particularly entangled with other tensors. Tensors are a tautology of entanglement.
tensor network (aka tennet): a network of tensors.
tentacled snake (Erpeton tentaculatum): an aquatic snake endemic to Southeast Asian waters; unique in having 2 tentacles protruding from the front of its head.
tergum (plural: terga): the upper or dorsal surface of an arthropod body segment.
Terminator, The (1984): an American science-fiction action film about a cyborg assassin (played by Arnold Schwarzenegger) sent back in time.
termite: a group of colonial eusocial insects, directly descended from cockroaches. Termites are only distantly related to ants. 4,000 termite species are known.
Termitomyces: a genus of fungi in the family Lyophyllaceae that are a food source for their cultivators: the termite subfamily Macrotermitinae.
tern: a slender, lightly built, graceful seabird that prefers an open habitat. Tern sexes look selfsame.
terpene (C5H8): a pungent hydrocarbon compound produced by various plants, notably conifers, and some insects, including termites and swallowtail butterflies. Terpene is antibiotic.
Tertiary (66–2.6 mya): a widely used but formally deprecated geological period which begins with dinosaur extinction and extends to the onset of the Quaternary glaciation.
tessellated darter (Etheostoma olmstedi): a small, freshwater darter native to North America, primarily the United States.
testicle (aka testis): the male reproductive gland in animals.
testosterone (C19H28O2): a steroid hormone found in reptiles, birds, and mammals; the primary male sex hormone. In men, testosterone levels are key in development of male reproductive tissues. Adult male testosterone levels are 7–8 times that of women.
Tethys Sea (aka Tethys Ocean): the ocean between the continents of Gondwana and Laurasia during much of the Mesozoic era (252–66 mya), before the opening of the Indian and Atlantic oceans during the Cretaceous period (145–66 mya). Continental shifts reduced the Tethys Sea, eventuating into the Mediterranean Sea.
tetra: a small freshwater fish in the Characidae family, native to Africa, Central and South America.
tetrachromacy: the ability to see 4 color channels, typically from infrared to ultraviolet. Fish, insects, amphibians, reptiles, and birds are generally tetrachromats. Mammals lost the ability, becoming trichromats (3 colors). Compare monochromacy, dichromacy, trichromacy.
tetrahydrocannabinol (C21H30O2; THC): a psychoactive (to humans) terpene produced by cannabis plants.
tetrahedron: a polyhedron with 4 faces.
tetrahydrocannabinol (THC; C21H30O2): the principal psychoactive compound in cannabis.
tetrapod: a 4-limbed animal.
tetraquark: a hadron with 4 quarks, particularly 2 quarks and 2 antiquarks. Tetraquarks are not accounted for in quantum physics’ standard quark model. Hadrons, such as baryons, are made of 3 quarks.
Tetraselmis convolutae: a species of phytoplankton that is a symbiont of the small marine flatworm Symsagittifera roscoffensis.
tetraterpenoid: a molecule with a skeleton of 40 carbon atoms.
tetraterpene (C40H64): a terpene of 8 isoprene units.
thalassemia: a heritable blood disorder via abnormal hemoglobin.
thale cress (aka mouse-ear cress, Arabidopsis thaliana): a small flowering plant native to Eurasia. Thale cress is commonly considered a weed, despite being in salads or eaten sautéed (that is, a food crop).
thallus (plural: thalli): an undifferentiated vegetative tissue, typical of certain algae, fungi, lichen, and liverworts.
theism: belief in a god, viewed as the creative source of Nature, who transcends and yet is immanent in the world; more generally, belief in a god or gods. Compare deism.
theobromine (C7H8N4O2): a bitter alkaloid produced by the cacao plant, found in chocolate and other foods, including tea leaves and the cola (kola) nut.
theocon (theological conservative): a conservative who advocates a Christian ideology and government.
theocracy (aka ecclesiocracy): a polity in which a deity is the supposed source from which political authority arises.
theology: the study and interpretation of religious faith and ideas.
theorem (mathematics): a proposition proved via axioms and postulates. Compare proof.
theory: fact-based explanation about the relations between concepts. Compare hypothesis. See physical theory.
