Conservapedia - User contributions [en]

User:Revilo314

2008-04-06T16:34:59Z

Revilo314: New page: == USER PAGE == Yes, it is. ETHNIC, LIBERAL, ATHEIST MERITOCRAT FROM THE UK

== USER PAGE ==

Yes, it is.

ETHNIC, LIBERAL, ATHEIST MERITOCRAT FROM THE UK

User talk:Billgates2

2008-04-06T16:29:09Z

Revilo314: New page: == RE: Ha! Front page == Be polite! i am liberal too don't worry ;) --~~~~

== RE: Ha! Front page ==

Be polite!
i am liberal too don't worry ;) --[[User:Revilo314|Revilo314]] 12:29, 6 April 2008 (EDT)

Natural selection

2007-05-25T19:55:36Z

Revilo314: /* "Natural selection = mutation" */

'''Natural selection''' is a principle that was first proposed by [[Charles Darwin]] and Alfred Russel Wallace, who noted that organisms which were better adapted to their environment tended to survive longer and reproduce more than less well-adapted organisms. They predicted that over time favorable traits which are inheritable would become more common.

According to the [[theory of evolution]], it is through a combination of natural selection and [[mutation]] that biological complexity and adaptation arise from earlier generations of life. This view is disputed by advocates of [[Intelligent Design]]. See also [[Creationism]].

== Variation ==

The prevailing theory in [[Biology]] is that natural selection is the mechanism by which [[allele]] frequency within a population changes over time due to [[genetic variation]] and selection pressures.

Natural selection is the mechanism in which members of a population exhibiting a specific [[phenotype]] have a reproductive advantage over other members of the population not exhibiting that phenotype. This is based on the current selection pressures in the environment. Due to this reproductive advantage, the group with the phenotype should produce more viable offspring that over time will increase their percentage in the overall population.

Genetic variation thus occurs due to several factors.

==='''Spontaneous''' [[genetic mutations]]===
These mutations change the [[gene]]s within the [[chromosome]]s of the organism and can result in new [[polypeptides]] being produced. These abnormal polypeptides can have significant affects on the biochemistry of the organism, for example [[sickle cell anemia]] occurs because one [[base]] within the gene for beta-[[hemoglobin]] is altered. Mutations may occur for several reasons such as [[chemical]] [[mutagens]] or exposure to [[ionizing]] [[radiation]], or because of errors made when DNA is copied inside a cell at the first stage of [[mitosis]]. Although most mutations are harmful due to their random nature (see the example regarding sickle cell anemia), beneficial mutations may also occur.
Mutations will not be inherited unless the affected cells are [[gamete]] producing cells or gametes themselves.

For example, there may be a spontaneous mutation in a [[germline]] (gamete producing) cell of an agouti (brown) rabbit that changes the allele so that it produces a polypeptide that dyes fur white and produces an [[albino]] rabbit. There are also alleles that produce chinchilla and Himalayan coats<ref>Biology 2, Jones M. & Gregory J., 2001, Cambridge University Press, ISBN 0-521-79714-4</ref>

==='''[[Meiosis]]''' and random [[fertilization]] of gametes===
Meiosis is the division of diploid germline [[cell]]s in the [[gonads]] of an organism to produce [[haploid]] gametes for [[sexual reproduction]]. During this process sections of [[homologous]] chromosomes ([[bivalents]] can get entangled and 'swap', in a process called crossing over, to form [[chiasmata]]. This process is random and produces unique gametes. Secondly, during the formation of gametes the distribution of the maternal and paternal chromosomes is random, causing further variation.

During fertilization, the genetic material ([[DNA]]) of a male gamete combines with the genetic material from a female gamete. The exact gametes which combine is also a random process. By these two processes gametes with unique [[genomes]] combine randomly to produce a unique offspring, and hence variation.

Continuing the rabbit example, whether the gamete coding for the albino polypeptide will fertilize another gamete containing the albino allele (this happens if both the sperm of the male and the egg of the female carry the albino allele) or not relies on coincidence. As the albino allele is recessive, there must be two copies present in the cells for it to be expressed.

