Search Results

10 | 25 | 50 | 100 items per page

1,187 results

Image

from article Acanthodii

Jaws of an Early Devonian ischnacanthid from northern Canada. The upper palatoquadrate and lower meckelian cartilages have tooth-bearing jawbones along their facing edges. (From University of Alberta, Laboratory for Vertebrate Paleontology…

Image

from article Acanthodii

Examples of acanthodians from the Early Devonian of northern Canada. (a) Primitive climatiiform Lupopsyrus. (b) Diplacanthid Tetanopsyrus. (c) Ischnacanthiform Ischnacanthus. (d) Unnamed mesacanthid acanthodiform. (From the University of Alberta,…

Image

from article Index fossil

Three cephalopod genera forming an evolutional sequence. Their short ranges (indicated by bars) and distinctive suture lines (the area between two sutures is shown in black) make them ideal index fossils for the early Pennsylvanian Period. (After A.…

Image

from article Index fossil

Different concepts of range zones based on various combinations of overlap of two or more index species. (From D. R. Prothero and F. Schwab, Sedimentary Geology: An introduction to Sedimentary Rocks, Freeman, 1996)

Image

from article Index fossil

Potential range versus actual range of an index fossil species. Note that the actual time of occurrence at a given locality is generally some fraction of the actual range of the species because of the limitations of environment, immigration, and…

Image

from article Index fossil

Graphic correlation method of Alan Shaw. Note that the X and Y axes of the graphs are scaled diagrams of measured sections of the two different outcrops to be correlated. The points plotted on the graphs are the corresponding heights of the first or…

Image

from article Psychosis

A colorized magnetic resonance imaging (MRI) scan of a human brain. Psychosis is a defective mental state in which there is a critical derangement of the mind (brain) involving abnormal contact with reality. (Credit: Govind Bhagavatheeshwaran and…

Image

from article Permian

Permian, the sixth period of the Paleozoic.

Image

from article Permian

Correlation of major Permian rock units.

Image

from article Permian

East-west section of the Permian System in its type area.

Image

from article Permian

Depositional and structural relationships in western Texas during Permian time.

Image

from article Permian

Section across the Capitan Reef Complex. 1 m = 3.3 ft; 1 km = 0.6 mi.

Image

from article Permian

Paleogeography during the earliest part of the Permian Period.

Image

from article Permian

Paleogeography near the middle of the Permian Period.

Image

from article Gastornithiformes

Gastornis giganteus (reconstruction), an extinct flightless bird belonging to the order Gastornithiformes. (Photo courtesy of the American Museum of Natural History, New York)

Image

from article Gaviiformes

Image

from article Microbialite

Modern examples of microbialites. (a) Elongated stromatolites from hypersaline Hamelin Pool in Shark Bay, Western Australia. Scale bar: 0.5 m (1.64 ft). (b) Stromatolites found in the intertidal zone of Hamelin Pool. (c) Open-marine stromatolites…

Image

from article Archaeopteridales

Archaeopteris macilenta. (a) Vegetative lateral branch system bearing simple leaves (from C. B. Beck, On the anatomy and morphology of lateral branch systems of Archaeopteris, Amer. J. Bot., 58:758–784, 1971). (b) Strobilus showing adaxial…

Image

from article Lepidodendrales

Reconstructions of tree-sized Carboniferous rhizomorphic tree-lycopsids, illustrating architectural variation. (After R. M. Bateman et al., Experimental cladistic analysis of anatomically preserved arborescent lycopsids from the Carboniferous of…

Image

from article Lepidodendrales

Primitive bisexual cone of the Flemingites type, borne by Paralycopodites, with apically concentrated microsporangia and basally concentrated megasporangia containing several megaspores. (After C. A. Arnold, An Introduction to Paleobotany,…

Image

from article Human-factors engineering

Human-factors engineers design modern computer equipment, including ergonomic keyboards and mouse devices, to accommodate the varied physical contours and dimensions of the human hand. (Credit: JG Photography/Alamy)

Image

from article Human-factors engineering

Human-factors engineering addresses problems related to the design of seats, workplaces, and consoles in terms of a user's physical size, comfort, strength, and visibility. (Copyright © McGraw-Hill Education)

Image

from article Human-factors engineering

Cognitive engineering and the development of new technology applications.

