Darwin + Wallace: <b>Descent with Modification</b>. <b>Variation</b> (heritable traits differ), <b>Struggle for Existence</b> (limited resources), <b>Survival of the Fittest</b> (differential reproduction). Leads to <b>Adaptation</b> over generations.

<b>Fossil Record</b>: Preserved remains show <b>Intermediate Forms</b> (transitional species, e.g., Archaeopteryx). <b>Relative Dating</b> (rock layers), <b>Radiometric Dating</b> (isotopes). <b>Index Fossils</b> identify time periods.

<b>Homologous Structures</b>: Same structure, different function (bat wing vs. human arm = common ancestry). <b>Vestigial Structures</b>: Reduced/nonfunctional remnants (human appendix, whale pelvis). <b>Analogous Structures</b>: Similar function, different origin (bat vs. insect wing = convergent evolution).

Geographic distribution reflects evolutionary history. <b>Island Species</b> (Galápagos finches). <b>Continental Drift</b> (fossils on separate continents, e.g., Mesosaurus).

<b>Embryological Similarities</b>: Early development stages similar across species. <b>Molecular Homologies</b>: DNA/Protein sequences reveal relatedness (more similar = more recent common ancestor).

Discredited theory: Traits acquired during lifetime passed to offspring (giraffes stretching necks). <b>Incorrect</b> because only genetic changes inherited.

Integration of Darwin's natural selection + Mendelian genetics + population genetics. Evolution = change in <b>allele frequencies</b> over time.

<b>Divergent</b>: Common ancestor → different forms (adaptive radiation, e.g., Darwin's finches). <b>Convergent</b>: Distantly related → similar forms (analogous structures, e.g., shark vs. dolphin streamlining).

<b>Gene Pool</b>: All alleles in a population. <b>Population Genetics</b>: Study of allele frequency changes. Evolution = change in allele frequencies over generations.

<b>No evolution</b> if: Large population, Random mating, No mutations, No migration, No natural selection. <b>Equations</b>: p + q = 1 (alleles), p² + 2pq + q² = 1 (genotypes).

<b>Directional</b> (one extreme favored), <b>Stabilizing</b> (average favored), <b>Disruptive</b> (both extremes favored). <b>Sexual Selection</b>: Traits for mating success.

Random changes in allele frequencies (smaller populations = greater effect). <b>Bottleneck Effect</b>: Population crash reduces diversity. <b>Founder Effect</b>: Small group colonizes new area with unrepresentative alleles.

Movement of alleles between populations via migration. <b>Increases</b> genetic diversity within populations, <b>decreases</b> differences between populations.

Ultimate source of new alleles. Can be beneficial, neutral, or harmful. <b>Point Mutations</b> (single nucleotide), <b>Chromosomal Mutations</b> (large-scale changes).

<b>Microevolution</b>: Small-scale changes within a population (allele frequency shifts). <b>Macroevolution</b>: Large-scale patterns over geological time (speciation, mass extinctions, adaptive radiation).

Formation of new species when populations can no longer interbreed. <b>Reproductive Isolation</b> (Prezygotic: Behavioral, Temporal, Geographic barriers; Postzygotic: Hybrid inviability/sterility).

Geographic separation prevents gene flow. <b>Vicariance</b> (barrier divides population), <b>Dispersal</b> (colonization of new area). Example: Darwin's finches.

Speciation without geographic separation. <b>Polyploidy</b> (extra chromosome sets, common in plants), <b>Behavioral/Sexual Selection</b> isolation.

<b>Adaptive Radiation</b>: Rapid diversification from common ancestor to fill niches (e.g., Hawaiian honeycreepers). <b>Coevolution</b>: Reciprocal evolutionary changes between interacting species (flowers ↔ pollinators).

<b>Taxonomy</b>: Science of naming/classifying organisms. <b>Binomial Nomenclature</b>: Genus + species (e.g., <i>Homo sapiens</i>). <b>Hierarchy</b>: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.

<b>Domains</b>: Bacteria (peptidoglycan cell walls), Archaea (extremophiles, unique lipids), Eukarya (membrane-bound nucleus). <b>Six Kingdoms</b>: Eubacteria, Archaebacteria, Protista, Fungi, Plantae, Animalia.

<b>Phylogeny</b>: Evolutionary history. <b>Phylogenetic Tree</b>: Diagram showing relationships. <b>Branch Points</b> (common ancestors), <b>Sister Taxa</b> (share recent ancestor), <b>Rooted Tree</b> (single common ancestor).

<b>Cladistics</b>: Classification by shared <b>Derived Characters</b> (evolutionary novelties). <b>Clade (Monophyletic Group)</b>: Ancestor + all descendants. <b>Maximum Parsimony</b>: Simplest evolutionary explanation preferred.

<b>Homologous</b>: Inherited from common ancestor (indicates relatedness). <b>Analogous</b>: Similar due to convergent evolution (does NOT indicate relatedness).

