Sexual Selection Essay Example for Free

Sexual Selection Essay Ornamental traits have always been known to be important in attracting mates. However, it has been unclear for a long time why this is the case. The sexy sons hypothesis proposes that females choose showier males and engage in polygamous relationships in order to maximize the viability of their offspring. The pathogen avoidance model states that females select for showier males in order to protect themselves and eventually their offspring from infection as these males are overall more healthy. Both theories fall short in that they do not acknowledge the importance of parenting in the health of offspring as sometimes, theoretically more viable offspring don’t thrive due to having low amounts of paternal care. I analyzed many different studies that have been performed throughout the years in an attempt to unravel this clash of views among many respected evolutionary biologists. Though it is inconclusive which theory of sexual selection is more representative of nature, this paper demonstrates the complexities involved in both theories and why potentially, both may be correct in one way or another. Introduction Sexual Selection is a very important driving force in nature and even in our everyday lives. However, it is important to note that it is only prevalent if it goes against mechanisms of natural selection. Essentially, secondary sex traits are costly to the individual and are therefore not optimal to have. Instead, one must acknowledge that the goal of an organism’s existence in an evolutionary standpoint is to reproduce. Having these costly ornaments is only selected for because they must in some way increases an individual’s likeliness to produce offspring—even at the cost of survivorship and viability. Two very important mechanisms of sexual selection that are known are the sexy son hypothesis and the pathogen avoidance model. The sexy son hypothesis states that females choose males with showier or more attractive traits in order to select for genes for pathogen resistance in order to pass those â€Å"good genes† onto their offspring. The pathogen avoidance model states that females select for males with secondary sex traits in order to distinguish between the diseased and the healthy males in order to stay safe from pathogens. Both theories are widely used to explain many evolutionary trends, but are they mutually exclusive? It is possible that both theories are correct in certain scenarios. However, one must look into the mechanisms of both in order to find out. Overview of Sexy Sons Hypothesis  The sexy son hypothesis which was popularized by Ronald Fisher is currently stated as a possible explanation for the great diversity of ornamental traits in animals. These ornamental traits are known to negatively affect the longevity of the individual but benefits its reproductive success. Essentially, females prefer to choose attractive and showier mates in order to produce attractive sons who are selected for by females, which leads to greater amount of grandchildren and so on. On top of that, through this theory, the idea is presented that females don’t simply select for the trait itself, but instead for the possession of the trait. The difference, no matter how subtle, is important to acknowledge because theoretically, a male may possess a trait that is actually harmful to the mating relationship but is still desirable. As long as the trait itself signals â€Å"better genes† in terms of offspring health, it doesn’t matter what the trait itself isthe possession of that trait is enough. One such example of this is the trait of infidelity in a monogamous relationship. Though it is â€Å"better† to remain in that single mate relationship for the female because it allows her genes to be passed down instead of another member of the same species, the trait of infidelity may actually signal vigor and health in males and thus, the female will still be attracted. This leads to children who are also non-monogamous and through many generations, the non-monogamous, â€Å"good genes† are passed down to multiple grandchildren, great grandchildren, etc. Another aspect of the sexy son hypothesis involves female selection for male genes through the selection of â€Å"good sperm†. In terms of long term success in reproduction (offspring which also produce many offspring), individuals should encounter many potential partners and when better partners are found, they should re-mate in order to maximize health of offspring. It is apparent the sexy son hypothesis argues heavily against monogamy and in favor of polygamy due to polygamy’s ability to maximize mate quality and quantity. The current social structure in many species today including humans revolves around monogamy, and the sexy son hypothesis proposes that monogamy is simply not optimal due to not maximizing reproductive success. The question arises: why does monogamy exist in many social constructs if it is contradictory to the single goal of evolutionto reproduce? Thus, it is important to justify the presence of monogamy in order for the sexy son hypothesis to hold true. It is a prevalent question in the scientific community to this day why monogamy exists. Most families in nature involve heavy emphasis on maternal care which leads the male to provide for and invest in less than the female parent. Natural selection has so far favored this relationship where females invest a lot of energy into caring for offspring while males compete with other males of the same species for females. What current evolutionary biology supports is that that optimal mating protocol involves the pursuit of many partners to