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from article Forest ecosystem
Forest in Moran State Park on Orcas Island, Washington. (Credit: Chris Willig)
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from article Forest ecosystem
Forest fire in No Name Creek area of Colorado. (Credit: Andrea Booher/FEMA)
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from article Forest ecosystem
Puma and cub in forest. (Credit: Grant Faint/Stockbyte/Getty Images)
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from article Forest ecosystem
Conceptual model of elemental cycling in a terrestial ecosystem, emphasizing the presence and activities of arthropod consumers. The indirect regulation of elemental movement by arthropods is indicated by the hourglass-shaped valves on these flows.…
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from article Forest ecosystem
The southern pine beetle (Dendroctonus frontalis) is a destructive insect pest of coniferous forests in the southern United States. (Credit: U.S. Forest Service)
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from article Forest ecosystem
Belowground food web. (Credit: Elaine Ingham)
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from article Vampyromorpha
Vampyroteuthis infernalis (vampire squid) living in the oxygen-minimum zone of Monterey Bay, California, at depths of 600–900 m (1970–2950 ft). (Photo courtesy of Kim Reisenbichler, Monterey Bay Aquarium Research Institute, Moss Landing, CA)
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from article Vampyromorpha
Vampyroteuthis infernalis (vampire squid) showing sensory filaments and photophores (light organs).
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from article Civet
Owston's palm civet (Chrotogale owston). (Photo copyright © by Mark Kostich)
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from article Medical waste
The uniform international biohazard symbol.
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from article Convection in the Earth
Pattern of magnetic stripes over the Reykjanes Ridge southwest of Iceland. (After J. R. Heirtzler, X. LePichon, and J. G. Baron, Magnetic anomalies over the Reykjanes Ridge, Deep Sea Res., 13:427, 1966)
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from article Convection in the Earth
Geographic setting of the Kurile Trench off the Kamchatka Peninsula, showing the deep ocean trench and the characteristic line of volcanoes in the vicinity of the subduction zone. The sections A′ and B′ illustrate the bathymetry normal to the trench…
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from article Convection in the Earth
Characteristic variation of heat flow and bathymetry. (a) Variation of surface heat flow as a function of age of the ocean floor in millions of years before present for the Pacific, South Atlantic, and Indian oceans. (b) Variation of sea-floor…
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from article Convection in the Earth
Global seismicity showing surface projections of all earthquakes which occurred during 1965–1975 with magnitudes in the range 4.5–5.5. Plate boundaries are located along the seams marked by high frequency of earthquake occurrence.
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from article Convection in the Earth
Map of global tectonic and volcanic activity over the past million years. (After The Physical World, National Geographic Society, Van der Grinten projection, 1975)
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from article Seawater
Vertical distribution of phosphate (PO43−) at three stations to show a range of characteristics found in major oceanic regions. North Atlantic is from a region in the central North Atlantic northeast of Bermuda and North Pacific is from the central…
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from article Seawater
Vertical distribution of total carbon dioxide concentrations at locations in the North Atlantic and North Pacific. Below depths of a few hundred meters, the distributions are generally characteristic of fairly large regions in the two oceans.
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from article Seawater
Layers in seawater in a section through the Atlantic Ocean from the Greenland Sea (right) to the Weddell Sea (left). The thick line represents depth. (a) Potential temperature; contour values are in °C (°F). (b) Salinity; contours are in parts per…
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from article Seawater
Layers in seawater in a section through the western Indian Ocean from India (right) to Antarctica (left). The thick line represents depth. (a) Potential temperature; contour values are in °C (°F). (b) Salinity; contours are in parts per thousand.
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from article Seawater
Layers in seawater in a section through the Pacific Ocean from the Aleutian Islands (right) to the Ross Sea (left). The thick line represents depth. (a) Potential temperature; contour values are in °C (°F). (b) Salinity; contours are in parts per…
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from article Patellogastropoda
Whitecap limpet (Acmaea mitra). (Photo by Douglas Eernisse)
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from article Patellogastropoda
Ribbed Mediterranean limpet (Patella ferruginea). (Photo by Georgina Rivera Ingraham)
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from article Patellogastropoda
Radula of the patellogastropod Notoacmea scapha.