Variation produces individuals within a population that have unique characteristics, such as different coat colors, blood groups or [[genetic disorders]].

== Selection pressures ==
Habitats place pressures upon their inhabitants. These can include, but are not limited to:
*Predation;
*Competition for food and water;
*Disease;
*Competition for space.

These environmental pressures can account for apparent over production by many species, especially those commonly regarded as prey species, and have large parts to play in [[population growth]].

But what will determine which individual organisms will survive? The key factor is the genome of the individual. Some individuals may have variations of the species' genome that enables them to cope will with these selection pressures. For example, if large butterflies were more visible to predating birds the allele for large butterflies will be slowly removed from the population as large insects are predated on and killed before they can reproduce. Conversely, if small butterflies were seen as unattractive to the opposite sex they would be unable to mate and their allele for smallness would be removed from the gene pool. Such pressures provide a mechanism that changes the ''frequency'' of a particular allele within a population.

Another example carries on the theme of rabbit coat color: If the rabbits are living in a temperate region where there is plenty of foliage and the predominant color is green/brown the it is clear that the agouti rabbits will have better protection from predatory foxes than albino rabbits and would be selected ''against'', reducing the albino allele frequency. However, if the climate were to change and become arctic the albino rabbits would have more of an advantage in camouflage and be selected ''for'', increasing their allele frequency. This is, of course, assuming that the rabbits would be able to survive in arctic conditions.

== Examples of natural selection ==
Following are good examples of natural selection in action.

==='''[[Antibiotic]] resistance'''===
As bacteria are exposed to increasing amounts of antibiotics only those that have or mutate genes for resistance survive as they are selected for. This is a problem in medicine as many antibiotic drugs are becoming less and less effective. The problem can be solved by:
*Ensuring that patients complete the course prescribed by them by their doctor.
*Only prescribing antibiotics when necessary - many people expect to be given a medicine when they visit their doctor even if one is not necessary.
*Using two or more antibiotics at once can help ensure that those bacteria that are resistant to one of the drugs is killed by the other. This system has the additional advantage of ensuring that, in order to survive the antibiotic attack, non-resistant bacteria would have to simultaneously mutate in such way as to evade both antibiotics.

==='''Industrial melanism'''<ref>[http://www.darwinismrefuted.com/mechanisms04.html| Darwinism Refuted] accessed on 24 March 2007</ref>===
In England during the industrial revolution pollution killed mosses and lichens on tree trunks, turning them from light colors to dark brown. Before this occurred most specimens of the peppered moth Biston betularia had white wings with black spots - giving a peppered appearance. During the period with dark tree trunks (1849 to circa 1970) the white version of betularia was easily predated on by birds, decreasing the frequency of the white-wing allele. Individuals with dark wings caused by high concentrations of melanin became much more frequent and the allele frequency for melanic moths increased. When pollution levels were reduced in the late 1960s the trees gained more moss and lichens, making the trunks lighter and predation selected against melanic forms of the peppered moth. It is now thought that the proportions of white to melanic moths in England have now returned to pre-1849 levels.

==='''Sickle cell anemia'''===
This is a condition where red blood blood cells have a sickle shape caused by faulty hemoglobin genes. Suffers with full sickle cell anemia have two alleles for the condition and none of their red blood cells are formed correctly. These cells get stuck in blood capillaries and cannot carry oxygen properly. This is clearly not advantageous and many sufferers die early in life. Even though death occurs in some parts of East Africa up to 50% of babies carry the genes for sickle cell anemia and 14% have anemia<ref>Biology 2, Jones M. & Gregory J., 2001, Cambridge University Press, ISBN 0-521-79714-4</ref>. This can be explained as an individual with one normal allele and one sickle cell allele will have mostly normal red blood cells and a few sickle red blood cells. This condition is not harmful and the carriers can live a normal life. However, the protoctist ''plasmodium'' that causes malaria cannot survive in sickle red blood cells, thus giving an advantage to carriers in a high-risk malaria area.

