Posts Tagged ‘Evolution’

Worm-like Marine Animal Providing Fresh Clues About Human Evolution

June 18, 2008

Research on the genome of a marine creature led by scientists at Scripps Institution of Oceanography at UC San Diego is shedding new light on a key area of the tree of life.

Linda Holland, a research biologist at Scripps Oceanography, and her colleagues from the United States, Europe and Asia, have deciphered and analyzed fundamental elements of the genetic makeup of a small, worm-like marine animal called amphioxus, also known as a lancelet.

Amphioxus is not widely known to the general public, but is gaining interest in scientific circles because of its position as one of the closest living invertebrate relatives of vertebrates. Although amphioxus split from vertebrates more than 520 million years ago, its genome holds tantalizing clues about evolution.

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Altruism In Social Insects Is A Family Affair

June 16, 2008

The contentious debate about why insects evolved to put the interests of the colony over the individual has been reignited by new research from the University of Leeds, showing that they do so to increase the chances that their genes will be passed on.

A team led by Dr Bill Hughes of the University’s Faculty of Biological Sciences studied ‘kin selection’ — the theory that an animal may pass on its genes by helping relatives to reproduce, because they share common genes, rather than by reproducing itself.

The concept of ‘kin selection’ was developed in 1964 by the evolutionary biologist Bill Hamilton, first proposed by Charles Darwin to explain, for example, why sterile workers evolved in social insect groups and why a honeybee would sacrifice its life to defend the colony. Charles Darwin recognized that such altruistic behaviour in highly social insect groups was at odds with his theory of natural selection, and Bill Hamilton’s theory of kin selection showed that this behaviour can evolve because it still fulfills the drive to pass on genes – but through relatives instead.

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Taxonomists Describe The Top 10 Most Surprising Species Discovered In 2007

June 3, 2008

Each year the scientific community identifies around 17,000 new animals and plants. To attract people’s attention on the discovery of species, a key for their evolution, survival and conservation, an international committee of experts has just published a list of the 10 most curious and surprising species described in 2007.

Of all living or extinct animal and plant species, discovered on the Earth in 2007, only ten have been selected for a Top 10 presented on the 23 May on the occasion of the anniversary of the birth of Carlos Linneo, initiator of the species classification and naming system. 2008 also marks the 250th anniversary of the start of animal identification.

In the list prepared each year by the International Institute for Species Exploration (IISE) at the University of Arizona (USA), in first place is an electric ray, Electrolux addisoni, whose name reflects the “vigorous action of hoovering as a method of feeding”, according to experts. Discovered on the east coast of South Africa, this peculiar ray “could compete with the well-known function of the hoover for hoovering, in its case, the ocean floor”.

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Did Walking On Two Feet Begin With A Shuffle?

May 29, 2008

Somewhere in the murky past, between four and seven million years ago, a hungry common ancestor of today’s primates, including humans, did something novel. While temporarily standing on its rear feet to reach a piece of fruit, this protohominid spotted another juicy morsel in a nearby shrub and began shuffling toward it instead of dropping on all fours, crawling to the shrub and standing again.

A number of reasons have been proposed for the development of bipedal behavior, or walking on two feet, and now researchers from the University of Washington and Johns Hopkins University have developed a mathematical model that suggests shuffling emerged as a precursor to walking as a way of saving metabolic energy.

“Metabolic energy is produced by what an animal eats, enabling it to move. But it is a limited resource, particularly for young-bearing females which have to take care of and feed their offspring. Finding food is vitally important, and an animal needs to save energy and use it efficiently,” said Patricia Kramer, a UW research assistant professor of anthropology and co-author of a recent study.

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Ancient Amphibian: Debate Over Origin Of Frogs And Salamanders Settled With Discovery Of Missing Link

May 22, 2008

The description of an ancient amphibian that millions of years ago swam in quiet pools and caught mayflies on the surrounding land in Texas has set to rest one of the greatest current controversies in vertebrate evolution. The discovery was made by a research team led by scientists at the University of Calgary.

The examination and detailed description of the fossil, Gerobatrachus hottoni (meaning Hotton’s elder frog), proves the previously disputed fact that some modern amphibians, frogs and salamanders evolved from one ancient amphibian group called temnospondyls.

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“Reverse Evolution” Discovered in Seattle Fish

May 22, 2008

When a historic cleanup helped clear the waters of a polluted lake near Seattle, a population of tiny, spiny fish called sticklebacks may have “evolved in reverse” to survive.

In the 1950s, Lake Washington, an inland lake that parallels Washington State‘s Pacific Coast, took on 20 million gallons (76 million liters) of phosphorous-laden sewage a day (see Washington State map).

By the 1960s it had become a 300,000-acre (121,400-hectare) cesspool.

Then an unprecedented U.S.-$140-million cleanup in the mid-1960s transformed the lake into the pristine boaters’ paradise that it is today.

But the lake’s recovery put at least one species in a pickle: the three-spine stickleback.

The small fish, formerly hidden in the murky depths, found itself swimming in plain view of predators like cutthroat trout.

Researchers now think the threat of predators spurred the fish into rapid evolution toward an older version of itself, evolutionarily speaking.

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6 Formerly Kick-A** Creatures Ruined by Evolution

April 11, 2008

Evolution isn’t perfect. Just as the Kennedy family can produce a Ted, some noble species go down the wrong genetic path and what used to be the Tyrannosaurus Rex can wind up as a modern chicken.

Here are six kicka**creatures that evolution apparently decided were just too awesome to exist and then, to add insult to injury, evolved them into the crappiest replacements possible.

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Rethinking evolution: Sex and complexity came a lot sooner than we thought

March 20, 2008

Two paleontologists studying ancient fossils they excavated in the South Australian outback argue that Earth’s ecosystem has been complex for hundreds of millions of years — at least since around 565 million years ago, which is included in a period in Earth’s history called the Neoproterozoic era.

Until now, the dominant paradigm in the field of paleobiology has been that the earliest multicellular animals were simple, and that strategies organisms use today to survive, reproduce and grow in numbers have arisen over time due to several factors. These factors include evolutionary and ecological pressures that both predators and competition for food and other resources have imposed on the ecosystem.

But in describing the ecology and reproductive strategies of Funisia dorothea, a tubular organism preserved as a fossil, the researchers found that the organism had multiple means of growing and propagating — similar to strategies used by most invertebrate organisms for propagation today.

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Tree Of Animal Life Has Branches Rearranged, By Evolutionary Biologists

March 5, 2008

A study led by Brown University biologist Casey Dunn uses new genomics tools to answer old questions about animal evolution. The study is the most comprehensive animal phylogenomic research project to date, involving 40 million base pairs of new DNA data taken from 29 animal species.

The study, which appears in Nature, settles some long-standing debates about the relationships between major groups of animals and offers up a few surprises.

The big shocker: Comb jellyfish — common and extremely fragile jellies with well-developed tissues — appear to have diverged from other animals even before the lowly sponge, which has no tissue to speak of. This finding calls into question the very root of the animal tree of life, which traditionally placed sponges at the base.

“This finding suggests either that comb jellies evolved their complexity independently from other animals, or that sponges have become greatly simplified through the course of evolution. If corroborated by other types of evidence, this would significantly change the way we think about the earliest multicellular animals,” said Dunn, assistant professor of ecology and evolutionary biology at Brown. “Coming up with these surprises, and trying to better understand the relationships between living things, made this project so fascinating.”

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