Showing posts with label evolution. Show all posts
Showing posts with label evolution. Show all posts

Saturday, May 2, 2009

Origin Of Life: What Are The Odds?

A mineral chimney and microbe mats on the sea floor in the Gulf of Mexico in one of the newfound scenes that scientists described as otherworldly. Mineral chimneys are associated with sea vents that release oil and gas. The microbe mats are lying on sediments next to the mineral chimney.Credit: Ian MacDonald, Texas A&M University

From Live Science:


And it really bothers us. "Many people, perhaps most, hate the idea that life might depend on chance processes," writes biologist Dave Deamer on his blog.

Scientists have hypothesized that it started around hot vents on the seafloor, or that things heated up between the mica sheets, or that it came in a comet (which doesn't really solve the origin problem). But nobody knows.

Those who promote intelligent design — an attack on the theory of evolution thought by many scientists to be a thinly veiled effort to get religious ideas into science classrooms — suggest the the astronomical odds of it point to a designer being involved, rather than pure chance.

Read more ....

Tuesday, April 21, 2009

What Makes Us Human?

Photo: The 1 percent difference: Humans are distinct from chimpanzees in a number of important respects, despite sharing nearly 99 percent of their DNA. New analyses are revealing which parts of the genome set our species apart. James Balog Getty Images

From Scientific American Magazine:

Six years ago I jumped at an opportunity to join the international team that was identifying the sequence of DNA bases, or “letters,” in the genome of the common chimpanzee (Pan troglodytes). As a biostatistician with a long-standing interest in human origins, I was eager to line up the human DNA sequence next to that of our closest living relative and take stock. A humbling truth emerged: our DNA blueprints are nearly 99 percent identical to theirs. That is, of the three billion letters that make up the human genome, only 15 million of them—less than 1 percent—have changed in the six million years or so since the human and chimp lineages diverged.

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Thursday, April 9, 2009

New Link Between The Evolution Of Complex Life Forms On Earth And Nickel And Methane Gas

Image: Banded iron formations like this from northern Michigan contain evidence of a drop in dissolved nickel in ancient oceans. (Credit: Image courtesy of Carnegie Institution)

From Science Daily:

ScienceDaily (Apr. 9, 2009) — The Earth's original atmosphere held very little oxygen. This began to change around 2.4 billion years ago when oxygen levels increased dramatically during what scientists call the "Great Oxidation Event." The cause of this event has puzzled scientists, but researchers writing in Nature have found indications in ancient sedimentary rocks that it may have been linked to a drop in the level of dissolved nickel in seawater.

"The Great Oxidation Event is what irreversibly changed surface environments on Earth and ultimately made advanced life possible," says research team member Dominic Papineau of the Carnegie Institution's Geophysical Laboratory. "It was a major turning point in the evolution of our planet, and we are getting closer to understanding how it occurred."

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Saturday, April 4, 2009

Muslim Students Weigh In On Evolution

Photo: The data could help teachers and students from diverse backgrounds work together better. Punchstock

From Nature News:

In Indonesia and Pakistan, questions about how science and faith can be reconciled.

In the first large study of its kind, a survey of 3,800 high-school students in Indonesia and Pakistan has found that teachers are delivering conflicting messages about evolution.

The Can$250,000 Islam and Evolution research project is the first large study of students, teachers and scientists in countries with significant Muslim populations to examine their understanding and acceptance of evolution. Some results from the three-year project were presented at a symposium at McGill University in Montreal, Canada, this week.

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Monday, March 23, 2009

A Machine That Speeds Up Evolution

Photo: Better bugs: Using a specially designed machine (shown here), scientists can rapidly engineer up to 50 genetic changes in bacteria, dramatically speeding the quest to design bacterial factories capable of efficiently producing drugs, biofuels, and other chemical products. Credit: George Church

From Technology Review:

A genome-wide approach to genetic engineering greatly speeds the manufacture of bacteria for making drugs and biofuels.

Rather than changing the genome letter by letter, as most genetic engineering is done, George Church and his colleagues have developed a new technology that can make 50 changes to a bacterial genome nearly simultaneously--an advance that could be used to greatly speed the creation of bacteria that are better at producing drugs, nutrients, or biofuels.

