* Astronomy

Blobrana · L

RE: Ancient life

Blobrana · L

Loch fossils show life harnessed sun and sex early on

Remote lochs along the west coast of Scotland are turning up new evidence about the origins of life on land.
A team of scientists exploring rocks around Loch Torridon have discovered the remarkably preserved remains of organisms that once lived on the bottom of ancient lake beds as long as a billion (1000 million) years ago.
These fossils illuminate a key moment in the history of evolution when life made the leap from tiny, simple bacterial (prokaryote) cells towards larger, more complex (eukaryotic) cells which would make photosynthesis and sexual reproduction possible. The team, from Oxford University, Sheffield University and Boston College, report their findings in this week's Nature.
Read more

Blobrana · L

Ancient enzymes

Blobrana · L

RE: Ancient life

Blobrana · L

Skeletons in the Pre-Cambrian Closet

The Cambrian explosion marked a major blossoming in the tree of life around 540 million years ago. Nearly all of the major phyla in the animal kingdom appeared in a sudden burst of evolution. One of the drivers of this rapid diversification was likely the appearance of skeletal-bearing animals a mere 10 million years before. Researchers are studying these first skeletons to gain a better understanding of what led to their development.

We have long taken for granted the benefit of a hard skeleton. Vertebrates like ourselves can grow large and nimble thanks to bones containing calcium and phosphorous. Mollusks and other animals are protected by shells made of calcium carbonate, whereas certain sponges construct an internal framework of silica to help them filter food.

Blobrana · L

Life on Earth suddenly exploded into being around three billion years ago, according to a new study.
Scientists have studied ancient genes to paint a picture of our planet's earliest inhabitants and believe the first life developed when microbes learned to use oxygen and energy from the sun to live.
Researchers from the Massachusetts Institute of Technology (MIT) studied 1,000 key genes that exist today and worked out how they evolved from the very distant past.
They created a 'genomic fossil' telling not only when genes came into being but also which ancient microbes possessed those genes.
Read more

Blobrana · L

Scientists decipher 3 billion-year-old genomic fossil

About 580 million years ago, life on Earth began a rapid period of change called the Cambrian Explosion, a period defined by the birth of new life forms over many millions of years that ultimately helped bring about the modern diversity of animals. Fossils help palaeontologists chronicle the evolution of life since then, but drawing a picture of life during the 3 billion years that preceded the Cambrian Period is challenging, because the soft-bodied Precambrian cells rarely left fossil imprints. However, those early life forms did leave behind one abundant microscopic fossil: DNA.
Because all living organisms inherit their genomes - the entire package of hereditary information existing in their DNA and RNA - from ancestral genomes, computational biologists at MIT reasoned that they could use modern-day genomes to reconstruct the evolution of ancient microbes. They combined information from the ever-growing genome library with their own mathematical model that takes into account the ways that genes evolve: new gene families can be born and inherited; genes can be swapped or horizontally transferred between organisms; genes can be duplicated in the same genome; and genes can be lost.
The scientists traced thousands of genes from 100 modern genomes back to those genes' first appearance on Earth to create a genomic fossil telling not only when genes came into being but also which ancient microbes possessed those genes. The work suggests that the collective genome of all life underwent an expansion between 3.3 and 2.8 billion years ago, during which time 27 percent of all presently existing gene families came into being.
Read more

Blobrana · L

Scottish rocks record ancient oxygen clues

Oxygen levels on Earth reached a critical threshold to enable the evolution of complex life much earlier than thought, say scientists.
The evidence is found in 1.2-billion-year-old rocks from Scotland.
These rocks retain signatures of bacterial activity known to occur when there is copious atmospheric oxygen.
The microbes' behaviour is seen 400 million years further back in time than any previous discovery, the researchers tell the journal Nature.
Read more

Blobrana · L

Scottish rocks reveal key point in evolution occurred 400 million years earlier

The history of evolution may be rewritten after scientists found evidence of life on Earth in the Highlands - 400million years earlier than previously thought.
The ancient rocks near Lochinver, in western Sutherland, were found to contain chemical signals suggesting the emergence of complex multi-cellular beings - which would later develop into humans - 1.2billion years ago.
The Scottish research team, led by Aberdeen University geologist John Parnell, detected traces of an important shift in the levels of oxygen in the Earth's atmosphere which allowed this key move from simple organisms to happen.
Read more

Blobrana · L

Professors Study Oldest Fossil Shrimp Preserved With Muscles

One of America's favourite seafood is shrimp. Did you know that they fossilise as well? Rodney Feldmann, professor emeritus, and Carrie Schweitzer, associate professor, from Kent State Universitys Department of Geology report on the oldest fossil shrimp known to date in the world. The creature in stone is as much as 360 million years old and was found in Oklahoma. Even the muscles of the fossil are preserved. Their study will be published in Journal of Crustacean Biology.
Read more