📚 Your Study Guide
Chemistry, Physics, Earth Science & Biology — all in one place. Click any topic to begin.
Atomic Structure
AMU, mole concept, Avogadro's number, isotopes
Periodic Trends
Atomic radius, ionization energy, electronegativity
Chemical Bonding
Ionic, covalent, VSEPR, hybridization, IMFs
Reactions & Equations
Synthesis, decomposition, redox, conservation of mass
Thermodynamics
Enthalpy, entropy, Gibbs free energy, spontaneity
Mechanics
Newton's laws, kinematics, pendulum, momentum
Electricity & Magnetism
Ohm's law, circuits, DC/AC, magnetic fields
Waves & Light
Transverse, longitudinal, EM spectrum, photon energy
Earth Structure
Plate tectonics, seismic waves, tectonic boundaries
Cell Biology
Organelles, prokaryotes vs eukaryotes, cell structure
Cellular Respiration
Glycolysis, Krebs cycle, ETC, fermentation
Evolution & Genetics
Hardy-Weinberg, natural selection, speciation
⚛️ Atomic Structure & Mass
Fundamental building blocks of matter
Subatomic Particles
Protons, neutrons, electrons
Atomic mass unit (AMU / u): 1 u = 1.660540 × 10⁻²⁷ kg — exactly 1/12 the mass of a C-12 atom
| Particle | Mass (AMU) | Charge |
|---|---|---|
| Proton | 1 | +1 |
| Neutron | 1 | 0 |
| Electron | ~0 (negligible) | −1 |
Key Definitions
Atomic number: Number of protons (determines the element)
Mass number: Total number of protons + neutrons
Isotopes: Same number of protons, different number of neutrons
Average Atomic Mass
= (mass₁ × %₁) + (mass₂ × %₂)
Weighted average of isotope masses
The Mole Concept
Avogadro's number & conversions
| Term | Definition |
|---|---|
| Avogadro's number | 6.022 × 10²³ particles per mole |
| Molar mass | Mass of one mole of a pure substance (g/mol) |
| Mole | Amount of substance with as many particles as atoms in 12 g of C-12 |
Conversions
Moles from mass
n = mass / M
M = molar mass (g/mol)
Moles from atoms
n = N / Nₐ
Nₐ = 6.022 × 10²³
📊 Periodic Trends & Properties
Organization and patterns of the periodic table
Periodic Table Organization
| Feature | Description |
|---|---|
| Groups (18 total) | Vertical columns; same valence electrons → similar properties |
| Periods | Horizontal rows; same number of electron shells |
Key Trends
| Property | Down a Group | Across a Period → |
|---|---|---|
| Atomic radius | ⬆ Increases | ⬇ Decreases |
| Ionization energy | ⬇ Decreases | ⬆ Increases |
| Electronegativity | ⬇ Decreases | ⬆ Increases |
Ionization energy: Energy required to remove one electron from a neutral atom
Element Classifications
| Type | Properties | Examples |
|---|---|---|
| Metals | Conductors, malleable, ductile, lustrous; lose e⁻ → cations | Fe, Cu, Al |
| Nonmetals | Poor conductors, brittle; gain/share electrons | O, N, Cl |
| Metalloids | Semiconductors | Si, Ge |
Special Groups
| Group | Characteristics | Ion Formed |
|---|---|---|
| Alkali metals (Group 1) | Very reactive | +1 |
| Alkaline earth metals (Group 2) | Less reactive | +2 |
| Halogens (Group 17) | Very reactive nonmetals | −1 |
| Noble gases (Group 18) | Very unreactive | None (stable) |
🔗 Chemical Bonding
Types of chemical bonds, VSEPR, intermolecular forces
Types of Bonds
| Bond Type | ΔEN Difference | Description |
|---|---|---|
| Nonpolar covalent | 0 – 0.3 | Equal sharing; identical/similar electronegativities |
| Polar covalent | 0.3 – 1.7 | Unequal sharing; partial charges |
| Ionic | 1.7 – 3.3 | Complete transfer; electrical attraction |
Bond Characteristics
Bond length: Distance between two nuclei at point of minimum energy
Bond energy: Energy required to break a chemical bond
