My Educational Philosophy A Reflective Comparison Free Essays

each pedagogue has the lower limit of five old ages of experience. In comparing my educational doctrine in which I have gain through their old ages of experience. I will besides contrast their doctrine along side of my ain. We will write a custom essay sample on My Educational Philosophy A Reflective Comparison or any similar topic only for you Order Now At manus there are assorted diverse constructions in doctrine utilized in our instruction construction today. It is non unnatural to separate extra doctrines integrated in a school or schoolroom environment. While incorporating the assorted educational positions in the schoolroom, one would be obliged to hold construction of their schoolroom community. An person who enjoys learning will invariably prevail to develop their comprehension and acclimatise with the changing era. PhD Elise Kirchoff an pedagogue of 25 plus old ages in instruction has the assurance, creativeness and bravery ; individualizing has she would show her instruction manner. She believes in being convenient in order to be lissome towards each pupil acquisition demands. PhD Kirchoff besides considers mortal true within our school territory ; instructors contain a kind of freedom in their academic professionalism when it extends to choose on methods of direction and developing lessons. Meaning it all depends on the territory 1 may work for. As clip goes by each coevals instruction, larning potency does vary. The instruction manner educated in the early 80 ‘s is most likely infective in today ‘s schoolroom. PhD Kirchoff agrees in non being prepared on holding to make â€Å" throng control † ( Kirchoff ) . Though in the methods of subject in maintaining a schoolroom orderly focused and respectful she replied, have zero tolerance in schoolroom breaks would maintain the le sson traveling. With 30 old ages of learning experience PhD Kirchoff feels NCLB has non aided in her ability to learn, it has footing an surplus in paper work as an option. However throughout her old ages of learning she has come to appreciate the diverseness of legion pupils and how each pupil acquisition demands are inimitable. There are no cooky cutter lessons for particular need pupils. Jason Keller with 10 old ages of learning experience nine old ages in physical instruction while one twelvemonth in particular instruction. Keller Teachs in the BIC unit ( behavioural unit ) he based his replies toward his category. He based entirely on the unit for the ground of, when I set up the interview he was merely able to reply as a particular instruction instructor non has physical instruction instructor in which he has 9 old ages of experience. That said Keller ‘s personal strengths he finds particularly helpful in learning is to be patient and understanding. The pupils who are placed here have utmost emotional, behavioural jobs non including their disablements. Keller describes his instruction manner geared toward positive support instead than ensue and hit oriented, more advancement and betterment based. In comparing to PhD Kirchoff, Keller besides deems on the belief of holding the freedom to academic methods of direction and developing lessons. Both feel the same about NCLB, how it has non made their occupation as pedagogues any easier. Merely it has been a load of paperwork. Where they experience the clip is wasted on alternatively on category direction. Jessica Morales five old ages of schoolroom direction, Morales finds strengths particularly helpful in her instruction describe as, willingness to ne’er give up. When feeling overwhelmed, one needs to be able to stay unagitated and take a deep breath. Her teaching manner is flexible a manner to suit to all her pupils demands. In pull offing her to be flexible for the diverseness of each of her pupils it takes some work, though she feels the more that she gets to cognize her pupils, the easier it becomes. It will ne’er be wholly easy, but you will larn to suit your pupils. In comparing to these fantastic pedagogues my educational doctrine I would depict as being able to intrust the instruction and development to every pupil in malice of cultural or cultural background or economic position. However, my educational doctrine encloses by wrought of legion effects ; in trusting on my philosophic foundation to assist me construct both content and teaching method. It is of import to hold strong beliefs, grounded in sound theory to steer our teaching.A It is every bit imperative to go on unfastened minded to innovative tendencies and techniques that may advance our students.A In naming an educational doctrine motionless it will non be eligible ; it alters with clip and apprehension, and I will persistently copy, detect, and filtrate what I believe and why I believe it. As I gain knowledge my doctrine will alter, take a few things out or taking a few things in. A Among these changes I am unfastened to anything and my positions will be flexible and as unfastened to sentiments as I can be. A When I tell my pupils to woolgather, purpose for the stars, I am stating they can suppress a new end each new twenty-four hours, and so I will hold succeeded in my schoolroom. As an pedagogue I have seen the impact on pupil ‘s lives as their instructor the positive influence we have towards them to go good function theoretical accounts in society. We as instructors and students to the system learn something every twenty-four hours. I anticipate bring forthing a affecting experience within my pupils ; whereby they develop comprehension, include an optimistic ego reg ard and connubial motivation.A The apprehension they attain will be nonsubjective oriented and syllabus driven.A The manner I achieve