These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus slowing decomposition. Stromatolites Lower Proterozoic Stromatolites from Bolivia , South America Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms , especially cyanobacteria. While older, Archean fossil remains are presumed to be colonies of cyanobacteria , younger that is, Proterozoic fossils may be primordial forms of the eukaryote chlorophytes that is, green algae. One genus of stromatolite very common in the geologic record is Collenia. The earliest stromatolite of confirmed microbial origin dates to 2. The most widely supported explanation is that stromatolite builders fell victims to grazing creatures the Cambrian substrate revolution , implying that sufficiently complex organisms were common over 1 billion years ago. Factors such as the chemistry of the environment may have been responsible for changes. Cyanobacteria as well as extremophile Gammaproteobacteria are thought to be largely responsible for increasing the amount of oxygen in the primeval earth’s atmosphere through their continuing photosynthesis.
15 Things You Might Not Know About St. Patrick’s Day
The earliest recorded fossil of Cryptomeria in East Asia is reported. Abstract Cryptomeria Cupressaceae is a relic genus that was widely distributed throughout Eurasia during the Cenozoic. Interpretation of the biogeographic history of this genus is currently limited by lack of fossil records from the Paleogene of East Asia. Here, we report on a new fossil species of Cryptomeria, Cryptomeria yunnanensis W. Sterile shoots are assigned to Cryptomeria based on gross-morphological and cuticular morphological characters and are compared with extant and fossils species described so far.
In Dr. Raul Esperante teamed up with Dr. Leonard Brand and others to investigate fossil whales within the Pisco Formation of Peru’s Atacama Desert.
Genetic change he genetic information specifies everything about an organism and its potential. Genotype specifies possible phenotypes, therefore, phenotypic change follows genetic change. This obviously should be one of the areas where evolutionary change is seen, and genetic change is truly the most important for understanding evolutionary processes. Extremely extensive genetic change has been observed, both in the lab and in the wild.
We have seen genomes irreversibly and heritably altered by numerous phenomena, including gene flow, random genetic drift, natural selection, and mutation. Observed mutations have occurred by mobile introns, gene duplications, recombination, transpositions, retroviral insertions horizontal gene transfer , base substitutions, base deletions, base insertions, and chromosomal rearrangements. Chromosomal rearrangements include genome duplication e. Once the genetic material was elucidated, it was obvious that for macroevolution to proceed vast amounts of change was necessary in the genetic material.
If the general observation of geneticists was that of genomic stasis and recalcitrance to significant genetic change, it would be weighty evidence against the probability of macroevolution. For instance, it is possible that whenever we introduce mutations into an organism’s genome, the DNA could back-mutate to its former state. However, the opposite is the case—the genome is incredibly plastic, and genetic change is heritable and essentially irreversible Lewin Cladistic classification, and thus, phylogenetic reconstruction, is largely based on the various distinguishing morphological characteristics of species.
Macroevolution requires that organisms’ morphologies have changed throughout evolutionary history; thus, we should observe morphological change and variation in modern populations. There have been numerous observations of morphological change in populations of organisms Endler
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A phenotypic characteristic, acquired during growth and development, that is not genetically based and therefore cannot be passed on to the next generation for example, the large muscles of a weightlifter. Any heritable characteristic of an organism that improves its ability to survive and reproduce in its environment. Also used to describe the process of genetic change within a population, as influenced by natural selection.
Radiocarbon dating (also referred to as carbon dating or carbon dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.. The method was developed in the late s by Willard Libby, who received the Nobel Prize in Chemistry for his work in It is based on the fact that radiocarbon (
Fossil Record The cyanobacteria have an extensive fossil record. The oldest known fossils, in fact, are cyanobacteria from Archaean rocks of western Australia, dated 3. This may be somewhat surprising, since the oldest rocks are only a little older: Cyanobacteria are among the easiest microfossils to recognize. Morphologies in the group have remained much the same for billions of years, and they may leave chemical fossils behind as well, in the form of breakdown products from pigments.