“The truth of a theory can never be proven, for one never knows if future experience will contradict its conclusions.” ~ Albert Einstein
theory of mind: the cognitive ability to attribute mental states to oneself and others. See mind perception.
Theory of Everything: the holy-grail physics theory that explains all (known) phenomena.
theridiid (aka cobweb, comb-footed, tangle-web): a web-building spider of over 2,200 species in 100 genera.
Therapsida: the group of synapsids from which mammals descended.
Theria: a subclass of mammals which includes marsupials (metatherians) and placental mammals (eutherians).
thermal (atmospheric): a column of rising warm air in the lower altitudes of the atmosphere. Thermals are one of many sources of lift that are used by birds that fly long distances.
thermal expansion: the tendency of matter to alter shape, area, or volume in response to a change in temperature (via heat transfer).
thermalization (physics): the process of a system reaching thermal equilibrium via an equipartition of energy that maximizes the system’s entropy.
thermoacidophile: an organism that prefers a habitat with temperatures of 70–80 °C and a pH of 2–3; a combination of acidophile and thermophile.
thermocline (ocean): a layer of seawater that separates upper, warmer water from colder, deeper water below.
thermodynamic system: a spatial region considered a self-contained system, characterized by certain characteristics, including temperature, pressure, entropy, and internal energy.
thermodynamics: the branch of physics concerned with the dynamics of heat and temperature, and their relation to energy and work.
thermohaline circulation: an aspect of large-scale ocean circulation driving by global seawater density gradients created by surface heat and freshwater thermal fluxes. Thermo- refers to temperature while -haline refers to saltiness. Thermohaline circulation is synonymous with ocean conveyor belt.
thermonastic tropism: plant movement in response to temperature.
thermophile: an organism that can survive a 60 °C or even hotter habitat.
Thermoplasma acidophilum: a species of highly flagellated thermoacidophilic archaea happiest at 56 °C and pH 1.8. Astonishingly, T. acidophilum lacks a cell wall. Its cell membrane is exposed to the outside environment.
thermosphere: the layer of Earth’s atmosphere below the exosphere and above the mesosphere. The thermosphere begins 80 km above the Earth’s surface.
Therocephalia (265–245 mya): a large-skulled carnivorous synapsid that evolved during the Late Permian and lived through the Triassic.
Theropoda: a lineage of bipedal saurischian dinosaurs that eventuated in birds. Compare Sauropoda.
thigmotropism: plant movement in response to touch.
Thiobacillus: a subfamily of thermophilic bacteria that consume sulfur.
thiol: an organosulfur compound that is the sulfur analogue of alcohols (replacing oxygen with sulfur in the hydroxyl group of an alcohol).
third law of thermodynamics: see 3rd law of thermodynamics.
Third World: a nebulous term that arose during the Cold War for economically undeveloped countries not aligned with NATO or the Communist Bloc. Since the fall of the Soviet Union, the term is used for the least-developed countries.
third-force psychology: see humanistic psychology.
Thomism: the philosophic school that arose as a legacy of Thomas Aquinas.
thorax: the midsection of an insect body, holding the legs, wings, and abdomen; termed the mesosoma in other arthropods. A thorax has 3 segments: prothorax, mesothorax, and metathorax.
thread-legged bug (Stenolemus bituberus): an Australian assassin bug that preys on web-building spiders.
Three Mile Island (TMI) mishap (28 March 1979): a partial nuclear meltdown in reactor 2 of the Three Mile Island nuclear power plant in Pennsylvania. TMI was the worst US commercial nuclear power accident, replete with a massive radioactivity leak. Mechanical failures compounded by operator incompetence caused the accident.
threespine stickleback (Gasterosteus aculeatus): a fish native to inland coastal waters north of 30° N which shows great morphological variation throughout its range and is quite tolerant of salinity changes.
thrip (aka thunderfly, thunderbug, thunderblight, storm fly, storm bug, corn fly, corn louse): a tiny, slender insect with fringed wings that feed on a large variety of plants and animals by puncturing its victim and sucking tissue fluids.