Lattice energy: Energy released when one mole of ionic solid forms from gaseous ions
VSEPR & Hybridization
VSEPR theory: Valence electron pairs repel each other, orienting as far apart as possible
| Electron Domains | Geometry | Bond Angle | Hybridization |
|---|---|---|---|
| 2 | Linear | 180° | sp |
| 3 | Trigonal planar | 120° | sp² |
| 4 | Tetrahedral | 109.5° | sp³ |
Intermolecular Forces
| Force | Description | Strength |
|---|---|---|
| Hydrogen bonding | H covalently bonded to F, O, or N | Strongest |
| Dipole-dipole | Attraction between polar molecules | Moderate |
| London dispersion | Instantaneous dipoles from electron motion | Weakest |
⚗️ Chemical Reactions & Equations
Reaction Types
| Type | General Form | Description |
|---|---|---|
| Synthesis | A + B → AB | Two substances combine |
| Decomposition | AB → A + B | One substance breaks down |
| Single replacement | A + BC → AC + B | One element replaces another |
| Double replacement | AB + CD → AD + CB | Ions exchange partners |
| Combustion | Hydrocarbon + O₂ → CO₂ + H₂O | Reaction with oxygen, releases energy |
Redox Reactions
| Process | Electron Change |
|---|---|
| Oxidation | Loses electrons (OIL) |
| Reduction | Gains electrons (RIG) |
Law of conservation of mass: Matter is neither created nor destroyed; total mass of reactants equals total mass of products
🌡️ Thermodynamics & Energy
Fundamental Laws
First Law: Energy cannot be created or destroyed, only converted between forms
First Law Equation
ΔU = q + w
ΔU = change in internal energy, q = heat, w = work done on/by system
Second Law: Natural processes increase the entropy of the universe
Key Quantities
| Quantity | Symbol | Definition | Sign Convention |
|---|---|---|---|
| Enthalpy | H | Heat content at constant pressure | ΔH > 0: endothermic; ΔH < 0: exothermic |
| Entropy | S | Measure of disorder | Increases with disorder |
| Gibbs free energy | G | Predicts spontaneity | ΔG = ΔH − TΔS |
Spontaneity Conditions
| ΔG | Process |
|---|---|
| ΔG < 0 | Spontaneous |
| ΔG > 0 | Non-spontaneous |
| ΔG = 0 | Equilibrium |
Heat Transfer Equations
Temperature change
Q = mcΔT
c = specific heat capacity
Phase change
Q = mL
L = latent heat
🏃 Physics: Mechanics & Motion
Newton's Laws & Forces
Newton's Second Law: F = ma
| Force Type | Equation | Description |
|---|---|---|
| Weight | W = mg | Gravitational force on mass |
| Centripetal force | F = mv²/r | Force toward center of circular motion |
| Gravitational force | Fɢ = Gm₁m₂/r² | Universal gravitation |
| Hooke's Law (springs) | F = kx | Spring restoring force |
Kinematics & Energy
Acceleration
a = Δv/Δt
Work
W = Fd cos θ
Kinetic Energy
KE = ½mv²
Potential Energy
PE = mgh
Momentum
p = mv
Power
P = W/t
Pendulum Period
T = 2π√(L/g)
T = period, L = length
Mech. Advantage
MA = output/input
Projectile Motion
Path follows a parabola
Horizontal velocity: constant (no horizontal acceleration)
Vertical motion: constant downward acceleration g = 9.8 m/s²
Four Fundamental Forces
| Force | Acts On | Strength | Range |
|---|---|---|---|
| Gravitational | Mass | Weakest | Infinite |
| Electromagnetic | Electric charges | Strong | Infinite |
| Strong nuclear | Nucleons | Strongest | ~10⁻¹⁵ m |
| Weak nuclear | Quarks, leptons | Weak | ~10⁻¹⁸ m |
⚡ Electricity & Magnetism
Basic Circuit Concepts
| Quantity | Symbol | Definition | Unit |
|---|---|---|---|
| Voltage | V | Potential difference; "pressure" driving electrons | Volt (V) = J/C |
| Current | I | Flow of electrons past a point | Ampere (A) = C/s |