==Common misunderstandings about natural selection==

===The "goal" of natural selection===
Natural selection does not have an ultimate goal or form and does not require guidance, but changes according to the environment. Since the environment is always changing, natural selection is an ever ongoing process.

==="Perfection"===
Natural selection will over the long term select organisms that are better adapted to the current environment. These organisms have to be able to survive long enough to reproduce, and produce viable offspring capable of the same, in order to ensure the continuing survival of their genetic traits. They do not have to be perfectly adapted to their environment; they only have to be able to survive in it.

Furthermore, an organism may be well adapted to one environment but not be able to survive in another, therefore there is no such thing as a perfect organism.

==="Natural selection = mutation"===
Natural selection is not [[mutation]]. It does not make anything new, alter anything, etc... Natural selection can cause extinction based on survival of the fittest, but the processes of creation and mutation lie outside the scope of natural selection. Natural selection simply "selects" from what variation available at that specific moment, this variation having been caused by mutation. [[Evolution]] is the process of mutation followed by natural selection.

== References ==
<references/>

[[Category:Biology]]
[[Category:Genetics]]
[[Category:Evolution]]

The Descent of Man

2007-04-22T18:14:28Z

Revilo314: extension of racism discussion

Charles Darwin wrote ''Descent of Man'' in 1871.

A quote from the work reads:

<blockquote style="background: #F9F9F9; border: 1px solid #AAAAAA; padding: .3em;">
"Civilized races of man will almost certainly exterminate the savage races throughout the world ... The break between man and his nearest allies will then be wider, for it will intervene between man in a more civilized state, as we may hope, even than the Caucasian, and some ape as low as a baboon, instead of as now between the negro or Australian and the gorilla."
</blockquote>

Some believe the [[Theory of Evolution|evolutionary ideas]] have contributed to racism<ref>http://www.answersingenesis.org/home/area/faq/racism.asp</ref><ref>http://www.icr.org/index.php?module=articles&action=view&ID=268</ref>.
However, anthropologists now discount any true distinguishing characteristics between different races of humans, and many have noted that everyone was racist in Darwin's sociological background. As such the book should not be called an advocation of racism, in the same way that Christianity does not support the views of certain disciples on White, or male supremacy.
== References ==
<references />

Dinosaur

2007-04-05T19:12:44Z

Revilo314: /* Humans and Dinosaurs Coexisting */

[[Image:Fdt566e4.jpg|right|thumb|400px|Triceratops skeleton at the American Museum of Natural History.]]
'''Dinosaurs''' were large, reptilian creatures which are now believed to be extinct. The word '''dinosaur''' was coined in 1841 by Richard Owen<ref>[http://www.answersingenesis.org/creation/v14/i3/dinosaurs.asp Dinosaurs and dragons: stamping on the legends], ''Answers in Genesis''</ref>, from the [[Greek]] word δεινόςσαύρα, meaning "terrible lizard".

==Highlights of the history of dinosaur paleontology==

In the United States during the 1900s, the public imagination was caught by the discoveries of [[Henry Fairfield Osborn]] (1857-1935) and the great competitive dinosaur hunters, [[Edward Drinker Cope]] (1847-1897) and [[Othniel Charles Marsh]] (1831-1899). Exploring in Wyoming, Colorado, and New Mexico, they found numerous fossil dinosaurs. Their museums worked out the techniques for mounting and displaying them.