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from article Beef cattle production
Angus bull with overall carcass merit. (Credit: Jim Koch/Agricultural Research Service, U.S. Department of Agriculture)
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from article Beef cattle production
Brahman (zebu) bull (Bos indicus). (Credit: Scott Bauer/Agricultural Research Service, U.S. Department of Agriculture)
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from article Beef cattle production
An exemplary purebred Hereford bull. (Credit: Michael MacNeil/Agricultural Research Service, U.S. Department of Agriculture)
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from article Beef cattle production
A group of Simmental cows. (Credit: Iowa Beef Industry Council)
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from article Beef cattle production
Three Charolais heifers. (Credit: Darcy Vial/Farm Service Agency, U.S. Department of Agriculture)
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from article Beef cattle production
In order to attain market weight, cattle are fed often in feedlots. (Credit: Dave Hughes/Getty Images)
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from article Beef cattle production
In the United States, beef animals used for food must be inspected extensively pre- and postmortem by federal officials. (Credit: Bob Nichols/U.S. Department of Agriculture)
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from article Huntington's disease
Huntington's disease is a hereditary disorder that affects approximately five to ten of every 100,000 persons. The average age at onset is between 35 and 40 years. Invariably fatal, the disease progresses gradually over time. (Copyright ©…
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from article Fruit, tree
Apple trees growing in an orchard. (Photo by Charles Rondeau)
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from article Fruit, tree
Apple scab on fruit. This disease, caused by the fungus Venturia inaequalis, leads to unsightly blemishes on ripe apples. (Photo courtesy of the University of Georgia Plant Pathology Archive)
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from article Fruit, tree
Brown rot, caused by the fungus Monilinia fructicola, on a peach. (Photo by Jonas Janner Hamann, Universidade Federal de Santa Maria, Brazil)
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from article Fruit, tree
Fire blight, caused by the bacterium Erwinia amylovora, on apple fruits and leaves. (Photo courtesy of the University of Georgia Plant Pathology Archive)
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from article Fruit, tree
Blue mold (Penicillium italicum) on a rotting orange. (Photo by G. L. Barron)
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from article Bicosoecida
A bicosoecid, Codomonas annulata.
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from article Rhizocephala
Loxothylacus texanus (arrow) attached to the abdomen of the blue crab (Callinectes sapidus). (After E. G. Reinhard, Parasitic castration of Callinectes, Exp. Parasitol., 5:79–107, 1956)
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from article Belladonna
Close-up view of the belladonna plant (Atropa belladonna), showing the leaves and berries, which are toxic. (Credit: Leo Michels)
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from article Pharmacy
Pharmacy is the science dealing with the preparation and dispensing of medicinal or therapeutic drugs. (Credit: Sanchai Rat/Shutterstock)
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from article Polychaeta
Examples of polychaetes. (a) Platynereis dumerilii antipoda. (b) Branchiomma sp. (c) Arenicola bombayensi. (After P. L. Beesley et al., 2000)
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from article Polychaeta
Platynereis dumerilii antipoda, showing the antero-dorsal end with the pharynx everted. (After P. L. Beesley et al., 2000)
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from article Polychaeta
Hololepidella laingensis; scanning electron microscope view of the anterior end with the pharynx everted. An: antennae; Pa: palps; Prb: proboscis; Prs: prostomium; TeC: tentacular cirrus. Numbers refer to the segments of the trunk. Magnification,…
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from article Polychaeta
Gastrolepidia clavigera; scanning electron microscope view of the anterior end. Mo: mouth; Ja: jaw; Pa: palps; Prb: proboscis. Magnification, 30×.
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from article Polychaeta
Gastrolepidia clavigera, scanning electron microscope view of the two first parapodia (Pa1, Pa2). Ch: chaetae; Ci: cirrus; Nop: notopodium; Nep: neuropodium. Magnification, 40×.
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from article Polychaeta
Section through a polychaete. (After E. E. Ruppert and R. D. Barnes, Invertebrate Zoology, Saunders College Publishing, Orlando, 1994)
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from article Ultrahigh-pressure metamorphism
Schematic cross-section contrasting the tectonic setting of generation and exhumation of (a) Alpine-type and (b) Pacific-type HP-UHP belts. (Modified after Maruyama et al., 1996)
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from article Ultrahigh-pressure metamorphism
P-T diagram showing (a) HP-UHP regimes and stability of coesite and diamond, (b) P-T-time paths for Dabie-Sulu eclogite and garnet peridotite, and (c) zoned zircon domains with sensitive high-resolution ion microprobe (SHRIMP) U/Pb ages for Sulu…
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from article Ultrahigh-pressure metamorphism
Photomicrographs of UHP index minerals. Inclusions of coesite in omphacite from (a) Dabie, and coesite pseudomorph in epidote from (b) Sulu, central-eastern China. Inclusions of (c) microdiamond in zircon, and (d) diamond + phengite in garnet, from…
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from article Barrier island
Generalized profile across a barrier island complex showing various environments.