this will fluctuate intrusting on the eccentricity of peculiar category and the pupils in the category. Finally, professional development is compulsory for whichever instructor who obtains unremitting self betterment. A I am non merely an pedagogue ; I am facilitator in the instruction development and supply a positive function theoretical account to society. A I contain an digesting answerability to magnify my comprehension of both capable affair and sophistication, and to invariably re-examine my proceedings and course of study in response to a continuously altering environment. As an educationist I need to be enthusiastically attentive of the place I participate in a pupil ‘s existence.A Life suggestions an incomputable district of educational duties, each forcing personal growing and extended cognition with each individual.A As a instructor, I need to be a supple to the character that validates an unqualified, reliable blessing of all my pupils and invariably petitions to help an instruction that counterparts each individual.A In my schoolroom, I will show a secure, an environment which encourages a regard of persons self construct and larning style.A Many have an of import input to suggest to this world.A In any circumstance I will help pupils in their hunt of their individuality immediate to the extended ends of instruction. How to cite My Educational Philosophy A Reflective Comparison, Essay examples

Macarthy era and salem witch trials Essay Example For Students

Macarthy era and salem witch trials Essay The McCarthy Era and the Salem Witch Trials The McCarthy era is very similar to the Salem Witch trials. They are both similar, because they both dealt with hysteria. Hysteria is an uncontrollable fear or outburst of emotion. Both things had to do with people accusing each other of people being communist, and people being witches. The McCarthy era, took place in the twentieth century. It had to do with people thinking that other people were communist. Since people thought that others were communist, they accused them of committing communism. Communism is, when people dont follow what the government says. The people that were accused of being communist, were persecuted by other people in the community. Then they were put to death. The U. S. senator Joseph Raymond McCarthy was the man who was against the rising of communism. His revolts against communism gave birth to the term McCarthyism. The Salem Witch trials took place in the seventeenth century in Salem, Massachusetts. They were considered to be Americas most notorious episode of witchcraft hysteria. As in the McCarthy era, people who were even accused of being witches were persecuted. Many innocent people were killed because of the result of false accusations and many other women were put through many trials to determine if they were witches. Witches were considered outcasts of society. It was also considered a hysteria because it was blown out of proprtion. Much of this hysteria soon ended due to the sermon delivered by Cotton Mather. In his statement he argued against the mass convictions of innocent people. Some clergy finally decided to listen to his ideas and many of the accused were released from jail by the decision of the governor and because jails were overflowing. Hysteria has no place in a society because it is wrong. It causes chaos and confusion and in these cases death. Hysteria can also cause paranoia and can cause fear and hatred among societies. Many societies have experienced their own witch hunts which has damaged societies greatly. Bibliography: Works Cited 1996 Grolier Encyclopedia The Social origins of Witchcraft (1974) The Salem Witchcraft Papers, 3 volumes (1977) Witchcraft at Salem (1969) Reading the Witch Trials of 1692 (1993) 1996 Encarta Encyclopedia Joseph Raymond McCarthy Internet Browser Joe McCarthy http://www.english. upenn.edu/afilreis/50s/mccarthy-bio.html .

Versions of Romeo and Juliet Essay Example For Students

Versions of Romeo and Juliet Essay The version which sticks closer to the play is Zefferellis version. Its more like what the scenery was like when it was written and would of take place then. The one that was more successful in my opinion is the Lurmans version, its more modern and more enjoyable to watch. I prefer Lurhmans simply because it is basically modern. I dont think I would be able to watch and enjoy Zefferellis because of the scenery and how old it is. Lurhmans is better to enjoy and would rather by me because new is better. Zefferellis can offer the background clothes and language used in his version. Lurhmans it again modern in his version. In his version they use props and clothes that we use today. The buildings in Zefferellis are palaces and castles and are replaced by buildings and office blocks. We will write a custom essay on Versions of Romeo and Juliet specifically for you for only $16.38 $13.9/page Order now The costumes and props used in Zefferellies film the period i.e swords and daggers and period clothing. Lurhmans they replaced swords with guns as well as replacing horses with cars. Costumes where what we wear today. The music in each version are what you would hear in that time. Zefferellis version, the music that was played was by a single hand trumpet and the type of tune played was dictated by the scene on screen i.e slow for conversations and fierce for fight scenes. Lurhmans soundtrack was orchestral instruments of operatic voices through other types of music i.e dance music, rock music for party scenes and background radio of a modern type was used. The scenery and settings of the play were changed, the palaces and mansions of old Verona were replaced with modern buildings and office blocks. They are very different from each