| Resistance | R | Opposition to electron flow | Ohm (Ω) |
Ohm's Law
V = IR
Electric Power
P = VI = I²R = V²/R
Current
I = Q/t
Q = charge, t = time
Circuit Components
| Component | Function |
|---|---|
| Resistor | Opposes current flow |
| Capacitor | Stores electric charge |
| Inductor | Current through coil creates magnetic field; changing field induces voltage |
Current Types
Direct Current (DC)
Flows in one direction only
Alternating Current (AC)
Flows back and forth with changing magnetic field
Magnetic Properties
Ferromagnetic materials: Iron, cobalt, nickel — can be magnets or attracted to magnets
Magnetic field lines point from north pole to south pole
Magnetic field unit: Tesla
Electric current produces magnetic field
Force on current-carrying wire: Perpendicular to both magnetic field and current
🌊 Waves & Light
Wave Types & Properties
| Classification | Description | Examples |
|---|---|---|
| Transverse | Particle motion perpendicular to wave direction | Light, water waves |
| Longitudinal | Particle motion parallel to wave direction | Sound, seismic P-waves |
Wave Properties
| Property | Symbol | Definition |
|---|---|---|
| Wavelength | λ | Distance between identical points on successive waves |
| Amplitude | A | Maximum displacement from equilibrium |
| Frequency | f | Number of waves passing a point per second (Hz) |
| Speed | v | v = fλ (determined by medium) |
Wave Phenomena
| Phenomenon | Description |
|---|---|
| Reflection | Bouncing off a surface; angle of incidence = angle of reflection |
| Refraction | Change of direction when passing between media |
| Diffraction | Bending around obstacles |
| Dispersion | Separation into colors (different wavelengths bend differently) |
| Interference | Constructive: waves amplify; Destructive: waves cancel |
| Resonance | Large amplitude vibrations at natural frequency |
Electromagnetic Spectrum
| Region | Wavelength | Notes |
|---|---|---|
| Radio waves | Longest | Communication |
| Microwaves | → | Heating |
| Infrared | Longer than red | Heat radiation |
| Visible light | 400–700 nm | Violet to red |
| Ultraviolet | Shorter than violet | Can damage cells |
| X-rays | → | Medical imaging |
| Gamma rays | Shortest | Highest energy |
Speed of Light
c = 3.00 × 10⁸ m/s
Photon Energy
E = hf
h = 6.63 × 10⁻³⁴ J·s (Planck's constant)
🔍 Optics: Lenses & Mirrors
Mirrors & Lenses
| Mirror Type | Effect | Image |
|---|---|---|
| Concave | Converges light | Magnifying or inverted |
| Convex | Diverges light | Small, upright images |
| Lens Type | Effect | f value |
|---|---|---|
| Convex (converging) | Converges light | f > 0 |
| Concave (diverging) | Diverges light | f < 0 |
Lens/Mirror Formula
1/f = 1/dₒ + 1/dᵢ
Magnification
M = hᵢ/hₒ = −dᵢ/dₒ
Sign Conventions
| Variable | Meaning |
|---|---|
| f > 0 | Converging lens/mirror |
| f < 0 | Diverging lens/mirror |
| dᵢ > 0 | Real image |
| dᵢ < 0 | Virtual image |
| M > 0 | Upright image |
| M < 0 | Inverted image |
🌍 Earth Science: Structure & Processes
Earth's Internal Structure
| Layer | Composition | Characteristics |
|---|---|---|
| Crust | Oxygen, silicon, aluminum | Thin, solid; oceanic (basalt) vs continental (granite) |
| Mantle | Iron, magnesium, silicon, oxygen | Plastic (flows slowly), hot |
| Outer core | Iron, nickel | Liquid |
| Inner core | Iron, nickel | Solid |
Lithosphere: Crust + outer mantle; rigid, brittle, broken into tectonic plates
Asthenosphere: Soft, semi-solid layer beneath; hot and fluid
Plate Tectonics
Evidence for Continental Drift (Wegener)
