Nature

Nature's services: ecosystem services, natural capital, and valuation Nature's services Survey of nature's services—ecosystem goods and services that sustain people and economies—covering concepts, categories, valuation methods, history (including Costanza's estimate)…

Naturism (Nudism): Philosophy, Practice and Social Context Naturism Naturism—also called nudism—is a social movement that promotes non-sexual social nudity for body acceptance, recreation and wellbeing. Practices, etiquette and laws vary widely by…

Naturopathy: Principles, Practices, History, and Contemporary Issues Naturopathy Naturopathy is a system of health care emphasizing natural therapies, prevention, and the body's self-healing. This article explains its principles, common modalities, history, evi…

Near-threatened species Near-threatened (NT) is a conservation status describing species close to qualifying for a threatened category. It signals the need for monitoring and preventive conservation to av…

Negentropy (negative entropy): order, information, and life Negentropy Negentropy, or negative entropy, denotes local increases in order or information. It appears in thermodynamics, biology and information theory and always depends on energy or resou…

Nera (Tiber tributary) Nera (Tiber) The Nera is a river in central Italy, rising in the Apennines of Marche, flowing mainly through Umbria and joining the Tiber. It is known for its gorges, the Velino confluence and…

Neurospora: biology, history, and role as a model organism Neurospora Neurospora is a genus of filamentous ascomycete fungi, best known for Neurospora crassa. Widely used in genetics and molecular biology, it has shaped our understanding of genes, me…

Night: Definition, Causes, Effects and Cultural Significance Night Night is the period when the Sun is below the horizon; it shapes ecology, human behavior, astronomy and culture, and varies with latitude, season and Earth's rotation.

Night vision: biological adaptations and technological systems Night vision Overview of night vision in animals and technology, how it works, main types (image intensification, thermal imaging), uses, history, limitations, and notable distinctions.

Nimbaphrynoides: viviparous toads of the Mount Nimba highlands Nimbaphrynoides A concise overview of the genus Nimbaphrynoides: taxonomy, viviparous reproduction, habitat on Mount Nimba (Guinea/Liberia/Côte d'Ivoire), threats from mining and habitat loss, and…

Noctiluca scintillans — the bioluminescent sea sparkle Noctiluca scintillans A concise overview of Noctiluca scintillans, a free‑living dinoflagellate known for bright bioluminescent displays, heterotrophic feeding, symbioses with phytoplankton, and episodi…

Non-renewable resource Naturally occurring material or energy source whose formation is far slower than human consumption; includes fossil fuels and uranium and has distinct environmental, economic and p…

Nude beach (clothing‑optional beach) Nude beach A nude beach is a shoreline where public nudity is permitted or expected. This article explains types, etiquette, legal status, cultural context, and safety considerations for clot…

Nudity (absence of clothing) Nudity An overview of nudity from biological, historical, social and legal perspectives, explaining contexts, cultural differences, and distinctions between non-sexual and sexual forms.

Nudity Nudity is the condition of wearing little or no clothing; it encompasses biological traits, cultural practices, history, religion, law, health, art, and social norms across societi…

Numinbah Nature Reserve — rainforest remnant in the Mount Warning caldera Numinbah Nature Reserve Protected subtropical rainforest reserve in the Mount Warning caldera (Border Ranges, NSW). Part of the Gondwana Rainforests World Heritage and Scenic Rim Important Bird Area, cons…

Nymph (biology) A nymph is the immature, wingless form of certain arthropods that develop by incomplete metamorphosis; nymphs resemble adults and grow through a series of molts called instars.

Observation: Processes, Tools, History, and Scientific Role Observation A clear overview of observation: what it is, its methods and instruments, historical development, scientific importance, and common limitations such as bias and reproducibility.

Old-growth forest A long-established, minimally disturbed woodland with complex structure, high biodiversity, abundant dead wood and major ecosystem services. Threats include logging, fragmentation,…

Opacity: optical, material, digital, and metaphorical meanings Opacity Opacity is the degree to which a medium blocks passage of light or information. It applies to optics and materials (absorption, scattering), digital graphics (alpha/opacity), and m…

Paper: composition, production, history, types and uses Paper Comprehensive overview of paper: its materials and manufacture, varieties, historical development, common uses, the pulp and paper industry, and environmental considerations.

Pasture: Managed Land for Grazing Animals Pasture A pasture is land cultivated or managed to provide forage for grazing animals. This article explains types, vegetation, management practices, history, uses, and how pasture differs…

Pebble: definition, formation, uses and significance Pebble Short article on pebbles: their size and classification, how they form, common rock types, uses in human culture and construction, ecological roles on shingle beaches, and geologic…

Pendjari National Park Pendjari National Park in northwestern Benin is a key savanna reserve in the W‑Arly‑Pendjari transboundary complex, notable for large mammals, diverse birdlife, and cross‑border co…

Photopsin (iodopsin): cone photopigments of vertebrate color vision Photopsin Photopsins (iodopsins) are light-sensitive proteins in cone photoreceptors that enable color vision. They are G-protein-coupled pigments tuned to different wavelengths and vary amo…

Pica d'Estats Pica d'Estats is a 3,143 m mountain on the Spain–France border in the Montcalm Massif. It is the highest point of Catalonia and the French department of Ariège, notable for its tri…

Poaching: illegal killing and capture of wildlife Poaching Poaching is the unlawful taking of wild animals for profit, subsistence, or conflict. This article explains what poaching is, common targets and methods, ecological and social impa…

Polyamide (polymers built from amide linkages) Polyamide Polyamides are polymers whose repeating units contain amide bonds. They occur naturally as proteins and are made synthetically as fibers and engineering plastics such as nylon and…

Pond: Small Freshwater Body, Ecology, Uses and Conservation Pond A pond is a shallow body of standing freshwater smaller than a lake. This article explains pond characteristics, origins, typical wildlife, human uses, ecological importance and co…

Prairie: Temperate Grassland Ecosystems and Their Ecology Prairie Prairies are temperate grassland ecosystems dominated by grasses and wildflowers, supporting distinctive wildlife and shaped by climate, fire, and grazing across North America and…

Pre-1600 Atlantic hurricane seasons Summary of what is known about Atlantic tropical cyclones before 1600: observational limits, paleotempestology methods, long-term activity patterns, and implications for coastal hi…

Psychedelic mushroom (psilocybin mushrooms) Psychedelic mushroom Fungi that contain psilocybin and related compounds, known for altering consciousness, traditional ritual use, and current medical research into mental health therapies.

Puddle: small uncontained collections of surface water Puddle A puddle is a shallow, uncontained accumulation of liquid on a surface. This article explains how puddles form, their physical properties, ecological roles, hazards, and ways they…

Puffball (fungus): identification, ecology, edibility and safety Puffball Puffballs are round, spore-filled fungi in Basidiomycota; this article explains their structure, habitats, edible species, lookalikes and safe identification practices.

Rain: Formation, Types, Measurement, and Impacts Rain Rain is liquid water falling from clouds. This article explains how rain forms, common types, how it is measured, its role in the water cycle, ecological effects, hazards, and huma…

Rainforest: ecology, distribution, structure and importance Rainforest A comprehensive overview of rainforests: climate, layered structure, global distribution, biodiversity, human uses and conservation challenges.

Raw material: definition, types, uses and economic importance Raw material Raw materials are naturally occurring substances used as inputs for manufacturing and energy. This article explains their types, extraction, processing, uses, environmental issues…

Red hair Red hair is a human hair color produced by high levels of pheomelanin and specific MC1R gene variants, most common in Northern and Western European populations and notable for its…

River Taw A major river in north Devon rising on Dartmoor and flowing north through Barnstaple to a wide estuary that joins the Torridge before entering the Bristol Channel.

Rose Quartz — Pink Variety of Quartz: Characteristics, Occurrence, Uses Rose quartz Rose quartz is a pink to rose-red variety of quartz valued for jewelry and ornamentation. This article summarizes its appearance, geology, historical use, treatments, and how it di…

Ruby (gemstone) Ruby Ruby is the red variety of corundum (Al2O3) colored by chromium; prized in jewelry and industry, with natural, treated and synthetic forms and several distinctive varieties.

Samara (winged fruit) Samara (fruit) A samara is a dry, winged, indehiscent fruit whose extended pericarp helps the seed travel on the wind. Common in maples, ashes, and elms, samaras aid plant dispersal through autor…

Satin bowerbird (Ptilonorhynchus violaceus) Satin bowerbird An Australian passerine noted for its glossy male plumage and elaborate courtship bowers decorated largely with blue objects; inhabits eastern forests and has complex social and ma…

Scoutcraft: practical outdoor skills, history, and modern practice Scoutcraft Scoutcraft refers to traditional woodcraft and backcountry skills—camping, navigation, first aid, shelter building and more—shaped by Scouting pioneers and adapted for recreation,…

Self-organization: spontaneous order in natural and artificial systems Self-organization Self-organization is the spontaneous emergence of structure or pattern from local interactions without central control, found across physics, chemistry, biology, social systems and…

Sequoia National Park Sequoia National Park protects dramatic Sierra Nevada landscapes and the giant sequoia groves, including the General Sherman tree, and reaches from foothill forests to the summit o…

Shade: meaning, formation, uses, and distinctions Shade Shade is the sheltered darker area created when an object blocks direct light; it also names darker variations of a color. This article explains formation, properties, uses, and ho…

Shadow A shadow is the dark shape produced when an object blocks light. This article explains how shadows form, their main types, effects of different light sources, roles in nature, art,…