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from article Barrier island
Sediment budget for barrier island complex. Solid lines are major interactions; broken lines are relatively minor intersections.
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from article Barrier island
Maps showing major coastal environments and directions, and directions of coastal processes of (a) wave-dominated barrier islands and (b) mixed-energy barrier islands. Large arrows indicate wave direction, and small arrows indicate direction of…
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from article Hepatitis C virus
Chronic hepatitis C with portal inflammation and interface hepatitis (erosion of the limiting plate of periportal hepatocytes by infiltrating mononuclear cells). (Copyright © McGraw Hill)
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from article Hepatitis C virus
Natural history of chronic hepatitis C. It is presumed that liver fibrosis progresses in a linear course from the time of acquisition of the infection to the development of cirrhosis. Stages of fibrosis are from the METAVIR (meta-analysis of…
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from article Hepatitis C virus
The genomic structure of hepatitis C virus (HCV) and potential targets for therapy. Through analysis of the genomic structure of HCV, additional therapies (for example, serine protease inhibitors, helicase inhibitors, and RNA polymerase inhibitors)…
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from article Stishovite
Comparison of the mean index of refraction and specific gravity of stishovite and other polymorphic modifications of silica.
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from article Chaetonotida
Marine gastrotrichs of the order Chaetonotida; dorsal views. (a) Xenotrichula (courtesy of W. D. Hummon). (b) Chaetonotus (after W. D. Hummon, Intertidal marine Gastrotricha from Colombia, Bull. Mar. Sci., 24:396–408, 1974).
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from article Melanterite
Fibrous crust of melanterite (a common mineral) in a sample from Kremnitz, Hungary. (Specimen from Department of Geology, Bryn Mawr College)
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from article Lychee
Fruit and leaves of lychee (Litchi chinensis). (Photo courtesy of Forest and Kim Starr)
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from article Tidal bore
Tidal curve of a river with a tidal bore.
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from article Tidal bore
Tidal bore of the Petitcodiac River, Bay of Fundy, New Brunswick, Canada. Rise of water is about 4 ft (1. 2 m). (New Brunswick Travel Bureau)
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from article Earth
The famous "Blue Marble" picture of Earth taken by astronauts during the Apollo 17 mission on December 7, 1972, while en route to the Moon. (Credit: NASA)
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from article Earth
Principal layers of Earth. (USGS)
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from article Earth
Global histogram (distribution of elevations) and hypsographic curve (cumulative elevations) of Earth's surface. (NOAA)
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from article Earth
Seafloor spreading. (USGS)
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from article Earth
Plate collisions: (a) continent-ocean plate collision; (b) continent-continent plate collision; (c) ocean-ocean plate collision. (USGS)
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from article Earth
Structure of the atmosphere. The log scale applies only to the ionization curve. 1 km = 0.6 mi; °F = (°C × 1.8) + 32.
