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from article Genetically modified organism (GMO)

Transgenic zebrafish cells. Green fluorescent protein (GFP) is a fluorescent protein first discovered in the jellyfish Aequorea victoria. GFP is commonly used as a reporter of gene expression in other species. Here, GFP is expressed by zebrafish…

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from article Genetically modified organism (GMO)

Genome editing technologies. In particular, targeted nucleases are a powerful tool for precise genome editing in GMOs. Among these tools are (a) transcription activator-like effector nucleases (TALENs), (b) zinc-finger proteins (ZFPs), (c) homing…

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from article Human ecology

Shacks and garbage along a dirty river in a slum in Manila, Philippines. Human ecology encompasses how individual people and their communities interact with their particular environment. In many cases, though, humans have created polluted…

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from article Human ecology

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from article Salmon

Salmon swimming in the Russian River, Alaska. (Credit: Ryan Hagerty/U.S. Fish and Wildlife Service)

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from article Salmon

Chinook salmon (Oncorhynchus tshawytscha). (Credit: National Estuarine Research Reserve System, National Marine Fisheries Service, National Oceanic and Atmospheric Administration)

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from article Fisheries ecology

The Atlantic bluefin tuna (Thunnus thynnus) is one of the world's most lucrative fish harvested by commercial fisheries. (Credit: Ugo Montaldo/Shutterstock)

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from article Fisheries ecology

Raceways (artificial channels used in the culturing of aquatic organisms) at Spring Creek National Fish Hatchery, Washington. (Credit: U.S. Fish and Wildlife Service)

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from article Fisheries ecology

Derelict fishing gear left in ocean waters can cause the needless deaths of millions of marine mammals, fish, birds, and invertebrates. (Credit: Joan Drinkwin/U.S. Fish and Wildlife Service)

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from article Salmon farming

Adult Atlantic salmon (Salmo salar). (Credit: William Hartley/U.S. Fish and Wildlife Service)

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from article Salmon farming

Atlantic salmon (Salmo salar) at a pre-smolt stage. (Credit: Edward Peter Steenstra/U.S. Fish and Wildlife Service)

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from article Salmon farming

A congregation of coho salmon (Oncorhynchus kisutch) released from a hatchery. Investigators continue to study the effects of farmed fish on neighboring populations of wild salmonids. (Credit: Salmon Ecology Team/Southwest Fisheries Science Center,…

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from article Neandertal DNA

The geographical range within which Neandertal remains have been found (dashed line). White dots show the sites of the discoveries used to estimate the almost-complete hypervariable segment I (HVS-I) sequence of the Neandertal mtDNA. The approximate…

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from article Neandertal DNA

The mtDNA hypervariable segment I (HVS-I) diversity found in eight Neandertals. The nucleotide substitutions and insertions relative to the Cambridge Reference Sequence (CRS) are shaded. (Credit: Igor Ovchinnikov and William Goodwin)

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from article Neandertal DNA

Phylogenetic analysis of the Neandertal mtDNA hypervariable segment I (HVS-I) sequence. (a) Neighbor-joining tree of the Neandertal mtDNA sequences and 2500 modern human HVS-I sequences from 43 modern populations. (b) Neighbor-joining tree of the…

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from article Grassland ecosystem

Grasslands cover the Great Plains region in North America, extending from southern Texas into Canada. (Credit: U.S. Forest Service)

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from article Grassland ecosystem

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from article Philosophy of science

Pulpit Rock Park in Colorado Springs, Colorado, photographed with camera equipment sensitive to infrared wavelengths of light outside of the visible portion of the electromagnetic spectrum that humans can perceive. The "invisible" light is rendered…

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from article Philosophy of science

Bust of the Greek polymath Aristotle. (Credit: Photos.com/Getty Images)

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from article Water conservation

Drying lake because of drought. (Credit: Tim McCabe/USDA Natural Resources Conservation Service)

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from article Population dispersion

Uniform distribution of a mature population of creosote bushes (Larrea tridentata). (Credit: Evelyn Jo Johnson)

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from article Population dispersion

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from article Pseudoscorpionida

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from article Pseudoscorpionida

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from article Pseudoscorpionida

Pseudoscorpion morphology. (a) Adult, in two views. (b) Chelicera of a male pseudoscorpion. (Illustration based on an original by H. S. Pratt)

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from article Conifer

A mixed conifer forest primarily composed of western white pine and mountain hemlock surrounding Cliff Lake, Lassen Volcanic National Park, California. (Credit: Amanda Sweeney/National Park Service)

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from article Conifer

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from article Conifer

Conifer seed cone structure. (a) Pine cone consisting of seed scales attached to the cone axis immediately above the bracts. One scale is bent back to reveal two seeds attached to the upper surface. (b) Fertile shoot from above a bract in an Emporia…