Osborn was a proponent of ''orthogenesis,'' as were many paleontologists up through the middle of the twentieth century. These paleontologists interpreted the fossil record as showing sustained, continuing, unidirectional trends in evolution, which they felt required some kind of driving principle in addition to natural selection. As the author of an encyclopedia article on variation and selection put it in 1911,
:Selection cannot create the materials on which it is supposed to operate... Both sides concur in the position assumed by Darwin, that the word "chance" in such a phrase as "chance variation" does not mean that the occurrences are independent of natural causation and so far undetermined, but covers in the first place our ignorance of the exact causation.... No doubt a large amount of variation is truly indefinite, so that many meaningless or useless variations arise... But there are several directions in which the field of variation appears to be not only limited but defined in a certain direction.... When beetles, or medusae, or cats vary, the range of possible variation is limited and determined by the beetle, medusa or cat constitution, and any possible further differentiation or specialization must be in a sense at least orthogenetic - that is to say, a continuation of the line along which the ancestors of the individual in question have been forced. Darwin himself showed that different species in a genus, or varieties in a species, tended to show parallel variations.<ref>Mitchell, Peter Chalmers (1911), ''Variation and Selection,'' ''Encyclopædia Britannica, 11th edition,'' volume 27 (TON-VES), p. 906</ref>

[[Roy Chapman Andrews]] (1884–1960), said to be the prototype for the fictional Indiana Jones, is famous for his discovery of fossil dinosaur eggs in Outer Mongolia.

In the 1970, Robert Bakker catalyzed a new era of dinosaur paleontology with evidence that dinosaurs were fully warm-blooded ([[endotherms]]) and fast-moving.<ref>Benton, Michael J. (2000), ''Vertebrate Paleontology'' [http://books.google.com/books?vid=ISBN0632056142&id=PQuKO7xqjNQC&pg=PA217&lpg=PA217&dq=%22robert+bakker%22&sig=imoHNyurTTCpztNV0Pp2EU7Fj6c p. 217]</ref>

==Dinosaur Species==
Dinosaurs were immensely varied, and included both herbivores and carnivores. Although many have been found in the fossil record, paleontologists expect that they have barely scratched the surface of the vast genus that the dinosaurs encompassed.<ref>[http://news.nationalgeographic.com/news/2006/09/060905-dinosaurs_2.html Vast Majority of Dinosaurs Still to Be Found, Scientists Say], ''National Geographic''</ref>

== Different Perspectives ==

Ever since the discovery of dinosaur fossils, there has been debate about whether and how dinosaurs fit into the history of life on Earth.

Christians are often caricatured as believing that God planted the fossils to test their faith, and it's true that some Christians believe that dinosaurs never existed.
However, no informed creationists believes this.
All viewpoints accept that dinosaurs existed.
Young-Earth creationists, however, reject the [[uniformitarian]] time-scale, and therefore believe that humans and dinosaurs co-existed.
Creationists also reject the now-popular idea that dinosaurs evolved into birds.

===Creationary Perspective===

[[Creationism|Young Earth Creationists]] believe, based primarily on Biblical [[sources]], that dinosaurs were created on day 6 of the [[Creation Week|creation week]]<ref>''Genesis'' 1:25</ref> approximately 6,000 years ago, along with other land animals, and therefore co-existed with humans.
As such, they reject the [[Theory of Evolution]] and the beliefs of evolutionary scientists about the age of the earth.

They believe that dinosaurs lived in harmony with other animals, (probably including in the [[Garden of Eden]]) eating only plants<ref>''Genesis'' 1:29-30</ref>; that pairs of each dinosaur [[kind]] were taken onto [[Noah's Ark]] during the [[Great Flood]] and were preserved from drowning<ref>[http://www.creationontheweb.com/content/view/3967/ Were dinosaurs on Noah’s Ark?], ''Creation Ministries International''</ref>; that many of the fossilized dinosaur bones originated during the mass killing of the Flood<ref>Carl Wieland, [http://www.creationontheweb.com/content/view/219/ Dinosaur bones—just how old are they really?], ''Creation'', vol. 21 No. 1 p. 54</ref>; and that some descendants of those dinosaurs taken aboard the Ark still roam the earth today.<ref Name="Today">Robert Doolan, [http://www.creationontheweb.com/content/view/833/ Are dinosaurs alive today?], ''Creation'', vol. 15 No. 4 p. 12.</ref>

They also use [[archeological]], [[fossil]], and documentary evidence to argue that dinosaurs co-existed with mankind until at least relatively recent times.