"What once took months now takes days," says Stephen del Cardayré, vice president of research and development at LS9, a biofuels company based in South San Francisco of which Church is a founder. LS9 soon plans to use the technology--called multiplex-automated genomic engineering, or MAGE--to accelerate development of bacterial cells that can produce low-cost renewable fuels and chemicals.

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Saturday, March 21, 2009

First 'Rule' Of Evolution Suggests That Life Is Destined To Become More Complex

Spiny lobster. In complex crustaceans, such as shrimps and lobsters, almost every segment is different, bearing antennae, jaws, claws, walking legs, paddles and gills. (Credit: iStockphoto/Tammy Peluso)

From Science Daily:

ScienceDaily (Mar. 18, 2008) — Researchers have found evidence which suggests that evolution drives animals to become increasingly more complex.

Looking back through the last 550 million years of the fossil catalogue to the present day, the team investigated the different evolutionary branches of the crustacean family tree.

They were seeking examples along the tree where animals evolved that were simpler than their ancestors.

Instead they found organisms with increasingly more complex structures and features, suggesting that there is some mechanism driving change in this direction.

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Wednesday, February 25, 2009

The Evolution of Human Aggression

From Live Science:

Everyone has experienced anger at one point in their lives and some of us — males mostly, going by statistics — have channeled that anger into violence, perhaps by throwing a punch during a hockey game or after too many beers at the bar.

Then there's aggression on a much more sinister scale, in the form of murder, wars and genocide. Trying to understand what fuels the different levels of human aggression, from fisticuffs to nation-on-nation battle, has long preoccupied human biologists.

Read more ....

Friday, February 13, 2009

Cooking Helped Humans Evolve ... With Side Effects


From Wired Science:

CHICAGO — Raw-food devotees take note: Your diet is not in any way natural. Humans are as adapted to cooking our food as cows are to eating grass, or ticks are to sucking blood.

"Cooking is a human universal," said Harvard primatologist Richard Wrangham at the American Association for the Advancement of Science meeting here Friday. While cooking kills parasites and other pathogens, Wrangham believes this health benefit is not its primary contribution.

"The fundamental importance of cooking is that it provides increased sources of energy," he said.

Read more ....

Saturday, January 31, 2009

Ancient Creature Points To Parallel Evolution

Light optical microscope images of placozoans.
(Image from NASA Astrobiology Institute)

From New Scientist:

AN UPDATED family tree of the animal kingdom could radically change the way we think about the evolution of species.

According to conventional thinking, simple animals, including sponges, jellyfish and corals, evolved step-by-step in a linear fashion into those with more complex bodies, such as mammals.

Now Rob DeSalle of the American Museum of Natural History in New York and his colleagues have challenged this way of thinking.

The team analysed DNA and other molecular evidence across the animal kingdom, including tiny sea creatures called placozoans. They have found that the placozoans are the closest living thing to the ancestor of all animals.

Read more ....

Monday, January 12, 2009

Super-Predators: Humans Force Rapid Evolution of Animals

Bighorn sheep are one of many species now documented as getting smaller, on average, due to trophy hunting that targets larger specimens and leaves smaller members of a population, and their genes, to reproduce. Image credit: Paul Paquet

From Live Science:

Acting as super-predators, humans are forcing changes to body size and reproductive abilities in some species 300 percent faster than would occur naturally, a new study finds.

Hunting and fishing by individual sportsmen as well as large-scale commercial fishing are also outpacing other human influences, such as pollution, in effects on the animal kingdom. The changes are dramatic and may put the survival of some species in question.

In a review of 34 studies that tracked 29 species across 40 different geographic systems, harvested and hunted populations are on average 20 percent smaller in body size than previous generations, and the age at which they first reproduce is on average 25 percent earlier.

Read more ....

