Z Click on an underlined word for more information on that subject. If the dinosaur or paleontology term you are looking for is not in the dictionary, please e-mail us. Coprolite – Fossilized Dung Coprolites from many animals have been found, including dinosaurs. Dinosaur coprolites up to 40 cm 16 inches in diameter have been found, probably from a sauropod , considering the size. Recently, a huge T. Coprolite meaning “dung stone” – kopros means dung and lithikos means stone in Greek is fossilized feces animal waste. And no, coprolite does not smell bad – it had undergone a fossilization process. Copro means “dung,” from the Greek word kopros. The ending “-lite” is a common ending for fossil or mineral terms, coming from the Greek word lithos, which means stone. The term coprolite was coined around when the earliest-known specimens were found.
Some pseudoscientific claims are based on an authoritative text rather than observation or empirical investigation. Creation science devotees, for example, make observations only to confirm dogmas, not to discover the truth about the natural world. Such dogmas are static and lead to no new scientific discoveries or enhancement of our understanding of the natural world.
See Article History Dating, in geology , determining a chronology or calendar of events in the history of Earth , using to a large degree the evidence of organic evolution in the sedimentary rocks accumulated through geologic time in marine and continental environments. To date past events, processes, formations, and fossil organisms, geologists employ a variety of techniques.
These include some that establish a relative chronology in which occurrences can be placed in the correct sequence relative to one another or to some known succession of events. Radiometric dating and certain other approaches are used to provide absolute chronologies in terms of years before the present. The two approaches are often complementary, as when a sequence of occurrences in one context can be correlated with an absolute chronlogy elsewhere. Ankyman General considerations Distinctions between relative-age and absolute-age measurements Local relationships on a single outcrop or archaeological site can often be interpreted to deduce the sequence in which the materials were assembled.
This then can be used to deduce the sequence of events and processes that took place or the history of that brief period of time as recorded in the rocks or soil. For example, the presence of recycled bricks at an archaeological site indicates the sequence in which the structures were built. Similarly, in geology, if distinctive granitic pebbles can be found in the sediment beside a similar granitic body, it can be inferred that the granite, after cooling, had been uplifted and eroded and therefore was not injected into the adjacent rock sequence.
Although with clever detective work many complex time sequences or relative ages can be deduced, the ability to show that objects at two separated sites were formed at the same time requires additional information.
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.
Anabaena The Three Domains of Life As previously noted, stromatolites are most often described as biogenically-produced structures formed by colonies of photosynthesizing cyanobacteria. However, this is an enormous oversimplification given that the weight of scientific evidence suggests that all three domains of life the Archaeans, Eubacteria, and Eukaryotes appeared in the Archaean Era, and thus the so-called microbial mats would have contained representatives among all three domains.
Just how and when the base of the tree of life split into the three main branches remains one of the most important questions in all of biology and science, and is the source of constant scientific dispute. Which of the prokaryotes came first, the Archaeans or the Eubacteria remains unresolved, and a consensus has emerged that these primitive microorganisms laterally exchanged genes further confounding attempts to validate what begat what during to course of early evolution on earth.
Lateral gene transfer belies the concept of the single common ancestor see Woese, While formation by colonies of cyanobacteria is probably the primary mechanism for formation of surviving stromatolites in the deep time of the Archaean and half way through the Proterozoic, it is unlikely to have been the only mechanism. Recent research Gupta, a, b, and an extensive literature indicates the other prokaryotic and the most genetically diverse domain of life, the Archaeans , evolved alongside each other and possibly swapped genes with the Eubacteria.
Introduction Hominid or hominin? Some scientists use a broader definition of Hominidae which includes the great apes, and instead call the group I am discussing “hominins”. The word “hominid” in this website refers to members of the family of humans, Hominidae, which consists of all species on our side of the last common ancestor of humans and living apes.
Hominids are included in the superfamily of all apes, the Hominoidea, the members of which are called hominoids. Although the hominid fossil record is far from complete, and the evidence is often fragmentary, there is enough to give a good outline of the evolutionary history of humans.
Joanne Abramson Joanne has taught middle school and high school science for more than ten years and has a master’s degree in education. Learn about the requirements to enter Kingdom Protista, one of the five kingdoms of life. Discover and read about the organisms that can be found there. What Is Kingdom Protista? Imagine you are cleaning or organizing around your house. To assist in this process, you separate your items into categories to help you locate them later.
