Wednesday, October 30, 2019
UK Government and Measures to Reduce the Alcohol Consume Essay
UK Government and Measures to Reduce the Alcohol Consume - Essay Example The article observes that none of the low-priced alcohol brands would have increased their prices within the new legislations.à Many of these products are on offer on major supermarkets such as Tesco which has such offers as 24 cans of Fosters that goes for a mere 10 pounds or even 3 fifteen packs of Strongbow cider being sold at 20 pounds. The minimum pricing policy is accompanied by VAT additions which the government hopes will help curb the norm of excessive drinking in UK.From this study it is clear that many see that the government efforts at setting minimum prices for alcoholic products will only solve half of the problem because there are many alcohol companies which have the capacity to produce alcoholic beverages at the set price and still rake in millions in profits. All that the legislation is doing to the market is removing any form of competition for the established manufacturers and distributors. Setting minimum prices will not effectively stop people from buying and sometimes, overindulging in alcohol.à In the mixed economy, resources are owned by both the government on behalf of the public, and the private sector. à It is the public sector which intervenes According to economics, the concept of scarcity implies that resources are scarce or limited. The resources that are available are not enough to satisfy the needs of everyone concerned. For instance, if someoneââ¬â¢s income is limited, it means that he cannot buy everything that he wants.... All that the legislation is doing to the market is removing any form of competition for the established manufacturers and distributors. Setting minimum prices will not effectively stop people from buying and sometimes, overindulging in alcohol. à 2. Explain why, in a mixed economy, the concepts of scarcity and opportunity cost are important for governments. Illustrate your answer with examples. Also explain reasons why governments tax goods like alcohol, cigarettes and petrol. Use economic concepts in your answer. In the mixed economy, resources are owned by both the government on behalf of the public, and the private sector. à It is the public sector which intervenes According to economics, the concept of scarcity implies that resources are scarce or limited. The resources that are available are not enough to satisfy the needs of everyone concerned. For instance, if someoneââ¬â¢s income is limited, it means that he cannot buy everything that he wants. Opportunity cost on the other hand is a measure of the cost of a certain choice, or what is refereed in economics to as the next best alternative forgone. For a person whose income is limited, he has to choose between different alternatives so that he can make good use of his limited income (Ward and Forker, 1993). In a mixed economy, opportunity cost is important for governments as it enables them to make strategic decision to control the market in a way that is likely to be more beneficial than the other. The concept of scarcity enables the government to plan and deliver its resources in the way it sees fit in order to meet as many of the market demands as possible. In the mixed
Monday, October 28, 2019
Six Habits of Highly Effective Teams Essay Example for Free
Six Habits of Highly Effective Teams Essay From this class, we have learned a lot about how to build up a team; the benefit and disadvantages of teamwork; communication between team members and training to improve teamwork, and so on. From Kohnââ¬â¢s book ââ¬Å"Six Habits of Highly Effective Teamsâ⬠I have learned six rules that make the team work effectively. The concepts are ââ¬Å"strengthening emotional capacity to improve team relationship, expanding team self-awareness, practicing empathy and respectfulness, establishing and regulating team norms, thinking laterally, entrusting team members with appropriate roles. â⬠(Kohn 2007) Next, I will combine with my team experiences to talk about the six rules. First of all, the concept ââ¬Å"strengthening emotional capacity to improve team relationshipâ⬠demonstrated the relationship between team menbers and team leader is important. A good relationship in a team is a sense of trust between the team members and keeping team identity and team efficacy. These three conditions require the teams ability to create a good emotional atmosphere and management to create emotional norms, and develop team emotional intelligence. Under this good emotional atmosphere, team members can understand each other, adapt to each other and respect each other. When the team members come up with different ideas, they can also consult, find out a way that everyone agrees with, and they can trust each other. This is exactly the right atmosphere in my family team. When we have some different ideas about travel, my uncle will give everyone a paper to write down their thought, and then I will read those thoughts in front of