Sciences & Math - PowerPoint Presentation

Slide1

Sciences & MathSlide2

Table of Contents

Chemical Elements

Moons

Classes of ParticlesMathematicians20th-Century Physicists Anthropologists

Planetary Moons

Phyla

Scientific Scales

Organelles

Plant DistinctionsSlide3

Chemical ElementsSlide4

Hydrogen (atomic symbol H, atomic number 1)

is

the first element on the periodic table and, by far, the most common element in the Universe. In addition to the main isotope (also called 

protium), there are two other significant isotopes of hydrogen: deuterium (2H or D), which has one neutron, andtritium (3H or T), which has two neutrons. It naturally exists as a diatomic gas (H2), which was discovered by British chemist Henry Cavendish. Hydrogen is highly flammable when exposed to high temperatures or electric current; a notable example of this was the 

Hindenburg

 disaster. It can react with nonmetals by losing an electron to form the H+ ion, or react with metals to form the hydride ion H

–

.Slide5

Helium  (He, 2)

is

the lightest noble gas and the second most abundant element in the Universe (after hydrogen). Discovered by Sir William Ramsey, Pierre Janssen, and Norman Lockyer, it has two stable isotopes, helium-3 and helium-4, with helium-4 by far the more common. Because of their different quantum properties (the helium-3 nucleus is a fermion, while the helium-4 nucleus is a boson), the isotopes of helium actually have significantly different physical properties. Helium-4 can exist in a zero-viscosity state known as 

superfluidity when its temperature drops below the lambda point. Helium has the lowest boiling point of any element; liquid helium is used for devices that need intense cooling, such as MRI machines. Most helium on Earth results from radioactive decay, since the helium nucleus is equivalent to an alpha particle.Slide6

Oxygen (O, 8)

is

, by mass, the most common element in Earth’s crust. It was discovered independently by Carl Scheele and Joseph Priestley; Priestley originally called it “

dephlogisticated air.” Oxygen normally exists in elemental form as a diatomic gas (O2), but it can also exist in a triatomic form, ozone(O3), which is known for its role in blocking UV rays in Earth’s stratosphere. Diatomic oxygen is, despite having an even number of electrons,paramagnetic

, meaning it has unpaired electrons. This points out a problem with traditional valence bond theories, which predict that oxygen should be diamagnetic; molecular orbital theory correctly explains this behavior. Because oxygen is easily capable of accepting electrons, reactions in which a species gives up electrons are known as 

oxidation

 reactionsSlide7

Nitrogen (N, 7)

is

the most abundant element in Earth’s atmosphere. Nitrogen, which was first isolated as “noxious air” by Daniel Rutherford, exists primarily as a diatomic molecule containing two triple-bonded nitrogen atoms (N

2). Because nitrogen gas is extremely stable, N2 is unusable for many biological and chemical purposes. To make it useful, it often undergoes fixation to convert it into usable nitrogen species such as the ammonium ion (NH4+)—as it is by bacteria in the root nodules of legume plants—or ammonia gas (NH

3

), as is done industrially in the Haber-Bosch process. Conversely, its stability makes it useful in preventing unwanted combustion reactions. It also has a relatively low boiling point (–196°C), which makes liquid nitrogen useful as a refrigerant.Slide8

Mercury (Hg, 80)

is

one of just two elements that is a liquid at standard temperature and pressure (the only other one is bromine). It has been known since antiquity, and is found in ores such as cinnabar. Older names for it, reflecting its liquid nature, include 

hydrargyrum (the source of its symbol) and quicksilver. Because it is a very dense liquid, it is commonly used in barometers to measure atmospheric pressure; the pressure exerted by the atmosphere equals the pressure exerted by a column containing 760 millimeters of mercury. Alloys of mercury with other metals are called amalgams, some of which have been used as dental fillings. Chronic exposure to mercury can cause psychological problems; its use in

hat making

led to the expression “mad as a hatter.” More recently, concerns about mercury exposure have led to the banning of mercury in thermometers.Slide9

Sulfur (S, 16)

was

widely known in the ancient world, and is referred to in the Bible as brimstone. Its nature as an element was first recognized by Antoine Lavoisier. Its most stable allotrope is an eight-membered ring that exists as a yellow solid. It is most often isolated by injecting superheated steam into the ground in the 

Frasch process. As an element, it is used in the vulcanization process to cross-link the polymer strands of rubber to increase rubber’s strength; similarly, sulfur-sulfur bonds hold many proteins together. Industrially, though, the majority of sulfur is used to make sulfuric acid, H

2

SO

4

 (in fact, sulfuric acid is the most widely produced chemical in the chemical industry). Sulfur compounds are noted for their strong and unpleasant odors; small quantities of hydrogen sulfide, H

2

S, are frequently added to natural gas, which is normally odorless, to help detect gas leaksSlide10

Iron (Fe, 26)

is

the most common metal in the Earth, and one of the major components of the core as well. Iron was known to the ancients; its atomic symbol Fe comes from the Latin name 

ferrum. Iron is the namesake of ferromagnetism; one of its ores is magnetite, Fe3O4, which contains iron in both of its most common oxidation states, 2+ and 3+. Iron(II) sulfide, FeS2

, is formally known as 

pyrite

, but because of its appearance has long been known

as

fool’s

gold

. Iron can react with oxygen in the air to form iron(III) oxide, Fe

2

O

3

, in a relatively slow but exothermic process; this process is used in “all-day” heat patches. 

Hydrated

 iron(III) oxide is better known as rust; rust only forms when iron is exposed to both oxygen 

and

 water. Its isotope 56 is “doubly magic” in that its nucleus has 28 protons and 28 neutrons; 28 is a magic number that carries special stability. As a result, iron-56 is one of the most stable of all nuclei, and it is the heaviest nucleus that is normally produced during stellar nucleosynthesis. The largest use of iron is in steel.Slide11

Carbon (C, 6)

is

found, by definition, in all organic compounds. It is the fourth most abundant element in the Universe. It has three major isotopes: isotope 12, which is stable; isotope 13, which is used in NMR spectroscopy; and isotope 14, which is radioactive and is the basis of 

carbon dating. Carbon’s ability to form four chemical bonds means that it has many different allotropes. The best-characterized natural isotopes are diamond, which consists of a tetrahedral network of carbon atoms, and graphite, which consists of planes of carbon atoms arranged in hexagons. Fullerenes such as buckyballs and carbon nanotubes, on the other hand, are generally produced synthetically; buckyballs

are roughly spherical. More recently, graphene, which is a single layer of atoms shaped like graphite, has proven to have remarkable properties; for example, it is nearly transparent while being about 200 times stronger than an equivalent mass of steel.Slide12

Aluminum (Al, 13)

is

the most common metal in Earth’s 

crust, and the first metal in the p block of elements. First isolated by Hans Christian Oersted, its primary ore is bauxite, from which it is refined using large amounts of electric current, via electrolysis, through the Bayer and Hall-Héroult processes. (Because aluminum exists only in a +3 oxidation state, it takes three moles of electrons to produce one mole of aluminum; as a result, it has been estimated that 5% of all electricity in the U.S. goes to purifying aluminum.) It is found in the mineral corundum, which is found in many gems, including sapphires and rubies; the specific impurities found in a gem determine its color. It is also found in 

aluminosilicates

 such as feldspar.Slide13

Gold (Au, 79)

was

known to the ancients as a relatively inert metal. Its atomic symbol Au comes from its Latin name, 

aurum. It is resistant to attack by most acids, but it (along with platinum) will dissolve in aqua regia, a mixture of concentrated nitric acid and hydrochloric acid. Among all metals, it has the highest electronegativity and electron affinity; it occasionally is found in a –1 oxidation state as Au–. Widely used in jewelry, it also has a number of scientific uses. Ernest Rutherford’s gold foil experiment demonstrated the existence of a positively charged nucleus. Scanning electron microscopy (SEM) often requires that specimens be “sputtered,” or thinly coated, with gold atoms to allow imaging. Suspensions of gold compounds have been used to treat rheumatoid arthritis.Slide14

