In the early Carboniferous, the but into the supercontinent called . The period from the to the late Permian about 260 mya is also called the , which had various stages of ice sheet development. It was the last ice age before the current ice age. About 325 mya, there was a , but others are doubtful, and the . It was caused by fluctuating sea levels due to the ice sheet advances and retreats and the continental uplift that resulted from the continents colliding to form Pangaea. The ended with that extinction and the began. That growing ice cap eventually destroyed the Carboniferous rainforest. Cooler oceans have less evaporation and therefore produce drier climates; that dynamic began reducing the Carboniferous rainforest, breaking them up into “patches” that kept shrinking, to eventually result in the rainforests' collapse. Only a few rainforest pockets survived into the Permian Period. As usual, scientists have , but climate change is probably the ultimate cause. The collapse of the rainforest ended the dominance of amphibians and flora and fauna adapted to warm, wet environments. The cooler, dryer conditions that ended the Carboniferous led to the dominance of and .

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A bonobo named Kanzi , and made Oldowan-style tools after being taught. But those who stone tools and the control of fire were the Einsteins and Teslas of their day. Hunter-gatherers today often start fires by banging flint against pyrite stones, which is a combination that produces generous sparks. Habilines probably used such stones when making tools. Even Darwin suggested that that may have been how protohumans discovered how to make fire, as they banged rocks together. I have not seen anybody else advocate it, but as with the likelihood that protohumans learned to make stone tools and the practice then spread, I consider it likely that the control of fire was learned only , and then spread. Richard Wrangham thinks that habilines first controlled fire, which led to the of . He could be right, and my reasoning follows.

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Some further examples of the complexity and debate follow. About when is supposed to have appeared, a fossil formed in a similar location, which was at least contemporary with . Where it fits in the human family tree is unknown at this time, but today it is called . This is perhaps a descendant of , which (who led the team that discovered it) argued is a member of a new genus. Because there is in the modern human genome, under the , have been placed within by some anthropologists. Some small fossils in , but are now designated as a subspecies. The have been widely considered as , but they have features that suggest that they may have been habilines or even australopithecines, which would dramatically change the current view on the first migrations past Africa. They may well have been Oldowan culture australopiths that migrated from Africa about when did, and they also controlled fire. Similarly, a relative of that precedes is called , but may also be a subspecies. The confusion and debate is partly because the differences between those “species” are minor and more on the order of regional variation than any radical change. They perhaps could have all interbred with each other. Other than the “hobbits,” there are no great anatomical changes and few noticeable cultural ones among the various specimens for more than a million years of evolution, so I refer to them all as , as do many anthropologists, particularly when writing for the lay audience. For those who want to explore the relatively fine distinctions, the material is readily available for study and can be another useful example of the process of science, if one of the more heated illustrations.

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During the process of photosynthesis, ..

Before the era of mass extinction investigation that began in the 1980s, a hundred hypotheses were presented in the scientific literature for the dinosaur extinction, but it was a kind of scientific parlor game. Scientists from all manner of specialties concocted their hypotheses. But even during the current era of scientific study of mass extinctions, much is unknown or controversial and even the data is in dispute, let alone its interpretation. Dynamics may have conflated to produce catastrophic effects, such as increasing atmospheric carbon dioxide concentration warming the land and oceans to the extent that otherwise stable on the ocean floor and in permafrost would be liberated and escape into the atmosphere. That situation is to the , , and extinctions, as well as helping end the . Today, there is genuine fear among climate scientists that , as global warming continues and hydrocarbons are burned with abandon, which could contribute to catastrophic runaway conditions. Wise scientists admit that humanity is currently conducting a huge chemistry experiment with Earth, and while the outcomes are far from certain, the .

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for almost all functions or elements of life

When , there was real economic benefit from their activities, not simply accounting legerdemain, and their was more sustainable. Venetians and Genoese engaged in early instances of a similar process, but it began ascending in earnest as Europe conquered the world. The basic tenet of mercantilism was the acquisition of “treasure” by the mother nation via “trade.” The classic mercantile situation was forcing subjugated people to produce raw material for shipment to the imperial nation for processing. The finished goods would be shipped back to the subjugated people at an inflated price, as the imperial nation slowly milked the subject nation by unfair terms of exchange that they controlled (or sold such cheaply produced goods to other nations). In mercantilist practice, they did not usually dictate how the workforce was organized or how they worked. The intervention was at the market level, by interposing themselves into the process in which producers were enslaved and bled dry by unfair pricing for both raw goods and finished goods. The imperial power had both captive producers and markets for finished goods. Early colonial efforts were largely mercantilist in nature when they were not simply gold rushes.

Air: Its Composition and Properties The Source of Industrial Gas Products Nitrogen, Oxygen, Argon

Overview & Purpose of Photosynthesis

Although long ago discredited, Plaster of Paris is often recommended as a source of calcium for ponds or aquariums in place of aragonite, Wonder Shells or similar.
This is NOT a substitute for Wonder Shells aragonite or similar and is not the same!

Plaster of Paris is a poor choice for GH or Calcium as Calcium needs to be in the proper ratios with other elements such as Magnesium to be utilized by aquatic life (such as osmotic function).
Lime is also similarly recommended for ponds for KH, GH and pH, however it is simply CaO and does not contains other elements necessary including bi-carbonates and magnesium to name but a few.

"Tums" are one more urban myth product recommended for GH & KH, but again this is Calcium Carbonate and does not provide the completer minerals necessary for mineral ion replenishment nor ANY KH buffering!

Here is a list of ingredients of Plaster of Paris:

For a further explanation of Plaster of Paris in aquariums and Ponds, please read this article: