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from article Regolith
Diagram showing the components of residual regolith.
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from article Galliformes
White-tailed ptarmigan (Lagopus leucurus), Glacier National Park, Montana. (Photo by Gerald and Buff Corsi, copyright © California Academy of Sciences)
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from article Climate history
Plot of the average temperature for the contiguous United States during the month of August from 1895 to 2016. (Credit: NOAA)
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from article Climate history
Global temperature relative to peak Holocene temperature, based on ocean cores. (Credit: NASA)
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from article Echinoida
Tripneustes ventricosus (Lamarck), tropical eastern and western Atlantic, found at depths of 0–55 m (0–180 ft). (From G. Hendler et al., Sea Stars, Sea Urchins and Allies: Echinoderms of Florida and the Caribbean, Smithsonian Press, Washington, DC,…
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from article Echinoida
A pyramid from Aristotle's lantern, showing epiphyses joined and tooth with keel. (After H. L. Hawkins, The lantern and girdle of some Recent and fossil Echinoidea, Philos. Trans. R. Soc. Lond. Ser. B, 223:617–649, 1934)
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from article Echinoida
An ambulacral plate from the test, with the lowest element being the largest. (After T. Mortensen, A monograph of the Echinoidea: Camarodonta, C. A. Reitzel, Copenhagen, 1943)
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from article Animal virus
Electron micrograph of negatively stained, purified bovine papilloma virions with icosahedral symmetry. (Credit: David Hill and John P. Sundberg)
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from article Animal virus
Electron micrograph of a thin section of chicken cells containing crystalline inclusion bodies formed by an avian reovirus during infection. (Credit: David Hill and John P. Sundberg)
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from article Food manufacturing
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from article Food manufacturing
Average composition of the United States diet dry weight per capita per day. Prior sanctioned substances were specifically approved by FDA or USDA for use in food prior to the passage of the Food Additives Amendment in 1958.
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from article Food manufacturing
Rank ordering of food ingredients by per capita annual disappearance.
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from article Food manufacturing
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from article Food manufacturing
Flow chart of the fiber-spinning technique used to prepare food analogs. (After N. R. Lockmiller, Increased utilization of protein in foods, Cereal Sci. Today, 18(3):77–81, 1973)
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from article Food manufacturing
Typical high-temperature extrusion process for production of a meat or seafood analog. (After O. B. Smith, in L. D. Hill, ed., Textured Vegetable Proteins, World Soybean Research, Interstate Printers and Publishers, 1976)
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from article Food manufacturing
Front view diagram of a horizontal dough mixer.
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from article Food manufacturing
Small integrated bread make-up system. A mass of bread dough is placed in the hopper of the divider (right) which cuts it into pieces of uniform weight. The rounder (center foreground) receives the rough pieces from the divider, forms them into…
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from article Food manufacturing
Tunnel oven. Loaf-size dough pieces enter the oven at left background and are carried through the baking chamber on a continuous metal belt which serves as the hearth. The baked loaves exit at right foreground. Ordinary pan bread would require sets…
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from article Food manufacturing
Schematic for production of shredded wheat biscuits. (After G. A. Leveille and M. A. Uebersax, Fundamentals of food science for the dietician: Wheat products, dietetic currents, vol. 7(1), pp. 1–8, Ross Laboratories, Columbus, Ohio, January–February…
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from article Food manufacturing
Small-scale abrasive dehulling machine in (a) upright and (b) dumping positions. (Plant Biotechnology Institute, National Research Council of Canada, Saskatoon)
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from article Food manufacturing
Flow chart for the preparation of fish meal, condensed fish solubles, and fish oil from whole fish by using the wet process. (Zapata Haynie Corp.)
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from article Food manufacturing
Common market forms of fresh or frozen fish.
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from article Food manufacturing
Processing steps in the canning of tuna.
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from article Food manufacturing
Schematic sectional view of a fish flesh-separating machine to produce minced fish.
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from article Food manufacturing
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from article Food manufacturing
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from article Paramecium
Photomicrograph of Paramecium caudatum. (Credit: Nancy Nehring/Getty Images)
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from article Heterodonta
Common heterodont bivalves. (Credit: Ronald V. Dimock, Jr.)
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from article Heterodonta
Common heterodont bivalves. (Credit: Ronald V. Dimock, Jr.)