everyone. Our family member will discuss the advantages and disadvantages for every plan and finally decide where to go, which way is the best one for us. So, we understand the personal feelings of the team members and we should establish the norms of mutual understanding to encourage members, in considering the problem and using the empathy approach. The team leader is an important part to build up a good atmosphere. When members disagree with the team decision, the leader should not always think the worst, and should try to find out why the members have different ideas and listen to them carefully. Facing the problem behavior, the team leader should point out the problem immediately, resolve contradictions with a sense of humor. When one or two people disagree with the team decision-making, we usually use the simple way; theà minority is subordinate to the majority. But sometimes, if we choose to stop and listen to opposing views, we may gain an unexpected, new and good idea. The most important points are respecting individuality and different points of view, not disparaging others, recognizing the members contribution, let them know that the team consider their ideas. One of the advantages in my family team is our team does not ignore the views of anyone, that we can exchange different ideas in an equal environment. Team members can feel the team focus on them; there is a sense of belonging. Second, ââ¬Å"expanding team self-awarenessâ⬠. Kohn in his book mentions, ââ¬Å"The essence of interpersonal empathy and effective empathetic behavior in organizations. The skillââ¬â¢s essential characteristics include: seeking first to understand. Being other-oriented. Feeling ââ¬Å"withâ⬠the other person or other people. Listening activelyâ⬠(PP 109). He also mentions, ââ¬Å"a team needs a nameâ⬠. I am agreeing with this. A companyââ¬â¢s goal or slogan often presents the spirit of their team. If a company can create the value of innovation, the employees of the enterprise can feel proud as an member of the company. such as Apple company which leading electronic technology trends, Appleââ¬â¢s employees that they work for change the society. And if a company needs a staff, then the staff will feel very proud, has a great sense of belonging. Also, employees that are interested in their own work and achieved excellent results, the completion of the work will bring him a sense of pride. In my family team, we also have a slogan, which is ââ¬Å"I love my familyâ⬠. We build up a group in social network, everyone can post their mood, thoughts and photos on it. Even though I am in the United States, they c an know my recent life. Third, ââ¬Å"practicing empathy and respectfulnessâ⬠. Empathy is a very important communication skill. In an enterprise, the employees may come from all over the world, and they have different backgrounds, experiences, hobbies, positions and capacity. Encountering problems, humanââ¬â¢s nature will always proceed from their positions, and thus conflicts may arise. If the team members could be mutual understanding, standing on each others position envisage the problem, the contradictions may easily be mitigated. In my family team, we also meet some problems too. Sometimes during our vacation, the schedule will change occasionally, but we may didnââ¬â¢t come up with a backup before. Argue will begin. But luckly, the communication between my family members are patient and moderate. We are know each other a lot and weà understand our common goal is a good vacation, let everybody enjoy the vacation. And we all love our family, sometimes we are even willing to compromise our views for the harmonious atmosphere of the family. Fourth, ââ¬Å"establishing and regulating team normsâ⬠. If a team does not have a system, then the team members do not have rules that can be followed. This is a terrible thing. Such as a game, if not the rules of the game, we do not know who are the losers who are the winner. When a project get a good harvest because of staffââ¬â¢s efforts, the leader should be know how to share the benefits with team members. Because to judge the leadership achievements is not focus on how much work the leader take, but what kind of performance he lead a team to be success. Therefore, the higher the teams achievements, the values of leadership are more obvious. When the leadership share this honor and achievement back to his staffs, the staffs will be grateful for a team and thank for they have such a leader. Fifth, ââ¬Å"thinking laterallyâ⬠, as Kohn mentions ââ¬Å"even though task oriented project have performed in the past, and with a little thinking, they will be done the same way in the immediate futureâ⬠¦ solutions that work tend to be and should be repeated. However, clients or organizations themselves have a need for innovation. They are looking for far more than simple bodies with requisite skills to handle tasks that keep the operation running smoothlyâ⬠(PP 142). I really appreciate this point of view; this is my favorite part in this book. Because of I am very