Natural Selection Compared to Sexual Selection in the Animal World

Importance of Trifling Morphological Characters Animals do not just have colors for beautification. Various animals have colors and tints that help them to survive in the harsh conditions of the jungle. Predators are always looking for food to eat. In this regard, animals usually have colors and tint that are similar to the surrounding environment in which they live. This is highly helpful to the animals in two ways.Advertising We will write a custom essay sample on Natural Selection Compared to Sexual Selection in the Animal World specifically for you for only $16.05 $11/page Learn More Firstly, prey animals are able to use these colors and tint to disguise themselves and thus avoid being seen by predators from long distances. This is a survival mechanism to ensure that at least these animals live to maturity. Secondly, the colors and tint can work in favor of predators. When predators have colors and tint which is almost the same as that of their ecolo gical niche, they can be able to trap their prey making hunting easier. In this regard, the colors and tint act as a hunting aid thus ensuring survival of the predators. What Natural Selection Modification cannot Do Natural selection will modify the structure of any animal so that the animal can survive. However, natural selection cannot modify the structure of an animal to its disadvantage. Structural modification of animals is always in favor of the animals. Therefore, if an animal is to undergo modification of its structure that may lead to disadvantages in a given section, the modification will be slow. At the same time, the section will be undergoing modification so that it is to the advantage of the animal. Natural selection will always ensure that the best species survives while the unfit perishes. In this regard, when natural conditions of an area change, natural selection will not modify the structure of an animal so that it cannot survive. On the contrary, natural selectio n will always be modifying the structure of any animal so that it is fit to survive on the prevailing natural conditions. In a nutshell, structural modification by natural selection is always aimed at ensuring that animals survive. Difference between Species and Varieties One basic difference between species and varieties is that while species are animals or plants which belong to the same genus, varieties are organisms belonging to the same species but with slight differences. Different species though belonging to the same genus, usually exhibit high degree differences which range from physical to morphological. Organisms of different species may not even live in the same ecological niche. On the other hand, organisms of different varieties usually belong to the same species but exhibit minor differences. It is important to note that differences of varieties are mostly physical. Organisms of different varieties may even be occupying the same ecological niche contrary to organisms o f different species. In this regard, it is important to note that the differences among members of different varieties are of lesser degrees compared to those among members of different species. In more instances, varieties come about as a result of sexual selection.Advertising Looking for essay on biology? Let's see if we can help you! Get your first paper with 15% OFF Learn More Traits Perpetuated through Sexual Selection Basic differences among animals of the same species are usually as a result of sexual selection. This includes color, shape of the mouth and other physical characters. As far as sexual selection is concerned, the characters of the dominant males are always the prevalent ones. It is important to note that sexual selection is not responsible for survival qualities of an organism. Nonetheless, sexual traits from a dominant male always prevail among the group. The trait of domineering and fighting other male members so as to remain a dominant male are a s a result of sexual selection. The offspring of a dominant male will always be good at fighting and endowed with the best fighting mechanism. On the other hand, offspring of weak male will always be in jeopardy because they do not have the requirements to protect themselves and their female partners. Natural Selection Compared to Sexual Selection Natural selection is about survival and every animal or plant that is not best suited will perish. Natural selection separates organisms with the best characters from animals with the bad characters. The results are clear to every organism; if it is not best suited it will die. On the other hand, sexual selection is about which male is strong enough to dominate and have offspring. The male can fight but it is not necessarily that death can result. A defeated male can move from that part and relocate to another ecological niche where it can continue surviving. The characters that are gained through sexual selection are important to ensure c ontinuity of the dominant male’s lineage. However, characters gained through natural selection are vital to ensure survival of the animal. Natural selection can modify an animal to ensure that it is fit to survive. However, no such modification occurs as a result of sexual selection. In this regard, natural selection is about life and death as opposed to sexual selection. A reason as to why Darwin says that sexual selection is less rigorous than natural selection. This essay on Natural Selection Compared to Sexual Selection in the Animal World was written and submitted by user Sadie U. to help you with your own studies. You are free to use it for research and reference purposes in order to write your own paper; however, you must cite it accordingly. You can donate your paper here.