DNA/protein sequences used to determine relationships. More similar sequences = more closely related. <b>Molecular Clocks</b> estimate divergence times.

<b>Eons</b>: Hadean, Archean, Proterozoic, Phanerozoic. <b>Eras</b>: Paleozoic, Mesozoic, Cenozoic. <b>Periods</b>: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene, Quaternary.

<b>Miller-Urey Experiment</b>: Organic molecules from inorganic precursors (simulated early Earth atmosphere). <b>Primordial Soup Hypothesis</b>. <b>RNA World</b>: Self-replicating RNA preceded DNA/proteins.

<b>Mitochondria</b> and <b>Chloroplasts</b> originated from engulfed prokaryotes. Evidence: Own DNA, double membrane, binary fission, ribosomes similar to bacteria.

<b>Permian</b> (~251 mya, 96% species lost), <b>Cretaceous</b> (~66 mya, dinosaurs extinct). Causes: <b>Asteroid Impacts</b>, volcanic eruptions, climate change. Lead to <b>Adaptive Radiation</b> of survivors.

<b>Cambrian Explosion</b> (rapid diversification ~540 mya), <b>Colonization of Land</b> (plants → arthropods → vertebrates), <b>Evolution of Flight</b> (insects, pterosaurs, birds, bats).

<b>Prokaryotes</b>: No nucleus. <b>Peptidoglycan</b> cell walls. <b>Shapes</b>: Cocci (spheres), Bacilli (rods), Spirilla (spirals). <b>Gram Staining</b>: Gram+ (thick peptidoglycan), Gram- (thin + outer membrane). <b>Cyanobacteria</b>: Photosynthetic, oxygenated atmosphere.

<b>Extremophiles</b>: Thermophiles (hot springs), Halophiles (salt lakes), Methanogens (produce methane). <b>Pseudopeptidoglycan</b> cell walls. More similar to Eukarya than Bacteria (genetics).

<b>Decomposers</b>, <b>Nitrogen Fixation</b>, <b>Pathogens</b> (disease). <b>Biofilms</b>: Communities in sticky matrix. <b>Horizontal Gene Transfer</b>: Conjugation (pilus), Transformation (uptake DNA), Transduction (virus).

Diverse eukaryotes. <b>Supergroups</b>: Excavata (Giardia), Chromalveolata (diatoms, brown algae), Rhizaria (forams), Archaeplastida (red/green algae), Amoebozoa (amoebas, slime molds), Opisthokonta (ancestors of fungi/animals). <b>Protozoa</b> (animal-like), <b>Algae</b> (plant-like), <b>Slime Molds</b> (fungus-like).

<b>Heterotrophs</b> (absorb nutrients). <b>Chitin</b> cell walls. <b>Hyphae</b> (filaments) form <b>Mycelium</b> (mass). <b>Saprobes</b> (decompose dead matter). <b>Spores</b> for reproduction.

<b>Chytridiomycota</b> (aquatic, flagellated spores), <b>Zygomycota</b> (bread mold), <b>Ascomycota</b> (sac fungi, yeasts, morels), <b>Basidiomycota</b> (club fungi, mushrooms), <b>Glomeromycota</b> (mycorrhizae).

<b>Lichens</b>: Fungus + photosynthetic partner (alga/cyanobacteria). <b>Mycorrhizae</b>: Fungus + plant roots (nutrient exchange). <b>Pathogens</b>: Mycoses (fungal infections), crop diseases.

<b>Cuticle</b> (waxy layer prevents water loss), <b>Stomata</b> (gas exchange pores), <b>Vascular Tissue</b> (Xylem: water/minerals up, Phloem: sugars down), <b>Roots</b> (anchor + absorb), <b>Alternation of Generations</b> (Sporophyte 2N ↔ Gametophyte N).

<b>Mosses, Liverworts, Hornworts</b>. No vascular tissue (small size, moist habitats). <b>Gametophyte-dominant</b>. Sperm require water for fertilization.

<b>Club Mosses, Horsetails, Ferns, Whisk Ferns</b>. Vascular tissue (larger than bryophytes). <b>Sporophyte-dominant</b>. Reproduce via <b>spores</b>. Still require water for fertilization.

<b>Conifers</b> (pines, spruces), <b>Cycads</b>, <b>Ginkgo</b>, <b>Gnetophytes</b>. Seeds in <b>cones</b> (not enclosed). <b>Heterosporous</b> (megaspores → female, microspores → male). <b>Pollen</b> (no water needed for fertilization).

<b>Flowers</b>: Sepals, Petals, Stamens (male: anther + filament), Carpel/Pistil (female: stigma, style, ovary). <b>Fruit</b> (mature ovary) protects/disperses seeds. <b>Monocots</b> (1 cotyledon, parallel veins) vs. <b>Eudicots</b> (2 cotyledons, netted veins).