Small fossilized cyanobacteria have been extracted from Precambrian rock, and studied through the use of SEM and TEM scanning and transmission electron microscopy. Pictured above are two kinds cyanobacteria from the Bitter Springs chert of central Australia, a site dating to the Late Proterozoic, about million years old. On the left is a colonial chroococcalean form, and on the right is the filamentous Palaeolyngbya.
Many Proterozoic oil deposits are attributed to the activity of cyanobacteria, such as Gloeocapsomorpha. Small concentrically layered structures called pisolites are also the result of fossilized bacteria. Cyanobacteria are otherwise rarely preserved in rocks other than chert, though some possible blue-green bacteria have been recovered from shale.
At right is a layered stromatolite, produced by the activity of ancient cyanobacteria. The layers were produced as calcium carbonate precipitated over the growing mat of bacterial filaments; photosynthesis in the bacteria depleted carbon dioxide in the surrounding water, initiating the precipitation.
Such time determinations are made and the record of past geologic events is deciphered by studying the distribution and succession of rock strata, as well as the character of the fossil organisms preserved within the strata. Grand Canyon wall cutaway diagram showing the ages of the rock layers. According to a long-standing principle of the geosciences, that of superposition, the oldest layer within a sequence of strata is at the base and the layers are progressively younger with ascending order.
Dec 05, · DNA from a fossil in Spain most closely matches another extinct human lineage, Denisovans, whose remains have been found thousands of miles away in Siberia.
But in the millennia since we started challenging each other, people have found some unconventional takes on the classic footrace. Camels Camel racing has been around for centuries, especially in arid countries where the animals have long been used as a mode of transportation. The gangly ungulates can reach speeds of up to 40 mph, and races are popular betting attractions.
Although we rarely incorporate camels into daily life here in the States, you can catch camel races occasionally around the country, even in the greater New York metropolitan area. Cockroaches Racing these resilient insects is said to have started at a hotel in Australia in At the first ever cockroach race, a roach named Soft Cocky took first place. Although the practice has since spread around the world, an annual race is still held in Australia on Australia Day January 26 at the same founding hotel.
Since linear races require a near-impossible level of training, crabs start in the center of a circle, and the first to cross the border wins. During a lawn mower race, the blades are removed as a safety precaution. Starting in , enthusiasts have gathered annually for a multi-day series of pogo stick exhibitions.
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One of the very foundations of evolution and popular science today is the “geologic column. Although not found in all locations and although it varies in thickness as well as the numbers of layers present, this column can be found generally over the entire globe. Many of its layers can even be found on top of great mountains – such as Mt. Everest and the American Rockies. In some places, such as the mile deep Grand Canyon, the layers of the column have been revealed in dramatic display. Certainly the existence of the column and its layered nature is quite clear, but what does it mean?
One of the very foundations of evolution and popular science today is the “geologic column.” This column is made up of layers of sedimentary rock that supposedly formed over millions and even billions of .
At the time that Darwin’s On the Origin of Species was published, the earth was “scientifically” determined to be million years old. By , it was found to be 1. In , science firmly established that the earth was 3. Finally in , it was discovered that the earth is “really” 4. In these early studies the order of sedimentary rocks and structures were used to date geologic time periods and events in a relative way. At first, the use of “key” diagnostic fossils was used to compare different areas of the geologic column.
Although there were attempts to make relative age estimates, no direct dating method was available until the twentieth century.
Click to share on Tumblr Opens in new window About a month ago, I watched Kendra Harrison break the m hurdles world record in London. I parked that for a later day. So that day has arrived. And so below is a discussion of the world records, and what they mean in the broader context of credibility of the sport.
acquired trait: A phenotypic characteristic, acquired during growth and development, that is not genetically based and therefore cannot be passed on to the next generation (for example, the large.
It could be likened to a movie recording the history of life across nearly four billion years of geological time. The problem is that only a small fraction of the frames are preserved, and those that have been preserved have often been chronologically scrambled. Viewed in this way, reconstituting the movie seems intractable, and yet science has done so. Frames are still missing, but the intricate, interwoven plots are largely revealed.