IMO Ballast Water Exchange and Performance Standards

IMO Ballast Water Exchange and Performance Standards In order to reduce damage from aquatic invasive species the International Maritime Organization (IMO) developed the â€Å"International Convention for the Control and Management of Ships Ballast Water and Sediments†. The BWM convention began with the IMO’s Marine Environment Protection Committee (MEPC) in 1991. Since then there have been many revisions. Some of these revisions were driven by advancing technology to remove unwanted organisms at flow rates that would not severely impact operations. Treatment of ballast water with the latest technology can meet standards at a rate of 2500 cubic meters (660,430 US Gallons) per hour. A large vessel may still take several hours per exchange to flush her ballast tanks at this rate. Flow rates and energy consumption must be acceptable to operators while producing no harmful effects on the environment. Ballast Water Standards There are two types of ballast water standards in the convention. Their differences are significant and they should not be directly compared. The first, Ballast Water Exchange, is based on specified distances and depths where a vessel may discharge. Ballast Water Performance is a standard based on the number of viable organisms allowed per unit of treated water. Some areas are instituting standards which exceed the IMO guidelines. Both California and the Great Lakes region of the United States have adopted stringent local guidelines. The US is one of many major shipping nations that have not signed the convention. Thirty nations who have a combined merchant gross tonnage of thirty-five percent of the global tonnage are needed to ratify the convention. Ballast Water Exchange The standard for ballast water exchange is fairly simple. A vessel must discharge foreign ballasts at a specified distance from shore and at a specified depth using a submerged discharge device. Regulation B-4 and D-1 of the BWM convention gives us the specifics. Exchange may take place 200 Nautical Miles (NM) from shore at a depth of 200 meters. If that is not possible for safety or other reasons then a vessel may use the next procedure.If neither of these scenarios is possible then a vessel may exchange â€Å"in an area designated by the port state†. While undertaking ballast water exchange a port state must not cause deviation or delay of a ship.Efficiency of exchange should be at least 95% of volume and must be repeated three times. Vessels which demonstrate high-efficiency exchanges may reduce the number of exchange cycles.Ballast Water Exchange should only be undertaken when the safety of the vessel and crew are guaranteed. Ballast Water Performance In the case of Ballast Water Exchange, ship operators are flushing untreated ballast out of the tanks. This is a practical if not perfect way of allowing older vessels to operate without the expense and logistical problems of ballast water treatment retrofits. New and retrofitted vessels are much less likely to transport unwanted species because the ballast water treatment systems eliminate a large proportion of the viable organisms from the ballast tanks before discharge. Systems like these significantly reduce the chances of unwanted species being introduced by inefficient exchange practices or in the event of an untreated near shore discharge for safety reasons. The IMO uses the following guidelines for the Ballast Water Exchange standard in regulation D-2. Ballast water must contain less than 10 viable organisms which are greater than or equal to 50 microns in size per cubic meter (264 US Gallons). For reference, 50 microns is about half the thickness of an average human hair.In addition, ballast water must contain less than 10 viable organisms that are less than 50 microns but greater than or equal to 10 microns per milliliter (1/1000th of a liter).Indicator Microbes may not exceed the following amounts; Vibrio Cholerae - less than 1 CFU (colony forming unit) per 100 Ml, E. Coli – less than 250 CFU per 100Ml, Enterococci – less than 100 CFU per 100Ml. Water treated to this standard is considered pure enough to discharge in most ports. These steps to re-mediate ballast water are only effective in the removal of unwanted organisms. It is still possible to carry toxins like copper and heavy metals often found in ports to other destinations in ballast water and these pollutants may concentrate in ballast tank sediment. Radioactive substances can also be transported in ballast but any serious cases would likely be found quickly by monitoring personnel.

Policy Sciences Essay Example | Topics and Well Written Essays - 1750 words

Policy Sciences - Essay Example It was more often that the advisors did not have any 'consideration of intellectual underpinnings, honesty, cumulative knowledge or independent evaluations' of the political and social scenario. There were also no recordings of the decisions and the reasons for such decisions written down. Most of advises, according to DeLeon, remained 'particularistic, ad hoc exercises' taken up when something was needed by the prince or the monarch. Documenting the decisions and supporting ideas were done during the later half of the nineteenth century. Subsequent growth of the policy science was based on the foundations and concepts that stemmed from these days. During and after World War II, there were major upheavals that were taking place all over the world. The concept of the nation state had taken firmer shape in the world and so did the concept of independence or freedom. The political economy and the political science itself underwent major changes in the way decisions were made. ... The advisors had to change their color based on the rising trend in these nation states and those states that were coming up just then. The fight against and for separatism is another major change in the thought process to become an independent state or nation! This was a serious motivator for the change in policy sciences in line with the thoughts that entered the circle. Similarly, the changes in the economic scenario and the rise of the new economic and political power in the form of the United States also meant that the entire political scene has to be reworked. While there are some uprisings that were anti imperialistic and others socialistic, all that it meant was that the advisors had a different role to play4. The social requirements and the needs of the people, had to be reflected to the monarch or to the heads of the government through these advisors or duly elected members of the parliament or governing council. Immediately after the World War II, the impact on the advisory policy took a major turn5. With more stress on economic growth and industrial growth, the rights of the labor and the people became more pronounced. In all the nations, the monarchies gave way to socialistic and democratic systems that took its power from the people. The advisory policy made a complete U turn here and slowly but steadily moved away from the monarchy and the power center shifted to the ministers or the advisory boards. And the major turn in the policy is the twist that could be visibly seen in terms of ethics and humanitarian issues6. Equality of human beings, racial equality and equality of nations were the main thrust of most of the policy advisors in this period of the policy making history. War on Poverty up to late 1970s War on Poverty was again