MoonsSlide15

Earth’s moon:

The

moon, also called Luna, is the fifth largest satellite in the solar system, the largest relative to the size of the planet it orbits, and the second densest. The USSR’s 

Luna unmanned spacecraft first reached the moon in 1959, and Apollo 8 became the first manned mission to orbit the moon, in 1968. The 1967 Outer Space Treaty guarantees the rights of all nations to explore the moon for peaceful purposes.The flat dark lunar plains are called maria (singular: mare) and are mainly concentrated on the near side of the moon. The most famous one is Mare Tranquillitatis, the Sea of Tranquility, where Apollo 11 first landed on the moon in 1969. The Apollo program landed on the moon five more times.Slide16

Phobos:

Both

Phobos (“fear”) and Mars’ smaller moon Deimos (“dread”) were discovered by Asaph Hall III in 1877. At just 3700 miles above the Martian surface, Phobos orbits more closely to its planet than any other moon in the Solar System. Because it orbits Mars faster than Mars rotates, each day it appears (from the Martian surface) to set twice in the east each day. Geological features on Phobos, including the Stickney Crater, are primarily named for either astronomers (Stickney was the maiden name of Asaph Hall’s wife) or characters from Jonathan Swift’s 

Gulliver’s Travels. In 1971 the US’s Mariner IX became the first spacecraft to provide close-up photos of Phobos.Slide17

Deimos:

One

seventh the mass of Phobos and further away from the Martian surface, Deimos was found by Asaph Hall at the US Naval Observatory six days before he discovered Phobos. Its largest and only named craters are Swift and Voltaire; Deimos’s surface doesn’t appear as rough as

Phobos’s because regolith has filled in some of the craters. A still-controversial and unproven hypothesis holds that Deimos (and possibly Phobos as well) were asteroids perturbed out of their orbit by Jupiter and then captured by the gravity of Mars.Slide18

Io 

is

the innermost of the four Galilean moons of Jupiter (the moons discovered by Galileo), the fourth-largest moon in the solar system, the densest moon, and the most geologically active body in the solar system due to its more than 400 volcanoes. Io’s features are named for characters from the Io story in Greek mythology; fire, volcano, and thunder deities from other mythologies; and characters from Dante’s 

Inferno. Io plays a significant role in shaping Jupiter’s magnetosphere. Pioneer 10 first passed by Io in December 1973.Slide19

Ganymede 

is

the largest moon in the solar system and the only one known to have its own magnetosphere. The third of the Galilean satellites, Ganymede was also first photographed close-up by Pioneer 10 in 1973. 

Galileo made six flybys of Ganymede between 1996 and 2000. Based on a suggestion from Simon Marius, Ganymede (along with many of the Jovian satellites) is named for one of Jupiter’s lovers in Roman mythology; Ganymede is the only such moon named for a male figure. Many of Ganymede’s features, including the Enki Catena, are given names from Egyptian and Babylonian mythology, although its largest dark plain is Galileo Regio. Ganymede is scheduled to be orbited by the European Space Agency’s Jupiter Icy Moon Explorer (JUICE), currently slated for a 2022 launch.Slide20

Titan 

is

the largest moon of Saturn and the second largest in the solar system. Until Voyager 1 visited in 1980, it was thought to be larger than Ganymede. It is the only known satellite with a dense atmosphere—so dense that it makes observation of surface features nearly impossible except from close up—and also the only known satellite for which there is evidence of stable bodies of surface liquid. Discovered in 1655 by Christiaan Huygens, it was visited by the Cassini-Huygens mission in 2004. Titan’s albedo features, such as the highly reflective area Xanadu, are named for sacred or enchanted places from world literature and mythology. Because of its nitrogen-rich atmosphere and the presence of surface liquid, Titan is often thought to be the most likely place in the solar system for microbial life to exist outside of Earth.Slide21

Iapetus [“eye”-AA-

pih

-

tuss]is Saturn’s third-largest moon after Titan and Rhea and, like them, was discovered by Giovanni Cassini in 1671. It was named based upon a suggestion from John Herschel (son of the discoverer of Uranus, William Herschel) for the Titans of Greek mythology, the brothers and sisters of Cronos (Saturn). Iapetus has a distinctive two-tone coloration; part of it is red-brown, while part is bright gray. Features on Iapetus are named for people and places from the French Song of Roland, including Charlemagne Crater and the bright northern region Roncevaux Terra. In 2004 the 

Cassini

 orbiter found an equatorial ridge running over 800 miles long and 10 miles wide that gives Iapetus some of the highest peaks in the solar system; its existence has not yet been explained.Slide22

Titanic and 

Oberon

:

Uranus’s largest moons, Titania and Oberon, are named for characters from Shakespeare’s A Midsummer Night’s Dream. (Other Uranian moons are named for characters from either Shakespeare or Alexander Pope.) They were discovered on the same day in 1787 by William Herschel, who also discovered Uranus itself in 1781. In 1986 Voyager 2 became the only spacecraft to date to visit the Uranian moons. Because Uranus orbits the sun almost on its side and Titania and Oberon orbit Uranus in the same plane as its equator, the moons have extreme seasons:

Titania’s

poles spend over 42 years in nonstop sunlight followed by 42 years of darkness. Most of

Titania’s

features are named for settings or female characters from Shakespeare—its largest crater is Gertrude Crater, after Hamlet’s mother—while most of Oberon’s are named after settings or male characters from Shakespeare. However, Oberon’s largest feature is

Mommur

Chasma

, which is named from a French epic poem.Slide23

Triton:

The

largest moon of Neptune and the only large moon with a retrograde orbit (that is, an orbit opposite to the rotation of its planet), Triton is the seventh-largest moon in the solar system and is thought to have been captured from the Kuiper Belt. For over 100 years after its 1846 discovery, Triton was thought to be Neptune’s only moon; Nereid wasn’t discovered until 1949 (there are 13 known satellites now). Triton is geologically active and has geysers that are assumed to erupt nitrogen. Because of the activity, impact craters on Triton are relatively scarce; most of the larger craters were formed by volcanic activity. Triton orbits around Neptune in almost a perfect circle. Voyager 2 visited Triton in 1989 and is the only space probe to have done so (and none are currently planned). Much of Triton’s western hemisphere consists of an unexplained series of fissures and depressions sometimes called “cantaloupe terrain.” Triton’s features are named after various water spirits, monsters, or sacred waters from mythology.Slide24

Charon:

The

largest satellite of the dwarf planet Pluto, Charon wasn’t discovered until 1978. (As of 2013, Pluto has five known moons, the last two discovered in 2011 and 2012.) Unlike Pluto, which is covered with nitrogen and methane ices, Charon appears to be covered in water ice and may also have active

cryo-geysers. Because the center of mass of the Pluto-Charon system lies outside of either one, Charon doesn’t truly orbit Pluto; when Pluto was reclassified as a dwarf planet in 2006, an argument was made (but not accepted) to classify Pluto-Charon as a binary system. The IAU still considers Charon, which is roughly half the size but has only 11% the mass of Pluto, to be a satellite. The New Horizons mission is scheduled to visit Charon and Pluto in 2015.Charon was named by its discoverer, James Christy of the Flagstaff Naval Observatory; the IAU approved the name in 1985. Internationally Charon is pronounced like the Greek mythological figure with a hard [k] sound; however, Christy’s choice of name was inspired by his wife Charlene, so NASA and New Horizons personnel use a soft [

sh

] sound.Slide25

Classes of ParticlesSlide26

Physics and chemistry are often difficult subjects for quiz bowl teams if those classes are taught during the junior or senior years since many players will not have completed them before encountering the subject matter at tournaments. One high-yield area of physics to study is the nomenclature of various groups of particles.