thrombin: a proteolytic enzyme that facilitates the clotting of blood.
thrush: a ground-dwelling passerine with a worldwide distribution.
thujone (C10H16O): a ketone and a monoterpene (C10H16) that has a menthol odor. Thujone is psychoactive. An ingested excess can cause seizures and other adverse effects via disrupting the central nervous system. Several shrubs and trees make thujone as an herbivore defense.
thylakoid: a membrane-bound compartment inside cyanobacteria and chloroplasts.
thymine (T) (C5H6N2O2): a DNA nucleobase. Thymine is complementary to adenine. In RNA, thymine is replaced by uracil.
thymocyte: a maturing T cell in the thymus.
thymus: an immune system organ that matures T cells.
Thyreophora: a group of beaked, armored, herbivorous ornithischians that arose in the early Jurassic and lived until the end of the Cretaceous.
thyroid: a vertebrate endocrine gland in the neck that controls how quickly the body uses energy, produces proteins, and controls sensitivity to other hormones.
thyroxine: a thyroid hormone which stimulates oxygen consumption, and so affect the metabolism of all cells and tissues.
Tibetan singing bowl: a singing bowl made in Tibet.
tidal friction: an effect of tidal forces between an orbiting natural satellite (e.g., the Moon), and the primary planet that it orbits (e.g., Earth).
tidal heating (aka tidal working): orbital and rotational energy dissipated as heat in planetary bodies through the tidal friction process.
tidal locking (aka gravitational locking, captured rotation): a gravitational process whereby one astronomical body always faces another, such as the Moon always facing Earth. Tidal lock is the eventual outcome of tidal friction.
tiger beetle: a beetle of over 2,600 species, known for its aggressive predation and running speed: the equivalent of a person going 770 km/h.
Tikopia: a 5 km2 island in the Solomon Islands whose native people have lived sustainably for 3,000 years.
tilapia: a freshwater fish in the Tilapiini cichlid tribe.
tiller (botany): a shoot produced by grass plants after the initial parent shoot grows from a seed.
time: the idea that there is a temporal vector comprising past, present, and future.
time dilation: that concept that time itself is relative to the motion of an observer.
time horizon: temporal orientation, whether looking to the future or the past (long-term and short-term time horizons respectively).
Time Warner: American media company resulting from the merger of Time (1922–), originally a magazine publisher, and Warner Brothers (1923–), originally a movie maker, along with other media companies.
tin (Sn (from Latin: stannum)): the element with atomic number 50; a silvery metal; first used as an additive combined with copper to produce bronze.
tinamou (plural: tinamous): a diurnal bird native to Middle and South America, with 47 species. Although some species are common, tinamous are shy, secretive birds. Though tinamou are ground-dwelling, and favor running away from danger, they are not flightless.
tipping point: the critical threshold of a self-organized criticality.
TirA (toll/interleukin-1 receptor A): a protein used by social amoeba to identify bacteria. A similar protein is used by animals for the same purpose.
tissue: an aggregate of cells in a eukaryotic organism that perform a specific function.
tit: a small passerine endemic to the northern hemisphere and Africa; in the Paridae family, which includes chickadees and titmice.
titan triggerfish (Balistoides viridescens): a large triggerfish found at reefs and in lagoons through the Indo-Pacific, though not near Hawaii. Titan triggerfish are busy workers, turning over rocks and stirring sand to scrounge shellfish, urchins, and crustaceans; much to the delight of smaller fish, who feed on the leftovers. Titan triggerfish also munch coral.
Titanic (RMS Titanic): an English passenger liner that sank in the North Atlantic Ocean 15 April 1912 after ramming an iceberg during her maiden voyage from Southampton to New York City.
titanium (Ti): the element with the autonomic number 22; a silvery, lustrous metal.
titi: a monogamous, territorial South American monkey.