Maybe you have a box for books, a drawer for school supplies, and a cubby for electronics. You start to realize, however, that you have a bunch of extra bits and pieces that do not fit into any of your other groups. So, you create a special container for them:
The Radiometric Dating Game Radiometric dating methods estimate the age of rocks using calculations based on the decay rates of radioactive elements such as uranium, strontium, and potassium. On the surface, radiometric dating methods appear to give powerful support to the statement that life has existed on the earth for hundreds of millions, even billions, of years.
We are told that these methods are accurate to a few percent, and that there are many different methods. We are told that of all the radiometric dates that are measured, only a few percent are anomalous.
Heating the stone tools zeroed out the electrical charge they had been carrying. That means any charge in the tools today would have been generated after they were buried, as the surrounding sediments bombarded the stone with natural radioactivity. The findings add Jebel Irhoud to a slim list of well-dated African fossil sites containing modern humans and their precursors. The find provides further evidence that at least two dramatically different species of hominins occupied Africa at the same time.
Find out more about Homo naledi. However, Hublin and his coauthor Shannon McPherron emphasize that they cannot yet say precisely where modern humans evolved on the continent. In addition, the finds present an intriguing dilemma: Should paleoanthropologists treat the Jebel Irhoud remains as part of the Homo sapiens species? For instance, John Hawks , a paleoanthropologist at the University of Wisconsin-Madison, is concerned about the study authors’ claims that the Moroccan fossils belong to the Homo sapiens clade.
An international team led by researchers from the University of California, Berkeley, found the skulls of two adults and a child dating from , years ago – 40, years earlier than the previous oldest remains of Homo sapiens. The discovery, described today in the journal Nature, fills a big gap in the human fossil record; the absence of accurately dated hominid remains in Africa between , and , years ago. Is Homo floresiensis a dwarf Homo erectus, the product of local evolution that has taken place over a period of at least , years in a confined habitat?
Scientists say there are two implications for palaeontology. Firstly they provide new evidence for the ‘Out of Africa’ theory – that modern humans evolved only in Africa and not in several places around the world. Secondly, says Clark Howell of UC Berkeley, “the fossils are unmistakably non Neanderthal and show that modern humans had evolved in Africa long before the European Neanderthals disappeared.
Derrick Arrington Derrick has taught biology and chemistry at both the high school and college level. He has a master’s degree in science education. Cells are made of many crucial parts that work together and perform specific functions. In this lesson, you will learn about the plasma membrane of a cell to gain an understanding of its structure and function. What is a Plasma Membrane?
Imagine a water balloon. Prick it with a needle and the water would burst out everywhere; no more water balloon. Now, imagine a new water balloon in a bathtub full of water. What if the balloon itself was porous and could choose when water could flow in and out of the balloon? That’s sort of like what a plasma membrane is to a cell. The plasma membrane is the boundary between the cell and its environment. It regulates what enters and exits the cell.
Cells must maintain an appropriate amount of molecules to function inside them. They must also have a way to keep things out or to allow things to enter.
Shea Anthropology Department, State University of New York at Stony Brook The origin of modern humans and the fate of the Neanderthals are two of the most hotly debated topics in paleoanthropology Stringer Once seen as dull-witted cavemen, new evidence suggests Neanderthals were intelligent, adaptable, and highly effective predators. Although many see Neanderthals as our possible ancestors, it is increasingly clear that they competed with early modern humans for tens of thousands of years in Europe and the Near East.
New research in Africa, Europe, and Asia suggests that the abrupt disappearance of the Neanderthals and the sudden appearance of early anatomically-modern humans throughout much of Western Eurasia after 47, BP is more than a coincidence. The last fifteen years in particular have seen flourishing scientific advances in areas such as improved radiometric dating techniques and the recent recovery of Neanderthal DNA.
See this page in: Hungarian , Russian , Spanish People who ask about carbon 14C dating usually want to know about the radiometric  dating methods that are claimed to give millions and billions of years—carbon dating can only give thousands of years. People wonder how millions of years could be squeezed into the biblical account of history. Clearly, such huge time periods cannot be fitted into the Bible without compromising what the Bible says about the goodness of God and the origin of sin, death and suffering —the reason Jesus came into the world See Six Days?
Christians , by definition, take the statements of Jesus Christ seriously. This only makes sense with a time-line beginning with the creation week thousands of years ago. It makes no sense at all if man appeared at the end of billions of years. We will deal with carbon dating first and then with the other dating methods.
How the carbon clock works Carbon has unique properties that are essential for life on Earth. One rare form has atoms that are 14 times as heavy as hydrogen atoms: Carbon is made when cosmic rays knock neutrons out of atomic nuclei in the upper atmosphere. These displaced neutrons, now moving fast, hit ordinary nitrogen 14N at lower altitudes, converting it into 14C.