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Two species of trilobites found in the Southwestern United States. Trilobites went
extinct 250 million years ago, long before the appearance of the first dinosaurs.
Credit: Dan Dry / University of Chicago |
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| An artist´ rendering, based on fossil evidence, of some of the bizarre life forms, now extinct, that emerged during the "Cambrian explosion." |
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| A modern-day sponge. Ancient sponges are believed to be one of the earliest complex animal life forms, from which all modern-day animals evolved. |
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| These Ediacaran-age fossils from Mistaken Point, Newfoundland, Canada, are among the oldest ever found of complex life forms. Credit: © G.M. Narbonne, Queen´ University, 2000 |
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The fossils discovered in Australia date back to 3.5 billion years ago –“ and age
known as the Archaean. The atmosphere at this time in Earth´ history was very
different than today. It was likely composed of methane, ammonia and other gases
toxic to most life that lives on our planet now. It is thought that life first
started appearing on Earth during the Early Archaean.
Credit: UC Berkeley |
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Samples were collected from Australia's Pilbara region, located in the northwestern
region of the country. The Pilbara covers an area of 507,896 km² and a number of
offshore islands. |
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X-ray imaging of beetles helps confirm that tracheal system design may limit size in
insects. More of the body is filled with air-filled tracheal tubes in larger
species, particularly in the legs, and so much larger species than exist today might
not have room for enough tubes.
Credit: Argonne National Laboratory
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Two of the most important events in the history of animal life occurred during the
Paleozoic. First was the Cambrian explosion, where almost all living animal phyla
known today appeared in just a few million years. Then, at the end of the Paleozoic,
the largest mass extinction in history wiped out approximately 90 percent of all
marine animal species.
Credit: UC Berkeley
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A "black mat" of algal growth in Arizona marks a line of extinction at 12,900 years
ago; Clovis points and mammoth skeletons were found at the line but not above it.
Credit: Allen West, UCSB |
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Shale samples were collected from a deep Canadian gold mine near Timmins, Ontario.
Credit: The University of Illinois at Chicago |
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| Amphiphiles self assemble to form a spherical container. Credit: Los Alamos National Laboratory |
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Eske Willerslev collects soil samples in the permafrost of Canada's Yukon Territory.
Samples for the study were also collected from Northeastern Siberia and Antarctica.
Credit: Duane Froese
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All cells degrade over time, but some cells are better at others in repairing damage
to their DNA and thereby extending their lifetimes.
Credit: PBS
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Wolbachia genes transferring to host's DNA.
Credit: Nicolle Rager Fuller, National Science
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This image show a Wolbachia gene that has been inserted into the fly genome.
Credit: University of Rochester
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Jack Werren, professor of biology at the University of Rochester.
Credit: University of Rochester
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Wolbachia infection inside fly ovaries.
Credit: University of Rochester
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| Grouped diatoms. Credit: UW-Madison Department of Botany. |
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Opsin genes (pictured in blue) are present in the cnidarian Hydra, the first
evidence of sight in animals.
Credit: David Plachetzki/UCSB
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Markus Poschmann with the fossil claw recovered from 390 million years old rocks.
Credit: Markus Poschmann / University of Bristol
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Representation of the size of the fossil sea scorpion compared to an average human.
Credit: Simon Powell / University of Bristol
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This image shows a solution of DNA molecules that has formed a
liquid-crystal phase. The small molecules pair to form DNA double
helices, which then stack end-to-end to make rod shaped aggregates.
Credit: Michi Nakata/ University of Colorado at Boulder
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Micas are a common group of minerals that contain potassium, magnesium,
iron, aluminum, silicon and water. Their most noticeable trait is that
they are composed of flat sheets of crystals that can be peeled apart.
Credit: USGS |
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Ribonucleic acid (RNA) is composed of a chain of nucleic acids. It is
similar to DNA, but RNA is typically present in cells as a single
strand. RNA is most famous for its role in translating genetic
information from DNA so that cells can use the information to make
proteins.