TMAO: see trimethylamine N-oxide.
toad: a frog with a dry, bumpy, leathery skin. The bumps visually break up a toad’s visible outline, hence helping it to blend into its environment. A toad differs from a frog only by look and its preference for a more terrestrial habitat.
toadfish: a family of mostly marine, large-mouthed, ray-finned fish, so-called for their toad-like appearance. Toadfish are benthic ambush predators that like to lurk on sandy or muddy substrates, where their cryptic coloration camouflages them. Male toadfish can sing, using their swim bladder to produce sound. They croon to attract mates.
toadstool: an inedible mushroom; from late 14th-century Middle English. Toads were then regarded as highly poisonous.
Toarcian (182.7–174.1 mya): an age in the Early Jurassic.
tobacco: an herbaceous plant or shrub in the Nicotiana genus in the nightshade family, indigenous to the Americas, southwest Africa, the South Pacific, and Australia.
tobacco hornworm (aka goliath worm, Manduca sexta): the larva of the Carolina sphinx moth. This caterpillar feeds on tobacco, tomatoes, and other plants in the nightshade family.
tofu (aka bean curd): firm soy paste.
tolerance adaptation: adaptation toward becoming generalist, capable of surviving in a wider variety of biomes.
tolerance induction: the process of lymphocytes learning to distinguish foreign matter from cellular substances belonging to the self.
tomato (Solanum lycopersicum): a plant and an edible berry in the nightshade family.
tone (music): a sound with a certain dominant pitch and resonance.
tone deafness (aka amusia): the inability to distinguish pitch.
Tonga plate: a small, southwest Pacific Ocean tectonic plate, bounded on the north and east by the large Pacific plate, and on the northwest by the Niuf’ou microplate. The Tonga plate is subducting the Pacific plate along the Tonga Trench, north of New Zealand. The Tonga Trench is a convergent plate boundary.
tongue: the primary taste organ in humans.
Tonian (1,000–720 mya): the 1st period of the Neoproterozoic era. The supercontinent Rodinia broke up during the Tonian. The first fossils (acritarchs) date from the Tonian.
tonne: a metric ton (1.102 US (short) tons).
toolkit gene: a gene which is ancient and highly conserved.
toothcarp: an 0.8–34 cm, freshwater, ray-finned fish. Toothcarps are not closely related to true carps. Many popular aquarium fish, such as killifish and guppies, are toothcarps.
toothed whale: a cetacean with teeth, rather than the filter-feeding baleen of whales; a suborder of cetaceans, including dolphins, beaked whales, and sperm whales.
topi (Damaliscus korrigum): a gregarious and fast antelope that lives on the grasslands of equatorial Africa. Topis have the most diverse social arrangements among antelopes, ranging from polygyny to leks.
topographic memory: a memory involving spatial orientation. Contrast episodic memory, semantic memory.
topology: the mathematical study of space. Topology is not constrained to 3d except that the human mind is ill-equipped to envision 4d (or higher) spatial dimensions.
torpor: a state of sluggishness, with mental and motor inactivity.
torque: the tendency of a force to rotate an object about an axis.
torsional angle: the angle between 2 planes.
Toryism: a British conservative ideology, advocating traditional values (traditionalism), including natural law.
totalitarian: dictatorial; autocratic; relating to a centralized government that does not tolerate dissent and exercises control over many aspects of life.
touch-me-not (Mimosa pudica): a plant with compound leaves that rapidly respond to touch.
Tourette’s syndrome: a disorder characterized by motor and vocal tics (convulsions). The disorder was named after its chronicler: George de la Tourette.
toxin-antitoxin system: a prokaryotic defense system using a set of 2 or more linked genes which together encode for both a toxin protein and a corresponding antitoxin.
Toxoplasma gondii: an obligate, intercellular, protozoan parasite of endotherms, causing them toxoplasmosis.
toxoplasmosis: a disease causing both physical and mental disabilities, including encephalitis (inflammation of the brain), heart, liver, hearing, vision, and neurological disorders. Toxoplasmosis can also invoke attention deficiency, obsessiveness, schizophrenia, and suicide.