maximize offspring. Fit males are defined by the statement that If x is fitter than y, then probably x will have more descendants than y (Pence, C., and Ramsey, G., 2013). Essentially, a fit individual is one whose probability of spreading their genes to the next generation is relatively high which only seems to back up the theoretical prevalence of polygamy where monogamy currently exists. Many theories for the justification of the presence of monogamy exist but I will be going over the process of male mate guarding. Male mate guarding is defined as the close association between a male and female prior to and/or after copulation for paternity assurance (Brotherton, et al. 2003). One thing that a group of evolutionary biologists discovered was that the availability of partners plays a large role in this discrepancy (Schacht, Ryan, and Adrian V. Bell 2016). What this means is that in communities where males are valued over females (male-biased gene pool), for example in humans, females to mate with may be a scarce resource. This may lead the males to act in their best interests and achieve paternity with one female. This is possibly because with a lack of females, each female is viewed as more â€Å"valuable† and thus paternity with multiple females may have too big of a time expended/risk to reward ratio as competition will be extreme. This leads to males that are more fit to mate with the limited number of females and the males that are not as fit will be left out as there are such limited resources. This shows that in the sexy sons hypothesis, the concept of limited female availability is not accounted for as the primary goal is to maximize offspring fitness and survivability by mating with numerous different mates. Though I have talked about male mate guarding, the same concept applies to females in the context of sexual selection as females must be choosy with males (limited males) and expending too much time with non fit males (time expended vs reward) takes away from potentially producing offspring.

The Role of Women in American Society Essay -- America Society Culture

The Role of Women in American Society Women and men are nestled into predetermined cultural molds when it comes to gender in American society. Women play the roles of mothers, housekeepers, and servants to their husbands and children, and men act as providers, protectors, and heads of the household. These gender roles stem from the many culture myths that exist pertaining to America, including those of the model family, education, liberty, and of gender. The majority of these myths are misconceptions, but linger because we, as Americans, do not analyze or question them. The misconception of gender suggests that biological truths no longer dictate our gender roles as men and women; they derive from cultural myths. We, as a nation, need to do severe critical thinking about this delusion of gender, how has limited us in the home, media, and education, how it currently limits us, and what the results of the current and future changes in gender roles will be. Throughout history, the roles of men and women in the home suggested that the husband would provide for his family, usually in a professional field, and be the head of his household, while the submissive wife remained at home. This wife’s only jobs included childcare, housekeeping, and placing dinner on the table in front of her family. The roles women and men played in earlier generations exemplify the way society limited men and women by placing them into gender specific molds; biology has never claimed that men were the sole survivors of American families, and that women were the only ones capable of making a pot roast. This depiction of the typical family has evolved. For example, in her observation of American families, author Judy Root Aulette noted that more families practice Egalitarian ideologies and are in favor of gender equality. â€Å"Women are more likely to participate in the workforce, while men are more likely to share in housework and childcare (apa†¦). † Today’s American families have broken the Ward and June Cleaver mold, and continue to become stronger and more sufficient. Single parent families currently become increasingly popular in America, with single men and women taking on the roles of both mother and father. This bend in the gender rules would have, previously, been unheard of, but in the evolution of gender in the family, it’s now socially acceptable, and very common. What i... ...s. A woman in the office no longer takes messages, makes coffee, and runs off copies for her male boss; she represents top clients, holds important business meetings, and flies across the country for professional conferences. A man no longer spends 85% of his time working to support a housewife and kids; he can stay at home, and run errands and raise children and not risk being put to social shame. Couples on TV sleep in the same bed rather than separate twin beds, with or without wedding bands, and not necessarily man and woman. American society needs to break from the mold of the myth of gender, which suggests that society and culture dictate our roles as men and women, as can only restrict us into unnecessary conformity. The opinion of society should no longer decide who we are, what we do, and what we’re capable of doing. We, as Americans, need to deeply analyze and question this fallacy of gender and the way it restricts us at home, in the media, and in the classroom. If we continue to follow the invisible guidelines of in invisible rulebook, we’re destined to hurt ourselves and our future generations by remaining nestled into our cultural cocoons and never shedding them.