Some conventions: The mass of particles is usually given in mega-

electronvolts

(MeV), where an electron-volt is the energy acquired by an electron when it crosses a potential difference of one volt. The energies are converted to masses by Einstein's famous equation E = mc2, where c is the speed of light. Charges are given in terms of the fundamental electric charge (the absolute value of the charge on an electron).

Every kind of particle also has a corresponding anti-particle made of anti-matter; when it is said that there "six leptons," anti-particles are not counted (so, in some sense, there are twelve). Anti-particles have the same mass, but the opposite charge, of the original. There are no particles with negative mass. Note that in some rare situations, a particle can be its own anti-particle.Slide27

Leptons 

are

one of the classes of "fundamental particles" (meaning that they cannot be broken down into smaller particles). There are six "flavors" of leptons: the electron, the muon, the

tauon, the electron neutrino (usually just called "the" neutrino), the muon neutrino, and the tauon neutrino. The three neutrinos are neutral (and were once thought to be massless), while the other three have a charge of -1. All neutrinos are fermions and the total number of leptons is conserved (counting regular leptons as +1 particle and anti-leptons as -1 particle). The word "lepton" comes from the Greek for "light" (as in "not heavy"), even though the muon and tauon are fairly massive.Slide28

Quarks 

are

another class of fundamental particle. They also come in six flavors: up, down, charm, strange, top (sometimes, "truth"), and bottom (sometimes, "beauty"). The up, charm, and top quarks have a charge of +2/3, while the down, strange, and bottom have a charge of -1/3. All quarks are fermions and they combine in pairs to form mesons and in triples to form baryons. The enormous mass of the top quark (178 GeV) made it difficult to create in particle accelerators, but its discovery in 1995 confirmed an essential element of the "Standard Model" of particle physics. The name "quark" comes from the line "Three quarks for Muster Mark" in 

Finnegans Wake that appealed to Murray Gell-Mann. The study of quarks (and the strong nuclear force) is quantum chromodynamics.Slide29

Baryons 

are

composite (i.e., non-fundamental) particles made from three quarks. The most common examples are the proton (two up quarks and one down quark) and the neutron (two down quarks and one up). All baryons are fermions. Quarks possess a characteristic called "color" (which has nothing to do with visual color) which can be either red, green, or blue (which are arbitrary names). A baryon must have one quark of each color so that the "total color" (analogous to mixing red, green, and blue light) is colorless (i.e., "white"). The word "baryon" comes from the Greek for "heavy." The total number of baryons is conserved (again, counting anti-baryons as -1).Slide30

Mesons 

are

composite particles generally made from a quark and an anti-quark. There are dozens of examples including the pion, kaon, J/Psi, Rho, and D. All mesons are bosons. The quark and anti-quark must have the same color (such as red and anti-red) so that the resulting meson is colorless (or "white"). It is also possible to make mesons out of two (or more) quarks and the same number of anti-quarks, but this kind of particle (a "

tetraquark") is rare, both in nature and in quiz bowl.Slide31

Fermions 

are

particles with half-integral spin. Spin is a form of "intrinsic angular momentum" which is possessed by particles as if they were spinning around their axis (but, in fact, they aren't). The values cited for spin are not (usually) the real magnitude of that angular momentum, but the component of the angular momentum along one axis. Quantum mechanics restricts that component to being 

n/2 times Planck's constant divided by 2 pi for some integer n. If n is even, this results in "integral" spin, if it is odd, it results in "half-integral" spin. Note that the exact value of the spin itself is a real number; it's the multiplier of h

/2pi that determines whether it is "integral" or not. The most significant thing about fermions is that they are subject to the Pauli Exclusion Principle: No two fermions can have the same quantum numbers (i.e., same state). The name "fermion" comes from that of the Italian-American physicist Enrico Fermi.Slide32

Bosons 

are

particles with integral spin. All particles are either bosons or fermions. The spin of a composite particle is determined by the total spin (i.e., the component of its intrinsic angular momentum along one axis) of its particles. For instance, an alpha particle (two protons and two neutrons) has four half-integral spin values. No matter how they are added up, the result will be an integral spin value (try it!), so an alpha particle is a (composite) boson. The Pauli Exclusion Principle does 

not apply to bosons (in fact, bosons prefer to be in the same quantum state). The name "boson" comes from that of the Indian-American physicist Satyendra Nath Bose.Slide33

Hadrons 

are

any particles made out of quarks (alternatively, any particle affected by the strong nuclear force). Generally, this means the baryons and the mesons. All hadrons are colorless (in the sense of the combined color of their constituent quarks). The name "hadron" comes from the Greek for "thick."Slide34

Gauge bosons (sometimes called "vector bosons")

are

fundamental bosons that carry the forces of nature. That is, forces result from particles emitting and absorbing gauge bosons. The strong nuclear force is carried by gluons, the weak nuclear force is carried by the W, Z

-, and Z+ particles, the electromagnetic force is carried by the photon, and gravity is carried by the (as yet unobserved) graviton. The name comes from the role of "gauge theories" in describing the forces (which are beyond the scope of this article).Slide35

Gluons 

are

the gauge bosons that carry the strong nuclear force and bind hadrons together. Gluons have no charge and no mass, but do have color (in the sense of quarks). This color cannot be observed directly because the gluons are part of the larger hadron. The name comes from their role in "gluing" quarks together.Slide36

Partons 

are

an older name that was used for the "internal parts" of hadrons before the discovery and widespread acceptance of the quark model. Models based on

partons are still used but, for the most part, it was determined that partons were quarks and the term is rarely used at the high school level except in historical contexts.Slide37

MathematiciansSlide38

Isaac Newton

The work of 

Isaac Newton

 (1643-1727, English) in pure math includes generalizing the binomial theorem to non-integer exponents, doing the first rigorous manipulation with power series, and creating "Newton's method" for the finding roots. He is best known, however, for a lengthy feud between British and Continental mathematicians over whether he or Gottfried Leibniz invented calculus (whose differential aspect Newton called "the method of fluxions"). It is now generally accepted that they both did, independently.Slide39

Euclid (c. 300 BC, Alexandrian Greek)

is

principally known for the 

Elements, a textbook on geometry and number theory, that was used for over 2,000 years and which grounds essentially all of what is taught in modern high school geometry classes. Euclid is known for his five postulates that define Euclidean (i.e., "normal") space, especially the fifth (the "parallel postulate") which can be broken to create spherical and hyperbolic geometries. He also proved the infinitude of prime numbers.Slide40

Carl Friedrich Gauss (1777-1855, German)

is

considered the "Prince of Mathematicians" for his extraordinary contributions to every major branch of mathematics. His 

Disquisitiones Arithmeticae systematized number theory and stated the fundamental theorem of arithmetic. He also proved the fundamental theorem of algebra, the law of quadratic reciprocity, and the prime number theorem. Gauss may be most famous for the (possibly apocryphal) story of intuiting the formula for the summation of an arithmetic series when given the busywork task of adding the first 100 positive integers by his primary school teacher.Slide41

Archimedes (287-212 BC,

Syracusan

Greek)

is best known for his "Eureka moment" of using density considerations to determine the purity of a gold crown; nonetheless, he was the preeminent mathematician of ancient Greece. He found the ratios between the surface areas and volumes of a sphere and a circumscribed cylinder, accurately estimated pi, and presaged the summation of infinite series with his "method of exhaustion."Slide42

Gottfried Leibniz (1646-1716, German)

is

known for his independent invention of calculus and the ensuing priority dispute with Isaac Newton. Most modern calculus notation, including the integral sign and the use of 

d to indicate a differential, originated with Leibniz. He also invented binary numbers and did fundamental work in establishing boolean algebra and symbolic logic.Slide43

Pierre de Fermat (1601-1665, French)

is

remembered for his contributions to number theory including his "little theorem" that 

ap - a will be divisible by p if p is prime. He also studied Fermat primes (those of the form 22n+1) and stated his "Last Theorem" that xn + 

y

n

 = 

z

n

 has no solutions if 

x

, 

y

, and 

z

are

positive integers and 

n

 is a positive integer greater than 2. He and Blaise Pascal founded probability theory. In addition, he discovered methods for finding the maxima and minima of functions and the areas under polynomials that anticipated calculus and inspired Isaac Newton.Slide44