interested in creativity and novelty. I even think that human development and invention cannot be separated from the creativity and innovation. Lateral thinking is to b ring vitality and creativity. Employeesââ¬â¢ lateral thinking lead the company can often produce surprising. Sixth, ââ¬Å"entrusting team members with appropriate rolesâ⬠. It is very important for an effective team to put a right person in a right position. A team leader should know how to identify the strengths and weaknesses of the team members, and to arrange them in the most appropriate position, so that they can stimulate their fullest potential. An employee is a non-essential role; the employee is not the role of positioning. Role of career planning is a basic, workers must consciously and autonomy in accordance with the role planning to develop themselves, had better establish a roles incentives. According to this mechanism, perhaps their subordinates jobs cannot go beyond the manager, but as a good role, work independently, the remunerationà may surpass manager; according to the managers role responsibilities analysis the subordinates are more competent, there must be a mechanism to enhance the subordinates. Above all of six habits, I have a clearer understanding of efficient team. Efficient team has a development goals to complete the task, the mutual trust of the team members under a effective leadership, good communication, work together positively. The building of an efficient team can be carried out from the following aspects. Through systematic analyzes, help the team member understand themselves in depth, explicit team members have advantages and disadvantages, work preferences, their different way to solve problems, the basic values ââ¬â¹Ã¢â¬â¹of differences; final get formed share the same beliefs and consistent view of the purpose of the team between the team members, in order to establish the rules of the game to running a team. The team also needs to provide education opportunities for employees and listen to the employeesââ¬â¢ views, encourage employees creativity. An effective team needs division of labor and cooperation. Enhanced the leadership. First, leaders must be a good example, to cohesion a team fully. Also, team cohesion is invisible spiritual strength, the cohesion of the team from the inner dynamics of the team members, from the consensus values. If we can use the value to lead the team, the team will be more effectively. Reference Kohn S, OConnell V. 6 Habits Of Highly Effective Teams [e-book]. Career Press; 2007. Available from: eBook Collection (EBSCOhost), Ipswich, MA. Accessed November 27, 2012.
Saturday, October 26, 2019
The Lady of Shallot Essay -- Lady of Shalott Essays
The Lady of Shallot à "The Lady of Shallot," by Alfred, Lord Tennyson, acts as a voice for people struggling with materialism of the industrial age. Tennyson became famous for reflecting the "idealism of an industrious society that was nonetheless racked by deep doubts about its materialism" (The Longman Anthology Of British Literature p. 1908). The curse of the mysterious lady of the poem could be thought ofà as the curse of the people subcombing to the dreaded materialism and giving up the Victorian innocent ideals. Furthermore, the lady represents Tennyson himself as he suffered from a personal battle between the desire for glamour's fame, and the need to stay an innocent poet. In Looking at the viewpoint of Tennyson towards Victorian tailed by an industrial society, we can both get a glance at the curse of the poet and the lady of his poem. Before Tennyson became rich and famous, the poet lived in desolation both financially and socially.à à à Tennyson embodied the "Victorian gospel of hard work", as evidenced in the way he "labored patiently, in poverty, w...
Thursday, October 24, 2019
Sample: Summary Mini-Lesson
Dr. R: Letââ¬â¢s talk about summary. Based on the APA homework and the diagnostic rough drafts, it's pretty clear some folks are still having difficulties discerning between summary and paraphrase. The distinction between these two is incredibly important to grasp, as your summary in your Essay 1 must be clear and concise. Note that you should be able to summarize the main argument claims of your chosen article in a single paragraph. OK, so what is a summary?When we talk about summaries, we are usually talking about the summary of the main ideas of an entire work (although, if weââ¬â¢re focusing on a specific chapter or article in a larger work, weââ¬â¢d then be summarizing that one major component. For instance, most of us are summarizing individual articles, not the entire issue of a magazine or journal). Summary is used to ââ¬Å"state the major ideas of an entire source or part of a source [see above] in your own wordsâ⬠(Faigley, 2010, p. 20). Note that the summari es are significantly shorter than the source.Most academic guides recommend that a summary be no longer than ? the length of the original source. In other words, if you have a four page article and your summary is two