Image

from article Trilobita

Two iron-stained trilobites (Paradoxides) on a bedding plane slab from Morocco, North Africa, of Cambrian age. (Credit: Alan Morgan)

Image

from article Trilobita

Trilobite diversity and preservation. (a) Olenellid, Lower Cambrian (British Columbia). External mold of exoskeleton in shale. (b) Ogygopsis, Middle Cambrian (British Columbia). Molt assemblage, with cranidium and pygidium aligned, but librigenae,…

Image

from article Trilobita

Morphological features of trilobites. (a) Calymene, Silurian (New York). Dorsal view of mineralized exoskeleton. (b) Phacops, Devonian (Ohio). Ventral (bottom) view of cephalon and anterior segments of the thorax, with hypostome attached. (c)…

Image

from article Trilobita

Triarthrus eatoni, Upper Ordovician (New York). Reconstruction with dorsal exoskeleton removed on right side to show appendages. Antennae are incomplete. Exites (gill branches) of the first nine postantennal appendages are removed to show the…

Image

from article Monoplacophora

Living and fossil Monoplacophora. (a) Neopilina galatheae. (b) Tryblidium reticulatum. (After R. C. Moore, ed., Treatise on Invertebrate Paleontology, pt. I, 1957)

Image

from article Monoplacophora

Side views of various helcionellacean and bellerophont univalved mollusks. (a) Cyrtonellopsis; (b) Hypseloconus; (c) Cyclocyrtonella; (d) Stenotheca; (e) Bellerophon; (f) Tropidodiscus. (After B. Runnegar, Class Monoplacophora, in R. S. Boardman, A.…

Image

from article Psychoanalysis

Sigmund Freud, the leading figure in the creation and development of psychoanalysis, in 1909. (Credit: Wellcome Images)

Image

from article Psychoanalysis

Psychoanalysis is often used by psychological therapists to treat patients with neurotic, character, or personality disorders. (Credit: Michael Jung/Shutterstock)

Image

from article Heterocorallia

Morphology of the heterocorallian skeleton. (a) External view. (b) Transverse thin section. (c) Median longitudinal thin section. (d) Enlarged part of c. (After R. C. Moore, ed., Treatise on Invertebrate Paleontology, pt. F, Geological Society of…

Image

from article Heterocorallia

Details of the heterocorallian body. (a) Generalized pattern of septal insertion (from O. Schindewolf, Grundfragen der Paläontologie, Schweizerbart, Stuttgart, 1950). (b) Reconstruction of the mesenterial in the soft body (from M. Gudo,…

Image

from article Umami taste receptor

Image

from article Umami taste receptor

Schematics of umami, sweet, and chimeric T1R receptors. The T1R1/T1R3 umami taste receptor and the T1R1-2/T1R3 chimeric receptor recognize umami ligands, whereas the T1R2/T1R3 sweet taste receptor and the T1R2-1/T1R3 chimeric receptor recognize…

Image

from article Selachii

Image

from article Apraxia

Language skills involve comprehension, speech, reading, and writing. The motor speech area (Broca's area) in the brain initiates speech motor functions. The Wernicke area aids in the interpretation of language. The primary motor cortex is…

Image

from article Insectivora

Buena Vista Lake ornate shrew (Sorex ornatus relictus) sitting on the palm of a hand. (Photo courtesy of California State University, Stanislaus; and the U.S. Fish and Wildlife Service)

Image

from article Insectivora

Reconstruction of Deinogalerix, an extinct giant insectivore (erinaceid) from the Miocene of Italy. (Adapted from M. Freudenthal, Deinogalerix koenigswaldi nov. gen., nov. spec., a giant insectivore from the Neogene of Italy, Scr. Geol., 14:1–19,…

Image

from article Insectivora

Skull of Kennalestes, an extinct proteutherian from the Cretaceous of Mongolia.

Image

from article Caprimulgiformes

Puerto Rican nightjar (Caprimulgus noctitherus). (Photo by Mike Morel, U.S. Fish and Wildlife Service)

Image

from article Chevrotain

Water chevrotain (Hyemoschus aquaticus). (Photo by Brent Huffman; courtesy of Ultimate Ungulate)

Image

from article Dinosauria

Titanosaurs (based on Rapetosaurus) in the nesting ground at Auca Mahuevo, Argentina. (Credit: Mark Hallett)

Image

from article Dinosauria

Partly excavated dinosaur fossils. (Credit: Bert Beekmans/Getty Images)

Image

from article Dinosauria

Image

from article Dinosauria

Relationships of the ornithischian dinosaurs. (Credit: Modified from an original diagram by P. C. Sereno)

Image

from article Dinosauria

Image

from article Dinosauria

A Triceratops fossil skull. (Credit: David Herraez/Alamy Stock Photo)

Image

from article Dinosauria

Image

from article Dinosauria

Computer-generated Allosaurus dinosaur skeleton. This saurichian carnivore could attain a height of 8.5 m (28 ft). (Credit: Science Photo Library/Alamy Stock Photo)

10 | 25 | 50 | 100 items per page

Search Site Content

Browse Articles...

Search Results

Refine this search

1,187 results

Learn more about AccessScience

Search Site Content

Refine this search

Search result paging links

1,187 results

Learn more about AccessScience

Topics