Reaching Effects Of The Gulf Oil Spill Environmental Sciences Essay

On April 20, 2010 an detonation occurred at the British Petroleum drill rig located in the Gulf of Mexico. The detonation at the drill rig Deepwater Horizon led to the Macondo good to leak out oil. This was to go the 2nd most detrimental environmental catastrophe in the universe and the worst environmental calamity in U.S. history. The United States Minerals Management Service ( USMMS ) recorded that eighteen out of 39 runawaies in the Gulf of Mexico are caused by cement jobs ( Kerr et al. , 674 ) . The destructive oil spill was either created by improper support with cement or a malfunction in the runaway preventer used to supervise the oil Wellss. Before the boring started, British Petroleum ( BP ) predicted that if the undertaking were to travel incorrect it would let go of about 162,000 barrels per twenty-four hours. When the undertaking did neglect the oil started to flux out at about 1,000 barrels per twenty-four hours so farther rose to 5,000 barrels per twenty-four hours ( Ke rr et al. , 674 ) . To halt the flow of the oil from the Macondo Well, Deepwater Horizon would hold to bore back into the sea floor to do a new hole and so make full the hole with clay to kill the flow of the oil. The procedure took about three months to decide and in this clip the undermentioned shorelines were affected: Texas, Louisiana, Mississippi, Alabama and Florida. The spill has affected biomes, ecosystems, nutrient ironss and carnal populations in all of these countries. A biome is a biotic factor characterized by clime and geographically belongings and the black spill hideously affected the marine biome, which intern annihilated two ecosystems: the coastal and Marine ecosystems. This death leads to the arrested development of effectivity of all nutrient ironss. Several anticipations can be made on how the environmental catastrophe will be affected from, five, 10 or twenty old ages from now. Many resources and environmental programs by the authorities and charity organisati on are in consequence to assist with control and to assist salvage the environmental by: acquiring rid of the oil spill, salvaging the animate beings and reconstructing their ecosystems in the different biomes. The Gulf of Mexico spill perilously affected the marine biome. As the oil start to lift and dispersants are added to the oil, they start to do the close shore soft deposits and the deep-sea deposits to decease out. Near shore soft deposits are beaches, salt fens, sea grass beds and mangrove swamps. They are extremely productive for ecosystems and consist of plentiful organic affair. The deep-sea deposits are boggy, flaxen countries chiefly located on the Continental inclines, Continental rises and abyssal fields ( Textbook ) . Estuaries and coral reefs are perceptive countries if impacted by oil rosin. They provide protection, eating, and populating for a many beings. About â€Å" 90 per centum of marine species in the gulf depend on coastal estuaries † largely located in Louisiana ( Crowley, 2010 ) . Louisiana was hit hard by the oil spill greatly impacting salt fens and barrier islands. The dispersants added to the oil causes it turn to tar balls which possible starts to loo k on beaches and stick to the workss. The big sums of oil on the coastal deposit will do the salt fen grasses and animate beings to decease out ( Kerr et al. , 962 ) . The oil sedimentations can harm the workss and causes the deposit to gnaw. If the deposit starts gnawing the workss will non travel through photosynthesis or gas exchange ( Kerr et al. , 675 ) . This may do the whole ecosystem to fall apart, because many beings may go unable to acquire nutrient and alimentary supply from the contaminated surrounding environment ( How Does the BP Oil Spill, 2010 ) . Harmonizing to the National Oceanic and Atmospheric Administration, research workers say that â€Å" direct contact with an oil spill may take to coral decease, but depending on coral species, growing signifier, life phase, and continuance of oil exposure ( How does an Oil Spill Affect Coral Reefs, 2010 ) . † Scientists say corals that are exposed at different concentration degrees of oil may kill coral but may non be instant. It would instead be a long-run consequence after the exposure has ended. Scientists are stating, the