Toyota (1937–): Japanese automaker.
trachea (aka windpipe): a channel in an animal respiratory system; a cartilaginous tube that connects the pharynx and larynx to the lungs.
tracheophyte: a vascular plant.
trade winds: the prevailing pattern of easterly surface winds found in the tropics. Historically, the trade winds were used by captains of sailing ships to traverse the oceans. These winds facilitating seafaring trade routes gave them their name.
tragedy of the commons: an economic theory about the inevitability of a shared, nonrenewable resource, where individual users, acting in their own self-interest, behave contrary to the common weal by depleting that resource. The term was coined by American Garrett Hardin in 1968, who warned of the dangers of overpopulation.
trained incapacity: a behavioral phenomenon in workers, characterized by the inability to appropriately respond to novel circumstances, or the inability to recognize when rules and procedures are outmoded or inapplicable; coined by American sociologist Thorstein Veblen in 1914. Compare random competence.
trait (biology): an organitypic feature of form and/or function; from an evolutionary perspective, a distinct variant of phenotype, mentotype, or envirotype.
trans fat: an unsaturated fat structure, where hydrogen atoms are bound on opposite sides of a carbon double bond. Contrast cis fat.
transceiver: a transmitter and receiver.
transcendence (consciousness): the state of consciousness where the mind is quiet while the body is resting but receptive to stimuli.
transcendence (religion): the belief that there is a God wholly independent of Nature, beyond the forces of physics. Contrast immanence. Compare supremism.
transcendental: being beyond the conceptual realm considered. Contrast immanent.
Transcendental Meditation® (TM): a meditation technique popularized by Maharishi Mahesh Yogi. TM employs a mantra as a mental vehicle to facilitate transcendence.
transcendental number: a non-algebraic real or complex number with decimal fractions which appear endless but are not a repeating sequence. The best-known transcendental numbers are and e. Most real and complex numbers are transcendental.
transcendental schema: a procedural rule that associates a concept with a sensory impression; proposed by Immanuel Kant in 1871.
transcription (genetics): the process of producing an RNA copy from a DNA sequence. Transcription is an early, major stage of DNA expression.
transcription factor: a protein that controls the flow of genetic information during transcription.
transcription unit: an RNA copy of a DNA sequence which encodes at least 1 gene. If a transcribed gene encodes a protein, the transcription unit is messenger RNA. Otherwise, the transcription unit may encode various other products: a noncoding RNA gene (such as microRNA), ribosomal RNA, a component used in protein assembly, or a ribozyme.
transdifferentiation (aka lineage reprogramming): a metaplasia in which a somatic cell transforms into another mature soma without undergoing an intermediate pluripotent state or becoming a progenitor cell type.
transduction (microbiology): the process of transferring DNA from one bacterium to another via a virus.
transduction (physiology) (sensory transduction): conversion of a sensory stimulus from one communicable form to another.
transfer RNA (tRNA): an adapter for bridging the 4-letter genetic code in messenger RNA with the 20-letter code of amino acids; used for protein synthesis.
transform boundary: a rubbing of tectonic plates at a shared boundary. A transform boundary is a specific type of strike-slip fault. Contrast convergent, divergent.
transformation (bacteria): the process of a bacterium picking up and incorporating genetic material from the environment.
transformer (electricity): a device for transferring electrical energy among circuits via electromagnetic induction.
transgression (biosphere): sea-level rise. Contrast regression.
transistor: a semiconductor device used to switch or amplify electronic signals and electrical power.
transitive inference: a form of deductive reasoning that allows one to derive a comparative relation between objects based only upon indirect evidence, such as understanding a relation between 2 people based solely upon each of the 2 persons’ interactions with a 3rd person.
translation (genetics): a later stage of gene expression as part of protein biosynthesis, after transcription. Translation transpires in a ribosome.
translocation (botany): the sugary sap distribution process in phloem.
translocation (genetics): untoward relocation of DNA sequences.
transmember protein: a protein which can travel through a cell membrane.
transmutation (chemistry): change of one element into another.
transpiration: normal, controlled release of water by plants.