Leonhard Euler (1707-1783, Swiss)

is

known for his prolific output and the fact that he continued to produce seminal results even after going blind. He invented graph theory with the Seven Bridges of

Königsberg problem and introduced the modern notation for e, the square root of -1 (i), and trigonometric functions. Richard Feynman called his proof that eiπ = -1 "the most beautiful equation in mathematics" because it linked four of math's most important constants.Slide45

Kurt Gödel (1906-1978, Austrian)

was

a logician best known for his two incompleteness theorems proving that every formal system that was powerful enough to express ordinary arithmetic must necessarily contain statements that were true, but which could not be proved within the system itself.Slide46

Andrew Wiles (1953-present, British)

is

best known for proving the

Taniyama-Shimura conjecture that all rational semi-stable elliptic curves are modular. This would normally be too abstruse to occur frequently in quiz bowl, but a corollary of that result established Fermat's Last Theorem.Slide47

William Rowan Hamilton (1805-1865, Irish)

is

known for extending the notion of complex numbers to four dimensions by inventing the quaternions, a non-commutative field with six square roots of -1: ±

i, ±j, and ±k with the property that ij = k, jk = i, and 

ki

 = j.Slide48

20th

-Century Physicists Slide49

Niels Bohr (1885–1962)

Bohr

reconciled Rutherford’s results from the gold foil experiment with Planck’s quantum theory to create a 

model of the atom in which electrons resided in specific energy levels at specific stable radii. This model was the basis for Balmer’s work with spectroscopy and Rydberg’s energy formula, which explicitly stated the frequency of light that an electron would emit if it went from a higher energy to a lower energy. Bohr and his son fled to the US in World War II under the pseudonym Baker and contributed to the Manhattan Project.Slide50

Louis de Broglie (1892–1987)

de

Broglie’s work quantifying the wave-particle duality of quantum mechanics earned him the 1929 Nobel Prize in Physics. His doctoral thesis, which proposed that all particles have a 

characteristic wavelength dependent on their momentum, was so groundbreaking that the reviewers passed it directly to Einstein, who endorsed it. In opposition to the probabilistic interpretation of quantum mechanics, de Broglie later worked to define a purely causal interpretation, but his work remained unfinished until David Bohm refined it in the 1950s. His last name is pronounced approximately [duh BROY].Slide51

Albert Einstein (1879–1955)

In

one year — 1905, called his 

annus mirabilis, or miracle year — Albert Einstein authored four papers that revolutionized modern physics. The first explained the photoelectric effect in terms of discretized electromagnetic radiation. The second formed the foundation for modern statistical physics by explaining the seemingly-random motion of particles in a fluid, a behavior called Brownian motion. The third reconciled Maxwellian electrodynamics with classical mechanics by positing a finite, constant speed of light. This is now known as 

special relativity

. The fourth paper contained his statement that the energy of a body is equal to its mass times the speed of light squared. Ten years later, in 1915, Einstein published his theory of 

general relativity

, which generalized special relativity to account for gravitational fields.Slide52

Enrico Fermi (1901–1954)

Fermi

is best known to the public as a main contributor to the Manhattan Project, his work with statistical physics laid the groundwork for modern electronics and solid-state technologies. He applied the 

Pauli exclusion principle to subatomic particles to create Fermi-Dirac statistics, which accurately predicted the low-temperature behavior of electrons. Particles which obey Fermi-Dirac statistics are called fermions in his honor. Fermi also suggested the existence of the neutrino in order to balance nuclear beta-decay chainsSlide53

Richard Feynman (1918–1988).

Feynman

developed a mathematical formalism called the path integral formulation of quantum theory that utilized the “sum over histories,” taking into account all possible paths a particle could take. This constituted the creation of 

quantum electrodynamics and earned him the 1965 Nobel Prize in Physics. He also used the sum over histories in developing Feynman diagrams, which illustrate the interaction of subatomic particles. Aside from being a prolific physicist, Feynman was also an accomplished bongo player and sketch artist.Slide54

George Gamow (1904–1968)

Gamow

was one of the first to explain the implications of the 

Big Bang theory of cosmology. He correctly predicted the abundance of hydrogen and helium in the early universe, nicknamed Alpher-Bethe-Gamow theory (an intentional pun on the first three letters of the Greek alphabet, alpha, beta, and gamma, for which the otherwise unrelated physicist Hans Bethe was included), and also theorized that the the heat from the Big Bang would still be visible as the cosmic microwave background radiation. Although Gamow received no Nobel for this prediction, the CMB’s discoverers, Arno Penzias and Robert Wilson, as well as two later observers, John Mather and George Smoot, did receive

Nobels

.Slide55

Werner Heisenberg (1901–1976)

Heisenberg

is most known for his matrix interpretation of quantum theory, which constructs observable quantities as operators, which act on a system. His famous 

uncertainty principle (better translated, however, as “indeterminacy principle”) states that the more accurately an object’s position can be observed, the less accurately its momentum can. This is because shorter wavelengths of light (use as a sort of measuring-stick) have higher energies, and disrupt a particle’s momentum more strongly. Heisenberg earned the 1932 Nobel Prize in Physics for discovering the allotropic forms of hydrogen.Slide56

Max Planck (1858–1947)

Planck

allowed quantum theory to move forward in the early 20th century by correctly modeling how an object radiates heat, solving the 

ultraviolet catastrophe, which was a predicted unbounded increase in the amount of radiation emitted at high frequencies. Planck’s Law of Radiation superseded the Rayleigh-Jeans Law, which was used until that point. He suggested that electromagnetic energy could only be emitted in specific packages, called quanta (singular quantum, from the Latin for “how much”), positing that the energy of this photon was equal to its frequency times a fixed value h, now known as Planck’s constant.Slide57

Ernest Rutherford (1871–1937)

Rutherford’s

gold foil experiment provided the first evidence that the atom was made up of a large, positively-charged nucleus, surrounded by a cloud of negatively-charged electrons. Rutherford won the 1908 Nobel Prize in Chemistry for this work. Rutherford was also an early leader in nuclear fission techniques, having discovered the decay of carbon-14 and providing the impetus for modern carbon dating. As part of this research, he discovered the proton and neutron, the latter in cooperation with James Chadwick. He is also the only native New Zealander with an element named after him (Rutherfordium, atomic number 104).Slide58

Erwin Schrödinger (1887–1961)

Schrödinger

contributed to the early formulations of quantum theory as a foil to Heisenberg, Bohr, and Dirac, criticizing their 

Copenhagen interpretation with thought experiments like his famous Schrödinger’s Cat argument. He formulated both the time-independent and time-dependent Schrödinger equations, partial differential equations which described how quantum systems behaved. Schrödinger’s work was the basis for Heisenberg’s matrix formalism, Feynman’s path integral formalism, and quantum mechanical perturbation theory, which considers the effects of a small disturbance to a quantum system.Slide59

Honorable mentions:

Marie

 (1867–1945) and 

Pierre (1859–1906) Curie rigorously isolated and experimented on radioactive materials, forming the basis for early nuclear and particle physics.Paul Dirac (1902–1984) was one of the first to attempt a generalization of quantum theory to relativistic speeds, the result of which was the Dirac equation.Murray Gell-Mann (born 1929) predicted the existence of quarks, which compose protons, neutrons, and other, heavier particles.

Robert Millikan

 (1868–1953; not to be confused with Robert Mullikan, a chemist) determined the charge of the electron by meticulously observing oil droplets in an electric field and noting the time it took them to fall a certain distance.

J. Robert Oppenheimer

 (1904–1967) oversaw much of the Manhattan project, but was later stripped of his security clearance during the McCarthy-era Red Scare, as a result of his acquaintance with communists and his enmity with Edward Teller.