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from article Surgery
Medical personnel performing a surgical procedure in a modern operating room. (Credit: OJO Images Limited/Alamy Stock Photo)
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from article Surgery
Operative view illustrating the position of various surgical instruments, including a surgical telescope, used to make an incision in a patient. (Copyright © McGraw Hill)
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from article Surgery
Close-up view of a surgeon organizing the instruments required for an operation. (Credit: ER Productions Limited/Blend Images)
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from article Surgery
A medical operation involving a robot. Robotic surgery is being implemented to perform procedures that once required the presence of an expert surgeon. (Credit: Master Video/Shutterstock)
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from article Baltic Sea
Postglacial development of the Baltic: (a) Baltic Ice Sea, 12,000–8000 B.C.; (b) Yoldia Sea, 8000–7250 B.C.; (c) Ancylus Sea, 7250–2000 B.C.; (d) Littorina Sea, 2000–A.D. 500. (After K. Grasshoff, in S. P. Riley and G. Skirrow, eds., Chemical…
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from article Skink
Five-lined skink (Plestiodon fasciatus; formerly Eumeces fasciatus). (Credit: George W. Robinson; copyright © California Academy of Sciences)
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from article Food allergy
Children (under the age of 18) who experience food allergies are more likely to experience other allergic conditions, including asthma (black), eczema/skin allergy (blue), and respiratory allergy (green). (Credit: National Center for Health…
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from article Food allergy
Allergic responses (immunological responses mediated by the IgE class of immunoglobulins) can be caused by certain foods. In a person with allergies, mast cells will be coated with IgE against one or a few antigens (allergens) that, upon entering…
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from article Food allergy
Peanuts are a common trigger of food allergies in both adults and children. (Credit: Christian Jung/Shutterstock)
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from article Sport-related concussion
Sport-related concussion is among the most frequent injuries experienced by athletes participating in contact and collision sports, including football. (Credit: Skynesher/Getty Images)
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from article Sport-related concussion
Medical imaging and scanning techniques can identify the brain areas affected by a sport-related concussion. (Credit: Puwadol Jaturawutthichai/Shutterstock)
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from article Sport-related concussion
A football helmet with anticoncussion padding. This type of helmet is recommended for youths who are active in contact and collision sports. (Copyright © McGraw Hill)
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from article Ephemeroptera
Ephemeroptera. (a) Mayfly, adult male, Hexagenia sp., in usual resting position (after A. H. Morgan, Field Book of Ponds and Streams, G. Putnam's Sons, 1930). (b) Mayfly, subadult male, Callibaetis sp., newly emerged from water, standing on surface…
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from article Prairie dog
Black-tailed prairie dogs (Cynomys ludovicianus). (Photo by Ron Singer, U.S. Fish and Wildlife Service)
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from article Streptococcus pneumoniae (pneumococcus)
Photomicrograph of Streptococcus pneumoniae bacteria that have been grown from a blood culture. Streptococcus pneumoniae is the most common bacterial cause of pneumonia in adults, but various forms of the bacteria have acquired resistance to…
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from article Percopsiformes
Trout-perch (Percopsis omiscomaycus). (Photo by Konrad P. Schmidt)
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from article Percopsiformes
Pirate perch (Aphredoderus sayanus). (Photo by Konrad P. Schmidt)
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from article Percopsiformes
Ozark cavefish (Amblyopsis rosae). (Photo courtesy of U.S. Fish and Wildlife Service)
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from article Prosobranchia
Common gastropods. (Top left) Murex troscheli. (Middle) Conus gloriamaris. (Top right) Lambis crocata. (Bottom) Angaria vicdani.
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from article Ocean
Pacific Ocean, Santa Cruz, California, USA. (Credit: Shutterstock/Lerner Vadim)
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from article Ocean
Range of (a) salinity and (b) temperature in the world’s oceans.
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from article Ocean
Major currents of the world’s oceans.
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from article Ocean
Role of the winds in establishing major current gyres that span ocean basins. Gyres are closed circulatory systems that are larger than whirlpools or eddies.
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from article Sauropterygia
Ceresiosaurus calcagnii, ventral view.
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from article Amblygonite
Amblygonite. (Credit: RF Company/Alamy)
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from article Phlogopite
Polyhedral models showing the one-layer monoclinic phlogopite atomic structure illustrating (a) a projection down the b axis and (b) near a-axis projection. The structural unit consists of only one layer; note that both layers shown are identical.…
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from article Zebu
Gray Brahman bull (Bos indicus). (Photo courtesy of Salinas Ranch, Carmine, Texas)
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from article Desertification
Overgrazing on North American rangelands contributes to soil compaction and alters the composition of vegetation. (Credit: Thomas Wikle)
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from article Desertification
Desertification can be accelerated by cultivation in areas better suited for herding, such as this field in Ethiopia. (Credit: Thomas Wikle)
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from article Desertification
Grazing animals have contributed to desertification in Africa’s Sahel region. (Credit: Thomas Wikle)
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from article Rock
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from article Rock
Classification of psammitic and pelitic rocks based on proportions of the three most common clastic minerals: quartz, feldspars, and clays—excluding calcilutites and calcarenites. (After E. W. Heinrich, Microscopic Petrography, McGraw-Hill, 1956)
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from article Rock
