Friday, March 20, 2020

Facts About Tylosaurus, a 35-Foot Cretaceous Predator

Facts About Tylosaurus, a 35-Foot Cretaceous Predator Name:  Tylosaurus (Greek for knob lizard); pronounced TIE-low-SORE-us Habitat:  Shallow Seas of North Ameria Historical Period:  Late Cretaceous (85-80 million years ago) Size and Weight: About 35 feet long and seven tons Diet:  Fish, turtles and other reptiles, including dinosaurs Distinguishing Characteristics: Long, sleek body; narrow, well-muscled jaws A Large and Vicious Predator The 35-foot-long, seven-ton Tylosaurus was about as well-adapted to terrorizing sea creatures as any marine reptile could be, considering its narrow, hydrodynamic body, blunt, its powerful head suited to ramming and stunning prey, its agile flippers, and the maneuverable fin on the end of its long tail. This late Cretaceous predator was one of the largest and most vicious of all the mosasaurs- the family of marine reptiles that succeeded the ichthyosaurs, pliosaurs, and plesiosaurs of the earlier Mesozoic Era, and that is distantly related to modern snakes and monitor lizards. Like one of those extinct plesiosaurs, Elasmosaurus, Tylosaurus figured in the famous 19th-century feud between the American paleontologists Othniel C. Marsh and Edward Drinker Cope (commonly known as the Bone Wars). Squabbling over a set of incomplete Tylosaurus fossils discovered in Kansas, Marsh suggested the name Rhinosaurus (nose lizard, a great missed opportunity if ever there was one), while Cope touted Rhamposaurus instead. When both Rhinosaurus and Rhamposaurus turned out to be preoccupied (that is, already assigned to an animal genus), Marsh finally erected Tylosaurus (knob lizard) in 1872. (In case youre wondering how Tylosaurus wound up in landlocked Kansas, of all places, thats because much of  the western U.S. was submerged beneath the Western Interior Sea during the late Cretaceous period.) Dazzling Discovery While Marsh and Cope squabbled endlessly, it was left to a third famous paleontologist, Charles Sternberg, to make the most dazzling Tylosaurus discovery of all. In 1918, Sternberg unearthed a Tylosaurus specimen harboring the fossilized remains of an unidentified plesiosaur, its last meal on earth. But thats not all: an unidentified hadrosaur (duck-billed dinosaur) discovered in Alaska in 1994 was found to harbor Tylosaurus-sized bite marks, though it seems that this dinosaur was scavenged by Tylosaurus after its death rather than plucked, crocodile-style, directly off the shoreline.

Wednesday, March 4, 2020

What a Main Idea Is and How to Find It

What a Main Idea Is and How to Find It Questions about the main idea of a passage are popular on reading comprehension tests, but sometimes, those questions are pretty difficult to answer, especially for students who are not completely sure they understand what the main idea really is.  Finding the main idea of a paragraph or longer passage of text is one of the most important reading skills to master, along with concepts like making an inference, finding the authors purpose, or understanding vocabulary words in context. Here are a few techniques to help understand what, exactly, is a main idea and how to identify it accurately in a passage. How to Define the Main Idea The main idea of a paragraph is the primary point or concept that the author wants to communicate to the readers about the topic. Hence, in a paragraph, when the main idea is stated directly, it is expressed in what is called the topic sentence. It gives the overarching idea of what the paragraph is about and is supported by the details in subsequent sentences in the paragraph. In a multi-paragraph article, the main idea is expressed in the thesis statement, which is then supported by individual smaller points. Think of the main idea as a brief but all-encompassing summary. It covers everything the paragraph talks about in a general way, but does not include the specifics. Those details will come in later sentences or paragraphs and add nuance and context; the main idea will need those details to support its argument. For example, imagine a paper discussing the causes of World War I. One paragraph might be dedicated to the role that imperialism played in the conflict. The main idea of this paragraph might be something like: Constant competition for massive empires led to increasing tensions in Europe that eventually erupted into World War I. The rest of the paragraph might explore what those specific tensions were, who was involved, and why the countries were seeking empires, but the main idea just introduces the overarching argument of the section. When an author does not state the main idea directly,  it should still be implied, and is called an implied main idea. This requires that the reader look closely at the content- at specific words, sentences, images that are used and repeated- to deduce what the author is communicating. How to Find the Main Idea Finding the main idea is critical to understanding what you are reading. It helps the details make sense and have relevance, and provides a framework for remembering the content. Try these specific tips to pinpoint the main idea of a passage. 1) Identify the Topic Read the passage through completely, then try to identify the topic. Who or what is the paragraph about? This part is just figuring out a topic like cause of World War I or new hearing devices; dont worry yet about deciding what argument the passage is making about this topic. 2) Summarize the Passage After reading the passage thoroughly, summarize it in your own words in one sentence. Pretend you have just ten to twelve words to tell someone what the passage is about- what would you say? 3) Look at the First and Last Sentences of the Passage Authors often put the main idea in or near either the first or last sentence of the paragraph or article, so isolate those sentences to see if they make sense as the overarching theme of the passage. Be careful: sometimes the author will use words like but, however,  in contrast, nevertheless, etc. that indicate that the second sentence is actually the main idea. If you see one of these words that negate or qualify the first sentence, that is a clue that the second sentence is the main idea. 4) Look for Repetition of Ideas If you read through a paragraph and you have no idea how to summarize it because there is so much information, start looking for repeated words, phrases, or related ideas. Read this example paragraph: A new hearing device uses a magnet to hold the detachable sound-processing portion in place. Like other aids, it converts sound into vibrations, but it is unique in that it can transmit the vibrations directly to the magnet and then to the inner ear. This produces a clearer sound. The new device will not help all hearing-impaired people- only those with a hearing loss caused by infection or some other problem in the middle ear. It will probably help no more than 20 percent of all people with hearing problems. Those people who have persistent ear infections, however, should find relief and restored hearing with the new device. What does this paragraph consistently talk about? A new hearing device. What is it trying to convey? A new hearing device is now available for some, but not all, hearing-impaired people. Thats the main idea! Avoid Main Idea Mistakes Choosing a main idea from a set of answer choices is different than composing a main idea on your own. Writers of multiple choice tests  are often tricky and will give you distractor questions that sound much like the real answer. By reading the passage thoroughly, using your skills, and identifying the main idea on your own, though, you can avoid making these 3 common mistakes: selecting an answer that is too narrow in scope; selecting an answer that is too broad; or selecting an answer that is complex but contrary to the main idea.   Resources and Further Reading How to Find a Stated Main IdeaHow to Find an Implied  Main IdeaFinding the Main Idea PracticeFinding Main Ideas In Paragraphs,  http://english.glendale.cc.ca.us/topic.htmlFinding the Main Idea, Columbia College Updated by Amanda Prahl