other. Zefferellis had little fruit stalls and someone behind selling the fruit. In Lurhmans version is basically replaced with shops selling a lot more than fruit. The interpretation of characters is (to me) very different from each other. I think Id get through Lurhmans movie understanding whats being said more than Zefferellis movie. The language in Lurhmans is more understanding than Zefferellis definitely. The way they dress is different, tights to trousers and so on. Rucushio in the modern one is more lively and understandable. In the old one he doesnt really know what hes on about, hes a step in step out person. The themes of the plays that I see if love, hatred, revenge, life and death. Maybe not a lot of revenge in Zefferellis. Lurhmans has everything, you can feel the themes of his version when watching his movie. Zefferellis you just cant really enjoy it mostly because its old. The concepts I would use if I was to stage William Shakespeares Romeo and Juliet would be the modern language, the modern setting and clothes. Maybe the guns instead of the swords, or using the guns and the swords in the one play. Make the setting what its like today not 6-7 years ago even though nothing has changed a bit. A scene I want to compare in both versions of Romeo and Juliet is the scene just at the end of each film at the chapel. They have different arrangements that happen through the whole scene. Zefferellis takes place in a dark, quiet room that isnt all that big. Romeo takes poison says his last goodbyes then Juliet awakes then is devastated and stabs herself with a dagger. Lurhmans version, Romeo takes poison, Juliet wakes up and shoots herself with a gun and they are in a much bigger chapel with neons and candles all around. My conclusion of what I have proved is that a lot has changed, the background, then clothes and the movie. We are in their 2000s not the 1900s or 1800s any more.

Definition and Examples of Pet Phrases in English

Definition and Examples of Pet Phrases in English Pet phrase is an informal term for an expression frequently used by an individual in speech and/or writing. A pet phrase may be widely known (a clichà ©, for instance) or peculiar to the individual who employs it. Examples and Observations [In the 1955 movie Kiss Me Deadly] Va-va-voom! Pretty pow! is Nick the Greeks running-gag description of Hammers sports car engines, connoting both their sexual potency and explosive potential (Nick removes two bombs from the Corvette).(Vincent Brook, Land of Smoke and Mirrors: A Cultural History of Los Angeles. Rutgers University Press, 2013)Shed work as an insurance saleswoman, save up a tidy sum of money, enjoy her days off, gazing at herself in the mirror of some brand-name stores. Who I really am . . . Who I really am . . . would become her pet phrase, but after working for three years, shed finally realize that the image shed created of herself wasnt who she really was at all.(Shuichi Yoshida, Villain, trans. by Philip Gabriel. Pantheon, 2010)Whenever his conscience pricked him too keenly he would endeavor to hearten himself with his pet phrase, All in a lifetime. Thinking over things quite alone in his easy-chair, he would sometimes rise up with these words on his lips, and s mile sheepishly as he did so. Conscience was not by any means dead in him.(Theodore Dreiser, Jennie Gerhardt, 1911) Desegregation With All Deliberate SpeedLawyers promptly set to work trying to pin down the origin and significance of with all deliberate speed. And as Supreme Court materials from the Brown [v. Board of Education] years gradually become available, scholars have made a cottage industry of working out how and why the phrase made it into the Brown order. Although the Court in Brown spoke only through its Chief Justice, Earl Warren, this was actually a pet phrase of Associate Justice Felix Frankfurter, who had used the expression deliberate speed in five different opinions since joining the Court in 1939.(James E. Clapp and Elizabeth G. Thornburg, Lawtalk. Yale University Press, 2011)Game Changer and Thinking Outside the BoxWe have to look creatively, said stadium board Chairman Don Snyder, UNLV’s acting president. We can’t get in the way of the (convention center project). . . . There’s a tremendous scramble for limited resources.No longer was Snyder rolling out hi s pet phrase of game changer to describe the stadium wish. Now, he’s using another phrase- thinking outside the box- to describe what it will take to pay for the proposed venue.(Alan Snel, UNLV Stadium Panel Members Begin Puzzling Out Funding Solutions. Las Vegas Review-Journal, February 27, 2014) Frank Sinatras Ring-a-Ding-Ding![Sammy Cahn] and the composer Jimmy Van Heusen were commissioned by [Frank] Sinatra to write a song using Sinatras catchphrase for his first Reprise album, which was called, not surprisingly, Ring-a-Ding-Ding! The phrase- like Shakespeares Hey nonny nonny- thumbed its nose at meanings and sincerity.(John Lahr, Sinatras Song. Show and Tell: New Yorker Profiles. University of California Press, 2000)Using Pet Phrases in WritingRepeat a distinctive thought or phrase of dialogue in the story. This connects an earlier part of the story to a later one without having to rely on an overt transitional device. Television shows frequently overuse this technique, giving one character a pet phrase that he repeats ad nauseam. One way to vary the device is to give it a different meaning each time its used. On Seinfeld, all the principal characters would use the same phrase, often with a different meaning, all in the same scene, creating a device all its own.(James V. Smith, Jr., The Writers Little Helper: Everything You Need to Know to Write Better and Get Published. Writers Digest Books, 2012) Pet Expressions in 19th-Century EnglandNobody who has busied himself with watching the peculiarities of contemporary speech can have failed to notice the prevalence of pet expressions. . . . The young man of the day, in particular, has a slow and sluggish mind, and can seldom be troubled to give a careful specification of the particular person or thing which forms the topic of his conversation. He finds it answers better for his purpose to choose some simple generic term which he can use when his thoughts fail him. What the trapeze is to the acrobat, his pet expression is to the modern young man. It serves as a rest to steady himself on and to sustain him until he takes his next awkward flight. Many a fall would that young man have, many an awkward hiatus or wrongly-chosen expression would there be in his discourse was not his pet phrase always near him to be rested on half-way whenever the exigencies of his narrative become too much for his powers of speech.The conversation of the y oung lady of the period is principally remarkable for its adjectives. Unlike the young man, she has rarely any pet substantive whereby to express most things that come under her notice; it may be that she refrains to use her brothers phrases for fear of being considered slangy. But she rejoices in a curious collection of qualifying adjectives, by the aid of which she manages to make her meaning known. Anything that pleases her, from a bracelet to a sunset, is dabbed by the title of quite too lovely, while its antithesis, whether used in reference to a public calamity or a bad floor at a dance, is pronounced to be quite too dreadful. Any act of kindness bestowed upon this young person wins from her the remark that such attention is truly affecting, and with this pet phrase, and a few more lovelys and preciouses, varied and qualified by the word quite and too being prefixed to them either singly or together, she manages to rub along very well. . . .The good talker has gone out of fash ion, and would now be voted a prosy old bore; it is not the fashion to be careful about the way you express a thing, or to appear to be giving yourself much trouble in entertaining your hearers. The words of the modern young man come out in disjointed fragmentsmuch as one might expect a Dutch doll to talk was it blessed with the power of speech; his sentences seem as if they dropped out of his lips without his own volition.He has one favorite word at a time, and he wears it threadbare. If you can understand it, all the better for you; if not, you would not like to show your ignorance by asking; so the young man distinctly scores one there. His pet phrase covers his ignorance or his laziness, and he is borne along with the tide instead of having to row against the stream.(Pet Expressions. Household Words: A Weekly Journal, January 5, 1884)Also  See:   BuzzwordCatchphraseChunkColloquialismPhraseSlangVogue Word

Finance Case Study Example | Topics and Well Written Essays - 1000 words

Finance - Case Study Example This involved the rise in the price of diesel, a shortage of drivers and an effort to maintain their depreciating fleets. Problem Statement The biggest challenge included debts from credit cards, commercial mortgages and machine financing. Exchange of money for a new issue of preferred stock and warrants was the beginning of GE Capital. This led to deterioration of the company at a remarkably fast rate. This deterioration, in turn, led to a fall in price of credit default swaps, lenders’ insurance and actual bonds of the company (Norton, Diamond and Pagach 245). Sales of common stock does not always imply a success in the financial position. Other Issues In debt and borrowing, it is of importance that GE Capital embraces its position with the AAA ratings. This rating is of the essence as it helps generate 40% of its revenue from the units. GE experienced a fall in earning up to below 110% of the fixed charges of the unit. This is defined as interest expense with an additional portion of rental costs. To gain financial stability, GE Capital needed to take the ratio back to 110%. A rise in the debt ratio above 8 to 1 would require the parent company to add more funds. Revenue was fixed at 170% at year end for GE Capital. This, however, was not matched by the equity to debt ratio as it was above 7.3 to 1 on the high end that was the case for various companies. Moreover, there is a greater share of more than $43 billion in loans that were securitized. Another problem was recruiting and employing quality drivers and raising finance for its operations. Other widespread concerns were the increasing expense on diesel fuel and machine parts and maintenance. There were also other concerns regarding the costs of operation related to complying with government regulations. Analysis Liquidity Current ratio Industry 2002 2001 2000 =1.1:1 2.3:1 2.8:1 3.4:1 Acid Test Ratio Industry 2002 2001 2000 =0.9:1 1.7:1 1.9:1 2.2:1 Working Capital Industry 2002 2001 2000 N/A 34,421 28,252 33,062 Profitability Return on Equity Industry 2002 2001 2000 30.2% 52.6% 13.0% 0.0% Stability Industry 2002 2001 2000 Debt/Equity 1.56:1 2.2:1 4.2:1 0.23:1 Interest Coverage N/A 5.5* 1.7* 1.0* Industry 2002 2001 2000 Age of Receivables 42.6 days 18days 16days 40days Age of Payables N/A 19days 14days 34days The liquidity ratio indicates that GE Capital has the ability to meet its financial needs. It is higher than the industry ratio. However, there is a decline in the ratios every year from 2000. There is no consistency in the levels of working capital throughout the three years. In 2002 working capital is greatest an indication that GE is doing well. Profitability of the company has been on the rise throughout the three years. It is higher than the industry level implying acceptable profitability. Stability of the company is higher than the industries as well as the repayment periods. This shows that the GE Capital is at a favorable financial position. Statement of Changes Sources: Other Receivable 53 Prepaid Expenses 1,172 Loan (New court) 13,631 Loan ( GE Capital) 189,000 Retained 56,999 Uses: (20,092) Net Cash Increase 300,732 Cash 31st Dec 2000 (3,877) Cash 31st Dec 2002 8107 The net cash increased by 300,732 and there was also an increase in cash in 2002 to 8107.It indicates the ability of GE Capital to meet its short term financial responsibility. It shows that the company has a remarkable liquidity. The Four C’s of Credit Character refers to the credibility of a business

Holidays Comparison Essay Example | Topics and Well Written Essays - 250 words

Holidays Comparison - Essay Example The essay "Holidays Comparison" presents the comparison of two holidays - the ‘4th of July’ and the ‘Christmas’. As holidays make our lives interesting, therefore, it is very common for people to wait for upcoming holidays. The main difference between these holidays is that the nature of both holidays differs to a large extent if we take a closer look at the reason for which they are celebrated. Christmas holidays have their origin in the Christian religion and for this reason, Christmas holidays may be regarded as having a religious feel. They are a reflection of the Christian belief system. And the 4th of July has a patriotic feel since it relates to a historical achievement of the American people in the history. Another prominent difference is the weather that is associated with these holidays. The 4th of July and summer appear to be bonded together and hence the celebrations are in accordance to the warm weather. Christmas is during the cold part of the year and so Christmas is celebrated in warm clothes coupled with snow. As far as similarities are concerned, both holidays are well recognized throughout the nation and both have national acceptance and approval; so the whole nation celebrates them in a unified form. Both holidays serve to give the message of being united at the national level; an aspect that is important in the international scenario. Both holidays provide a means of interaction and recreation to the masses, who are otherwise absorbed in their busy daily lives throughout the year.

Importance Of Scale In Ecology Biology Essay

Importance Of Scale In Ecology Biology Essay The concept of scale in ecology is seen as increasingly important in our understanding of the functioning of ecological communities and the interaction of individual species with the environment. This has been recognised globally by the awarding of the 2011 Crafoord Prize to Ilka Hanski for his work on the concept of metapopulations (www.crafoordprize.se). The importance of scale in ecology was only seriously recognised in the late 80s and 90s by ecologists (Krebs 1985; Wiens 1989; Levin 1992; Bissonette 1997). Krebs (1985) stated: the importance of scale in ecology is a focal issue for the 1980s as we attempt to gain a finer understanding of how ecological systems operate in the real world. This is further highlighted by the fact that Karieva and Anderson (cited in Wiens 1989 and Bissonette 1997) showed that about half of all studies conducted between January 1980 and January 1987 were done on plots a metre or less in diameter. The two major types of scale are spatial scale and temporal scale. Spatial scale can be considered in terms of grain size and extent. The grain size is the resolution of the sampling. It describes the size of an individual sample. A common example for grain size in ecology would be a quadrat. The extent describes the area (or volume) within which all the samples are taken. Temporal scale can be thought of as the frequency of sampling. The importance of scale when studying migrations was shown by Hanski and his colleagues (Hanski 1999, Hanski et al. 1994). Previous work has suggested that there are two types of butterfly populations; open and closed. This is due to the mobility of different species of butterflies with some migrating long distances like the monarch butterfly and others only a few kilometres. It was observed that the majority of species of butterflies in closed populations remained in their natal habitat patch. However, Hanski states that nobody had conducted extensive mark-recapture work simultaneously in many habitat patches (populations) to really establish the extent of migration. In other words he suggested that by looking at the metapopulation instead of population level, a better picture of the butterfly migration would be had (Hanski 1999). When this was done it was found that some populations were not as closed as they seemed (Hanski 1999, Hanski et al. 1994). Insect herbivores life-history strategies According to Bale (2002) there are six different types of life-history strategies found in insect herbivores: Methuselah. Growth and development is dependent on climatic conditions. The life cycle can last several years. For example, the periodic cicadas have a 13 or 17-year life cycle (Williams and Simon 1995). Stop go. Growth and development is controlled by environmental cues. It starts and stops in synchrony with seasonal changes. This can be seen in the heather psyllid Strophingia ericae (Miles et al. 1998). Grab it. There is close synchrony of life cycle with host plant phenology because the duration of the availability of the plant as a food resource is limited to an interval during the growing season. There is usually only a single generation per year. For example, in the spruce bud moth (Zieraphera canadensis) larvae surviviorship decreases significantly for those hatched 4-5 days after bud burst (Quiring, 1992). Keep trying. The host plant allows for continuous development during a limited growing period. Two or more insect generation may occur per season depending on temperature and host plant condition. For example, the southern pine beetle Dendroctonus frontalis can have up to five generations per season depenting on temperature (Rudinsky 1962). Hop about. The insect changes host plant depending on suitability. An example of this strategy can be seen in the moth Hyles lineata (Cates 1980). Never give up. In non-seasonal environments, continuous development occurs on a single host with several generations per year. In seasonal conditions, insects are adapted to survive unfavourable periods in any one of all stages. A seasonal synchronization mechanism may be included in the life cycle (e.g diapause and photoperiodic inhibition of development). An example of this strategy in seasonal conditions can be seen in the corn borer Pyrausta nubilalis (Babcock, cited in Masaki 1961) and in non-seasonal environments in the beetle Chelobasis perplexa (Strong and Wang 1977). When studying any aspects linked with growth and development in insect herbivores, it is therefore important to know what type of life-history strategy the study species displays when choosing the temporal scale of the study. A species with a never give up strategy can be sampled continuously throughout the year but this is not the best sampling process for a species with a methuselah strategy because growth and development is dependent on climatic conditions and, to study its whole life cycle, sampling would have to take place over several years. Temporal and spatial influence on community ecology Krebs (1985) recognised five traditional characteristics of communities that have been measured or studied; species diversity, growth form (e.g. trees, shrubs, herbs, and mosses) and structure, dominance amongst species, relative abundance of species, and trophic structure. Temporal changes to these characteristics are known as successions and lead to a stable climax community A climax is the final or stable community in a successional series. It is self-perpetuating and in equilibrium with the physical and biotic environment (Krebs 1985). Krebs describes the floral development of abandoned farmland in Oklahoma as example of plant succession. Booth (1941) analysed the different plant stages and their duration in the succession. His findings are tabled below. Table 1. Plant succession stage and its duration. (After Krebs 1985) Stage Duration of Stage Weeds 2 years Annual Grass (Aristida oligantha) 9-13 years Bunchgrass (Andropogon scoparius) 25+ years Tall grass prairie Climax vegetation The replacement of weeds by annual grass can be explained to be due to weed species producing chemical inhibitors that affected themselves but not the annual grass. A. oligantha can survive in a low nitrogen environment and nitrogen levels are low after crop abandonment. As the soil improves, the bunchgrass replaces the annual grass and in turn is replaced by the prairie grass. Temporal changes that occur in a stable community are known as cyclic changes. An example of this type of change can be seen in the population of lemmings in Greenland (Gilg et al. 2003). The collared lemming (Dicrostonyx groenlandicus) in Greenland is preyed upon by four species of predators; the arctic fox (Alopex lagopus), the stoat (Mustela ermine), the snowy owl (Nyctea scandiaca), and the long tailed skua (Stercorarius longicaudus). Gilg et al. were able to show that there is a 4-year cycle in lemming and stoat numbers. They were also able to predict this 4-year periodicity in lemming dynamics by constructing a predator-prey model. This and the Gilg et al. observations of the 4-year cycle were graphed and can be seen in Fig. 1 below. Fig. 1. The top graph is a visual demonstration of the lemming (black squares) and the stoat (grey circles) 4-year cycle based on field observations. The bottom graph demonstrates the cycle predicted by a model. (Gilg et al. 2003) They also highlight that there is a similar cycle in the arctic fox in Greenland. Using data from trapping records, they demonstrated that arctic fox numbers between 1935 and 1960 peaked at intervals of 4, 5, 4, 4, and 4 years. Like the changes in stoat numbers, they suggest that this cycle is due to changes in lemming densities. Spatial influence on community ecology is especially obvious when considering the theory of island biogeography put forward by MacArthur and Wilson (1967). This theory states that on an island, the number of species is proportional to the size of the island and its distance from the source population (usually the mainland). This theory does not work solely on island populations. It has been adapted to work on fragmented forests, lakes and ponds, caves, and mountaintops (Harris 1984, Lassen 1975, Culver et al. 1973, Riebesell 1982). Communities can have different species diversity depending on their latitude. Simpson (1964) recognised a north-south gradient in the abundance of mammals in North America. He identified a clear but irregular gradient with a minimum number of 13 species in a quadrat (240 km2) in one of the nothernmost areas (latitude 70Â °) and a maximum number of 163 species in one of the southernmost areas (latitude 10Â °). This gradient can be explained due to the warm temperatures found in the tropics which favour the diversification of the biota (Krebs 1985, Jacobsen et al. 1997). Krebs (1985) states that the increase in species diversity towards the tropics could be due to an increase in spatial heterogeneity. This influence has been recognised in forest ecosystems by Burnett et al. (1996) and in bird species