Transportation Security Administration (2001–): US agency responsible for the security of the traveling public.
transporter: a protein within a cell membrane that shuttles material in and/or out of a cell.
transposable element: a transposon or retrotransposon.
transposon: a DNA sequence which can change its position within a genome (typically by placing a copy elsewhere).
transvection (epigenetics): gene activation or repression resulting from allele interactions on homologous chromosomes.
transverse wave: a wave in which displacement is perpendicular to wave propagation. Contrast longitudinal wave.
traveler’s palm (aka traveler’s tree, Ravenala madagascariensis): a palm-like fruit-bearing angiosperm in the bird-of-paradise genus, native to southern Africa.
traveling salesman problem: the problem of determining the shortest route for multiple nonlinear waypoints; one of the most intensively studied problems in computational mathematics, as it is NP-hard (non-deterministic polynomial-time hard).
The traveling salesman problem was mathematically defined in the mid-1800s by William Rowan Hamilton and Thomas Kirkman. To this day, a provably correct algorithmic solution to the traveling salesman problem has not been found. Practically, humans are not nearly as good as bumblebees in solving it. (Only bumblebees have been studied. Doubtlessly such problem-solving acumen applies to other foragers which rely upon checking many locations for food by memory.)
Treaty of Versailles: the peace treaty that ended World War 1, signed on 28 June 1919. The harsh terms imposed on Germany upon France’s insistence practically guaranteed another major war within a few decades, which duly came.
tree: a perennial plant with a woody trunk, branches, and leaves.
tree frog: a frog that spends a lot of time in trees.
tree of life (biology): a metaphor for categorizing organisms by evolutionary descent, used by Charles Darwin in 1872, though the term has ancient philosophic roots.
tree pangolin (aka scaly anteater, white-bellied pangolin, three-cusped pangolin, Phataginus tricuspis): a small pangolin endemic to equatorial Africa.
treepie: an arboreal corvid of 4 genera.
trehalose (aka tremalose, mycose) (C12H22O11): a disaccharide comprising 2 molecules of glucose.
trematode (aka fluke): a class of parasitic flatworms.
Trematosauria: one of the 2 major clades of temnospondyl amphibians that survived the Permian–Triassic extinction event, the other being Capitosauria.
Treponema pallidum: a spirochaete bacterium with subspecies that cause treponemal diseases, including syphilis, bejel, pinta, and yaws.
triad: a group of 3 people. Compare dyad.
trial and error: an iterative method of problem-solving via learning from mistakes.
triangle-weaver spider: a spider of ~15 species in the Hyptiotes genus, which constructs a triangular web and uses part of the web as a catapult to capture prey.
Triassic (252–201 mya): the 1st period of 3 in the Mesozoic era, following the Permian period and preceding the Jurassic. Earth’s land mass was in a single supercontinent, Pangea, during the Triassic. Dinosaurs appeared during the Triassic but did not dominate until the Jurassic. The start and close of the Triassic are marked by major extinction events. The Triassic is named after the 3-layer rocks, found throughout northwestern Europe, that characterize the period.
Triassic–Jurassic extinction event (217–199 mya): a major extinction event, profoundly affecting life on land and in the oceans, where 20% of all marine families were wiped out. Many large land species were wiped out, including amphibians, and all sizable curotarsans (ancestors to crocodiles).
tribalism: strong in-group loyalty.
tribe: a social group with a shared culture. Compare clan.
trichloroethane (C2H3Cl3): an organochloride solvent.
trichloroethylene (C2HCl3): a clear, nonflammable, toxi liquid with a sweet smell.
Trichoderma: a genus of fungi present in all soils.
trichomonad: a single-celled, flagellated, anaerobic protozoan.
Trichomonas vaginalis (Tv): a parasitic trichomonad which causes trichomoniasis.
trichomoniasis (aka trich): the sexually transmitted infectious disease caused by Trichomonas vaginalis.
trichromacy: having 3 types of color vision receptors. Marsupials and primates are the only known mammalian trichromats, with different receptor types for red, green, and blue wavelengths. Some insects, such as honeybees, are trichromats, but their reception is shorter wavelengths: green, blue, and ultraviolet. Trichromats can distinguish 1 million colors. Compare monochromacy, dichromacy, tetrachromacy.
triclosan (C12H7Cl3O2): an antibacterial and antifungal agent found in many consumer products and surgical cleaning treatments.
trigeminal nerve: the largest of the cranial nerves in human body, innervating the face and scalp, as well as providing motor control for biting and chewing.
trigger plant (Stylidium): a flowering plant of a diverse ~300 species, indigenous to Australia. Trigger plants are extremely sensitive to touch.
triglyceride: a fat common in organisms; technically, an ester derived from glycerol and 3 fatty acids.
trigonometry: the branch of mathematics that deals with the relations of triangles.
