Origins of the Universe, Big Bang Theory Information, Big Bang Facts, News, Photos -- National Geographic The most popular theory of our universe's origin centers on a cosmic cataclysm unmatched in all of history—the big bang. This theory was born of the observation that other galaxies are moving away from our own at great speed, in all directions, as if they had all been propelled by an ancient explosive force. Before the big bang, scientists believe, the entire vastness of the observable universe, including all of its matter and radiation, was compressed into a hot, dense mass just a few millimeters across. Big bang proponents suggest that some 10 billion to 20 billion years ago, a massive blast allowed all the universe's known matter and energy—even space and time themselves—to spring from some ancient and unknown type of energy. The theory maintains that, in the instant—a trillion-trillionth of a second—after the big bang, the universe expanded with incomprehensible speed from its pebble-size origin to astronomical scope. Origins of the Theory
The oldest land plants (1) Fossils tell the story About fourhundred and fifty million years ago, at the end of the Ordovician and in the beginning of the Silurian, the land was desolate and empty. Barren, hardly wethered rockgrounds, empty sand-, gravel- and clayplains, no green. The oldest indications for the existence of real land plants have been found in cores from boreholes in Oman. Cooksonia The first fossils of macroscopic land plants have been found in the Middle Silurian of Ireland. more common and also more complete. The evolution from algae to land plants must have been a lengthy process. Another problem for land plants is that they miss the upward force of the water. Species of Cooksonia are found at several places on earth, e.g. in Wales, Scotland, England, Czechia and Canada. Baragwanathia A plant, almost as old as Cooksonia, is Baragwanathia longifolia. Enigmatic plants At the time of the first Cooksonias a completely different group of plants has evolved, which tried to colonize the land.
Fossil of ancient multicellular life sets evolutionary timeline back 60 million years -- ScienceDaily A Virginia Tech geobiologist with collaborators from the Chinese Academy of Sciences have found evidence in the fossil record that complex multicellularity appeared in living things about 600 million years ago -- nearly 60 million years before skeletal animals appeared during a huge growth spurt of new life on Earth known as the Cambrian Explosion. The discovery published online Wednesday in the journal Nature contradicts several longstanding interpretations of multicellular fossils from at least 600 million years ago. "This opens up a new door for us to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way," said Shuhai Xiao, a professor of geobiology in the Virginia Tech College of Science. The discovery sheds light on how and when solo cells began to cooperate with other cells to make a single, cohesive life form.
Timeline: The evolution of life By Michael Marshall There are all sorts of ways to reconstruct the history of life on Earth. Pinning down when specific events occurred is often tricky, though. For this, biologists depend mainly on dating the rocks in which fossils are found, and by looking at the “molecular clocks” in the DNA of living organisms. There are problems with each of these methods. Modern genetics allows scientists to measure how different species are from each other at a molecular level, and thus to estimate how much time has passed since a single lineage split into different species. These difficulties mean that the dates in the timeline should be taken as approximate. 3.8 billion years ago? This is our current “best guess” for the beginning of life on Earth. At some point far back in time, a common ancestor gave rise to two main groups of life: bacteria and archaea. How this happened, when, and in what order the different groups split, is still uncertain. 3.5 billion years ago 3.46 billion years ago
Commonly found fossils | National Trust Belemnites 'If you find a bullet-shaped fossil you could well have found the remnants of an ancient squid. These fossils are called belemnites.' says our wildlife and countryside officer Pete Brash. The original creature was a ten-armed squid-like cephalopod related to the modern cuttlefish, and it lived in the seas up until 66 million years ago, dying out at the same time as the dinosaurs. Ammonites 'Ammonites look a lot like coiled snail shells, but they were actually sea predators,' says our expert Rod Hebden. The ammonite was a tentacled sea creature that lived between 400 and 66 million years ago, similar to today's nautilus but more closely related to octopuses and squid. Ammonite fossils can be found in Dorset, and you can see two polished ammonites at Arlington Court, in Devon. Devil’s Toenails (Gryphaea) Although these commonly found fossils look like the claw of an ancient animal or, indeed, a devil, they were created from oysters that once lived on shallow sea beds. Shark’s teeth
Australia's fossil past Australia, the world's oldest visible geology Ediacara fossils from the Flinders Ranges. Photograph courtesy of the Australian Heritage Council. A fossil is the impression of a living organism that has been preserved. Fossils are preserved in substances such as sediments, coal, tar, oil, amber, or frozen in ice. There are three main types of fossils: body, trace and chemical. As well as body fossils, which are actual skeletal remains, there are impressions of soft animals, plants and footprints which have been left as mud hardened. Large numbers of fossils indicate that an enormous number of plants and animals have lived on Earth since life evolved more than 3,500 million years ago. Because of its relative isolation over millennia, Australia has a rich, unique fossil record, dating from approximately 3.2 billion years ago, close to when the Earth was stabilising its formation. Fossil sites Riversleigh, north-west Queensland, one of the most important fossil sites in the world. Useful links
Fossils, Rocks, and Time: Fossil Succession If we begin at the present and examine older and older layers of rock, we will come to a level where no fossils of humans are present. If we continue backwards in time, we will successively come to levels where no fossils of flowering plants are present, no birds, no mammals, no reptiles, no four-footed vertebrates, no land plants, no fishes, no shells, and no animals. The three concepts are summarized in the general principle called the Law of Fossil Succession: The kinds of animals and plants found as fossils change through time. When we find the same kinds of fossils in rocks from different places, we know that the rocks are the same age. How do scientists explain the changes in life forms, which are obvious in the record of fossils in rocks? Scientific theories are continually being corrected and improved, because theory must always account for known facts and observations. The study of fossils and the rocks that contain them occurs both out of doors and in the laboratory.