Wednesday, December 17, 2008

Earth's Original Ancestor Was LUCA, Not Adam Nor Eve

From E! Science News:

Here's another argument against intelligent design. An evolutionary geneticist from the Université de Montréal, together with researchers from the French cities of Lyon and Montpellier, have published a ground-breaking study that characterizes the common ancestor of all life on earth, LUCA (Last Universal Common Ancestor). Their findings, presented in a recent issue of Nature, show that the 3.8-billion-year-old organism was not the creature usually imagined. The study changes ideas of early life on Earth. "It is generally believed that LUCA was a heat-loving or hyperthermophilic organism. A bit like one of those weird organisms living in the hot vents along the continental ridges deep in the oceans today (above 90 degrees Celsius)," says Nicolas Lartillot, the study's co-author and a bio-informatics professor at the Université de Montréal. "However, our data suggests that LUCA was actually sensitive to warmer temperatures and lived in a climate below 50 degrees."

Read more ....

Sunday, November 23, 2008

How Warfare Shaped Human Evolution

Iran - Iraq War

From The New Scientist:

IT'S a question at the heart of what it is to be human: why do we go to war? The cost to human society is enormous, yet for all our intellectual development, we continue to wage war well into the 21st century.

Now a new theory is emerging that challenges the prevailing view that warfare is a product of human culture and thus a relatively recent phenomenon. For the first time, anthropologists, archaeologists, primatologists, psychologists and political scientists are approaching a consensus. Not only is war as ancient as humankind, they say, but it has played an integral role in our evolution.

The theory helps explain the evolution of familiar aspects of warlike behaviour such as gang warfare. And even suggests the cooperative skills we've had to develop to be effective warriors have turned into the modern ability to work towards a common goal.

Read more ....

Friday, November 14, 2008

Which Came First? Eggs Before Chickens, Scientists Now Say

Frrm Live Science:

A rare fossilized dinosaur nest helps answer the conundrum of which came first, the chicken or the egg, two paleontologists say.

The small carnivorous dinosaur sat over her nest of eggs some 77 million years ago, along a sandy river beach. When water levels rose, Mom seems to have fled, leaving the unhatched offspring.

Researchers have now studied the fossil nest and at least five partial eggs. The nest is a mound of sand that extends about 1.6 feet (half a meter) across and weighs as much as a small person, or about 110 pounds (50 kg).

Read more ....

Wednesday, November 12, 2008

Oldest Evidence For Complex Life In Doubt

The earliest life on Earth consisted of prokaryotes — small single-celled organisms without nuclei. These earliest organisms were anaerobic — they did not require oxygen to live.
(Image from Lunar And Planetary Institute)

From Astrobiology:

Oldest Evidence for Life in Doubt

Chemical biomarkers in ancient Australian rocks, once thought to be the oldest known evidence of complex life on Earth, may have infiltrated long after the sediments were laid down, new analyses suggest.

The evidence was based on biomarkers - distinctive chemical compounds produced today by modern-day relatives of cyanobacteria and other complex life forms. In 1999, a team of researchers contended that the biomarkers in the 2.7-billion–year-old rocks pushed back the origins of cyanobacteria by at least 550 million years and of eukaryotes by about a billion years.

Although some scientists interpret the new findings, published in the Oct. 23 Nature, as disproving the older dates, others contend that the results still allow for the presence of the organisms or their kin at that time.

Read more .....

Friday, November 7, 2008

Japanese Clone Mouse From Frozen Cell, Aim For Mammoths

This handout picture, released by Japan natural science research center shows a cloned mouse (left) created with a new technology by using a frozen dead cell of a mouse. (AFP/Teruhiko Wakayama)

From Breitbart/AFP:

Japanese scientists said Tuesday they had created a mouse from a dead cell frozen for 16 years, taking a step in the long impossible dream of bringing back extinct animals such as mammoths.

Scientists at the government-backed research institute Riken used the dead cell of a mouse that had been preserved at minus 20 degrees Celsius (minus 4 degrees Fahrenheit) -- a temperature similar to frozen ground.

The scientists hope that the first-of-a-kind research will pave the way to restore extinct animals such as the mammoth.

The findings were published in the Proceedings of the National Academy of Sciences in the United States.

The scientists extracted a cell nucleus from an organ of the dead mouse and planted it into an egg of another mouse which was alive, leading to the birth of the cloned mouse, the researchers said.

Read more ....

Sunday, October 26, 2008

Study: Humans Almost Became Extinct 70,000 Years Ago -- FOX News

From FOX News:

WASHINGTON — Human beings may have had a brush with extinction about 70,000 years ago, an extensive genetic study suggests.