pages long, thatââ¬â¢s not an effective summary. Faigley even mentions that summaries are often ââ¬Å"a paragraph or perhaps even a sentenceâ⬠(emphasis mine] (2010, p. 631). Note the key ideas in the section aboveââ¬âsummaries are short and they are in your own words. They only focus on the ââ¬Å"main points, not most of the examples or supporting materialsâ⬠(Faigley, 2010, p. 20).To put this in laymanââ¬â¢s terms for you as you check your summary work, note that this means that words like ââ¬Å"uses examplesâ⬠or ââ¬Å"uses statisticsâ⬠or ââ¬Å"Smith discusses a man in Ireland whoâ⬠are not summary appropriateââ¬âthose are areas where you are actually paraphrasing supporting data/details, not summarizing the authorââ¬â ¢s main ideas. How are paraphrase and summary different? First, we tend to paraphrase specific examples or sentences. A paraphrase of a statement is often used to help clarify the ideas in that one statement, rather than to give an overview of an entire work.We most often use paraphrase after weââ¬â¢ve quoted a workââ¬âyou use that paraphrasing to help situate and show connection between the quoted material and your own ideas, for instance. As Faigley notes, ââ¬Å"[w]hen you paraphrase, you represent the idea of the source in your own words at about the same length as the originalâ⬠(emphasis mine] (Faigley, 2010, p. 631). Note that the main distinctions between summary and paraphrase are the length and the purpose of the tasks. Paraphrase is all about explaining a specific single idea at about the same length while summary is an overview of the entire piece that is much shorter.What are some strategies for effective summary? One tip is to look at the overall document. Are there headings in the source? If so, those headings should directly relate to the main ideasââ¬âthey are like little summary bullet points for the article, which means the author did some of the work for you! If there are not clearly marked sections of the source (which there often are not), youââ¬â¢re going to have to create some notes to work from. Read the article from start to finish, just reading. Then, on a second reading, read one paragraph at a time.Once you read the paragraph over, write in the margins what the main point of that paragraph is. ( A print out of the article is great for this, but if you are paperless, you can copy the article into Word and type in your paragraph notes in a different color font or use the insert comment feature to annotate the source). Once you have created that list of notesââ¬âone phrase or sentence per paragraphââ¬âyou can then take those and read through them. What main ideas are repeated that you can group together? Wha t paragraphs seem to just list supporting examples and should be therefore excluded from your summary?Use those notes to actually develop a single paragraph of summaryââ¬âyour summary should have no more sentences in it than the source has paragraphs (and in most cases, should have fewer). Common Summary Errors 1. Including supporting details or discussing data and examples from the source. 2. Adding evaluation or commentary to the summary from your own point of view. 3. Writing the summary by focusing on retelling the entire sourceââ¬âthis is paraphrasing and can often be identified by the keywords in the long section that include things like ââ¬Å"he beginsâ⬠and ââ¬Å"he goes on to discussâ⬠andâ⬠having covered X, he moves on to Y. Those are phrases that indicate youââ¬â¢re including minor details an retelling everything, not summarizing. 4. Including quotations. 5. Incorporating additional sources (other than the thing you are summarizing). 6. Lackin g signal phrasing that indicates key points. Your summary should set up the thesis/position of what is being summarized and follow with the main ideas or claims. Using signal phrasing like ââ¬Å"Smithââ¬â¢s main argument isâ⬠and ââ¬Å"one reason Smith argues X isâ⬠will help you make smoother transitions and remind the reader you are summarizing the main points only. Resources Columbia University School of Social Work (n. . ). Writing summaries. Writing Center Handouts. Retrieved from http://www. columbia. edu/cu/ssw/write/handouts/summary. html Faigley, L. (2010). Writing: A guide for college and beyond. New York: Longman. Student Development Centre (2009). Writing resources: Summary Writing. The University of Western Ontario. Retrieved from http://www. sdc. uwo. ca/writing/index. html? handouts [direct link: www. sdc. uwo. ca/writing/handouts/Summary%20Writing. pdf ] The Write Place (1997). Process for writing a summary. LEO: Literacy Education Online. Retrieved fr om http://leo. stcloudstate. edu/acadwrite/summary. html
Wednesday, October 23, 2019
Marketing Cars Effectively By Knowing Your Customers Well