Fit of continents (puzzle-like match)
Fossil evidence (same species on separated continents)
Rock & mountain similarities
Climate evidence (glacial deposits in tropical areas)
Plate Boundary Types
| Boundary | Movement | Features |
|---|---|---|
| Divergent | Away from each other | Sea floor spreading, rift valleys, volcanoes, weak earthquakes |
| Convergent (Oceanic-Continental) | One subducts under another | Trenches, volcanic arcs, earthquakes |
| Convergent (Continental-Continental) | Collide and crumple | Fold mountains, earthquakes |
| Transform | Slide past each other | Fault lines (e.g. San Andreas), earthquakes |
Seismic Waves
| Wave | Speed | Medium | Note |
|---|---|---|---|
| P-waves (Primary) | Fastest | Solid, liquid, gas | First to arrive |
| S-waves (Secondary) | Slower | Solid only | Cannot travel through liquid outer core |
| Surface waves | Slowest | Surface only | Most destructive |
Isostasy: Concept that crust floats on mantle like ice on water. Thick crust (mountains) has deep roots. When mass is removed, crust rebounds upward.
🪨 Rocks & Minerals
Minerals
Mineral: Naturally occurring, inorganic solid with definite chemical composition and crystal structure
| Property | Description |
|---|---|
| Hardness | Resistance to scratching |
| Luster | Metallic or nonmetallic shine |
| Cleavage | Tendency to break along flat planes |
| Fracture | Irregular breaking (no cleavage) |
Three Rock Types
1. Igneous Rocks (from cooled magma/lava)
| Type | Formation | Crystals | Example |
|---|---|---|---|
| Intrusive (plutonic) | Inside Earth, slow cooling | Large crystals | Granite |
| Extrusive (volcanic) | Surface lava, fast cooling | Small/no crystals | Basalt, obsidian |
2. Sedimentary Rocks (from sediments)
| Type | Formation |
|---|---|
| Clastic | Rock fragments |
| Chemical | Minerals precipitated from water |
| Organic | Remains of living organisms |
3. Metamorphic Rocks (changed by heat/pressure)
| Type | Characteristics | Formation |
|---|---|---|
| Foliated | Bands or layers | Direct pressure |
| Non-foliated | No bands; random structure | Recrystallization |
The Rock Cycle
Magma → (cooling) → Igneous Rock → (weathering/erosion) → Sediments
↑ ↓
└── (melting) ← Metamorphic Rock ← (heat/pressure) ← Sedimentary Rock
🌤️ Atmosphere & Climate
Atmospheric Layers
Atmospheric composition: Nitrogen 78%, Oxygen 21%, Argon 1%
| Layer | Altitude | Characteristics |
|---|---|---|
| Troposphere | 0–10 km | All weather; temperature decreases with altitude |
| Stratosphere | 15–50 km | Contains ozone layer; temperature increases |
| Mesosphere | 50–85 km | Coldest layer; meteors burn up here |
| Thermosphere | 85–600 km | Contains ionosphere; huge temperature increase |
| Exosphere | 600–10,000 km | Fades to space |
Climate Concepts
Greenhouse effect: Sunlight reaches Earth → surface heats up → CO₂, CH₄, N₂O, water vapor absorb and re-radiate heat
Coriolis effect: Earth's rotation causes moving air/water to curve rather than travel straight (no effect at equator)
Circulation Cells
| Cell | Latitude | Characteristics |
|---|---|---|
| Hadley Cell | 0°–30° | Warm air rises at equator; creates rain bands |
| Ferrel Cell | 30°–60° | Air moves toward poles; weather changes |
| Polar Cell | 60°–90° | Cold air sinks at poles; cold climates |
💧 Hydrosphere & Water Cycle
Water Distribution & Cycle
| Source | Percentage |
|---|---|
| Saltwater (oceans) | 97.2% |
| Freshwater | 3% |
| Readily accessible freshwater | 0.3% |
Key property: Water freezes from the top down (ice floats)
