Tuesday, March 17, 2020
Therizinosaurs - The Weirdest Dinosaurs
Therizinosaurs - The Weirdest Dinosaurs Therizinosaurs reaping lizardswere some of the strangest dinosaurs ever to roam the earth during the Cretaceous period. Technically part of the theropod familythe bipedal, carnivorous dinosaurs also represented by raptors, tyrannosaurs and dino-birdstherizinosaurs were endowed by evolution with an unusually goofy appearance, including feathers, pot bellies, gangly limbs, and extremely long, scythe-like claws on their long front hands. Even more bizarrely, theres ample evidence that these dinosaurs pursued a herbivorous (or at least omnivorous) diet, a sharp contrast to their strictly meat-eating theropod cousins. (See a gallery of therizinosaur pictures and profiles.) Adding to their mystery, only a few genera of therizinosaurs have been identified, most of them hailing from eastern and central Asia (Nothronychus was the first therizinosaur to be discovered on the North American continent, followed soon after by Falcarius). The most famous genusand the one that gave this family of dinosaurs its nameis Therizinosaurus, which was discovered in Mongolia a few years after World War II. In the absence of other remains, which were only discovered years later, the joint Soviet/Mongolian excavation team that unearthed the partial fossil of this dinosaur barely knew what to make of its three-foot-long claws, wondering if theyd stumbled on some kind of ancient killer turtle! (Some earlier texts reference therizinosaurs as segnosaurs, after the equally mysterious genus Segnosaurus, but this is no longer the case.) Therizinosaur Evolution Part of what makes therizinosaurs so baffling to scientists is that they cant comfortably be assigned to any existing dinosaur family, although theropods are certainly the closest fit. To judge by some clear anatomical similarities, it was once thought that these dinosaurs were closely related to prosauropods, the sometimes bipedal, sometimes quadrupedal herbivores that were distantly ancestral to the sauropods of the late Jurassic period. That all changed with the discovery of the middle Cretaceous Alxasaurus, a primitive therizinosaur equipped with some distinctly theropod-like characteristics, which helped put the evolutionary relationships of the entire breed in sharper focus. The consensus now is that therizinosaurs evolved in their unusual direction from an earlier, more primitive branch of the theropod family. From a biologists perspective, the oddest thing about therizinosaurs wasnt their appearance, but their diet. Theres a convincing case to be made that these dinosaurs a) used their long front claws to slice and dice copious amounts of vegetation (since these appendanges were too ungainly to slash fellow dinosaurs), and b) harbored an extensive network of intestines in their prominent pot bellies, an adaptation that would only have been needed in order to digest tough plant matter. The inescapable conclusion is that therizinosaurs (distant relatives of the prototypically carnivorous Tyrannosaurus Rex) were largely herbivorous, in much the same way that prosauropods (distant relatives of the protopically plant-eating Brachiosaurus) probably supplemented their diets with meat. A stunning recent discovery in Mongolia, in 2011, has shed some much-needed light on the social behavior of therizinosaurs. An expedition to the Gobi Desert identified the remains of no less than 75 therizinosaur eggs (genus undetermined), in 17 separate clutches of a few eggs apiece, some of which had apparently hatched before being fossilized. What this means is that the therizinosaurs of central Asia were social, herding animals, and may have provided their hatchlings with at least a couple of years of parental care before abandoning them in the wild.
Sunday, March 1, 2020
Effective Cooperative Learning Strategies
Effective Cooperative Learning Strategies Cooperative learning is an effective way for students to learn and process information quickly with the help of others. The goal of using this strategy is for students to work together to achieve a common goal. It is essential that each student understands their cooperative learning group role. Here we will take a brief look at a few specific roles, expected behavior within that role, as well as how to the monitor groups. Assign Individual Roles to Help Students Stay on Task Assign each student a specific role within their group, this will help each student stay on task and help the overall group work more cohesively. Here are a few suggested roles: Task Master/Team LeaderThis role entails the student to make sure his/her group stays on task. Sample statements: Have we read the paragraph on George Washington yet? We need to move on, we only have ten minutes left.CheckerThe checkers role is to make sure that everyone agrees with an answer. A Sample statement may be, Does everyone agree with Jens answer on the year Washington was born?RecorderThe role of the recorder is to write down everyone in the groups responses once they have all agreed to them.EditorThe editor is responsible for correcting all of the grammatical errors and to check for neatness.GatekeeperThe role of this person can be described as the peacemaker. He/she must make sure that everyone is participating and getting along. Sample statement: Lets here from Brady now.PraiserThis role entails a student to encourage other students to share their ideas and to work hard. A sample statement may be, Great idea Reesa, but lets keep trying, we can do this. Responsibilities and Expected Behaviors in Groups An essential element of cooperative learning is for students to use their interpersonal skills in a group setting. In order for students to accomplish their task, each individual must communicate and work collectively (use theà talking chips strategy to control noise).à Here are a few of the expected behaviors and duties each student is responsible for: Expected behaviors within the group: Everyone must contribute to the taskEveryone must listen to others within the groupEveryone must encourage group members to participatePraise good ideasAsk for help when neededCheck for understandingStay on task Responsibilities for each individual: To tryTo askTo helpTo be politeTo praiseTo listenTo be present 4 Things to Do When Monitoring Groups In order to ensure that groups are working effectively and together to complete the task, the teachers role is to observe and monitor each group. Here are four specific things that you can do while circulating around the classroom. Give Feedback:à If the group is unsure on a specific task and needs help, give your immediate feedback and examples that will help reinforce their learning.Encourage and Praise:à When circulating the room, take the time to encourage and praise groups for their group skills.Reteach Skills:à If you notice that any group does not understand a particular concept, use this as an opportunity to reteach that skill.Learn About the Students:à Use this time to learn about your students. You may find that one role works for one student and not another. Record this information for future group work.
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