Brand new cars are usually attractive to a certain demographic market: better income generating men and women with urban lifestyles and parents, especially fathers. People purchase products or services for three basic reasons: to satisfy basic needs, to solve problems and to make them selves feel good (Guille, 2007). One of the basic needs that a car would be able to answer is of course is the necessity of transportation. Another need it answers is the need to belong which is an intrinsic motivation to affiliate with others and be socially accepted. (Van Wagner, 2007) If one would surf the pages of the website of Toyota, this basic need is met by the selling points that car manufacturers give. ââ¬Å"Buy a Camry Hybrid now, and you may be eligible for Federal Tax Benefits. Plus, several states now allow single-occupant use of the carpool lane for Camry Hybrid.â⬠(Toyota Motors Sales, 2007) is Toyotaââ¬â¢s way of showing that if one purchases a Camry, he or she will be socially accepted enough to have tax benefits and permission to use the carpool lane. People with disability have a great need to be socially accepted and General Motors addresses this issue by providing the GM Mobility Reimbursement Program that says, ââ¬Å"General Motors is committed to helping persons with disabilities equip their vehicles for easier and safer travelâ⬠(General Motors Corporation, 2007). Targeting the male population is what Volvo does best by showing how the Volvo Your Concept car was conceptualized: ââ¬Å"If you meet the expectations of women, you exceed the expectations of me. ââ¬â Marti Barletta, Gender Trend specialist.à (Volvo Car Corporation, 2007). People, especially parents, are always concerned about safety and car manufacturers recognize this need with the establishment of certain accessories to their products. Some of Toyotaââ¬â¢s safety features for the Camry are airbags, Front and rear crumple zones and side-impact door beams and Vehicle Stability Control (VSC) [20] with Traction Control (TRAC) that ensures less danger when the roads are slippery. General Motorsà has the OnStar facility that provides a built in phone that a driver can use hands free. Also, when the airbags are deployed, these send signals to GMC so that if the driver cannot call emergency, OnStar staff would be able to detect where the accident happened and rescue will thus be sent. Volvoââ¬â¢s Safety Concept Car has Cue transparent window pillars, infra-red night vision and seats, controls and pedals that move to ensure the driver is at the best possible position. Toyota has been able to avoid nuances of forgetting to turn off interior lights by a battery-saver that deactivates these after 20 minutes. General Motors has the remote door unlock, wherein people who have mistakenly left the car keys inside their automatic locking cars can be helped. Car manufacturers are great in showing how owning their cars can be a source of pride. Toyota uses phrases like ââ¬Å"comfortable interior modifies to your changing life,â⬠and ââ¬Å"Bigger. Wider. More powerfulâ⬠to coax a customerââ¬â¢s self-esteem. General Motors on the other hand, offers GM:OnStar vehicle diagnostics which makes the owner feel like a boss by getting instant and regular reports on how to maintain the car. Volvo is the best among them in fueling pride by putting very comfortable accessories like a trunk containing chilled and heated compartment and the ability to connect to your entertainment library at home. Car manufacturers like Toyota, General Motors and Volvo have done their marketing assignments well by completely fulfilling the needs of their target markets and this ensures their leading positions in their industry. References General Motors Corporation. (2007). Driving Confidence with OnStar. Retrieved May 23, 2007 from http://www.gm.com/ Guille, M. (2007). How To Find And Sell To Your Target Market. Retrieved May 25, 2007, from http://sbinfocanada.about.com/cs/marketing/a/targetmarket_2.htm Toyota Motor Sales U.S.A. (2007). Camry ââ¬â¢07. Retrieved May 23, 2007. Van Wagner, K. (2007). Need to Belong. Retrieved May 25, 2007, from Volvo Car Corporation. (2007). Volvo Concept Cars. Retrieved May 23, 2007, from http://www.volvocars.com/All-Cars/conceptcars/ à à à Ã
Tuesday, October 22, 2019
Free Essays on From The New World
Dvorak?s ?From the New World? The late nineteenth century America was a place of energy, vigor, and youth; at least that was how it was seen through the eyes of one of the greatest Czech composers in history, Antonin Leopold Dvorak. Born September 8, 1841, he was the son of a butcher and innkeeper in a poor unsophisticated town, Nelahozeves. Surprisingly enough, from these humble beginnings Dvorak would go on to become one of the most renowned Bohemian composers and forever leave his mark in history as influencing not only his native Czech nationalistic school, but helping to pave the way for Americans to develop their own national music. Dvorak received his first musical education learning to play the violin in his village school. His parents ?recognized their son?s musical talent from the first and did all they could to encourage it? (Boynick). In 1857 he was sent to the Prague Organ School where he graduated as a trained organist, second in his class. After working in Prague for several years giving