Trigonopterus: a flightless weevil of over ~200 species native to the Malay Archipelago. Trigonopterus oblongus, endemic to Papua, has a nut-and-screw joint connecting its legs to its hips.
triiodothyronine (aka T3): a thyroid hormone which affects almost every physiological process in the body
trilobite (526–250 mya): a Cambrian arthropod; among the most successful of early animals, diversifying to at least 17,000 species and roaming the oceans for over 270 million years.
trimethylamine (N(CH3)3): a metabolite of gut flora from digesting nutrients such as choline and carnitine.
trimethylamine N-oxide (TMAO; (CH3)3NO): a class of amine oxides. TMAO results from oxidation of trimethylamine, a common animal metabolite.
Tripedalia cystophora: a 1-cm box jellyfish, native to the Caribbean Sea and the Central Indo-Pacific.
Triplaris (aka ant tree): a genus of plants and trees native to the Americas, best known for their mutualism with ants (e.g., T. americana).
triple-α process: the process of forming carbon-12 from 3 helium-4 atoms, owing to nuclear clustering.
triple bond: a chemical (covalent) bond of sharing 3 pairs of electrons. Compare single bond and double bond.
triple point: the temperature and pressure at which a specific molecular structure coexists in the 3 phases: gas, liquid, and solid.
triplet (chemistry): a diradical with a spin = 1. O2 at room temperature exists in a triplet state. Contrast singlet and doublet.
triploid: having 3 sets of chromosomes within a cell nucleus. Seedless watermelons, tardigrades, and marbled crayfish are triploids. See polyploidy.
trisomy: 3 copies of a chromosome instead of the normal 2.
Triton: Neptune’s largest moon; the 7th largest moon in the solar system.
triune brain: an unsubstantiated hypothesis by Paul MacLean that the human brain has 3 levels: reptilian, limbic, and neocortex.
trivalent: an element with a chemical valence of 3.
trophic: nutritional.
trophic cascade: the dynamic of predator-prey linkages, particularly in affecting carrying capacity.
tropic efficiency: the efficiency of converting food into energy for at a trophic level.
trophic level: a stratum of the food chain.
trophic pyramid: a stratified view of a food chain, from a base of producers to herbivores to predators.
tropopause: the transition layer between the troposphere, where temperature drops with altitude, and the stratosphere, where temperature rises with altitude.
troposphere: the atmospheric layer of life: the lowest portion of Earth’s atmosphere. The troposphere extends from the Earth’s surface 7–20 km up, depending upon location and season.
TRPA (an acronym for: transient receptor potential ankyrin): a protein which acts as a cell stress sensor and pain initiator in animals.
true bug: an insect in the Heteroptera group of the Hemiptera order, comprising 40,000 species. Most species have forewings with both membranous and hardened portions. Bedbugs, assassin bugs, stink bugs, plant bugs, seed bugs, and water bugs are exemplary true bugs. The formal classification of Heteroptera has become confused in recent decades through suggested revisions, and there is not even ubiquitous consensus on the extent of what a “true bug” is.
TruGreen: American lawn-care company.
trust (verb): to believe in.
truth: conformity with reality. Compare theory.
trypanosome (aka trypanosomatid): a group of single-celled protozoa with only a single flagellum.
tryptophan (C11H12N2O2): an essential amino acid for many organisms, which typically acts as a precursor for other necessary bioproducts, such as the growth hormone auxin for plants and the neurotransmitter serotonin for animals.
tsetse fly (aka tik-tik fly): a large biting fly endemic to central Africa that lives on the blood of its vertebrate victims. Tsetse flies are known for transmitting parasitic protozoa called trypanosomes which weaken and kill infected animals.
tuatara: a unique gray and greenish-brown lizard-like reptile, but not a lizard, native to New Zealand.