diversity by Roth (1976). Another factor to this gradient might be that towards the equator diversity in species is greater because the area is greater and species richness is scale depe ndent; it increases with area (Willig et al. 2003). How communities are structured/evolve A community is formed from processes which occur at very large spatial and temporal scales such as speciation, vicariance, and dispersal (Holt 1993). Two types of community structures are the physical structure and the biological structure (Krebs 1985). The physical structure refers to the structures within which species distribute themselves, for example, trees and shrubs. Krebs (1985) recognised three components to the physical structure of communities; growth forms, vertical stratification and seasonality which will be discussed in the next section. The growth form refers to the architecture of a plant in terms of its form, method of branching and arrangement of its shoot system, and underground system if possible (Gimingham 1951). They can be classified into six major growth forms: Trees Lianas Shrubs Epiphytes Herbs Thallophytes All communities have a vertical structure. This stratification is associated with a decrease in light (Krebs 1985). Biological structure involves species composition and abundance, temporal changes in communities, and relationships between species in a community (Krebs 1985). Examples of temporal changes and relationships between species in communities were given in the previous section. All these characteristics of the community structure are interlinked. This is best shown in Fig. 2. Fig. 2. The relationships between factors that influence the structure of a community. (After Krebs 1985) The evolution of a community is not dependant on individual biological components but of the pattern of interaction expressed in the community structure (Olson 1966). Although, it could be argued that changes in a species can change an interaction in the community structure (Brooks and McLennan 2002). Changes in one of the factors in Fig. 2. can contribute to the evolution of a community. The evolution of a community can also be thought of in terms of succession as a community changes until it reaches a stable climax community. The extent to which a community can evolve is dependent on species density. A community which has a number of species that is below equilibrium numbers has a greater chance of evolving than a community in equilibrium (Brooks and McLennan 2002). Factors influencing the structure and longevity of communities Seasonality is a major component of the physical structure of communities. The structure of all communities is affected by seasons, and seasonal events are important to the functioning of communities (Krebs 1985, Wiens 1974). It can also be considered as affecting the biological structure since the physical structure of a community affects its biological structure (Krebs 1985, Wiens 1974). Wiens (1974) states that the highly seasonal distribution of precipitation and production found in grassland habitats can influence the species abundance or the size of the resident population. He also describes how climatic irregularities can limit the number of species in a community, especially in large unfragmented grasslands where there are few places for opportunistic species to reside. He argues that in grassland which covers a small area, populations of species can take refuge in a different habitat type until conditions are favourable for them. Also, natural hazards (e.g. fires and floods) and anthropogenic influences can affect community structure (Zimmerman 1992, Dale et al. 2001). The longevity of a community is dependent on its resilience. Resilience indicates how fast a community can return to an equilibrium state after a perturbation (Pimm 1984). If a community is resilient it does not mean that it is unstable. In fact, Holling (1973) states that the spruce budworm forest community is highly unstable and because of this it is very resilient. Measurements of resilience are specific to a type of perturbation. A community can be resilient to one type of perturbation (e.g. low temperatures) but not at all resilient to another (e.g. increased nutrients) (Krebs 1985). Two factors that can affect the resilience of a community are patchiness and dispersal (Krebs 1985, Holling 1973). Some communities are resilient because they reside in a patchy environment. When a perturbation occurs in one patch, species can disperse to another patch until conditions are favourable again (Krebs 1985, Wiens 1974). Species composition and biodiversity can also affect resilience (All ison 2004, Griffiths et al. 2000). According to Pfisterer and Schmid (2002) greater number of species can express a greater range of responses to environmental perturbations. Differences in immigration/emigration between guilds, species, and kingdoms Different organisms have different success in migrating. For example, Walsh and Kay (1995) showed that when eucalyptus trees were introduced to New Zealand from the Australia, woodborers, sapsuckers and defoliators species immigrated to New Zealand to colonise the eucalyptus number of species being roughly equally distributed amongst the three guilds. At around the same time, pine trees from the North America were introduced to New Zealand. Half the amount of woodborer species that colinised the eucalyptus emigrated to colonise the pines while only a quarter of the numbers of sapsuckers that colinised the eucalyptus colonised the pines and no defoliators managed to establish in the pines. The succes of the insects, considered to be pests to trees, is due to the distance of their source population from New Zealand (Fig. 3). The insect that colonised the