Wolfgang Pauli

’s (1900–1958) namesake exclusion principle prohibits most types of particles from occupying the same state, and forms the basis for chemical bonds.Slide60

AnthropologistsSlide61

Franz Boas (1858–1942)

Often

called the founder of modern anthropology, this first professor of anthropology at Columbia University trained Mead, Benedict, Alfred Kroeber, author Zora Neale Hurston, and many others. He conducted fieldwork on the

Inuits of Baffin Island and the Kwakiutl (now referred to as Kwakwaka’wakw) on Vancouver Island. His publications include 1911’s The Mind of Primitive Man, which describes a gift-giving ceremony known as the “potlatch.”Slide62

Margaret Mead (1901–1978)

For

her best-known work, 

Coming of Age in Samoa, Mead interviewed young girls on the island of Ta’u, which led her to conclude that adolescence in Samoan society was much less stressful than in the United States; in The Fateful Hoaxing of Margaret Mead, Derek Freeman claimed that she was lied to in those interviews. She also studied three tribes in New Guinea — the Arapesh, Mundugumor, and Tchambuli — for her book on 

Sex and Temperament in Three Primitive Societies

.Slide63

Ruth Benedict (1887–1948)

A

colleague and friend of Mead, Benedict studied the Zuni,

Dobu, and Kwakiutl cultures in Patterns of Culture, using them to illustrate the idea of a society’s culture as “personality writ large.” She also described Japanese culture in The Chrysanthemum and the Sword, a work written during World War II at the request of the U.S. government.Slide64

Bronislaw Malinowski (1884–1942)

The

Polish-born Malinowski, whose name is pronounced [BRAH-

nuss-waf mah-lih-NAWF-skee], studied at the London School of Economics, where he would later spend most of his career. He described the “kula ring” gift exchanges found in the Trobriand Islands in Argonauts of the Western Pacific, and the use of magic in agriculture in 

Coral Gardens and Their Magic

. He also argued, in opposition to Sigmund Freud, that the Oedipus complex was not a universal element of human culture in his book on 

Sex and Repression in Savage Society

.Slide65

Claude Lévi-Strauss (1908–2009)

In

the 1930s, Lévi-Strauss did fieldwork with the Nambikwara people of Brazil, which formed the basis for his thesis on “The Elementary Structures of Kinship.” He held the chair in social anthropology at the

Collèege de France from 1959 to 1982, during which time he published such books as The Savage Mind and a tetralogy about world mythology whose volumes include The Raw and the Cooked. He pioneered in applying the structuralist methods of Ferdinand de Saussure to anthropology, which led him to study cultures as sets of binary oppositions.Slide66

Clifford Geertz (1926–2006)

Geertz

is best known for his work in symbolic anthropology, a view that he expounded in his book 

The Interpretation of Cultures. In that book, he introduced the term “thick description” to describe his method of analyzing behavior within its social context. One such “thick description” appears in his essay “Deep Play: Notes on the Balinese Cockfight,” in which Geertz discusses cockfighting as a symbolic display of a certain kind of masculinity.Slide67

Alfred Radcliffe-Brown

 (1881–1955)

Radcliffe-Brown

is considered the founder of a school of anthropology known as structural functionalism, which focuses on identifying the groups within a society and the rules and customs that define the relationships between people. His own early fieldwork was conducted in the Andaman Islands and Western Australia, where he studied the social organization of Australian tribes. After teaching in Australia, South Africa, and at the University of Chicago, he returned to England, where he founded the Institute of Social and Cultural Anthropology at Oxford.Slide68

James Frazer (1854–1941)

Frazer

was a Scottish anthropologist who primarily studied mythology and comparative religion. His magnum opus, 

The Golden Bough, analyzed a wide range of myths that center on the death and rebirth of a solar deity; the original publication controversially discussed the crucifixion of Jesus as one such myth. The work’s title refers to a gift given to Persephone by Aeneas so that he could enter the underworld in the Aeneid.Slide69

Thor Heyerdahl (1914–2002)

In

1947, Heyerdahl and five companions sailed across the Pacific Ocean — going from Peru to the Tuamotu Islands — on a balsa-wood raft named 

Kon-Tiki, after the Incan sun god Kon-Tiki Viracocha. He later built two boats from papyrus (Ra, which failed in 1969, and Ra II, which succeeded in 1970) to sail across the Atlantic Ocean. These voyages demonstrated the possibility that ancient people could have migrated around the globe using only primitive rafts.Slide70

Jane Goodall (born 1934)

Goodall

is a British primatologist who is best known for her work with chimpanzees in

Gombe Stream National Park in Tanzania. Her first research was carried out with Louis Leakey at Olduvai Gorge. In her pioneering work with primates, which is detailed in such books asIn the Shadow of Man, she discovered that chimpanzees have the ability to use tools, such as inserting grass into termite holes to “fish” for termites.Slide71

Planetary MoonsSlide72

Charon (Pluto)

Named

for the mythical boatman of the Greek underworld. Its expected pronunciation of "KAIR-

en" is not the correct one, which is actually "SHAHR-en", in honor of Charlene Christy, wife of Jim Christy, its discoverer. The largest moon relative to the size of its orbiting planet, Charon not only is in synchronous orbit with Pluto, but the two show the same face toward each other at all times. The relative sizes of the two bodies has led some to call Charon and Pluto a double planet system. Charon's surface is believed to be water ice.Slide73

Deimos and Phobos

 (Mars)

Named

for two sons of Ares and Aphrodite. Phobos and Deimos (Greek for "fear" and "panic") are the two moons of Mars and both were discovered in 1877 by Asaph Hall. Phobos orbits closer to the planet and has as its most prominent feature the crater Stickney (Hall's wife's maiden name). Unlike the Earth's moon, it rises in the west and sets in the east, about twice per Martian day. This is due to it being below the radius for synchronous orbit. This position also means it will either impact Mars or break into a ring in around 50 million years. Deimos is the smallest moon in the solar system. It was discovered two days before Phobos. Deimos was likely an asteroid brought into Mars' orbit after being disturbed by Jupiter.  Like

Phobos

, Deimos is heavily cratered, rich in carbon, and believed to have water ice.Slide74

Europa (Jupiter)

One

of the Galilean moons, discovered in 1610 by Galileo (the others are

Callisto, Ganymede, and Io). It resembles Io, and to a degree, Earth, in its composition of silicate rocks. However, it is coated in a thin layer of ice, which causes it to be exceedingly smooth. This ice layer may also provide a thin atmosphere as hydrogen and oxygen are released when the planet is exposed to sunlight. There is the possibility of an active sea of liquid water beneath the surface. The most striking feature of the surface is a series of dark streaks that may be due to geysers or volcanic eruptions.Slide75

Ganymede (Jupiter)

The

largest satellite in the solar system, this Galilean moon is larger than Mercury, but has only half its mass. Based on the observations of the Galileo spacecraft, it is thought to have a three-layer structure of a molten iron core, silicate mantle, and ice exterior. Its surface is marked by older, dark, highly cratered regions, mixed with lighter, grooved regions. These grooves indicate tectonic activity, but Ganymede does not appear to have undergone recent tectonic shifts.Slide76

Io (Jupiter)

Like

Europa, Io (named for a lover of Zeus) is primarily formed of silicate rock. Its surface, however, is unlike any other satellite. Rather than craters, Io is dotted with active volcanoes, calderas, and other signs of geological activity. The eruptions are believed to consist of sulfurous compounds that comprise Io's thin atmosphere. The tremendous activity is due to tidal warming from the gravity of Jupiter and other satellites. Additionally, as Io orbits it is heated electrically from currents produced by Jupiter's magnetic field. This action strips material from Io, producing a radiation field and increasing Jupiter's magnetosphere.Slide77

Nereid (Neptune)

Discovered

by Gerard Kuiper (who also discovered Miranda, Titan's atmosphere, and an asteroid belt), Nereid (named for the daughters of