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from article Restoration ecology
Restored sand dune habitat at Cape Canaveral, Florida. To help prevent erosion, 180,000 shrubs, including grasses, sunflowers, vines, sea grapes, and saw palmettos, were planted. (Credit: Dan Casper/National Aeronautics and Space Administration)
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from article Weathering processes
Exchange-energy relationships between a rootlet and three minerals. (a) A potassium-bearing, primary silicate mineral. (b) A clay mineral well stocked with exchangeable metal cations. (c) A clay mineral scantily stocked with metal cations. The…
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from article Weathering processes
Comparison of binding energy (calories per gram-equivalent weight) on nutrient metal cation (indicated by M) by rocks and soil minerals with exchange binding energy on cation by plant roots. The relation of plant nutrition to weathering and…
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from article Prehnite
Prehnite in reniform aggregates, Paterson, New Jersey. (Specimen from Department of Geology, Bryn Mawr College)
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from article Aye-aye
Aye-aye (Daubentonia madagascariensis). (Photograph by Urs Thalmann, Anthropological Institute, University of Zürich)
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from article Tick virus diseases
A deer or black-legged tick (Ixodes scapularis). (Credit: U.S. Centers for Disease Control and Prevention)
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from article Tick virus diseases
Diagram depicting the life cycle of Ixodes scapularis. This deer tick can transmit viruses and other pathogens that cause a number of important diseases, including Lyme disease, anaplasmosis, and babesiosis. The risk of human infection is greatest…
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from article Tick virus diseases
World map depicting the locations of human tick-borne disease cases. Heartland, Bourbon, and Colorado tick fever virus cases are unique to North America. Powassan encephalitis cases are reported in North America and Russia. Tick-borne encephalitis…
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from article Tick virus diseases
Cases of Powassan encephalitis reported in the United States from 2006 to 2015. Most of the reported cases are in Minnesota, New York, and Wisconsin. (Credit: ArboNET, Arboviral Diseases Branch, U.S. Centers for Disease Control and Prevention)
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from article Anaerobic infection
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from article Euryalida
Aboral body of a basket star, Euryale aspera (family Euryalidae, order Euryalida), clinging to a red soft coral colony and spreading its branching arms.
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from article Euryalida
A snake star, Astrochele pacifica (family Gorgonocephalidae, order Euryalida): (a) aboral body; (b) aboral arms; and (c) a scanning electron microscope (SEM) image of a separated microscopic hook. (Credit for photo a: Shimoda Marine Research Center,…
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from article Degenerative neural diseases
Factors leading to degenerative neural diseases. Abbreviations: AD, Alzheimer's disease; AD/PD, Alzheimer's disease with parkinsonism; ALS, amyotrophic lateral sclerosis; DLB, dementia with Lewy bodies; FTD, frontotemporal dementia; MID,…
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from article Biological productivity
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from article Pinnipeds
Walrus (Odobenus rosmarus). (Credit: Donna Dewhurst Collection/U.S. Fish and Wildlife Service)
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from article Pinnipeds
Steller sea lion and pup (Eumetopias jubatus). (Credit: Alaska Image Library/U.S. Fish and Wildlife Service)
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from article Pinnipeds
Evolutionary relationships and stratigraphic ranges of major groups of pinnipeds. Shaded bars correspond to known ranges, and white bars correspond to inferred ranges. Ma = million years ago. (Copyright © McGraw-Hill Education)
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from article Panda
Giant panda (Ailuropoda melanoleuca). (Credit: John White)
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from article Panda
Red panda (Ailurus fulgens). (Credit: John White)
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from article Eocrinoidea
Reconstructions of Cambrian and Ordovician eocrinoids. (a) Gogia spiralis, from the Middle Cambrian of Utah, showing the primitive holdfast; sutural pores between the numerous thecal plates; and long, spiraled brachioles attached to the summit…
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from article Kinetoplastida
Representative genera of families of order Kinetoplastida. (a) Oikomonas (family Oikomonadidae), one anterior flagellum. (b) Amphimonas (family Amphimonadidae), two equally long anterior flagella. (c) Monas (family Monadidae), two unequally long…
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from article Ergot and ergotism
Ergot life cycle. Parts a–d explained in text.
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from article Giraffe
Giraffe (genus Giraffa). (Credit: Arthur J. Emmrich; copyright © California Academy of Sciences)
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from article Exotic viral diseases
A colorized negative stained transmission electron micrograph depicting a number of Marburg virus virions. Marburg virus disease is a rare, exotic viral disease that affects both humans and nonhuman primates. (Credit: Frederick A. Murphy/Centers for…
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from article Sarcosporida
Cross section of Miescher's tube filled with Sarcocystis spores (probably S. lindemanni) from a monkey.