deep-sea corals are non affected by the oil spill and hardly touched by it ( How does an Oil Spill Affect Coral Reefs, 2010 ) . Steve Ross, a research worker from the Center for Marine Science at the University of North Carolina at Wilmington, says, â€Å" Originally, when we saw the flight for the oil spill and where it was traveling, we were really concerned that these home grounds would be impacted ( Skoloff, 2010 ) . † Ross and other research w orkers from his squad are carry oning a research to see if the corals have been damaged or will it be a long-run impact based on the reproduction rates. Ross said â€Å" We thought surely that†¦ we would see marks of harm and we ‘re really pleased to state so far, in these locations, we have n't seen a big graduated table harm to the coral home grounds. We ‘re still looking, but so far, it ‘s good ( Skoloff, 2010 ) . † As the marine biome are affected by the oil spill, this to boot affects two types of ecosystems in the country. The two ecosystems, marine ecosystem and coastal ecosystem, are extremely disrupted by the oil spill doing nutrient ironss to be non as efficient. The impact of the environment by dispersants of oil is greatly effectual, and the scientists are worried the harm would jeopardize the nutrient web ( Layers of Life, 2010 ) . In the Marine ecosystem, the oil started to flux out of the Macondo Well each twenty-four hours, it started to impact different Marine beds. The marine biome consists of four Marine zones, but merely three zones were affected by the oil spill: the epipelagic zone, mesopelagic zone, and bathypelagic zone ( Textbook ) . Microscopic droplets from the Macondo Well endanger the aquatic life. The heavier oil compounds would either absorb to the deposit or turn into pitch balls and rinse up to the shore or autumn to the seafloor. When dispersants are added to the oil, it breaks down the oil and forestalling it to come on land. The sunshine can assist extinguish the volatile oil compounds. As the huge figure of phytoplankton, fish eggs, and larvae are affected, they are an indispensable to giants, fish, and other beings. They are the bases of the nutrient concatenation life at the epipelagic zone. The microscopic oil and methane gas from the spill do the plankton to go hypoxic-depleted of O ( Bourne Jr. , 51 ) . As the phytoplankton is the bases for the marine ecosystem nutrient web, by being effected by the oil spill, the nutrient web would non be every bit efficient as it would be because other animate beings and beings are dependent on them. Marine scientist, Rob Condon, says, â€Å" You change the base of the nutrient web, it ‘s traveling to ruffle through the full nutrient web and finally it ‘s traveling to impact fishing and present a batch of contaminations into the nutrient web ( Brown and Masti, 2010 ) . † Like runt, pediculosis pubis, tuna, or ruddy snapper provender on phytoplankton, these animate beings would decease out b ecause the deficiency of foods in the system doing other animate beings to endure which will interrupt down the nutrient web. Pyrosomes are another indispensable base of foods for animate beings. If they are effected it would do a rippling in the nutrient web which would consequence on polo-necks and larger fishes ( Brown and Masti, 2010 ) . The ecosystem would get down to deteriorate because of the deficiency of foods and addendum eating for beings. Correspondingly the oil injuries sea birds, which the H2O soaks through their plumes, doing them cold, taking to hyperthermia, and harder to derive nutrient. The mahimahis are to endure from organ harm from take a breathing the toxic bluess or consuming the oil. As for the sea turtles they are at high hazard because they feed at the oil surface. The applied scientists try to utilize dispersants by the well so the sea birds and mammals are protected from the oil but on the other manus it can impact a Bluefin tuna or other fishes from the toxic consequence ( Kerr et al. , 675 ) . The counter current gas exchange would impact the fish because of less O in the H2O doing the blood to have O, which leads to the decease of fishes ( Textbook ) . Scientists from National Institute for Undersea Science and Technology ( NIUST ) with several other establishments will follow oil over the following couple months as it moves through the nutrient concatenation