lessons and attempting to compose, his career was greatly aided by the established composer Johannes Brahms who found Dvorak a publisher and got his career underway. Throughout his career Dvorak derived much guidance from other greats such as Brahms, Liszt, and especially Smetena who started the nationalist movement and whom Dvorak studied under. After a period of being ignored as serious musicians, these composers set forth a standard of nationalistic music that emphasized Slavic folk music & dances and established Czech music on the world scene. In June 1891, after receiving world acclaim for many of his works, Dvorak was offered the post of Director of the National Conservatory of Music in America by Jeannette Thurber. At the time America seemed the promise land for the Czech composer as opposed to his Austrian ruled homeland. With a salary of $15,000 annually, it was a position Dvorak could hardly refuse. It was here, in an ?e... Free Essays on From The New World Free Essays on From The New World Dvorak?s ?From the New World? The late nineteenth century America was a place of energy, vigor, and youth; at least that was how it was seen through the eyes of one of the greatest Czech composers in history, Antonin Leopold Dvorak. Born September 8, 1841, he was the son of a butcher and innkeeper in a poor unsophisticated town, Nelahozeves. Surprisingly enough, from these humble beginnings Dvorak would go on to become one of the most renowned Bohemian composers and forever leave his mark in history as influencing not only his native Czech nationalistic school, but helping to pave the way for Americans to develop their own national music. Dvorak received his first musical education learning to play the violin in his village school. His parents ?recognized their son?s musical talent from the first and did all they could to encourage it? (Boynick). In 1857 he was sent to the Prague Organ School where he graduated as a trained organist, second in his class. After working in Prague for several years giving lessons and attempting to compose, his career was greatly aided by the established composer Johannes Brahms who found Dvorak a publisher and got his career underway. Throughout his career Dvorak derived much guidance from other greats such as Brahms, Liszt, and especially Smetena who started the nationalist movement and whom Dvorak studied under. After a period of being ignored as serious musicians, these composers set forth a standard of nationalistic music that emphasized Slavic folk music & dances and established Czech music on the world scene. In June 1891, after receiving world acclaim for many of his works, Dvorak was offered the post of Director of the National Conservatory of Music in America by Jeannette Thurber. At the time America seemed the promise land for the Czech composer as opposed to his Austrian ruled homeland. With a salary of $15,000 annually, it was a position Dvorak could hardly refuse. It was here, in an ?e...
Monday, October 21, 2019
The Evolution of the First Tetrapods
The Evolution of the First Tetrapods Its one of the iconic images of evolution: 400 or so million years ago, way back in the prehistoric mists of geologic time, a brave fish crawls laboriously out of the water and onto land, representing the first wave of a vertebrate invasion that leads to dinosaurs, mammals, and human beings. Logically speaking, of course, we dont owe any more thanks to the first tetrapod (Greek for four feet) than we do to the first bacterium or the first sponge, but something about this plucky critter still tugs at our heartstrings. As is so often the case, this romantic image doesnt quite match up with evolutionary reality. Between 350 and 400 million years ago, various prehistoric fish crawled out of the water at various times, making it nearly impossible to identify the direct ancestor of modern vertebrates. In fact, many of the most celebrated early tetrapods had seven or eight digits at the end of each limb and, because modern animals adhere strictly to the five-toed body plan, that means these tetrapods represented an evolutionary dead end from the perspective of the prehistoric amphibians that followed them. Origins The earliest tetrapods evolved from lobe-finned fishes, which differed in important ways from ray-finned fishes. While ray-finned fishes are the most common type of fish in the oceanà today, the only lobe-finned fish on the planet are lungfish and coelacanths, the latter of which were thought to have gone extinct tens of millions of years ago until a live specimen turned up in 1938. The bottom fins of lobe-finned fishes are arranged in pairs and supported by internal bones- the necessary conditions for these fins to evolve into primitive legs. Lobe-finned fishes of the Devonian period were already able to breathe air, when necessary, via spiracles in their skulls. Experts differ about the environmental pressuresà that prompted lobe-finned fish to evolve into walking, breathing tetrapods, but one theory is that the shallow lakes and rivers these