<b>Symmetry</b>: Asymmetrical (sponges), Radial (cnidarians), Bilateral (most animals). <b>Germ Layers</b>: Diploblasts (2 layers: ectoderm + endoderm), Triploblasts (3 layers: + mesoderm). <b>Coelom</b>: Acoelomates (no cavity), Pseudocoelomates (partial cavity), Eucoelomates (true coelom). <b>Development</b>: Protostomes (mouth first) vs. Deuterostomes (anus first).

<b>Porifera (Sponges)</b>: Asymmetrical, no tissues. <b>Choanocytes</b> (collar cells filter food), <b>Spicules</b> (support). <b>Cnidaria</b>: Radial symmetry, diploblasts. <b>Cnidocytes</b> (stinging cells), <b>Nematocysts</b> (harpoons). <b>Polyp</b> (sessile) vs. <b>Medusa</b> (free-swimming). Classes: Hydrozoa, Scyphozoa (jellyfish), Cubozoa (box jellies), Anthozoa (corals, anemones).

<b>Platyhelminthes (Flatworms)</b>: Acoelomates, bilateral. Turbellaria (planarians), Trematoda (flukes), Cestoda (tapeworms), Monogenea. <b>Nematoda (Roundworms)</b>: Pseudocoelomates, complete digestive system, cuticle. <b>Annelida</b>: True coelomates, <b>Metamerism</b> (segmentation), <b>Chaetae</b> (bristles). Classes: Polychaeta, Oligochaeta (earthworms), Hirudinea (leeches).

<b>Mollusca</b>: <b>Mantle</b> (secretes shell), <b>Radula</b> (scraping tongue), <b>Ctenidia</b> (gills). Classes: Gastropoda (snails), Bivalvia (clams), Cephalopoda (squid, octopus). <b>Echinodermata</b>: <b>Radial symmetry</b> (adults), <b>Water Vascular System</b>, <b>Endoskeleton</b> with spines. Deuterostomes. Classes: Asteroidea (sea stars), Echinoidea (sea urchins), Holothuroidea (sea cucumbers).

<b>Jointed Appendages</b>, <b>Segmentation</b>, <b>Exoskeleton</b> (chitin), <b>Molting</b>. <b>Hemocoel</b> (open circulatory system). Subphyla: <b>Chelicerata</b> (spiders, scorpions), <b>Myriapoda</b> (millipedes, centipedes), <b>Hexapoda</b> (insects: 3 body segments, 6 legs, wings), <b>Crustacea</b> (crabs, lobsters, barnacles).

<b>Chordata</b>: <b>Notochord</b>, <b>Dorsal Hollow Nerve Cord</b>, <b>Pharyngeal Slits</b>, <b>Post-Anal Tail</b> (at some life stage). Subphyla: Cephalochordata (lancelets), Urochordata (tunicates), <b>Vertebrata</b> (vertebral column replaces notochord).

<b>Agnatha</b> (jawless: lampreys, hagfish). <b>Chondrichthyes</b> (cartilaginous: sharks, rays; <b>Ampulla of Lorenzini</b>, placoid scales). <b>Osteichthyes</b> (bony fish): <b>Actinopterygii</b> (ray-finned), <b>Sarcopterygii</b> (lobe-finned, ancestors of tetrapods). <b>Swim Bladder</b>, <b>Lateral Line</b>, <b>Operculum</b>.

<b>Amphibia</b>: <b>Dual life</b> (aquatic larvae → terrestrial adults). <b>Cutaneous Respiration</b> (skin breathing), moist skin. <b>Metamorphosis</b>. Orders: Anura (frogs/toads), Urodela (salamanders), Apoda (caecilians). First vertebrates on land.

<b>Reptilia</b>: <b>Amniotic Egg</b> (shell + membranes), <b>Scales</b> (keratin), <b>Ectotherms</b>. Orders: Testudines (turtles), Squamata (lizards, snakes), Crocodilia (crocodiles, alligators), Sphenodontia (tuatara). <b>Aves (Birds)</b>: <b>Endotherms</b>, <b>Feathers</b>, <b>Pneumatic Bones</b> (hollow), <b>One-Way Air Flow</b>, <b>Down Feathers</b> (insulation). Evolved from theropod dinosaurs.

<b>Mammalia</b>: <b>Hair</b>, <b>Mammary Glands</b> (milk), <b>Endotherms</b>, <b>Heterodont Teeth</b>, <b>Diphyodont</b> (2 sets teeth), <b>Sebaceous/Sudoriferous Glands</b>. <b>Monotremes</b> (egg-laying: platypus, echidna), <b>Marsupials</b> (pouch: kangaroos, opossums), <b>Eutherians (Placentals)</b>: Complex placenta. <b>Primates</b>: Opposable thumbs, stereoscopic vision, large brain, nails (not claws). Prosimians vs. Anthropoids (monkeys, apes, humans).