from individual celled algae to tuna fi sh ( Kerr et al. , 963 ) . As the concentration of the methane gas additions, there is a fright that there will be oxygen depletion making â€Å" dead zones † in the ecosystem where no marine life to can remain. The cause of dead zones is by algae start to organize where they feed on the foods of methane on high concentration. Bacteria so eat the algae, which causes the depletion in O. Marine life, such as fish, is non able to last in this environment which scientists called it â€Å" dead zones † ( McNulty, 2010 ) . The marine ecosystem is extremely at hazard due to the oil, gas or dispersants. With all the effects on the system it affects the nutrient concatenation and how the marine life is seeking to last utilizing other resources or migrating out of the oil spill environment. This affects how they would accommodate to new countries in the ocean. The Rhizophora mangle wood, fresh H2O, salt H2O environment to the coral reefs make a nourishment country and supply a home ground for wildlife and protection from the pollution. The coastal ecosystem is affected as the oil moves in closer to the shore. The animate beings such as birds, boodles, oysters and corals are extremely at hazard because of the toxic consequence in their system. As boodles and oysters can be a beginning of nutrient to other beings, like otters or worlds, which live around the coastal country will impact the nutrient concatenation. Similarly, animate beings that unrecorded by seawater fens, coastal prairies, mangrove forest and hayfields and are dependent on workss as a primary beginning of foods will be affected due to the deficiency of gas exchange and photosynthesis of the workss because of the oil toxic degrees in the workss. The coastal grass fens created for coastal Marine and mammals for life. The oil amendss water bird, polo-necks and marine mammals an d perchance embryos and larvae of invertebrates and fish ( Weise and Rice, 2010 ) . Additionally, the emmets, crickets, and spiders are of import factors of the coastal nutrient web. They aid in dirt irrigation, seed dispersion, pollenation and nutrient beginning. If the insect population survives so fish and birds will last. If the fish and birds survive the community will last besides, but if insects do non last the system will fall apart ( Bui, 2010 ) . Felicia Coleman, from Florida State University Coastal and Marine Laboratory in St. Teresa, says, â€Å" Panama City, Florida to Tampa, Florida is one of the largest bases of sea grass in the U.S. Those grasses contain likely the largest hatcheries and baby's room land for piscaries in the Gulf of Mexico ( Weise and Rice, 2010 ) . † This cause would impact the growing of new species of fishes and impact the nutrient web for consumers. There populating would be destroyed and would be difficult to accommodate to new countries due to the predation and environment. She besides says, â€Å" One of the last pristine, most biologically diverse coastal home grounds in the state is about to acquire wiped out. And there ‘s non much we can make about it ( Weise and Rice, 2010 ) . † There are legion beings that are affected by the spill. One animate being that is extremely diminishing in size of population are the pelicans, chiefly the brown pelicans. As of mid-July 2010, the U.S. Fish and Wildlife Service ( FWS ) , the brown pelican was hit the hardest by the oil spill about 50 eight per centum of the pelicans that were either dead or injured ( Tangley, 2010 ) . The effects of oil on the brown pelicans are really detrimental to the organic structure. As the oil sticks to the plumes, it starts to lose the sealing oils that maintain them from acquiring cold. As the oil start to rub off and deteriorate, the brown pelicans could decease from hypothermia. If a thick coat of oil sticks to the organic structure, the bird will non be able fly either doing it to rinse up shore and dice. When the brown pelican provenders on marine life in the sea, such as fish, it can consume little sums of oil if the fish is contaminated. If everything in ecosystem is contaminated with, the birds will non able to feed and feed at that place immature and do low reproduction rates because they would decease ( Rosenberg, 2010 ) . If the tendency continues, the whole population of brown pelicans would decease out and would