Why Did Crocodiles Survive the K/T Extinction

You already know the story: at the end of the Cretaceous period, 65 million years ago, a comet or meteor struck the Yucatan peninsula in Mexico, triggering extreme changes in the global climate that resulted in what we call the  K/T Extinction. Within a short period of time—estimates range from a few hundred to a few thousand years—every last dinosaur, pterosaur, and marine reptile had disappeared off the face of the earth, but crocodiles, oddly enough, survived into the ensuing Cenozoic Era. Why should this be surprising? Well, the fact is that dinosaurs, pterosaurs, and crocodiles are all descended from archosaurs, the ruling lizards of the late Permian and early Triassic periods. Its easy to understand why the earliest mammals survived the Yucatan impact; they were small, tree-dwelling creatures that didnt require much in the way of food and were insulated by their fur against plunging temperatures. The same goes for birds (only substitute feathers for fur). But some Cretaceous crocodiles, like Deinosuchus, grew to respectable, even dinosaur-like sizes, and their lifestyles werent all that different from those of their dinosaur, pterosaur or marine reptile cousins. So how did crocodiles manage to survive into the Cenozoic Era? Theory #1: Crocodiles Were Exceptionally Well-Adapted Whereas dinosaurs came in all shapes and sizes—huge, elephant-legged sauropods, tiny, feathered dino-birds, towering, ravenous tyrannosaurs—crocodiles have stuck with pretty much the same body plan for the last 200 million years (with the exception of the very first Triassic crocodiles, like Erpotosuchus, which were bipedal and lived exclusively on land). Perhaps the stubby legs and low-slung posture of crocodiles allowed them to literally keep their heads down during the K/T upheaval, thrive in a wide variety of climatic conditions,  and avoid the fate of their dinosaur pals. Theory #2: Crocodiles Lived Near the Water As stated above, the K/T Extinction wiped out land-dwelling dinosaurs and pterosaurs, as well as sea-dwelling mosasaurs (the sleek, vicious marine reptiles that populated the worlds oceans toward the end of the Cretaceous period). Crocodiles, by contrast, pursued a more amphibious lifestyle, perched halfway between dry land and long, winding freshwater rivers and saltwater estuaries. For whatever reason, the Yucatan meteor impact had less of an impact on freshwater rivers and lakes than it did on saltwater oceans, thus sparing the crocodile lineage. Theory #3: Crocodiles Are Cold-Blooded Most paleontologists believe that theropod dinosaurs were warm-blooded and thus had to constantly eat to fuel their metabolisms—while the sheer mass of sauropods and hadrosaurs made them slow to both absorb and radiate heat, and thus able to maintain a steady temperature. Neither of these adaptations would have been very effective in the cold, dark conditions immediately following the Yucatan meteor impact. Crocodiles, by contrast, possess classically reptilian cold-blooded metabolisms, meaning they dont have to eat very much and can survive for extended periods in severe darkness and cold. Theory #4: Crocodiles Grew More Slowly Than Dinosaurs This is closely related to theory #3, above. Theres an increasing amount of evidence that dinosaurs of all types (including theropods, sauropods, and hadrosaurs) experienced a quick growth spurt early in their life cycles, an adaptation that better enabled them to avoid predation. Crocodiles, by contrast, grow steadily and slowly throughout their lives and would have better been able to adapt to the sudden scarcity of food after the K/T impact. (Imagine a teenaged Tyrannosaurus Rex experiencing a growth spurt suddenly needing to eat five times as much meat as before, and not being able to find it!) Theory #5: Crocodiles Were Smarter Than Dinosaurs This is probably the most controversial hypothesis on this list. Some people who work with crocodiles swear that theyre almost as smart as cats or dogs; not only can they recognize their owners and trainers, but they can also learn a limited array of tricks (like not biting their human trainer in half). Crocodiles and alligators are also fairly easy to tame, which may have allowed them to adapt more readily to the harsh conditions after the K/T impact. The problem with this theory is that some end-Cretaceous dinosaurs (like Velociraptor) were also fairly smart, and look what happened to them! Even today, when numerous mammal, reptile, and bird species have gone extinct or are seriously endangered, alligators and crocodiles around the world continue to thrive (except for those targeted by shoe-leather makers). Who knows—if things keep on going the way they have been, the dominant forms of life a thousand years from now may be cockroaches and caimans!

The Pros and Cons of Illegal Immigration in the USA

Immigration is an increasingly hot controversy in southern California; there have even been various rallies recently with many supporting a path to citizenship and others arguing that we need to close our boarders and prosecute violators. Immigration is the spotlight not due to money, but because it affects problems like race, the role of government, national identity and change. There are more advantages than disadvantages on supporting illegal immigration and supporting an amnesty. Many Americans like Michael Scott a business man from southern California argue that the continued invasion low-skilled, uneducated illegal immigrants has depressed earnings an limited opportunities. I disagree with Michael Scott view that†¦show more content†¦Immigrants are not taking are jobs, they do the work we necessarily do not want to do—gardener, housekeeper, fieldwork, etc. Many of us are very stereotypical, many Americans believe that â€Å"Illegal aliens† do not come to work, but cause crime and we should deport them. I agree we should seal the boarders and deport any serious offenders—like rapes, sex offenders, murderers, etc.-- after they do their time sentence, but like our justice system, illegal immigrants should have the right to an attorney, a day in court in front of a jury (if needed), and â€Å"the punishment (if required) has to fit the crime,† like David DeCosse said in his article â€Å"Ethical Considerations Support Amnesty for Illegal Immigrants.† One of the biggest concerns many Americans argue to seal the boarders and deport all undocumented immigrants is because they are afraid of another terrorist attack. 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Braveheart Essay Research Paper This movie is free essay sample