Nereus and Doris) has the most eccentric orbit of any known satellite, ranging from 1.3 million kilometers to 9.6 million. The oddity of this orbit indicates it is likely a captured asteroid.Slide78

Triton (Neptune)

By

far the largest of Neptune's satellites, Triton is also unusual for its retrograde orbit, which indicates that it was not part of the natural formation of Neptune's other moons. It also features seismic activity in the form of ice volcanoes, a tenuous nitrogen-methane atmosphere, and a southern hemisphere "ice cap" of nitrogen and methane. All of these may be caused by Triton's odd rotational axis, which tends to alternate polar and equatorial regions facing the sun.Slide79

Oberon (Uranus)

Named

for the King of the Fairies in 

A Midsummer Night's Dream (all of Uranus' satellites are named for literary, rather than mythological, characters), Oberon is both the second largest of Uranus' satellites, and the outermost of its large satellites. Like all large Uranian moons, its structure is about half water ice, half rock. Large faults are visible across its southern hemisphere, but its surface is heavily cratered, indicating long-term tectonic stability. Some craters have dark floors that could possibly indicate post-impact upwellings of water.Slide80

Titania (Uranus)

Another

of Herschel's discoveries, Titania is named for Oberon's wife, the Queen of the Fairies, and is the largest of the

Uranian satellites. Its surface is an odd mix of craters and valleys. One theory regarding this is that it began as a liquid, then cooled surface first. Once ice had formed, the interior, freezing forced surface cracks which formed the valleys. This also accounts for the appearance of some craters, where ice appears to have melted and filled in.Slide81

Titan (Saturn)

The

largest of Saturn's satellites, Titan 

might be the largest satellite in the solar system, but this awaits more accurate measurements. Those measurements are difficult because of Titan's major characteristic: It is the only satellite to have a substantial atmosphere. Its significant atmosphere, a mix of nitrogen (80%), methane (20%), and argon (trace), also makes it unique among satellites.Slide82

PhylaSlide83

Plant, algal, and fungal "phyla" are often referred to as "divisions." Some taxonomists also extend this usage to bacteria, while others advocate replacing the term "division" with "phylum" for all organisms.

Taxonomists do not always agree on the usage of even the most common terms. Some textbooks and other publications will use alternate names or spellings to describe taxonomic groups, or will lump or split groups in different ways.

Under NAQT rules, unless the question states otherwise, both Latin names (Mollusca) or Anglicized names (

molluscs) are acceptable for a given taxon.Note that spelling and pronunciation are not completely standardized in the taxonomic world, so other sources may have slightly different versions of these phyla.Estimates of phylal diversity vary. Because many invertebrates are inconspicuous, all estimates are probably low. Unless stated otherwise, numbers represent an estimate of the number of species that have been named.Slide84

Porifera (pore-IH-

fer

-ah; 5,000 species)

The sponges are all water-dwellers (98% marine, 2% freshwater), and are sometimes classified separately from other animals because of their asymmetric bodies and lack of distinct tissues. They are sessile (immobile) except in early dispersing stages, and collect food particles via the sweeping motions of flagellated cells called choanocytes [koh-ANN-oh-sites].Slide85

Cnidaria (

nih

-DARE-

ee-ya; 10,000 species)Also called Coelenterata [se-LEN-ter-AH-tah], the cnidarians develop from a diploblastic (two-layered) embryo, and have two separate tissue layers and radial body symmetry. Many cnidarians have two life stages, the mobile, usually bell-like medusa and the sessile polyp. All cnidarians have nematocysts, or stinging cells, for capturing prey, and some can inflict painful stings on swimmers. Examples include the hydras, sea anemones, corals, jellyfishes, and Portuguese man-o-war (which is actually an aggregation of colonial cnidarians).Slide86

Platyhelminthes (PLAT-

ee

-

hel-MIN-theez; 15,000 species)The flatworms are the most primitive phylum to develop from a triploblastic (three-layered) embryo. They have bilateral body symmetry, and are acoelomate (lacking a true body cavity), so that the space between the digestive tract and the body wall is filled with tissue. As the name implies, they are generally flat-bodied. They have a true head and brain, but the digestive system has only one opening that functions as both mouth and anus. Most are hermaphroditic. This phylum includes parasites such as the tapeworms and flukes, as well as free-living (i.e., non-parasitic) organisms such as the planarians.Slide87

Nematoda (NEM-ah-TOE-dah; 15,000 species)

The

roundworms are unsegmented worms that live in a variety of habitats. They are

pseudocoelomate; the three tissue layers are concentric, but the body cavity is not lined with tissue derived from the mesoderm (middle embryonic layer). They include both free-living and parasitic species; human parasites include hookworms and the causative agents of elephantiasis, trichinosis, and river blindness. Soil nematodes may be crop pests, while others are beneficial predators on other plant pests. The nematode species Caenorhabdis elegans is a common subject in genetics and developmental-biology labs.Slide88

Annelida (AN-el-LEE-dah; 11,500 species)

The

annelids are segmented worms and represent the first lineage of truly

eucoelomate (having a body cavity lined with mesoderm-derived tissue) animals; their body cavities are lined with tissue derived from the embryonic mesoderm. Annelid classes include the marine Polychaeta, as well as the mostly terrestrial Oligochaeta (including the earthworms, Lumbricus) and the mostly-aquatic Hirudinea, or leeches. Characteristics of annelids include nephridia (kidney-like structures), blood vessels, and, in some classes, hermaphroditism.Slide89

Arthropoda (

ar

-THROP-oh-dah or AR-thro-POE-dah; over 800,000 species described; estimates of actual diversity vary but go as high as 9 million species

)The most diverse and successful animal phylum on earth (incorporating about 75% of all described animal species), the Arthropoda are characterized by jointed legs and a chitinous exoskeleton. Like annelids, they are segmented, but unlike annelids, their segments are usually fused into larger body parts with specialized functions (such as the head, thorax, and abdomen of an insect). Arthropods are often divided into four subphyla:Uniramia (insects, centipedes, millipedes); 

Chelicerata

 (arachnids, sea spiders, horseshoe crabs); 

Crustacea

 (shrimps, lobsters, crabs, crayfish, barnacles,

pillbugs

), and 

Trilobitomorpha

 (the trilobites, now extinct).Slide90

Cycliophora (CY-

clee

-oh-FORE-ah; 1 species)

The most recently named phylum; its only known member is Symbion pandora, a tiny invertebrate first identified in 1995 when a Danish biologist found specimens on the mouthparts of a Norwegian lobster. It is believed to be closely related to the marine phyla Entoprocta and Ectoprocta (Bryozoa), which are not discussed here.Slide91

Mollusca (

mol

-LUS-

kah; 50,000 species)The molluscs are second in diversity only to the arthropods. Body plans within this phylum are diverse, but general characteristics include a soft body covered by a thin mantle, with a muscular foot and an internal visceral mass. There are two fluid-filled body cavities derived from mesodermal tissue; a small coelom and a large hemocoel that functions as an open circulatory system. Many molluscs have a shell composed of calcium carbonate and proteins, secreted by the mantle. Familiar groups within the Mollusca include the classes Gastropoda

 (slugs, snails),

Bivalvia

 (clams, oysters, scallops), and 

Cephalopoda

 (nautilus, squids, octopi).Slide92

Echinodermata (

ek

-KY-no-der-MAH-

tah; 6,500 species)Characteristics of this phylum include an endoskeleton composed of many ossicles of calcium and magnesium carbonate, a water vascular system (WVS), a ring canal around the esophagus, and locomotion by tube feet connected to the WVS. Unique to echinoderms is the five-fold radial symmetry obvious in sea stars (seafish), sea urchins, and sea lilies. Others, like sea cucumbers, have varying degrees of bilateral symmetry. In the echinoderm body plan, a true head is absent; the anatomical terms oral (mouth-bearing) and 

aboral

 (away from the mouth) are used to describe orientation of the body surfaces. Feeding adaptations include particle feeding through the WVS, everting the stomach to engulf prey (sea stars), and a scraping device called 