Because the term only came into use in the 19th century, the [[Bible]] does not use the word "dinosaur." However, they are alleged to be mentioned in numerous places throughout the biblical account. For example, the '''behemoth''' in [[Job]] and the '''leviathan''' in [[Isaiah]] are sometimes said to be references to dinosaurs,<ref>Allan K. Steel, [http://www.creationontheweb.com/content/view/1799 Could Behemoth have been a dinosaur?], ''Journal of Creation'' vol. 15 No. 2 p. 42.</ref> <ref>[http://www.answersincreation.org/job4041a.htm], ''Answers in Creation''</ref>, although others have claimed that Behemoth and Leviathan are references to a hippopotamus or elephant and a crocodile respectively. Young-Earth creationists point out that the descriptions don't fit these creatures, including that hippopotamuses and elephants don't have a "tail like a cedar".

==== Extinction ====

Creationists reject the "Great Impact Theory" that a meteor struck the earth and caused climatic changes which caused the extinction of dinosaurs and point out multiple problems evidentially with this theory. <ref>Jonathan Sarfati, [http://www.creationontheweb.com/content/view/2426 Did a meteor wipe out the dinosaurs?], ''Refuting Evolution'', chapter 4.</ref>

Creationists assert that evolutionists are frequently coming out with a "New Theory of Dinosaur Extinction" and that their theories are laden with false assumptions. <ref>Michael Matthews, [http://www.answersingenesis.org/docs2002/1115dinosaur.asp Dinosaur demise theory, version #451], ''Answers in Genesis''</ref> It is worth noting, however, that more and more of these theories are being harmonized with one another.<ref>[http://www.spaceref.com/news/viewpr.html?pid=21082 More Than a Meteor Likely Killed Dinosaurs 65 Million Years Ago], ''SpaceRef.com''</ref>

==== Dinosaurs and birds ====

Creationists contend that the idea that birds are descendants of dinosaurs is not demonstrated by the evidence <ref>[http://www.creationontheweb.com/content/view/3833/106/ Bird evolution?], ''Creation Ministries International''</ref> <ref>Andy McIntosh, [http://www.creationontheweb.com/content/view/540/ 100 years of airplanes—but these weren’t the first flying machines!], ''Creation'' vol. 26 No. 1 p. 44</ref>, and that the dinosaur-bird connection is even disputed by some evolutionists.

Dr. [[Jonathon Safarti]] wrote regarding dinosaurs being descendants of birds:
<blockquote style="background: #F9F9F9; border: 1px solid #AAAAAA; padding: .3em;">
The same logic applies to the dinosaur-[[Bird|bird]] debate. It is perfectly in order for creationists to cite [[Alan Feduccia|Feduccia]]’s devastating criticism against the idea that birds evolved ‘ground up’ from running dinosaurs (the cursorial theory). But the dino-to-bird advocates counter with equally powerful arguments against Feduccia’s ‘trees-down’ (arboreal) theory. The evidence indicates that the critics are ''both'' right — birds did not evolve either from running dinos or from tree-living mini-crocodiles. In fact, birds did not evolve from non-birds at all!
<ref>Jonathan Sarfati, [http://www.creationontheweb.com/content/view/2610 15 ways to refute materialistic bigotry], ''Creation Ministries International''</ref>
</blockquote>

Creationists also cite the evolutionist [[Ernst Mayr]] who in 1942 stated the following:

“It must be admitted, however, that it is a considerable strain on one’s credulity to assume that finely balanced systems such as certain sense organs (the eye of vertebrates, or the bird’s feather) could be improved by random mutations." <ref>[http://www.creationscience.com/onlinebook/ReferencesandNotes10.html In the Beginning: Compelling Evidence for Creation and the Flood], ''Center for Scientific Creation''</ref>

The March 2003 issue of Scientific American is also cited by creationists:

<blockquote style="background: #F9F9F9; border: 1px solid #AAAAAA; padding: .3em;">
"Of all the body coverings nature has designed, feathers are the most various and the most mysterious...The origin of feathers is a specific instance of the much more general question of the origin of evolutionary novelties--structures that have no clear antecedents in ancestral animals and no clear related structures (homologues) in contemporary relatives. Although evolutionary theory provides a robust explanation for the appearance of minor variations in the size and shape of creatures and their component parts, it does not yet give as much guidance for understanding the emergence of entirely new structures, including digits, limbs, eyes and feathers...." <ref>Michael Matthews, [http://www.answersingenesis.org/docs2003/0313sciam.asp Scientific American admits creationists hit a sore spot], ''Answers in Genesis''</ref> <ref>[http://www.sciam.com/article.cfm?articleID=000CD7F6-B16F-1E41-89E0809EC588EEDF Which Came First, the Feather or the Bird?], ''Scientific American''</ref>
</blockquote>

Creationists also assert that the comparative anatomy analysis done by evolutionists comparing bird bones and dinosaur bones is flawed. <ref>Dr. David N. Menton, [http://www.answersingenesis.org/docs2005/0328discovery.asp "Ostrich-osaurus" Discovery?], ''Answers in Genesis''</ref>

====Humans and Dinosaurs Coexisting====
Creationists use a number of lines of evidence to support their view that dinosaurs and man coexisted. For example, explorers have reported seeing a live dinosaur.<ref name="Today" />
A thousand people reported seeing a dinosaur-like monster in two sightings around Sayram Lake in Xinjiang according to the Chinese publication, China Today.
An expedition which included Charles W. Gilmore, Curator of Vertebrate Paleontology with the United States National Museum, examined an ancient pictograph which is claimed to portray dinosaurs and man coexisting.<ref>[http://www.creationism.org/swift/DohenyExpedition/Doheny01Main.htm Doheny Scientific Expedition, Hava Supai Canyon, Arizona], ''Creationism.org''</ref><ref>[http://www.christiancourier.com/articles/read/the_hava_supai_dinosaur_carving The Hava Supai Dinosaur Carving], ''ChristianCourier.com''</ref>.
The World Book Encyclopedia states that: "The [[dragon]]s of legend are strangely like actual creatures that have lived in the past. They are much like the great reptiles [dinosaurs] which inhabited the earth long before man is supposed to have appeared on earth." <ref>Quoted in [http://www.creationscience.com/onlinebook/FAQ25.html What about the Dinosaurs?], ''CreationScience.com''</ref>.
Dragons exist in the folklore of many European and Asian cultures.<ref name="WB2000">''Dragon'' entry in World Book Millennium 2000 CD ROM</ref>
World Book Encyclopedia says, "In Europe, dragons are traditionally portrayed as ferocious beasts that represent the evils fought by human beings. But in Asia, especially in China and Japan, the animals are generally considered friendly creatures that ensure good luck and wealth."<ref Name="WB2000" />
Dragons appear in the flag of [[Wales]], and in traditional Chinese New Years' Day celebrations.
The Nile Mosaic of Palestrina, a second century piece of art, is said to appear to be a piece of artwork that shows a dinosaur and man coexisting. <ref>[http://www.s8int.com/dinolit2.html Dinosaurs in Literature, Art & History-- Page 2], ''s8int.com''</ref>
Creation scientists also see the recent dinosaur tissue find as a strong rebuttal of the claim that dinosaurs lived millions of years ago. <ref>Carl Wieland, [http://www.creationontheweb.com/content/view/3042 Still soft and stretchy], ''Creation Ministries International''</ref> More obvious evidence is the fact that we know the names of dinosaurs, and as such, humans must have come into contact with dinosaurs.