The process of descent with modification through natural selection, or evolution , that Darwin published in the mid 19th century became the framework for many scientific disciplines to use fossils to recover the missing frames and their ordering in time. Some one hundred years after Darwin the mechanisms of genetic memory and common descent have been elucidated at the molecular level. In this new era of sequencing the genomes and proteomes of multiple species, where science can infer protein lineage dating back into the Proterozoic, the tangible evidence in the imperfect fossil record remains paramount to the delineation of still missing frames of the movie.
Global Warming Skeptic Organizations
View images by clicking on link or reduced image: Each image opens into a new window. These primitive, medium sized apes lived in rain forests between 18 and 22 million years ago. This species and others such as Dryopithecus existed before the hominid line diverged on the path to humans. This lineage ancestral gibbons is believed to have diverged from the great ape and human lineages between 17 and 25 Mya Avers, Oreopithecus ‘s hand closely matches the pattern of early hominids, with a grasping capability including firm pad-to-pad precision gripping that apes are unable to perform presumably as a response to similar functional demands to hominids Moya-Sola et al,
Fossil folly A misleading museum display seems to want to exclude the truth of Genesis ‘by definition’ by David Catchpoole. Increasingly, people are questioning .
Measurement of N, the number of 14 C atoms currently in the sample, allows the calculation of t, the age of the sample, using the equation above. The above calculations make several assumptions, such as that the level of 14 C in the atmosphere has remained constant over time. The calculations involve several steps and include an intermediate value called the “radiocarbon age”, which is the age in “radiocarbon years” of the sample: Radiocarbon ages are still calculated using this half-life, and are known as “Conventional Radiocarbon Age”.
Since the calibration curve IntCal also reports past atmospheric 14 C concentration using this conventional age, any conventional ages calibrated against the IntCal curve will produce a correct calibrated age. When a date is quoted, the reader should be aware that if it is an uncalibrated date a term used for dates given in radiocarbon years it may differ substantially from the best estimate of the actual calendar date, both because it uses the wrong value for the half-life of 14 C, and because no correction calibration has been applied for the historical variation of 14 C in the atmosphere over time.
The different elements of the carbon exchange reservoir vary in how much carbon they store, and in how long it takes for the 14 C generated by cosmic rays to fully mix with them. This affects the ratio of 14 C to 12 C in the different reservoirs, and hence the radiocarbon ages of samples that originated in each reservoir.
29+ Evidences for Macroevolution
See Article History Alternative Title: Dinosauria Dinosaur, the common name given to a group of reptiles , often very large, that first appeared roughly million years ago near the beginning of the Middle Triassic Epoch and thrived worldwide for nearly million years. Most died out by the end of the Cretaceous Period , about 66 million years ago, but many lines of evidence now show that one lineage evolved into birds about million years ago.
The English anatomist Richard Owen proposed the formal term Dinosauria in to include three giant extinct animals Megalosaurus , Iguanodon , and Hylaeosaurus represented by large fossilized bones that had been unearthed at several locations in southern England during the early part of the 19th century.
Ancient Fossil Bacteria: Pictured above are two kinds cyanobacteria from the Bitter Springs chert of central Australia, a site dating to the Late Proterozoic, about million years old. On the left is a colonial chroococcalean form, and on the right is the filamentous Palaeolyngbya.
Yet several prominent global warming skeptic organizations are actively working to sow doubt about the facts of global warming. These organizations play a key role in the fossil fuel industry’s “disinformation playbook,” a strategy designed to confuse the public about global warming and delay action on climate change. Who are these groups? And what is the evidence linking them to the fossil fuel industry? Here’s a quick primer on several prominent global warming skeptic organizations, including examples of their disinformation efforts and funding sources from the fossil fuel industry.
Many have received large donations from foundations established, and supported, by the fossil fuel billionaire Koch brothers.