The Evolutionary Arms Race - Natural Selection

The Evolutionary Arms Race - Natural Selection Species, in order to evolve, must accumulate adaptations that are favorable for the environment in which they live. These preferred traits are what make an individual more fit and able to live long enough to reproduce. Since ​natural selection chooses these favorable characteristics, they get passed down to the next generation. Other individuals that do not exhibit those traits die out and, eventually, their genes are no longer available in the gene pool. As these species evolve, other species that are in close symbiotic relationships with those species must also evolve. This is called co-evolution and it is often compared to an evolutionary form of an arms race. As one species evolves, the other species it interacts with must also evolve or they may go extinct. Symmetrical Arms Race In the case of a symmetrical arms race in evolution, the co-evolving species are changing in the same way. Usually, a symmetrical arms race is a result of competition over a resource in an area that is limited. For example, the roots of some plants will grow deeper than others to obtain water. As the water level goes down, only the plants with the longer roots will survive. Plants with shorter roots will be forced to adapt by growing longer roots, or they will die. The competing plants will keep evolving longer and longer roots, trying to outperform each other and get the water. Asymmetrical Arms Race As the name implies, an asymmetrical arms race will result in the species to adapt in different ways. This type of evolutionary arms race still results in the co-evolution of the species. Most asymmetrical arms races come from a predator-prey relationship of some sort. For instance, in the predator-prey relationship of lions and zebras, the result is an asymmetrical arms race. The zebras become faster and stronger to escape the lions. That means the lions need to become stealthier and better hunters in order to keep eating zebras. The two species are not evolving the same types of traits, but if one evolves, it creates the need in the other species to also evolve in order to survive. Evolutionary Arms Races and Disease Humans are not immune to the evolutionary arms race. In fact, the human species is accumulating adaptations constantly to fight disease. The host-parasite relationship is a good example of an evolutionary arms race that can include humans. As parasites invade the human body, the human immune system will kick in to try to eliminate the parasite. Therefore, the parasite must have a good defense mechanism to be able to stay in the human without being killed off or expelled. As the parasite adapts and evolves, the human immune system must adapt and evolve as well. Similarly, the phenomenon of antibiotic resistance in bacteria is also a type of evolutionary arms race. Doctors often prescribe antibiotics for patients that have a bacterial infection in hopes that the antibiotics will stimulate the immune system and kill off the disease-causing pathogen. Over time and repeated uses of antibiotics, only bacteria that have evolved to be immune to the antibiotics will survive and the antibiotics will no longer be effective in killing off the bacteria. At that point, another treatment will be necessary and force the human to either co-evolve to fight off the stronger bacteria, or find a new cure to which the bacteria are not immune. This is the reason why it is important for doctors not to overprescribe antibiotics every time a patient is sick.

Business English Writing Resources

Business English Writing Resources Written communication is especially important at work. Business writing often follows specific expectations. There are a wide range of standard phrases that are expected in business English that are generally not used in everyday English. Examples Please find attached ...We regret to inform you that ...It has come to our attention that ... Another challenge is that business writing follows very specific formulas in structure. Take the resume, ​for instance, the writing style you use, the points you highlight about your career or education, and the overall look and feel can play a very important role in deciding whether you are offered a job or not. There are also a number of documents that are common to business writing. These include office memos, e-mails, and reports. These business writing documents also take on different styles depending on the audience of those who receive the documents. This guide to business writing points you in the direction of the wide variety of resources available on the site. Basic Business Letters These two articles provide an overall framework for writing business letters. They outline specific issues of salutation, structure, letter layout and language use. Finally, there is also a Business Letter Writing Basics - Business Letter Writing Basics for English learners. Guide to basic style questions and standard phrases used in business English letters. How to Write a Business Letter - This how to provides a quick step by step guide to writing a basic business letter. Specific Business Letters Building on basic business letters, these business letters provide specific examples of letters written for common business writing tasks such as making an inquiry, sales letters, placing an order, etc. They include key phrases commonly found in each of business letter types, as well as an example letter on which to model your own English business correspondence. Letters of AcknowledgementMaking a Sale - Sales LetterPlacing an OrderMaking a ClaimAdjusting a ClaimMaking an inquiryReplying to an inquiryNew Account Terms and ConditionsBasic Business LettersWriting a Cover Letter when Applying for a Job Specific Business Documents There are a number of standard business documents that are used on a daily basis at the office. These documents follow standard outlines. This example provides important structural details, an introduction and example document on which to model your own reports. How to Write a Business Report Job Applications It is extremely important that these key business documents are in order when applying for a job. The cover letter and the resume are key to successfully winning a job offer during the interviewing process. Finding a Job - Writing a Cover LetterExample Cover Letter 1Writing Your Resume