Evolution and the Fossil Record by John Pojeta, Jr. and Dale A. Springer Dating the Fossil Record (Previous Page || Next Page) The study of the sequence of occurrence of fossils in rocks, biostratigraphy, reveals the relative time order in which organisms lived. Although this relative time scale indicates that one layer of rock is younger or older than another, it does not pinpoint the age of a fossil or rock in years. The discovery of radioactivity late in the 19th century enabled scientists to develop techniques for accurately determining the ages of fossils, rocks, and events in Earth's history in the distant past. Determining the age of a rock involves using minerals that contain naturally-occurring radioactive elements and measuring the amount of change or decay in those elements to calculate approximately how many years ago the rock formed. About 90 chemical elements occur naturally in the Earth. To help in the identification and classification of elements, scientists have assigned an atomic number to each kind of atom. (Previous Page || Next Page)
600-Million-Year-Old Embryos Found By William J. Cromie Gazette Staff Embryos of relatively advanced animals, together with plants similar to modern seaweeds, have been found in rocks almost 600 million years old by Harvard scientists. The discovery moves the bottom line of animal life tens of millions of years back in time and dramatically clarifies our view of the evolutionary history of Earth. Most of today's animals can be traced back to fossils about 540 million years old. But now, beautifully preserved three-dimensional embryos and seaweeds have been dug from a phosphate mine in southern China by Andrew Knoll, professor of biology, and graduate student Shuhai Xiao. "It's amazing that the embryos are so similar to modern ones," Knoll comments. Bilateral animals have bodies in which the left and right sides are mirror images of each other. "The algae are similar to red, brown, and green seaweeds you can find along shallow coastlines today, although they are smaller in size," notes Xiao. Mining History Reading the Rocks
New 600-Million-Year-Old Fossil is the World's Oldest Sponge We shared a common ancestor with SpongeBob SquarePants hundreds of millions of years ago, though exactly how long ago has been up for debate. Now, analyses of a newly discovered 600-million-year-old fossil suggests that sponge-like animals predate the Cambrian by 60 million years. And if an advanced sponge-like form was already around during the Precambian period, that means that similarly advanced fossils of our (very early) ancestors from that long ago are also waiting to be found. The findings were published in Proceedings of the National Academy of Sciences this week. Previous studies have suggested that the last common ancestor shared by animal sponges and almost all other animals—called eumetazoans, which includes people and clams alike—existed more than 200 million years before the Cambrian period began around 541 million years ago. Unfortunately, unequivocal fossil evidence of this common ancestor is scant. Read this next: Love Hormone Oxytocin Helps Men Eat Better
Paleontologists Find 600-Million-Year-Old Microfossils of Complex Multicellular Organisms Pre-Cambrian microfossils discovered in rocks in southern China hint that complex multicellular life may have appeared as early as 600 million years ago. This Megasphaera fossil displays unexpected evidence of complexity: arrow marks a matryoshka and arrowhead denotes dyads. Scale bar – 100 μm. Image credit: Lei Chen et al. Mysterious spherical microfossils from the Ediacaran (630-542 million years ago) – the period immediately preceding the Cambrian – were uncovered from phosphorite rocks of the Doushantuo Formation in central Guizhou Province, China, in 1997. Several previous studies have interpreted these microorganisms, called Megasphaera, as bacteria, single-cell eukaryotes, algae, bilaterally symmetrical animals or transitional forms related to modern animals such as sponges and sea anemones. Their complex multicellularity is inconsistent with the simpler forms typically expected 600 million years ago. Lei Chen et al.
Results: Museum Victoria Museum Victoria home Skip to main content Discovery Centre Resources Topic > Dinosaurs %2526 Fossils Dinosaurs %2526 Fossils 11 Results Dinosaur digestion We can learn about what dinosaurs ate and how they digested their meals by looking at their fossil skeletons, examining stomach contents preserved in some specimens and by peering into their fossilised dung. Dinosaur Dreaming – The Inverloch Fossil site Information about the Dinosaur Dreaming fossil site near Inverloch, Victoria, including how to get involved as a volunteer. Dinosaur eggs While the dinosaurs have been extinct for millions of years, there are clues that can help us to piece together how they reproduced. Dinosaurs in Australia An introduction to the major dinosaur discoveries around Australia and their significance for scientific research. Fossil collecting: methods A summary of fossil collecting methods and techniques. Fossil insects – 400 million years of evolution Insects fossils date back 375 million years. Tweet
Smithsonian - Dinosaurs in Our Backyard - Finding Fossils Lots of fossils are still in the ground awaiting discovery. Here you can learn about maps and other resources that may help you find them. Were there dinosaurs in your backyard? Click to zoom, then drag the magnifying glass across the map to take an even closer look. This map shows (in green and dark blue) the regions of North America where rocks that formed during the Age of Dinosaurs -- 225 to 65.6 million years ago, are exposed at the surface of the Earth. In some parts of the country, especially the Northeast and Midwest, most rocks are too old to contain dinosaur fossils. In addition to looking for rocks of the right age, it is important to identify rocks that formed in the right environments. What types of fossils have been found near your home? The Paleontology Portal web site provides information about the ages of rocks found throughout North America. Visit the Paleontology Portal web site. View easy to follow video instructions for using the “Navigator” version of this site.