RESEARCH BASE
Search 3,721 documents across 34 fields — every claim tier-rated by evidence
3,633 are the core, quality-scored corpus (34 lettered sections — see How We Work); the remaining 88 are cross-corpus synthesis documents (68 InterDocs, 12 Connections, 8 Theories) also indexed here.
2,439 results for "ur" — page 93 of 122
R_3_03 — Evo-Devo: Evolutionary Developmental Biology
Evolutionary developmental biology ("evo-devo") reveals one of biology's most profound discoveries: the same small set of "toolkit" genes (Hox, Pax6, Sonic hedgehog, BMP, Wnt, etc.) controls body plan development across
R_3_13 — Evolution of the Immune System
The immune system is one of evolution's most elaborate and costly creations — vertebrate adaptive immunity alone employs V(D)J recombination to generate over 10¹¹ distinct antibody specificities from fewer than 400 gene
R_5_20 — Mass Extinction Recovery: Post-Crisis Adaptive Radiation
Life on Earth has survived at least five major mass extinctions — the "Big Five" — each eliminating 75–96% of species. Yet each catastrophe was followed by a remarkable recovery phase in which surviving lineages radiated
R_5_13 — Biological Invasions: Introduced Species and Ecosystem Disruption
Biological invasions — the introduction and spread of species beyond their native range, typically aided by human activity — represent one of the top five drivers of global biodiversity loss, alongside habitat destructio
R_5_14 — Thermoregulation: Endothermy, Ectothermy, and Metabolic Evolution
Thermoregulation — the ability to maintain body temperature within functional limits — is a fundamental challenge of animal life, and the strategies organisms employ span a continuum from pure ectothermy (relying on envi
R_5_07 — Ethnobotany: Plants, People, and Traditional Knowledge
Ethnobotany — the study of the relationships between plants and people across cultures and throughout history — documents how human societies have used plants for food, medicine, shelter, textiles, tools, dyes, poisons,
R_2_05 — Missing Fossil Record and Punctuated Equilibrium
Darwin himself called the fossil record "the most obvious and gravest objection which can be urged against my theory" — because if evolution occurred through gradual transformation, we should find smooth transitional seq
R_2_14 — Recent Human Evolution: Lactase Persistence, Altitude Adaptation, and Malaria Resistance
Human evolution did not stop with the emergence of Homo sapiens ~300,000 years ago — natural selection has continued to shape human biology in response to agriculture, diet, disease, climate, and altitude, producing some
R_2_13 — Mammalian Radiation: Post-Cretaceous Diversification
The Cretaceous-Paleogene (K-Pg) mass extinction 66 million years ago — triggered by an asteroid impact and possibly exacerbated by Deccan Traps volcanism — eliminated the non-avian dinosaurs and opened vast ecological ni
R_2_07 — Stoned Ape Hypothesis — Psilocybin, Cognitive Evolution, and the McKenna Theory
The "Stoned Ape Hypothesis," proposed by ethnobotanist Terence McKenna in Food of the Gods (1992), posits that the consumption of psilocybin-containing mushrooms by early hominids (particularly Homo erectus and Homo erga
R_2_02 — Convergent Evolution and the Aquatic Ape Hypothesis
Convergent evolution — the independent development of similar features in unrelated lineages — is one of biology's most profound patterns. Eyes evolved independently at least 40-65 times (Fernald 2006). Echolocation evol
R_2_01 — Human Brain Evolution and the Cognitive Revolution
The human brain tripled in size over 3 million years — from ~400 cm³ (Australopithecus) to ~1,400 cm³ (modern Homo sapiens). This is the most dramatic encephalization in the history of life, and NO consensus exists on wh
R_1_11 — Extinction, Recovery, and Adaptive Radiation
The history of life is punctuated by mass extinction events — catastrophic biodiversity losses that eliminate >75% of species in geologically brief intervals — followed by recovery phases and adaptive radiations during w
R_1_01 — Abiogenesis & Origin of Life Theories
Abiogenesis — the emergence of life from non-living chemistry — remains one of the deepest unsolved problems in science. The oldest confirmed microfossils date to ~3.5 billion years ago (Pilbara, Western Australia), with
R_1_03 — Mass Extinction Events
Life on Earth has endured at least five catastrophic mass extinctions in 540 million years, each eliminating 60–96% of all species. The "Big Five" are: End-Ordovician (~443 Mya, ~85% species lost), Late Devonian (~372 My
R_1_05 — Quantum Biology
Until recently, quantum effects were thought impossible in warm, wet biological systems. The standard assumption held that thermal noise at physiological temperatures (~310 K) would destroy quantum coherence within femto
R_1_02 — The Cambrian Explosion
Between ~541 and ~520 million years ago, nearly ALL major animal body plans (phyla) appeared in the fossil record in an evolutionary "instant" — roughly 20 million years. Before this, life had been single-celled for ~3 b
R_1_15 — The Chirality Problem: Why Life Uses Left-Handed Amino Acids
One of the deepest unsolved problems in the origin of life is homochirality — the fact that all known life on Earth uses almost exclusively L-amino acids (left-handed) for proteins and D-sugars (right-handed) for nucleic
R_1_19 — Deep-Sea Hydrothermal Vent Origin of Life
The deep-sea hydrothermal vent hypothesis for the origin of life proposes that life on Earth began at submarine hydrothermal systems — either high-temperature black smoker vents (>350°C, acidic, rich in transition metals
R_1_04 — Extremophile Biology and the Limits of Life
Life exists in conditions once considered impossible: boiling hot springs (121°C+), deep-sea hydrothermal vents at crushing pressures, Antarctic ice, pH 0 acid lakes, nuclear reactor cooling pools, kilometers below Earth
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