Braveheart Essay, Research Paper This film is about war between the English and the Scots rebellion people. A score brave knight ( William Wallace ) comes to take his people of Scotland to triumph in a few conflicts with the English, which makes a menace to the male monarch of England. The English male monarch sends his Gallic girl in jurisprudence to negociate peace with the barbarian warier. The scene begins as the warier approaches the beautiful princess with worn out apparels. The princess, have a expression of anxiousness in her eyes as she recognizes Wallace as a barbarian individual. The princess invites Wallace to her collapsible shelter to discourse the male monarch # 8217 ; s proposals of peace. In the collapsible shelter she describes Wallace # 8217 ; s actions of killing her hubby # 8217 ; s cousin of being barbarian. Consequently he defends his actions by uncovering the offenses that the baronial adult male committed to the hapless adult females and guiltless kids of Scotland. We will write a custom essay sample on Braveheart Essay Research Paper This movie is or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page The princess seems surprised, as she knew nil about it. Wallace adds to her information that the male monarch has done things worst than merely hanging adult females and kids on the walls of the metropolis, when it comes to killing guiltless people. The princess # 8217 ; s bodyguard interfers by stating her that Wallace is a lier in some other linguistic communication so Wallace will non understand, which lead Wallace to answer at the escort in the same linguistic communication that he spoke. Besides showing to the princess that he is capable of talking other linguistic communications as good. The princess looks more surprised and dismisses her escort. The two talk about the peace and the male monarch # 8217 ; s corrupt to Wallace, which would do him one of the affluent Lords. Wallace refuses the offer and tells the princess about the male monarch # 8217 ; s false word of peace by exposing the yesteryear of the male monarch when he hung the villagers after giving them his word of peace. Wallace besides portions with the princess his secret of his matrimony to his beloved, and how the English murdered her. The princess shows fondness. In decision, the princess has nil more to state, because she now knows the truth about the state of affairs. Consequently she returns persuaded of what Wallace told her about the male monarch # 8217 ; s unlawful behaviors. The Yale theory trades with the larning attack of the message, hence, the more individual learns about the message, the more he becomes persuaded by it. From the text, Carl Covland at Yale University conducted the first systematic, comprehensive research undertakings that dealt with attitude alteration. ( Page 63 persuasive COM. ) . The research started with a inquiry # 8220 ; how are people persuaded? # 8221 ; the research plan investigated and came up with the Factors, underlying Process, and Persuasion outcome based on message larning attack. There are Independent Variables such as, the message, beginning, receiver, and the channel. Each of these variables has it # 8217 ; s ain features that affects the Internal Mediating Process, which are the attending where the receiving systems attending is drown. The com grasping understanding the message. Yielding accepting and being persuaded by the message, and keeping something the receiving system takes with him so he can retrieve the message. Followed by the Consequent Communication Effect that changes the attitude, belief and the behaviour of the receiving system. The research concluded that the receiving systems must retain the information in order to be persuaded. And when persuasion occurs, they will fell rewarded by acquiring persuaded by that message. In this scene we can utilize Yale # 8217 ; s theoretical account of attitude alteration. The beginning is William Wallace and the receiving system is the princess. The channel is a strong media, which was a direct face to confront conversation. The first message, which was delivered by the princess, is that the actions of Wallace by killing the baronial adult male are barbarian. The other message by Wallace ( transmitter ) to the princess ( receiving system ) is that the guiltless people of Scotland are being massacred and slaved in atrocious ways, which makes it emotional. In add-on, the score people are merely contending for their freedom, which is a rational behaviour. Hence, Wallace # 8217 ; s message is repeated many times throughout the scene, which gave his state of affairs a positive facet and made the princess stops in being bias towards the English. Consequently, Wallace got the princess # 8217 ; s attending. Wallace has helpful persuasive features. He has a worm voice with fine-looking face and guiltless eyes that made the princess trust him. In add-on, Wallace has rational grounds of supporting his people. Wallace was an expert of war issue every bit good as a leader to his ground forces. Consequently, the princess knew that if he says that he desire # 8217 ; s to occupy England, so he is series. So she was careful to listen to his words. Agai n we can detect the giving up of the princess to Wallace # 8217 ; s expertness. Wallace was good educated, as the princess realized after she knew that speaks different linguistic communications, which got her attending more, in the grade that she dismissed her escort to be entirely with Wallace, which besides shows that she trusted him. The princess comprehended Wallace # 8217 ; s point of position and his state of affairs. Wallace # 8217 ; s strong character and the reason of his message persuade the princess. In being a female receiving system, which would do her perceive the message more emotionally than work forces do, the princess seemed to hold with Wallace particularly after he shared with her what happened to his married woman. Again she is affected emotionally by the message. Obviously, the princess was intelligent and good educated adult female. As a consequence, it made her understand the message faster than a normal individual would. Finally the princess changes her attitude and believes about the score warier to the positive side, every bit good as the alteration of believes, attitude and behaviour towards the male monarch and her hubby. Furthermore, the princess falls in love with Wallace and becomes a sure beginning for him, as we in the remainder scenes of the film.