fish lived in were subject to drought, favoring species that could survive in dry conditions. Another theory has it that the earliest tetrapods were literally chased out of the water by bigger fish- dry land harbored an abundance of insect and plant food, and a marked absence of dangerous predators. Any lobe-finned fish that blundered onto land would have found itself in a veritable paradise. In evolutionary terms, its hard to distinguish between the most advanced lobe-finned fish and the most primitive tetrapods. Three important genera nearer the fish end of the spectrum were Eusthenopteron, Panderichthys, and Osteolopis, which spent all of their time in the water yet had latent tetrapod characteristics. Until recently, these tetrapod ancestors nearly all hailed from fossil deposits in the northern Atlantic, but the discovery of Gogonasus in Australia has put the kibosh on the theory that land-dwelling animals originated in the northern hemisphere. Early Tetrapods and Fishapods Scientists once agreed that the earliest true tetrapods dated from about 385 to 380 million years ago. That has all changed with the recent discovery of tetrapod track marks in Poland that date to 397 million years ago, which would effectively dial back the evolutionary calendar by 12 million years. If confirmed, this discovery will prompt some revision in the evolutionary consensus. As you can see, tetrapod evolution is far from written in stone- tetrapods evolved numerous times, in different places. Still, there are a few early tetrapod species that are regarded as more-or-less definitive by experts. The most important of these is Tiktaalik, which is thought to have been perched midway between the tetrapod-like lobe-finned fishes and the later, true tetrapods. Tiktaalik was blessed with the primitive equivalent of wrists- which may have helped it to prop itself up on its stubby front fins along the edges of shallow lakes- as well as a true neck, providing it with much-needed flexibility and mobility during its quick jaunts onto dry land. Because of its mix of tetrapod and fish characteristics, Tiktaalik is often referred to as a fishapod, a name that is also sometimes applied to advanced lobe-finned fish like Eusthenopteron and Panderichthys. Another important fishapod was Ichthyostega, which lived about five million years after Tiktaalik and achieved similarly respectable sizes- about five feet long and 50 pounds. True Tetrapods Until the recent discovery of Tiktaalik, the most famous of all the early tetrapods was Acanthostega, which dated to about 365 million years ago. This slender creature had relatively well-developed limbs, as well as such fishy features as a lateral sensory line running along the length of its body. Other, similar tetrapods of this general time and place included Hynerpeton, Tulerpeton, and Ventastega. Paleontologists once believed that these late Devonian tetrapods spent significant amounts of their time on dry land, but they are now thought to have been primarily or even totally aquatic, only using their legs and primitive breathing apparatuses when absolutely necessary. The most significant finding about these tetrapods was the number of digits on their front and hind limbs: anywhere from 6 to 8, a strong indication that they couldnt have been the ancestors of later five-toed tetrapods and their mammalian, avian, and reptilian descendants. Romers Gap Theres a 20-million-year-long stretch of time in the early Carboniferous period that has yielded very few vertebrate fossils. Known as Romers Gap, this blank period in the fossil record has been used to support Creationist doubt in the theory of evolution, but it is easily explainable by the fact that fossils only form in very special conditions. Romers Gap particularly affects our knowledge of tetrapod evolution because, when we pick up the story 20 million years later (about 340 million years ago), there is a profusion of tetrapod species that can be grouped into different families, some coming very close to being true amphibians. Among the notable post-gap tetrapods are the tiny Casineria, which had five-toed feet; the eel-like Greererpeton, which may already have de-evolved from its more land-oriented tetrapod ancestors; and the salamander-like Eucritta melanolimnetes, otherwise known as the creature from the Black Lagoon, from Scotland. The diversity of later tetrapods is evidence that a lot must have happened, evolution-wise, during Romers Gap. Fortunately, we have been able to fill in some of the blanks of Romers Gap in recent years. The skeleton of Pederpes was discovered in 1971 and, three decades later, further investigation by tetrapod expert Jennifer Clack dated it smack to the middle of Romers Gap. Significantly, Pederpes had forward-facing feet with five toes and a narrow skull, characteristics seen in later amphibians, reptiles, and mammals. A similar species active during Romers Gap was the large-tailed Whatcheeria, which seems to have spent most of its time in the water.
Subscribe to:
Posts (Atom)