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from article Turnip
Purple Top turnip (Brassica rapa). (Credit: Stami Kieren Donovan; courtesy of Greenpatch Organic Seeds, Glenthorne, New South Wales, Australia)
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from article Dill
Flowering of dill (Anethum graveolens). (Photo courtesy of Forest and Kim Starr)
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from article Fiber crops
Cotton, the most important textile fiber crop grown in the world. (Photo by Gary Kramer, Natural Resources Conservation Service, U.S. Department of Agriculture)
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from article Conulariida
Conulariid morphology. (a) Paraconularia byblis, a well-preserved specimen in siderite (iron carbonate) from the Carboniferous (Mississippian) of Ohio showing two adjacent sides meeting at a deep corner groove (arrow). Ridges along each side meet at…
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from article Conulariida
Conulariid paleoecology and taphonomy. (a) Cluster of Conularia congregata compacted in shale from the Devonian of New York. The specimens show apical walls (lower arrow), indicating detachment from, or nonpreservation of, their attachment stalks.…
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from article Agricultural soil and crop practices
A crop of wheat is harvested by a combine harvester, which is a key machine that helps to implement various agricultural soil and crop practices. (Credit: Orientaly/Shutterstock)
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from article Agricultural soil and crop practices
A farmer in a tractor plowing the land for sowing. (Credit: Oticki/Shutterstock)
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from article Agricultural soil and crop practices
A tractor pulls a tilling machine. Stubble remains on the cornfield after the previous harvest. The soil must be properly tilled and cultivated for spring planting. (Credit: Lynn Betts, Natural Resources Conservation Service, U.S. Department of…
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from article Agricultural soil and crop practices
A cotton stripper, which harvests a cotton crop by stripping both the cotton and bolls from the stalks. (Credit: David Hughes/Getty Images)
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from article Aspidogastrea
Examples of adult Aspidogastrea: Stichocotyle, Rugogaster, and Aspidogaster. Note Stichocotyle with a single longitudinal row of suckers, Rugogaster with a single row of rugae, and Aspidogaster with four rows of alveoli.
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from article Aspidogastrea
Larva of Multicotyle purvisi (ventral view). Note the pharynx, single cecum, posterior sucker, two pigmented eyes, ten ciliary tufts, the layer of microfila, and the two excretory bladder cells at the anterior margin of the sucker.
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from article Aspidogastrea
Life cycle of Lobatostoma manteri. Adult worms produce eggs in the small intestine of the snubnose dart, the carangid fish Trachinotus blochi; eggs shed by fish are ingested by snails of various species, in which the larva (with a posterior sucker,…
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from article Cyprinodontiformes
Female marsh killifish (Fundulus confluentus). (Illustration copyright © by Joseph R. Tomelleri)
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from article Ankerite
Ankerite. (a) Specimen of the mineral (specimen from Department of Geology, Bryn Mawr College). (b) Crystal habits (after C. Klein, Manual of Mineralogy, 21st ed., John Wiley & Sons, Inc., 1993).
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from article Cicada
Brood IX periodical cicada in Athens, West Virginia. (Photo by Louie H. Yang)
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from article Cicada
Periodical cicada life cycle. Counterclockwise from lower left: Nymphal cicada feeding on plant roots belowground; ants and other detrivores feeding on dead cicada litterfall; teneral adult cicada recently emerged from the nymphal exuviae; bird…
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from article Cicada
Brood X periodical cicadas in Boyce, Virginia. (Photo by Louie H. Yang)
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from article Lava
Examples of lava. (a) Pahoehoe lava (in Kilauea, Hawaii) has a smooth and wavy surface formed by a thin layer of cooler lava at the surface. The surface layer is pushed into folds from the faster-moving, hot fluid lava beneath (photograph by J. D.…
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from article Tektite
Dumbbell-shaped tektite (irgizite) from the Zhamanshin meteoritic impact crater, Northern Aral Region, Russia. The glass is so dark brown that it appears black in reflected light.
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from article Misophrioida
Side view of typical misophrioidan.