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from article Protective coloration

The protective coloration of a hawk moth resembles the color pattern of the bark of a tree, helping to camouflage the animal from predators. (Credit: Wilm Ihlenfeld/Shutterstock)

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from article Protective coloration

A mountain hare (Lepus timidus) with white fur sitting in snow in winter. (Credit: Peter Wey/Shutterstock)

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from article Protective coloration

The coloration of a pygmy sea horse resembles that of the soft coral, fooling predators of the sea horse. (Credit: Stephen Frink/Image Source)

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from article Neandertals

Neandertal cranium excavated from Forbes' Quarry, Gibraltar. Note the pronounced brow ridges, large braincase, and receding forehead. (Credit: Clive Finlayson/Gibraltar Museum)

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from article Neandertals

Gorham's Cave, Gibraltar, is the last known site of Neandertal occupation, being dated possibly to 30,000 years ago. (Credit: Clive Finlayson/Gibraltar Museum)

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from article Neandertals

Reconstructed skull of a Neandertal from the cave at La Chapelle-aux-Saints, France. (Credit: Illustration adapted from an original drawing by M. F. Ashley Montagu)

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from article Prehistoric technology

Elements of stone flaking. (a) Relationship between the core and the flake. (b) Major feature of the ventral or release surface of the flake. (After I. Tattersall, E. Delson, and J. A. Van Couvering, eds., Encyclopedia of Human Evolution and…

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from article Prehistoric technology

Principal techniques of stone-tool manufacture. (a) Hard-hammer, with free-hand percussion. (b) Anvil technique. (c) Bipolar technique. (d) Soft-hammer percussion. (e) Indirect percussion or punch technique. (f) Pressure flaking. (After…

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from article Prehistoric technology

Potters from the village of Harappa, Pakistan, display their wares in front of a replica of a two-chambered kiln used by ancient potters in the Indus Valley civilization. (Photo courtesy of R. P. Wright)

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from article Paleoecology

Zonation of Silurian (425 million year old) marine communities in the Welsh Basin, United Kingdom. Marine animal communities were typically arranged in belts parallel to the shoreline and related to water depth. A classic study using fossil…

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from article Paleoecology

Classification of shales in terms of percentages of three benthic habitat groups: epifaunal suspension-feeding bivalves (those living at the sediment-water interface and filtering seawater), infaunal (living within and feeding on the sediment), and…

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from article Paleoecology

Comparison of four developmental stages in four ancient reef masses. (After K. R. Walker and L. P. Alberstadt, Ecological succession as an aspect of structure in fossil communities, Paleobiology, 3:238–257, 1975)

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from article Paleoecology

Formation and burial sequence of Bobcaygeon hardground. (a) Soft-bottom community of strophomenid brachiopods and infaunal burrowers inhabiting carbonate mud. (b) Hardground community consisting of boring and encrusting organisms. (c)…

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from article Paleoecology

Tiering or vertical depth stratification in marine communities through time. Note the rapid rise of the highest-tier (level) organisms (crinoids or sea lilies, bryozoans) from a few centimeters to over a meter above the sea floor during the…

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from article Paleoecology

The three great marine evolutionary faunas of the Phanerozoic. The Cambrian fauna, composed of trilobites, primitive groups of brachiopods, and mollusks, arose early during that period to a diversity of about 50 families, and then dwindled during…

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from article Coral reef structural complexity

A fire coral before and after bleaching, which can occur when coral are environmentally stressed. The fire coral on the left is healthy, whereas the one on the right is completely bleached. (Credit: XL Catlin Seaview Survey)

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from article Coral reef structural complexity

Underwater photographs of Cane Bay (St. Croix, U.S. Virgin Islands) in 1980 (left) and 2007 (right). Note the common overgrowth of fleshy macroalgae between the sparsely distributed corals in 2007 compared to the more open substrate in 1980 between…

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from article Coral reef structural complexity

Historical changes related to coral reef decline since the 1600s. The emergence of temperature-related responses (bleaching and disease) is coincident with the loss of urchins (Diadema) and the increase of nutrient loading.

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from article Coral reef structural complexity

Three dominant shallow-water communities in the waters surrounding Easter Island. (Left) Since the 1950s, fleshy algae, such as Sargassum, were the dominant cover, and coral was rare in shallow waters. (Middle) In the 1980s, global climate change…

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from article Ecological succession

A plant succession involves a predictable set of vegetative changes through a series of successional stages. (U.S. Environmental Protection Agency)

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from article Ecological succession

A spruce tree growing among a stand of cottonwoods. Spruce trees may eventually become the dominant species in this ecosystem. (U.S. National Park Service/Kay White)

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from article Applied ecology