tube worm: an aquatic, wormlike, sessile invertebrate that anchors its tail to an underwater surface, then secretes a mineral tube shelter around its body into which it can withdraw.
tuber: a plant structure that enlarges to store nutrients.
tuberculosis: an infectious disease caused by various strains of mycobacteria, notably Mycobacterium tuberculosis.
tubulin: one of several members of a family of globular proteins, comprising 5 subfamilies. The most common tubulins–α-tubulin and β-tubulin–make up microtubules. Tubulins are instrumental in deriving cell organization and organ placement in organisms.
tundra: a biome where tree growth is hindered by low temperature and short growing seasons. Tundra occurs near the poles and toward the summits of the most majestic mountains.
Túngara frog (Engystomops pustulosus): a frog found in Mexico and northern South America.
tunicate: a marine invertebrate chordate.
tunnel vision: narrow-mindedness; extremely narrow viewpoint.
Tunisia: a small country in the Maghreb region. Tunisia was home of the Berbers in ancient times, before Phoenician immigration in the 12th century BCE and the founding of Carthage. The country became a major mercantile power and military rival to the Roman Republic, which defeated and occupied Tunisia in 146 BCE. Arabs conquered Tunisia in the 1st wave of Islamic expansion (7th century). The Ottomans took over in the mid-16th century and held sway for over 3 centuries. Colonial French conquered in 1881, holding on until 1957. Tunisia then became a republic with a repressive regime. In 2011, revolution resulted in a parliamentary democracy.
turaco: a medium-sized, arboreal, largely herbivorous, gregarious bird endemic to sub-Saharan Africa, in the family Musophagidae.
turbinate (aka nasal concha): nasal airway.
turbine: a machine designed to capture energy from a moving fluid to put to work.
turgidity: a state of distension/swelling.
turgor: the normal state of turgidity and tension in living cells, particularly the distension between the protoplasmic layer and plant cell wall by fluid contents.
turgor pressure: a pressure (turgidity) against cells caused by osmotic water flow. Healthy plant cells rely upon turgidity to maintain rigidity. Other beings with cell walls, such as fungi, protists, and bacteria, appreciate turgor pressure. In contrast, animals lack the cell walls needed to support this function.
Turing pattern: a pattern that emerges from distributed activity of nonlinear dynamic (reaction-diffusion) systems which exhibits local excitatory and sparse inhibitory connectivity.
turion: a specialized overwintering bud produced by aquatic plants. Turions are produced in response to autumnal conditions, such as decreasing day length and lowering temperature. Turions are often rich in sugars and starch, allowing them to act as storage organs.
turkey: a large bird native to the Americas; related to grouse.
turmeric (Curcuma longa): an indigenous plant of southeast India whose rhizome is used to make the spice of the same name.
turnover pulse hypothesis: a hypothesis suggesting that evolution is nominally conservative, with speciation only when forced by environmental change. Compare punctuated equilibria, opportunistic evolution.
Turritopsis nutricula: an immortal hydrozoan which can reincarnate itself by reverting specialized adult cells to undifferentiated status (transdifferentiation).
turtle: a reptile with a unique, defensive, bony shell developed from its ribs, in the Testudines order. Originating 220 mya via saltation, turtles are one of the oldest reptile groups.
tuskfish: a fish of several species in the wrasse family, endemic to the Indian and Pacific oceans.
Tutankhamun: Egyptian pharaoh who ruled 1332–1323 BCE.
tya (aka kiloannum or ka): thousands of years ago.
tympanum: an external animal hearing structure.
type (programming language): a syntactic method for enforcing levels of abstraction in the source code of software programs.
“Types are the leaven of computer programming; they make it digestible.” ~ English computer scientist Robin Milner
tyrannosaur: a family of large theropod dinosaurs that lived during the Jurassic and Cretaceous periods.
tyranny: unrestrained exercise of power; despotic abuse of authority.
tyrosine: an essential amino acid that cells use to synthesize proteins. Tyrosine is abundant in insulin and papain. Tyrosine is prominent in proteins that participate in extracellular signaling.