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from article Reproductive behavior
The mating of dragonflies encompasses a number of reproductive behaviors. Typically, the male is in front and the female is behind. If the female is willing to mate, she bends her abdomen forward to collect sperm from the male's accessory genitalia,…
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from article Reproductive behavior
Sage-grouse lek. Males stake out and defend territories on a traditional breeding ground. Females breed with males in selected territories. (Credit: U.S. Fish and Wildlife Service)
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from article Reproductive behavior
Two bull northern elephant seals fighting for dominance on the beach. (Credit: eoind/Getty Images)
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from article Reproductive behavior
Natterjack toad giving a mating call with its vocal sac expanded. (Credit: Bobby Bok)
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from article Reproductive behavior
Mating behavior of sticklebacks: (a) zigzag dance of a male, which leads a female to the nest; (b) the male stimulates the female in the nest to lay eggs; (c) schematic portrayal of the events in a courtship sequence. (Credit: Based on original…
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from article Reproductive behavior
Lordosis in a female rodent. When mounted, the females of many mammalian species adopt the lordotic posture, rendering copulation possible. Note the concave arching of the spine. (Credit: Based on an original drawing by L. C. Drickamer and S. H.…
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from article Reproductive behavior
A black-browed albatross feeding a chick. This is one example in which parental care may be extensive and prolonged. (Credit: Vetta/Getty Images)
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from article Toxin
Bacteria, such as Clostridium perfringens, often produce exotoxins that have deleterious effects on other organisms. Clostridium perfringens can cause foodborne disease by contamination of raw food materials. (Credit: Don Stalons/Centers for Disease…
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from article Toxin
Taiwan banded krait (Bungarus multicinctus). Certain elapid snakes known as kraits produce a venom that contains bungarotoxins, which are potent neurotoxins. (Credit: LiCheng Shih)
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from article Tree diseases
White pine blister rust (Cronartium ribicola) on eastern white pine (Pinus strobus). The blisters are masses of aeciospores (rust spores). (Photo courtesy of the Minnesota Department of Natural Resources Archive)
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from article Tree diseases
Chestnut blight on an American chestnut tree (Castanea dentata). This devastating disease is caused by Cryphonectria parasitica. (Photo by Joseph O'Brien, U.S. Department of Agriculture Forest Service)
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from article Tree diseases
Sulfur shelf fungus (Laetiporus sulphureus) on a tree. This wood-rotting fungus enters through tree roots and wounds, decaying the heartwood and sapwood of both hardwoods and softwoods. (Photo by William Jacobi, Colorado State University)
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from article Tree diseases
Symptoms of Dutch elm disease, caused by Ophiostoma ulmi, on an elm (Ulmus species). Typically, the foliage of an infected tree will begin to wither and yellow in the summer months. (Photo by Joseph O'Brien, U.S. Department of Agriculture Forest…
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from article Tree diseases
An American elm (Ulmus americana) infected with bacterial wetwood. The causal agent for this disease is Enterobacter nimipressuralis. The bacterial ooze (slime flux) is coming from a wound. (Photo by Mike Schomaker, Colorado State Forest Service)
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from article Celiac disease
Small bowel biopsy showing villous atrophy, which is found in individuals affected by celiac disease. (Credit: Ed Uthman/National Institutes of Health)
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from article Celiac disease
Antigen presentation of gliadin peptide to a CD4 T cell. Gliadin peptides bind to pockets P1, P4, P6, P7, and P9 of the (a) HLA-DQ8 and (b) HLA-DQ2 molecules. (Copyright © McGraw-Hill Education)
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from article Concussion
A three-dimensional magnetic resonance imaging (MRI) view of a human brain. The red-colored areas indicate temporary injury to the brain's covering following a concussion. (Credit: Lawrence Latour, Center for Neuroscience and Regenerative Medicine,…
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from article Craniiformea
Isocrania egnabergensis (Retzius): (a) dorsal valve interior; (b) dorsal valve exterior; (c) ventral valve interior; (d) ventral valve exterior; (e) complete shell, lateral view, dorsal valve above; 8 mm (0.32 in.) in width. Danocrania tuberculata…
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from article Craniiformea
Muscle system of Novocrania viewed (top) dorsally and (bottom) laterally. (Adapted from O. M. B. Bulman, Muscle systems of some inarticulate brachiopods, Geol. Mag., 76:434–444, 1939; after R. L. Kaesler, ed., Treatise on Invertebrate Paleontology,…
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from article Ciliophora
A typical ciliate member of the phylum Ciliophora. (Credit: Don Loarie)
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from article Ciliophora
Illustration showing the major structures of a representative ciliate, Paramecium (phylum Ciliophora). The anterior end is shown at the top; the posterior end is shown at the bottom. (Copyright © McGraw-Hill Education)
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from article Ciliophora
Binary fission and stomatogenesis in the ciliate Tetrahymena. Argentophilic basal bodies form part of the silverline system and infraciliature.
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from article Ciliophora
Ciliates (not drawn to the same scale): (a) primitive form, Holophyra; (b) intermediate form, Tetrahymena; and (c) highly complex form, Diophrys.
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from article Deep-marine sediments
Bathymetric display of the northern Gulf of Mexico based on high-resolution bathymetric swath data. The data are displayed to give a 3-D perspective of present-day shelf, slope, and basin settings. Note the highly irregular sea-floor topography and…
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from article Deep-marine sediments
Map showing long-distance transport of modern slides of about 300 km (186 mi) downslope from the shelf edge (100-fathom, 183-m, or 600-ft contour line) off northwestern Africa. Thickness of slide = 25 m (82 ft). (From R. D. Jacobi, Sediment slides…
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from article Deep-marine sediments
Conceptual model showing interaction between channelized (axial) turbidity currents, overbank turbidity currents, and bottom currents (contour currents) in deep-sea environments. (From G. Shanmugam, T. D. Spalding, and D. H. Rofheart, Process…
