Diapause - Definition of the Term Diapause

Diapause - Definition of the Term Diapause Diapause is a period of suspended or arrested development during an insects life cycle. Insect diapause is usually triggered by environmental cues, like changes in daylight, temperature, or food availability. Diapause may occur in any life cycle stage – embryonic, larval, pupal, or adult – depending on the insect species. Insects inhabit every continent on Earth, from the frozen Antarctic to the balmy tropics. They live on mountaintops, in deserts, and even in the oceans. They survive frigid winters and summer droughts. How do insects survive such extreme environmental conditions? Â  For many insects, the answer is diapause. When things get tough, they take a break. Diapause is a predetermined period of dormancy, meaning its genetically programmed and involves adaptive physiological changes. Environmental cues arent the cause of diapause, but they may control when diapause begins and ends. Quiescence, in contrast, is a period of slowed development that is triggered directly by environmental conditions, and that ends when favorable conditions return. Types of Diapause Diapause can be either obligatory or facultative: Insects with obligatory diapause will undergo this period of arrested development at the predetermined point in their life cycle, regardless of the environmental conditions. Diapause occurs in every generation. Obligatory diapause is most often associated with univoltine insects, meaning insects that have one generation per year.Insects with facultative diapause undergo a period of suspended development only when conditions require it for survival. Facultative diapause is found in most insects and is associated with bivoltine (two generations per year) or multivoltine insects (more than two generations per year). Additionally, some insects undergo reproductive diapause, which is a suspension of reproductive functions in adult insects. The best example of reproductive diapause is the monarch butterfly in North America. The migrant generation of late summer and fall goes into a state of reproductive diapause in preparation for the long journey to Mexico. Environmental Factors That Trigger Diapause Diapause in insects is induced or terminated in response to environmental cues. These cues may include changes in the length of daylight, temperature, food quality and availability, moisture, pH, and others. Â  No single cue solely determines the start or end of diapause. Their combined influence, along with programmed genetic factors, controls diapause. Photoperiod – A photoperiod is the alternating phases of light and dark in the day. Seasonal changes to the photoperiod (such as shorter days as winter approaches) cue the start or end of diapause for many insects. Photoperiod is the most importantTemperature – Along with photoperiod, changes in temperature (such as an extreme cold spell) can influence the start or end of diapause. The thermoperiod, alternating phases of cooler and warmer temperatures, also influences diapause. Some insects require specific thermal cues to end the diapause phase. For example, the woolly bear caterpillar must endure a period of chilling to trigger the end of diapause and continuation of the life cycle.Food – As the growing season ends, the diminishing quality of their food sources may help trigger a diapause phase in an insect species. As potato plants and other hosts turn brown and dry, for example, Colorado potato beetle adults will enter a state of diapause. Â   Sources: Encyclopedia of Entomology, 2nd edition, edited by John L. Capinera.Borror and DeLongs Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson.The Insects: An Outline of Entomology, by P. J. Gullan and P. S. Cranston.Biology of Arthropoda, by D. R. Khanna.Developmental Biology, 10th edition, by Scott F. Gilbert.

3 Sentences That Cause Confusion

3 Sentences That Cause Confusion 3 Sentences That Cause Confusion 3 Sentences That Cause Confusion By Mark Nichol In each of the following sentences, a word or phrase is an obstacle to comprehension. The discussion and revision that follows each example suggests a path to clarity. 1. Technology companies have a very different mind-set to traditional financial institutions. Comparisons structured as one is in this sentence should employ from rather than to, and note the insertion of the phrase â€Å"that of the† to indicate that the comparison is between mind-sets and not the entities that have the mind-sets: â€Å"Technology companies have a very different mind-set from that of traditional financial institutions.† 2. The agency found that contrary to its claims, World Wide Wickets failed to employ reasonable and appropriate measures to protect data. This sentence has an unclear antecedent: The pronoun its appears to refer to â€Å"the agency,† because no other entity has yet been identified, but it is a reference to the company subsequently mentioned. For clarity, use a specific proper noun (for example, â€Å"World Wide Wickets†) or a specific common noun (for example, â€Å"(the) company†) first, then a pronoun (or, in this case, use a proper noun on first reference and a common noun on second reference, bypassing the need for a pronoun at all): â€Å"The agency found that contrary to the claims of World Wide Wickets, the company failed to employ reasonable and appropriate measures to protect data.† 3. Jones faces criticism of others who oppose his policy positions, as does opponent John Smith and many others. This sentence is ambiguous- it could mean that Smith and many others face the same criticism as Jones, or the phrase â€Å"as does† could apply not to the verb faces but to the verb oppose. (In this case, the latter option applies.) To eliminate possible confusion, chose a clearer word or phrase in place of the nebulous â€Å"as does†: â€Å"Jones faces criticism of others who oppose his policy positions, including opponent John Smith and many others.† Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Style category, check our popular posts, or choose a related post below:Fly, Flew, (has) FlownFlied?75 Idioms and Expressions That Include â€Å"Break†Oppose and Opposed To

The changing role of hr management Essay Example | Topics and Well Written Essays - 1000 words

The changing role of hr management - Essay Example Starbucks and Southwest Airlines are the perfect examples of such companies, where globalization and change in business trends have modified the traditional roles of HR management. Let us discuss how each of these factors affects the role of HR management in the 21st century. Globalization â€Å"Globalization is said to bring people of all nations closer together, especially through a common medium like the economy or the Internet† (Ellis-Christensen, 2011). Globalization has opened new dimensions and areas of consideration for the HR managers of the today’s world. Globalization has put a significant impact on the role of HR management in the success of a company. Today, any company or organization wants to expand its business to the international world in order to increase productivity and profitability, and when a company plans to go global, the management of that company needs to consider many important factors related to business, such as, different cultures, langua ges, social behaviors, and employment and government laws. The role of HR management changes when a company plans to operate the business in foreign countries. ... treme importance to the understanding of international cultures and languages because it plays a critical role in the international success of multinational companies. Another important factor to which today’s HR managers give extreme importance is international employment laws. When a company goes global, the management needs to consider international employment laws while setting up employment plans for the international employees. Technology The advancement in the field of technology has led the focus of HR managers towards hiring highly technical employees for the companies. When a company starts making use of new and latest technology for running any specific business activity, such as, manufacturing, it needs to hire such employees who should be skilled in using that technology. Today, HR managers prefer highly skilled and technical candidates as compared to such candidates who are although high qualified but not skilled enough to make use of technology. Moreover, inform ation technology has also played a role in changing the role of HR management in the today’s business world. Information technology provides managers with such software products and applications, which not only assist them in doing performance appraisal but also helps in improving the overall human resource management. In the past, keeping record of large-scale human resources was not an easy task (Rankonda, 2010). The human resource management system (HRMS) is an example of information technology, which not only assists human resource managers in keeping large records but also helps them in carrying out many tasks, such as, keeping attendance, labor distribution, automated record keeping, and many other tasks. Ethics â€Å"Business ethics is the behavior that a business adheres to in its daily