Aristotle's lantern

 (sea urchins).Slide93

Chordata (

kor

-DAH-

tah; 44,000 species)Our home phylum is divided into three subphyla: Urochordata, the sea squirts; Cephalochordata, the lancelets, and the true vertebrates (Vertebrata, the most diverse subphylum). Defining traits of chordates include pharyngeal gill slits, a notochord, a post-anal tail, and a dorsal hollow nerve cord. In vertebrates, some of these structures are found only in embryonic stages. The lancelet Amphioxus (Branchiostoma

)

 is often used as a demonstration organism in biology labs.Slide94

Scientific ScalesSlide95

Linear scales

Linear scales are based on straight lines: equal differences between values on the scale indicate equal differences in the phenomenon being described.Slide96

Mach number:

Mach

numbers measure speed. Based on a suggestion by Swiss aeronautical engineer

Jakob Ackeret, it was named after Ernst Mach, an Austrian physicist who studied—among other things—the Doppler effect, sensory perception, and the origin of inertia. The Mach number is defined as the ratio of the speed of an object to the speed of sound in the same medium. So an object moving at the speed of sound (which in dry air at 20°C is about 343 m/s) has a speed of Mach 1, and an object moving at twice the speed of sound has a speed of Mach 2.Slide97

Temperature scales:

The

scales most frequently used to measure temperatures in science are the Kelvin and Celsius scales. The 

Celsius scale, developed by Swedish scientist Anders Celsius in the early 1700s, assigns a value of 0°C to the freezing point of water (at a pressure of 1 atmosphere), and 100°C to the boiling point of water (at the same pressure). The Kelvin scale is based on the triple point of water, the point at which water’s solid, liquid, and gaseous phases can coexist in equilibrium: 1 K is defined as 1/273.16 of the temperature of water at its triple point.Kelvins are treated like all other SI units

: a temperature of 100 K is read as “one hundred kelvins,” not “one hundred degrees kelvin.”

Differences on the Celsius scale have the same magnitude as differences on the Kelvin scale: a gap of 1°C between temperatures is the same as a gap of 1 K. Therefore the lowest possible temperature, absolute zero (0 K) is equal to –273.15°C, and (at a pressure of 1 atmosphere) water freezes at 273.15 K and boils at 373.15 K.Slide98

Logarithmic scales

Logarithmic

scales are based on the concept of logarithms: a gap of one unit between measurements on the scale always corresponds to the same 

ratio between the phenomena being described.Slide99

Decibel scale:

The

decibel scale can describe any kind of power, but is most commonly used to describe the intensity of sound waves. The decibel (abbreviated dB) is one tenth of a larger unit, the bel (abbreviated B), named after inventor Alexander Graham Bell. The intensity of a sound in decibels is given by the formula 

I = 10 log(P1/P0), where P1 is the intensity of the sound being measured (in watts per square meter) and P

0

 is a 

reference intensity

, which is based on the least powerful sound wave that can be detected by the average human ear (namely 10

–12

 W/m

2

). A 10 dB increase in sound intensity corresponds to 

multiplying

 the energy of the sound wave by 10. A normal conversation has a volume of about 70 

dB.Slide100

pH scale:

The

pH scale, developed by S. P. L.

Sørensen in 1909, is used to quantify acidity. The pH (power of hydrogen) of a solution is defined as the opposite of the (base-10) logarithm of the concentration of protons in a solution: pH = –log10[H+]. (The brackets are standard notation in chemistry for “the concentration of.”) Thus, greater concentrations of protons correspond to smaller pH values. At 25°C, the neutral (neither acidic nor basic) pH is 7; solutions with a pH less than 7 are considered acidic, and solutions with a pH greater than 7 are considered basic.Slide101

Richter scale:

The

Richter scale measures earthquake intensity. Developed by Caltech professor Charles Francis Richter, it measures the 

shaking intensity associated with earthquakes, as quantified by the amplitude of vibrations on a seismograph. A magnitude 5.0 earthquake will have an amplitude 10 times larger than that of a magnitude 4.0 quake. The energy associated with an earthquake is actually proportional to the 3/2 power of the magnitude: a 1-point difference on the Richter scale corresponds to a 103/2-fold (about 31.6) difference in energy. Because of difficulties in measuring the magnitudes of large earthquakes, the Richter scale has been superseded by the moment magnitude scale, which uses a different formula but retains the logarithmic nature (and correlates to measurements on the Richter scale).Slide102

Power scales

While

logarithmic scales take the logarithm of the measured number, power scales raise it to an exponent. These two scales happen to use an exponent of 3/2:Slide103

Beaufort wind force scale:

The

first official use of the Beaufort scale was on the voyage of the HMS 

Beagle in 1831, which was led by Robert FitzRoy, who had been trained by the scale’s namesake, Sir Francis Beaufort, a rear admiral in the British Navy. The Beaufort scale is primarily based on wind speed, but also incorporates descriptions of wave height, sea conditions, and land conditions. It starts at 0, corresponding to “calm” winds with a speed less than 1 knot. In most parts of the world, it stops at 12, which is designated “hurricane-force winds.” Scores of 2 to 6 are called “breezes,” and scores of 7 to 10 are called “gales.” Since 1946 the median wind speed for each step has been defined as 1.87B3/2, where B

 is the number on the Beaufort scale.Slide104

Fujita-Pearson and Enhanced Fujita scales:

These

scales measure tornado strength. The Fujita-Pearson scale was introduced in 1971 by Ted Fujita, a meteorology professor at the University of Chicago, and Allen Pearson, director of what is now the Storm Prediction Center. The original scale went from F0 (wind speeds lower than hurricane force, which should cause little to no damage) to F5 (wind speeds of 260 miles per hour, which should cause “incredible damage”). Fujita also included an “inconceivable damage” category for tornados exceeding 319 miles per hour (theoretically possible, but no such tornado has ever been observed). In 2007 the Enhanced Fujita (EF) scale was introduced, narrowing the speed ranges for each category: an EF5 begins at “just” 200 miles per hour.Slide105

Empirical scales

These

scales assign numbers that make sense relative to each other, but are arbitrary in the sense that there is no fixed quantitative relationship between values on the scale.Slide106

Mohs scale:

Invented

by Friedrich Mohs in 1812, the Mohs scale is based on the abilities of minerals to scratch one another. The original scale assigned a value of 1 to talc, which can be scratched by essentially every solid known, and a value of 10 to diamond, which (among naturally occurring minerals) can only be scratched by other diamonds. The steps are of arbitrary size, with a 1-point difference corresponding to anywhere from a 1.5-fold to a 4-fold increase in 

hardness; diamond is about 1600 times harder than talc. Following the discovery of more ultra-hard minerals, scientists have proposed extending the scale so that diamond is 15 instead of 10.)Slide107

Pauling scale:

The

Pauling scale, devised by Linus Pauling in 1932, is one of several scales that measure 

electronegativity, the attraction of atoms for electrons in chemical bonds. Higher values correspond to stronger attractions. Francium has the lowest value, about 0.7, while fluorine has the highest value, about 4.0. (Noble gases are not assigned values on the Pauling scale, since they were not known to form any bonds when Pauling devised it.) Differences in electronegativity characterize bonds: the greater the difference, the more ionic the bond.Slide108

Saffir-Simpson scale:

The

Saffir-Simpson scale is a measure of wind speed and damage from hurricanes. It was developed in 1971 by Herbert Saffir, a civil engineer, and Robert Simpson, then the director of the National Hurricane Center. It rates hurricanes on a 1-to-5 scale: a 1 corresponds to a wind speed of 74 to 95 miles per hour, which causes “some damage.” A 5 causes “catastrophic damage,” with wind speeds over 157 miles per hour and affected areas uninhabitable for weeks or months.Slide109