Among those who believe in the existence of the [[Loch Ness Monster]], one popular theory is that it is a living [[plesiosaur]].<ref>"New Quest Is Haunted By 'Nessie'", ''The New York Times,'' July 14, 1992, p. C4: "Believers say it resembles a plesiosaur and was trapped in Loch Ness during the Ice Age 12,000 years ago. The plesiosaurs were marine reptiles who are thought to have lived 65 million to 200 million years ago."</ref>

Talk.Origins argues<ref>[http://www.talkorigins.org/indexcc/CH/CH712.html Claim CH712], ''TalkOrigins.org''</ref> that the inclusion of dinosaurs within many cultures is based on the existence of fossils. Ancient people, unaware that the ancient fossils uncovered by erosion were of extinct animals, attributed the bones to living, magical creatures. This would explain the importance of dragons in Chinese culture - there are a large number of dinosaur (as well as non-dinosaur) fossils to be found in China. CreationWiki's response<ref>[http://creationwiki.org/Dragons_were_dinosaurs Dragons were dinosaurs] (rebuttal of Talk.Origins' claim CH712)</ref> is that the fossils reminded people of the legends, not that the fossils inspired the legends.

----

===Evolutionary Perspective===

The view of evolutionists and others who accept the uniformitarian timescale is that dinosaurs existed on earth from 230 million years ago to 65 million years ago.
In this view, the entire population of dinosaurs were wiped out by a mass extinction event (usually thought to be an asteroid) about 65 million years ago.
Of course this precludes humans and dinosaurs co-existing.

====Extinction====

According to most scientists, close to 65 million years ago, at the end of the [[Cretaceous]] period, and the beginning of what is called the [[Tertiary]] period, an event occurred which has come to be known as the [[K-T Event]]. This event would have obliterated most life on Earth, plunging the world into something that would now be likened to global nuclear winter, through which few extant species could survive. Although these scientists dispute the nature of the K-T Event (selecting among any number of catastrophes that could have caused the significant global cooling that resulted), most find that the claimed K-T Event was caused by the collision of a massive asteroid with the Earth, the dust and debris from which would have shrouded the sky for thousands of years, cooling Earth considerably.<ref>Kevin O Pope, "Meteorite impact and the mass extinction of species at the Cretaceous/Tertiary boundary," Proceedings of the National Academy of Science, available at [http://www.pnas.org/cgi/content/full/95/19/11028]</ref> According to this view, the dinosaurs did not survive this cataclysm.<ref>[http://news.nationalgeographic.com/news/2002/08/0823_020823_asteroid.html Prehistoric Asteroid "Killed Everything"], ''National Geographic''</ref> The dust from this impact is supposedly still visible as a line of metal of extraterrestrial origin and is often visible in sediment worldwide, occurring as a result of the vaporization and then fall of dust from the meteorite's impact, and its compression within the subsequent geological record.<ref>''Ibid''</ref> The crater is also visible.<ref>[http://news.nationalgeographic.com/news/2003/03/0307_030307_impactcrater.html "Dinosaur-Killer" Asteroid Crater Imaged for First Time], ''National Geographic''</ref>

====An Explosion of new species ====

The mass extinction of the dinosaurs removed a major food competitor, and predator, of smaller animals. As a result of a new "vacancy" in the food chain, following the [[K-T Event]], vast speciation occurred, as the evolutionary pressure of a new cold age propelled animal species to adapt or die out. According to this view, [[mammals]] were some of the main beneficiaries of this explosion: their fur allowed them to adapt to the cold, and their small size allowed them to conserve energy relative to the huge dinosaurs of the previous age.<ref>Bennet, Shostak, Jakotsky, "Life in the Universe," viewable at [http://www.amazon.com/Life-Universe-Jeffrey-Bennett/dp/0805385770]</ref>

====Dinosaurs and Birds====

As a number of feathered fossils (claimed to be dinosaurs) have been discovered, and evolutionary scientists claim the similarity in the bone structure between birds and dinosaurs show that modern birds are a descendants of dinosaurs. This is often cited as an example of [[macroevolution]].<ref>[http://news.nationalgeographic.com/news/2004/10/1006_041006_feathery_dino.html New Dinosaur Discovered: T. Rex Cousin Had Feathers], ''National Geographic''</ref>

==References==
<references/>

[[Category:Biology]]