The Water Cycle
1. Evaporation + Transpiration — water enters atmosphere
2. Condensation — water vapor cools and forms clouds
3. Precipitation — water falls as rain, snow, etc.
4. Infiltration — water seeps into ground
5. Runoff — water flows over surface
Ocean Features
| Feature | Description | Associated Boundary |
|---|---|---|
| Ocean ridges | Underwater mountain chains | Divergent boundaries |
| Trenches | Deep depressions | Subduction zones |
| Volcanic arcs | Chains of volcanoes | Convergent boundaries |
🌋 Volcanoes & Seismic Activity
Types of Volcanoes
| Type | Shape | Eruption Style | Example |
|---|---|---|---|
| Shield volcanoes | Gentle sloping, dome-like | Non-explosive, lava flows | Mauna Loa |
| Composite (Stratovolcanoes) | Tall, steep sides | Very eruptive | Mount St. Helens |
Subduction: Where one oceanic plate slips under another plate. Key features: trenches, volcanic arcs, strong earthquakes, explosive volcanoes.
🔬 Cell Biology
Organelles & Functions
Nucleus
Control center; contains DNA; membrane-bound
Mitochondria
ATP synthesis; "powerhouse"; own DNA, double membrane
Chloroplast
Photosynthesis; own DNA; double membrane (plant cells)
Ribosomes
Protein synthesis; found in all cells
ER (Rough)
Protein processing and transport
ER (Smooth)
Lipid synthesis, detoxification
Golgi Apparatus
Package and ship proteins and lipids
Lysosomes
Digest waste using enzymes (animal cells)
Vacuoles
Store water/nutrients; large central vacuole in plants
Peroxisomes
Break down fatty acids; detoxify harmful substances
Cytoskeleton
Maintains cell shape; allows movement of organelles
Cell Wall
Plants: cellulose; Fungi: chitin; Bacteria: peptidoglycan
Prokaryotes vs. Eukaryotes
| Feature | Prokaryotes | Eukaryotes |
|---|---|---|
| Nucleus | Absent — nucleoid region | Present — membrane-bound |
| Membrane-bound organelles | Absent | Present |
| DNA form | Circular chromosome | Linear chromosomes |
| Ribosomes | Smaller (70S) | Larger (80S) |
| Size | 1–10 μm | 10–100 μm |
| Examples | Bacteria, archaea | Plants, animals, fungi, protists |
Endosymbiosis Theory
Endosymbiosis: Process where one cell lives inside another — formed eukaryotes when large prokaryotic cells engulfed smaller bacteria
| Endosymbiont | Modern Organelle | Evidence |
|---|---|---|
| Engulfed aerobic bacterium | Mitochondria | Double membrane, own DNA, similar to bacteria |
| Engulfed photosynthetic cyanobacterium | Chloroplasts | Double membrane, own DNA, similar to cyanobacteria |
🫁 Cellular Respiration
Breaking down glucose to make ATP
Overall equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP
Stage 1: Glycolysis
Cytoplasm | Anaerobic
| Feature | Details |
|---|---|
| Location | Cytoplasm |
| Input | Glucose |
| Output | 2 pyruvate, 2 ATP, 2 NADH |
| Oxygen required | No (anaerobic) |
Stage 2: Krebs Cycle (Citric Acid Cycle)
Mitochondrial matrix
| Feature | Details |
|---|---|
| Location | Mitochondrial matrix |
| Input | Pyruvate (from glycolysis) |
| Output | 2 CO₂, 2 ATP, NADH, FADH₂ |
| Carbon fate | Released as CO₂ |
Stage 3: Electron Transport Chain (ETC)
Inner mitochondrial membrane
| Feature | Details |
|---|---|
| Location | Inner mitochondrial membrane |
| Input | NADH, FADH₂, O₂ |
| Output | ~32 ATP, H₂O |
| Oxygen role | Final electron acceptor |
Total ATP yield: Approximately 36–38 ATP per glucose molecule
Fermentation (Anaerobic)
Fermentation: Enables cells to produce ATP without oxygen — allows glycolysis to continue by recycling NAD⁺