OrganellesSlide110

Nucleus 

The

nucleus is the "command central" of the cell because it contains almost all of the cell's DNA, which encodes the information needed to make all the proteins that the cell uses. The DNA appears as chromatin through most of the cell cycle but condenses to form chromosomes when the cell is undergoing mitosis. Commonly seen within the nucleus are dense bodies called nucleoli, which contain ribosomal RNA. In eukaryotes, the nucleus is surrounded by a selectively-permeable nuclear envelope.Slide111

Ribosomes

Ribosomes

are the machines that coordinate protein synthesis, or translation. They consist of several RNA and protein molecules arranged into two subunits. Ribosomes read the messenger RNA copy of the DNA and assemble the appropriate amino acids into protein chains.Slide112

Mitochondria 

The

"mighty

mitos" are the powerhouses of the cell. Mitochondria are double-membrane-bound organelles that are the site of respiration and oxidative phosphorylation, processes that produce energy for the cell in the form of ATP. The inner membrane of a mitochondrion forms folds called cristae [KRIS-tee], which are suspended in a fluid called the matrix. The mitochondrial matrix contains DNA and ribosomes.Slide113

Endoplasmic Reticulum (ER) 

The

ER is a network of tube-like membranes continuous with the nuclear envelope that comes in rough (with ribosomes) and smooth (without ribosomes) varieties. In the ER, proteins undergo modifications and folding to yield the final, functional protein structures.Slide114

Golgi Apparatus 

The

stack of flattened, folded membranes that forms the Golgi apparatus acts as the "post office of the cell." Here proteins from the ribosomes are stored, chemically modified, "addressed" with carbohydrate tags, and packaged in vesicles for delivery.Slide115

Lysosomes 

Lysosomes

are membrane-bound organelles that contain digestive enzymes that break down proteins, lipids, carbohydrates, and nucleic acids. They are important in processing the contents of vesicles taken in from outside the cell. It is crucial to maintain the integrity of the lysosomal membranes because the enzymes they contain can digest cellular components as well.Slide116

Chloroplasts 

Found

only in plants and certain protists, the chloroplast contains the green pigment chlorophyll and is the site of photosynthesis. Like the mitochondrion, a chloroplast is a double-membrane-bound organelle, and it has its own DNA and ribosomes in the stroma. Chloroplasts contain grana, which are stacks of single membrane structures called thylakoids on which the reactions of photosynthesis occur.Slide117

Vacuoles 

Found

mainly in plants and protists, vacuoles are liquid-filled cavities enclosed by a single membrane. They serve as storage bins for food and waste products. Contractile vacuoles are important for freshwater protists to rid their cells of excess water that accumulates because of salt imbalance with the environment.Slide118

Cilia/Flagella 

Cilia

and flagella are important organelles of motility, which allow the cell to move. Flagella are long, whip-like structures, while cilia are short hair-like projections. Both contain a 9 + 2 arrangement of microtubules in cross section and are powered by molecular motors of kinesin and dynein molecules.Slide119

Centrioles 

Not

found in plant cells, centrioles are paired organelles with nine sets of microtubule triplets in cross section. They are important in organizing the microtubule spindle needed to move the chromosomes during mitosis.Slide120

Plant DistinctionsSlide121

Bryophytes vs. pterophytes:

Not

all plants produce seeds. Seedless plants are divided into 

bryophytes (mosses, liverworts, and hornworts) and pterophytes (ferns, club mosses, quillworts, and horsetails). Both of these groups, like all other plants, reproduce by producing sperm and eggs on a structure called the gametophyte. The gametes fuse to form another structure called the sporophyte, which produces spores that disperse and grow into new gametophytes. Both groups produce flagellated sperm that require water for fertilization. Note that these uses of “bryophyte” and “

pterophyte

” here are informal, and should not be confused with the actual phyla

Bryophyta

(true mosses) and

Pteridophyta

(true ferns).Slide122

Bryophytes 

are

small enough that water and nutrients can diffuse to all parts of the plant without any specialized vascular tissue. They lack true leaves and roots, instead fastening themselves to the ground with 

rhizoids. Unlike other land plants, bryophytes have a prominent gametophyte stage that is usually dioicous, meaning that an individual plant produces only one type of gamete (either sperm or egg). The short-lived sporophyte grows from the female gametophyte.Slide123

pterophytes

The more complex 

pterophytes

 can grow taller thanks to vascular tissues (see number 4 below) that provide structural support and transport water and other materials throughout the plant. Many of them do have true leaves and roots. Pterophytes have a prominent sporophyte stage that grows from a small, short-lived gametophyte. Pterophyte gametophytes may be dioicous or monoicous, producing both sperm and egg on the same plant.Slide124

Angiosperms vs. gymnosperms

:

Seed-producing

plants can be divided into gymnosperms (cycads, ginkgos, conifers, and gnetophytes) andangiosperms (phylum Anthophyta, or flowering plants). Most of these plants produce male gametophytes that grow into the female, allowing fertilization to take place in relatively dry conditions. Many of them also exhibit secondary growth

 of woody tissues, allowing them to grow even taller than the pterophytes

.

The word 

gymnosperm

 means “naked seed,” referring to the fact that their gametophytes develop on the surface of leaves or on the scales of cones. In contrast, 

angiosperm

 means “receptacle seed.” Their gametophytes develop enclosed within flowers. Angiosperms are further classified based on their seed

structure.Slide125

Monocots vs. dicots:

Most

(

but not all) angiosperms fall into one of two classes based on the number of cotyledons, or embryonic seed-leaves, in the plant embryo. Monocots, or Monocotyledonae, have one cotyledon, while dicots, or Dicotyledonae, have two. While there are no other hard-and-fast distinguishing characteristics between the two groups, plants in each category tend to share other characteristics:Slide126

Monocots 

produce

pollen grains that have a single furrow (

monosulcate); flower parts in multiples of three; numerous, fibrous roots; parallel leaf veins; and stems with scattered vascular bundles. They also lack secondary growth, remaining herbaceous throughout their lives. Slide127

Dicots

on

the other hand, tend to have pollen with three furrows (

tricolpate); flower parts in multiples of four or greater; taproot systems; stems with rings of vascular tissue; and branching leaf veins. Many of them exhibit secondary growth that produces wood.Slide128

Xylem vs. phloem:

There

are two types of vascular tissue in plants. 

Xylem transports water and soluble nutrients from the roots to the leaves. Phloem, on the other hand, carries nutrients like sucrose from their origin of synthesis or absorption to all parts of the plant. Both tissues originate in the procambium of the apical meristems of both the stems and roots

. In woody plants, secondary vascular tissues arise in the 

vascular cambium

.

Xylem contains distinct elongated cells called 

tracheids

 that have 

lignified

 cell walls and help provide structural support. 

Vessel elements

 are also reinforced by lignin, but they are open at each end at 

perforation plates

 and connect to form long tubes for water transport. Xylem functions via

transpirational

pull and osmosis. Cell types in phloem include companion cells, fibers, and 

sclereids

. In trees, it is usually the innermost layer of

the

barkSlide129

Flower parts:

The

calyx is composed of sepals, specialized green leaves that protect the flower as a bud and provide support for the fully bloomed flowerThe stem supporting a flower is called the peduncle. If multiple flowers bloom from a peduncle, the stems supporting each flower are called

pedicels

. The 

torus

 is the swelling at the top of the pedicel or peduncle, just below the calyx.

Petals

 are specialized leaves, often brightly colored to attract pollinating species. Collectively, they are called a 

corolla

.

The pollen-producing reproductive organ of the flower is called the 

stamen

. The stamen consists of a thin filament topped by an 

anther

, which actually contains the 

pollen

.

The 

pistil

, or female reproductive organ of the flower, is composed of leaf-like 

carpels

. The 

ovary

-containing 

ovules

 are at the base of the pistil, while a tube called a 

style

 topped by a sticky, pollen-receptive 

stigma

 rises from the ovary. There may be one or many pistils in each flower.