The human population at that time had been gradually reduced to small isolated groups across eastern and southern Africa, apparently because of massive droughts lasting tens of thousands of years, according to an analysis released Thursday.

The report notes that a separate study by researchers at Stanford University estimated the number of early humans may have shrunk as low as 2,000 before numbers began to rapidly expand again in the period known as the Late Stone Age.

Read more ....

Tuesday, October 21, 2008

Volcanoes May Be Original Womb Of Life

Close view of Stromboli Volcano erupting incandescent molten lava fragments.
Credit: USGS and B. Chouet in December 1969

From Live Science:

Fifty years ago, a chemist named Stanley Miller conducted a famous experiment to investigate how life could have started on Earth.

Recently, scientists re-analyzed his results using modern technology and found a new implication: The original sparks for life on our planet could have come from volcanic eruptions.

The 1950s experiment was designed to test how the ingredients necessary for life could arise.

Miller and his University of Chicago mentor Harold Urey used a system of closed flasks containing water and a gas of simple molecules thought to be common in Earth's early atmosphere. They zapped the gas with an electric spark (representing lightning on ancient Earth), and found that after a couple of weeks the water turned brown. It turned out that amino acids, the complex molecules that make up proteins, had formed from the simple materials in the flasks.

Read more ....

Saturday, October 11, 2008

How We Evolve


From Seed Magazine:

When the previous generation of life scientists was coming up through the academy, there was a widespread assumption, not always articulated by professors, that human evolution had all but stopped. It had certainly shaped our prehuman ancestors — Australopithecus, Paranthropus, and the rest of the ape-men and man-apes in our bushy lineage — but once Homo sapiens developed agriculture and language, it was thought, we stopped changing. It was as though, having achieved its aim by the seventh day, evolution rested. "That was the stereotype that I learned," says population geneticist and anthropologist Henry Harpending. "We showed up 45,000 years ago and haven't changed since then."

The idea makes a rough-and-ready kind of sense. Natural selection derives its power to transform from the survival of some and the demise of others, and from differential reproductive success. But we nurse our sick back to health, and mating is no longer a privilege that males beat each other senseless to secure. As a result, even the less fit get to pass on their genes. Promiscuity and sperm competition have given way to spiritual love; the fittest and the unfit are treated as equals, and equally flourish. With the advent of culture and our fine sensibilities, the assumption was, natural selection went by the board.

Read more ....

Saturday, September 20, 2008

Where Is Human Evolution Heading?


From U.S. News And World Report:

The race's DNA is changing faster than ever; what it means for our descendants

If you judge the progress of humanity by Homer Simpson, Paris Hilton, and Girls Gone Wild videos, you might conclude that our evolution has stalled—or even shifted into reverse. Not so, scientists say. Humans are evolving faster than ever before, picking up new genetic traits and talents that may help us survive a turbulent future.

Much remodeling has gone on since the dawn of agriculture about 10 millenniums ago. "People who lived 10,000 years ago were much more like Neanderthals than we are like those people," says John Hawks, a professor of anthropology at the University of Wisconsin. "We've changed."

Hawks is among a growing number of scientists who are using whole-genome sequencing and other modern technologies to zero in on just how we've changed. Their research is helping illuminate not only how humans became what we are but also where we might be headed. For instance, some scientists speculate that changes in human mating patterns may be contributing to the increase in autism. Others track how humans have morphed in response to changing circumstances, including enhanced abilities to metabolize sugar and fight disease. Some people are genetically more resistant to the HIV virus, for instance, and that trait should become more common in the future, as those people are more likely to survive and have children who are resistant. Yet for some people, the makeover isn't big enough or fast enough. Some parents have started using DNA testing to choose the genetic makeup of their children, rejecting embryos with inherited flaws or embracing those with desired traits—such as being the right sex.

Read more ....

Monday, September 1, 2008

Evolution And Human Nature


David Friedman On Evolution And Human Nature -- Future Pundit

David Friedman says that while Leftists generally accept that evolution occurred they reject all implications evolution has for human nature.

People who say they are against teaching the theory of evolution are very likely to be Christian fundamentalists. But people who are against taking seriously the implications of evolution, strongly enough to want to attack those who disagree, including those who teach those implications, are quite likely to be on the left.

Read more ....