eucalyptus trees came from Australia and had no problem in immigrating. However, the insect pests to the pines originate from North A merica and would have had to travel a long distance to reach introduced pines. The defoliators could not emmigrate and synchronise their life history with the introduced pines. The woodborers are well-adapted to travelling long distances because their life history is isolated from their environment. Sapsuckers are not as well adapted to travelling long distances but only one female need to arrive at the destination to colonise because of their parthenogenesis capability. Fig. 3. An adaptation of the MacArthur and Wilson (1967) model for the prediction of the number of pests that can colonise a host. (Walsh and Kay, 1995) Insects have more success in establishing themselves in a new environment if they migrate on an east-west axis as opposed to a north-south (Kay, 2005). This is because there is more of a chance of phenological synchrony of pests and host in east-west dispersal because season reversal is encountered when travelling north-south. How does this assist our understanding of ecology on a local and global scale? When choosing scale one must be aware of the characteristics of the processes that might influence your study (if they are not the subject of the study themselves) and the characteristic of organisms in the study. For example, if we are studying the potential threat of an invasive herbivore insect to a community, it is not enough to study the community structure to see if it can accommodate the insect but the distance of the source population must be known as well and also the life-history strategy of the insect. Although spatial and temporal scales are usually positively correlated to achieve high predictability in a study (Wiens, 1989) this is not the case when looking at the evolution of a community. When studying succesion, a later sequence can survive longer than the investigator (Connel and Slayter, 1977). This means that you could be looking at the succesion of a local community in a small area using years of data. Hanski (1999) makes an argument of not restricting to a local scale when studying a local population. By looking at a more global scale you can make an inference on a local population. It is important to note that even when a community is in a stable condition, temporal changes can still occur and lead to population dynamics. These cyclic changes could affect data and therefore the temporal scale of a study done on species in a stable climax community would have to take this into consideration. For example, if one were looking at the stoat population in Greenland between 1996 and 1999 (Fig. 1.) one would assume that there is a pattern with number of individuals gently rising, unaware of the cyclic changes in their population. Since when we look at evolution we look at changes against time it is safe to say that time is the main process influencing the evolution of a community. This is visually demonstrated in Fig. 2. where time is on top of the diagram showing the factors that influence community structure. However, there is a spatial influence on the evolution of a community as well. Spatial heterogeneity, as previously discussed, can dictate the species diversity. Also, the species density (amount of species per area) affects the ability of a community to change. The theory of island biogeography can be applied on a local and global scale. The Culver et al. (1973) study on cave-limited species in the Greenbrier valley in West Virginia can be considered to be done on a local scale compared to the MacArthur and Wilson (1967) study on amphibians and reptiles in the West Indies using data collected by Preston (1962). On a global scale, we see that species diversity increases on a gradient from one of the poles to the equator. This can be attributed to the change climate, spatial heterogeneity, or simply because of the greater amount of space available towards the equator. Seasonality can have an ecological effect on global as well as local scale. On a local scale, it can effect species abundance and population density in a community. Seasonl irregularities can affect species diversities in spatially homogenous communities. On a global scale, seasonality can lead a community to be species specific. Some herbivorous insect cannot colonise certain areas because they are unable to synchonise their life cycle with the potential host plant phenology due to change in seasons. A communitys longevity is not dependent on how stable it is but on its resilience. A communitys resilience is influenced by how patchy is the environment it occupies. If its environment is heterogenous, species can disperse between habitat types to avoid perturbations. Biodiversity is also important for resilience and , as already mentioned, is affected by spatial and temporal forces. Success of migration in species is dependent on the scale of the migration. Walsh and Kay (1994) showed that woodborers, sapsuckers and defoliators had much more success in immigrating to New Zealand from Australia than from North America. There was also variation in successes to the emigration of the three guilds from North America due to the different influences that seasonality has on the guilds. In brief, the main conclusion of this review is that a study should not be restricted to one scale. When possible, different observations should be done on different scale. For example, when studying species diversity we know that it can be affected by spatial heterogeneity (local scale) and latitude (global scale). We have already established that different processes work on different scale but it is important to note that some processes work on multiple scales.