| Type | Organisms | Pathway | Note |
|---|---|---|---|
| Lactic acid | Muscle cells, some bacteria | Glucose → pyruvate → lactic acid | Causes muscle fatigue/burning |
| Alcoholic | Yeast, some bacteria | Glucose → pyruvate → ethanol + CO₂ | CO₂ makes bread rise |
🌿 Photosynthesis
Making glucose from CO₂ and light energy
Overall equation: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂
Stage 1: Light-Dependent Reactions
Thylakoid membrane
| Feature | Details |
|---|---|
| Location | Thylakoid membrane |
| Input | Light + H₂O |
| Output | O₂, ATP, NADPH |
| Key event | Water split (photolysis) — releases O₂ |
Stage 2: Calvin Cycle
Stroma | Light-independent
| Feature | Details |
|---|---|
| Location | Stroma |
| Input | CO₂ + ATP + NADPH |
| Output | Glucose |
| Carbon fixation | CO₂ incorporated into organic molecules |
🚪 Cell Membrane & Transport
Plasma Membrane Structure
| Component | Description |
|---|---|
| Phospholipid bilayer | Hydrophilic heads face outward, hydrophobic tails face inward |
| Proteins | Embedded or surface — transport, signaling, structural |
| Cholesterol | Maintains membrane fluidity |
| Carbohydrates | Cell recognition, signaling |
Key property: Selectively permeable — controls what enters and exits
Transport Mechanisms
| Type | Energy | Direction | Examples |
|---|---|---|---|
| Passive transport | No energy | Down concentration gradient | Diffusion, facilitated diffusion, osmosis |
| Active transport | Requires ATP | Against concentration gradient | Protein pumps |
Osmosis & Cell Tonicity
| Condition | Solute Concentration | Water Movement | Cell Effect |
|---|---|---|---|
| Hypotonic | Lower outside cell | Enters cell | Cell may swell or burst (lysis) |
| Hypertonic | Higher outside cell | Leaves cell | Cell shrinks (crenation) |
| Isotonic | Equal | No net movement | Cell maintains shape |
Sodium-potassium pump: Maintains high K⁺ inside cell and high Na⁺ outside cell — essential for nerve function
🌱 Plant Anatomy
Transport Tissues: Xylem & Phloem
| Tissue | Function | Direction | Special Features |
|---|---|---|---|
| Xylem | Moves water and minerals | Upward from roots (one-way) | Dead cells at maturity; lignin for strength; tracheids & vessel elements |
| Phloem | Moves sugars (products of photosynthesis) | Two-way flow (to and from leaves) | Sieve plates between cells; living cells |
Root Systems
| Type | Structure | Examples |
|---|---|---|
| Taproots | One main root with smaller lateral branches | Dandelions, carrots, beets |
| Fibrous roots | Many small roots spread out | Grasses, monocots, onions |
Leaf Structure
| Structure | Description | Function |
|---|---|---|
| Cuticle | Waxy layer | Prevents water loss |
| Epidermis | Protective outer layer | Protection, gas exchange regulation |
| Mesophyll | Cells rich in chloroplasts | Where photosynthesis occurs |
| Veins | Contain xylem and phloem | Transport water, minerals, sugars |
| Stomata | Tiny pores | Gas exchange; regulated by guard cells |
Flower Structure & Reproduction
| Structure | Description | Function |
|---|---|---|
| Sepals | Outermost, often green | Protect flower bud |
| Petals | Often colorful, scented | Attract pollinators |
| Stamens (male) | Anther + filament | Produce pollen |
| Carpel/Pistil (female) | Stigma + style + ovary | Contains ovule with female gametophyte |
Fertilization & Development
| Stage | Process | Result |
|---|---|---|
| Pollination | Pollen transferred to stigma | — |