Credit: Princeton University |
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| Cretaceous Period insect. Credit: Oregon State University. |
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| Tick found in Burmese amber. Credit: Oregon State University. |
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| Reconstructed dinosaur skeletons. Credit: Natural History Museum of Los Angeles. |
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The Mesozoic Era lasted from 245 million years ago –“ 65 mya. At the beginning of the Mesozoic most land was bound up in the supercontinent Pangaea, but it started breaking apart into separate land masses toward the middle of the Mesozoic Era.
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Researchers studied fossils of the Ediacara in order to understand how major
branches of life evolved. Ediacara are the oldest complex, multicellular organisms
known and lived in the Earth¡¯s oceans before the Cambrian Explosion.
Credit: Virginia Tech
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The crystal structure of an RNA molecule bound to a protein was used by researchers
to study a stage of evolution.
Credit: Barbara Golden, Purdue University Department of Biochemistry
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Fossil (left) and depiction (right) of extinct armored machaeridian worm. Colors
indicate the trunk (yellow), limb (red), bristles (gray), attachment of shell plates
(green), gut (purple) and dorsal linear structure (blue).
Credit: Vinther, et al Nature
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| This image shows the fossilized skull of the infamous saber-toothed Lycaenops, a predator that existed during the late Permian. The Lycaenops was a therapsid, or "mammal-like" reptile. The research team studied organisms like the Lycaenops in order to understand how ecological communities recovered after one of Earth's largest-ever mass extinctions. Credit: Michael Benton |
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A hydrogen bond is a unique type of dipole-dipole bond that can occur between two
molecules or within a single molecule. Water molecules are polar, resulting in a
partial negative charge near the oxygen atom and partial positive charges near the
hydrogen atoms. This uneven distribution of charge causes water molecules to attract
one another –“ forming the 'hydogen bond' shown above. Hydrogen bonds are what give
water unique properties that are ultimately essential for water's role in making
life on Earth possible.
Credit: University of Arizona
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Photo micrograph of synthetic Mycoplasma genitalium genome taken over a ~0.6 second
period.
Credit: JCVI
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M. genitalium is the smallest free-living bacterium known today.
Image Credit: PBS-NOVA
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New research could help us understand how similar genes find each other in order to
allow key processes in evolution.
Credit: Imperial College London
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Lost City is located about 2,300 miles east of Florida on the Mid-Atlantic Ridge,
one of the world's largest undersea mountain ranges.
Credit: University of Washington
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The carbonate structures at the Lost City Field include these spires stretching 90
feet tall. The white, sinuous spine is freshly deposited carbonate material. Added
digitally to this image are the remotely operated vehicles Hercules and Argus that
were used to explore the hydrothermal vent field during an expedition in 2005 funded
by the National Oceanic and Atmospheric Administration.
Credit: Kelley, U of Washington, IFE, URI-IAO, NOAA
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Gases are collected from the top of one of the hydrothermal vents that make up Lost
City.
Credit: University of Washington, IFE, URI-IAO, NOAA
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This image shows a close-up view of the Diplodocus teeth (skull from the Chicago
Field Museum).
Credit: UC Berkeley, Photos © Richard Harwood, Black Hawk College.
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Sauropod dinosaurs were herbivorous, and some reached sizes as large as ten
full-grown elephants.
Credit: UC Berkeley |
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This image shows the front view of a Diplodocus skull from the Chicago Field Museum.
The Diplodocus was a giant sauropod dinosaurs.
Credit: UC Berkeley, Photos © Richard Harwood, Black Hawk College. |
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This image shows the structure of a translation elongation factor
protein from yeast (in yellow). Scientists chose to study this protein
because bacteria have slightly different forms of elongation factor, and
the differences depend on the environment in which the bacteria live.
Credit: Robert Wood Johnson Medical School |
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Photomicrograph of Acaryochloris marina.
Credit: Phototrophic Prokaryotes Sequencing Project
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The giant frog Beelzebufo, or "devil frog," was the largest frog ever to live on Earth.
Credit: SUNY-Stony Brook |
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This photo (field of view about 0.15 millimeter in width) is of an
exceptionally preserved eukaryotic fossil from the Doushantuo Formation
(635-551 million years old) in South China. High-resolution geochemical
data from the Doushantuo Formation indicate that the early
diversification of eukaryotes may have coupled with episodic oxygenation
of Ediacaran oceans.
Credit: Photograph by Shuhai Xiao
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