| Fertilization | Sperm fertilizes egg in ovule | Zygote forms |
| Ovule → Seed | Fertilized ovule develops | Seed (embryo + nutrients) |
| Ovary → Fruit | Ovary tissue develops | Fruit (protection + dispersal) |
🔄 Evolution & Natural Selection
Types of Evolution
Natural selection is NOT random — advantageous traits accumulate over time through differential survival and reproduction
| Type | Description | Example |
|---|---|---|
| Convergent evolution | Unrelated species evolve similar traits | Wings in birds and insects |
| Divergent evolution | Closely related species evolve different traits | Darwin's finches |
| Coevolution | Species evolve in response to each other | Predator-prey arms races, pollinators and flowers |
| Adaptive radiation | Rapid diversification to fill ecological niches | Darwin's finches |
Five Factors Leading to Evolution
| Factor | Mechanism | Effect |
|---|---|---|
| Genetic drift | Random changes in allele frequencies | Stronger in small populations |
| Gene flow | Movement of alleles between populations | Makes populations more genetically similar |
| Mutations | Random DNA changes | Ultimate source of new genetic variation |
| Sexual selection | Selection for traits improving mating success | Favors reproductive success |
| Natural selection | Selection for advantageous survival traits | Adapts populations to environment |
Extinction Types
| Type | Rate | Cause |
|---|---|---|
| Background extinction | Slow, continuous | Normal environmental pressures, competition |
| Mass extinction | Rare, intense, global | Catastrophic events: asteroid impacts, volcanism, climate change |
Specialization Patterns
Punctuated Equilibrium
Rapid speciation events followed by long periods of stability
Gradualism
Slow, continuous evolutionary change over time
Miller-Urey Experiment
Setup: Methane (CH₄), ammonia (NH₃), hydrogen (H₂), water vapor + heat and electrical sparks for one week
Result: Produced organic materials including amino acids — building blocks of life
Significance: Demonstrated that organic molecules could form spontaneously under early Earth conditions; supported primordial soup hypothesis
🦕 Geological Eras & Periods
Geological Timeline
1. Precambrian
Only multicellular animals with soft parts
No fossils — soft parts don't preserve
2. Paleozoic Era — "Age of ancient life"
| Period | Key Events |
|---|---|
| Cambrian | Cambrian explosion: Rapid diversification; marine invertebrates (trilobites) abundant |
| End of Cambrian | Mass extinction |
| Ordovician & Silurian | First vertebrates; marine animals on the rise |
3. Mesozoic Era — "Age of reptiles"
| Period | Key Events |
|---|---|
| Triassic | Mass extinction; dinosaurs, birds, flowering plants, mammals appear |
| Jurassic | Dinosaurs radiated — dominant group |
| Cretaceous | Mass extinction (dinosaurs) |
4. Cenozoic Era — "Age of mammals"
Mammals diversified — filled niches left by dinosaurs
Modern humans appeared
🧬 Genetics & Hardy-Weinberg
Hardy-Weinberg Equilibrium
Hardy-Weinberg Equations
p² + 2pq + q² = 1
p + q = 1
| Term | Meaning |
|---|---|
| p | Frequency of dominant allele (A) |
| q | Frequency of recessive allele (a) |
| p² | Frequency of homozygous dominant (AA) |
| 2pq | Frequency of heterozygous (Aa) |
| q² | Frequency of homozygous recessive (aa) |
Application: Must know frequency of recessive homozygotes (q²) to calculate other frequencies. Assumption: No evolution occurring — population is at equilibrium.
Isolation & Speciation
| Isolation Type | Mechanism |
|---|---|
| Geographic isolation | Physical barriers prevent gene flow |
| Reproductive isolation | Biological barriers prevent successful mating |
Shared Characteristics (Universal)
Bacteria + plants + animals all share: specific enzymes, cell membranes, metabolic pathways, the genetic code in DNA, ribosomes
Interpretation: Shared traits originated in prokaryotes
🐵 Primates & Bipedalism
Primate Classification
| Group | Characteristics | Examples |
|---|---|---|
| Prosimians | Oldest living primates; nocturnal, rely on smell | Tarsiers, lemurs, lorises, galagos |
| Anthropoids | Human-like; larger brains, diurnal, color vision | Monkeys, apes, humans |
Anthropoid Subgroups
| Subgroup | Distribution | Characteristics |
|---|---|---|
| New World monkeys | Central/South America | Prehensile tails, flat noses (platyrrhine), arboreal |
| Old World monkeys | Africa, Asia | Non-prehensile tails, narrow noses (catarrhine) |
| Hominoids | Worldwide | No tails, larger brains, apes and humans |
Hominoid Groups
| Group | Members |
|---|---|
| Lesser apes | Gibbons, siamangs |
| Great apes | Orangutans, gorillas, chimpanzees, bonobos, humans |
Bipedal Adaptations
| Feature | Function |
|---|---|
| Curved pelvis | Supports upright posture; repositions muscles |
| Aligned knees | Efficient weight bearing directly below body |
| S-shaped spine | Shock absorption, maintains balance over pelvis |
| Centered skull (foramen magnum) | Balanced head position directly above spine |
| Shorter, broader pelvis | Stability for upright stance |
| Longer legs | Efficient stride |
| Arched feet | Shock absorption, propulsion |
📋 Key Equations & Quick Reference
Everything you need to memorize for the exam
Chemistry Formulas
Moles from mass
n = m / M
Gibbs free energy
ΔG = ΔH − TΔS
Heat transfer
Q = mcΔT
Phase change
Q = mL
1st Law Thermo
ΔU = q + w
Physics Formulas
Newton's 2nd
F = ma
Kinetic Energy
KE = ½mv²
Potential Energy
PE = mgh
Momentum
p = mv
Work (with angle)
W = Fd cos θ
Ohm's Law
V = IR
Power
P = VI = I²R
Wave speed
v = fλ
Photon energy
E = hf
Pendulum period
T = 2π√(L/g)
Lens/Mirror
1/f = 1/dₒ + 1/dᵢ
Gravitational
F = Gm₁m₂/r²
Biology Key Processes
| Process | Location | Key Products |
|---|---|---|
| Glycolysis | Cytoplasm | 2 ATP, 2 NADH, 2 pyruvate |
| Krebs cycle | Mitochondrial matrix | 2 ATP, NADH, FADH₂, CO₂ |
| Electron Transport Chain | Inner mitochondrial membrane | ~32 ATP, H₂O |
| Light reactions | Thylakoid membrane | ATP, NADPH, O₂ |
| Calvin cycle | Stroma | Glucose |
Human Body Systems
| System | Primary Function | Key Components |
|---|---|---|
| Circulatory | Transport | Heart, arteries, veins, capillaries, blood |
| Respiratory | Gas exchange | Lungs, alveoli, diaphragm, trachea |
| Digestive | Nutrient processing | Stomach, intestines, liver, pancreas |
| Nervous | Control & communication | Brain, spinal cord, nerves, neurons |
| Endocrine | Hormone regulation | Pituitary, thyroid, adrenal glands, pancreas |
| Immune | Defense | White blood cells, spleen, bone marrow |
| Reproductive | Offspring production | Gonads, reproductive tract structures |
Hardy-Weinberg
Genotype frequencies
p² + 2pq + q² = 1
Allele frequencies
p + q = 1