be considered as being on the endangered list once more as they have 50 old ages ago due to DDT pesticides in the late fiftiess. The DDT pesticide resided in contaminated fishes, this causes the reproduction of eggshells. The eggshells are thinned and during incubation the eggs would accidently check by the parents, doing them low reproduction in the country ( Tangley, 2010 ) . Surveies say, when affected by oil, they have a low to good endurance rates depending on the country they live in ( Rosenberg, 2010 ) . Cleaning the environment of the ecosystem and the brown pelicans would increase the survival rate. The authorities and community have been addressed to the environmental crisis. The authorities should be involved in the oil catastrophe. The Environmental Defense Fund ( EDF ) has provided offer to the Obama disposal and Congress to retrieve the harm environment. Five stairss need to be taken: 1 ) to halt the flow of the oil and prevent making the shore, 2 ) design a long term clean up plan, 3 ) supply economic aid the fishermen, 4 ) proctor the short term effects of the spill by scientific research, and 5 ) supply a $ 4 billion budget to reconstruct the hundred square stat mis ecosystems. Obama has taken in consideration to go through a $ 4 billion exigency measure ( Crowley, 2010 ) . I truly suggest that the authorities should take this into consideration because it includes all parts of how the budget money would assist reconstruct the environment back to normal. Numerous AIDSs and financess were proposed authorities ; they should take a expression at the proposition and make the ir ain measure to assist with the oil spill calamity. I contemplate the British Petroleum should assist with the bulk of the financess of scientific research and assistance in Restoration of the environment. This would assist derive their regard back but plus assist the community and nature. The community should take in deliberation to be voluntaries and subscribe up with organisation to assist with attempts of the oil spill. They would assist clean animate beings, like birds, and the dust on the coastal shores, which will assist in the short-run effects of the ecosystem. The major organisations, such as: National Wildlife Federation, NOAA, Global Green and other organisations have been taken to consequence and assisting the damaged ecosystem. The community and organisations should work together to reconstruct the biome with the assistance of persons as voluntaries and the financess provided. Many scientists and research workers are assisting with the service of reconstructing of th e biome. They are carry oning research and experiments and how they can supply aid to repair the jobs. Expression at the long-run impact of the spill from five, 10, or twenty old ages from now will alter how the biome is working. Five old ages from now, the Restoration of the coastal land of workss and some animate beings will be conveying back the home ground to normal due to the fact the sunshine, H2O and heat will assist interrupt down some factors of the oil in the deposits, to boot aid of oil eating bacteriums ( Barcott, 71 ) . The marine ecosystem will still be damaged because of the monolithic sums of oil in the ocean, in different Marine zones. In ten old ages, some of the marine ecosystem, the epipelagic zone, will get down to better back to its normal map such as corals and animate beings reside in those parts of the system, because corals have a short-run consequence of the oil. As the twelvemonth ‘s advancement, in twenty old ages, half of the marine biome, the mesopelagic zone and some of bathypelagic zone, will be start map usually and the nutrient web will be effi cient, making an betterment of reproduction and survival rate of animate beings and beings.

What Is the Freezing Point of Alcohol

The freezing point of alcohol depends on the type of alcohol and the atmospheric pressure. The freezing point of ethanol, or ethyl alcohol (C2H6O), is around  Ã¢Ë†â€™114  C, −173  F, or 159  K. The freezing point of methanol, or methyl alcohol (CH3OH), is around  Ã¢Ë†â€™97.6  C, −143.7  F, or 175.6  K. Youll find slightly different values for the freezing points depending on the source because the freezing point is affected by atmospheric pressure. If there is any water in the alcohol, the freezing point will be much higher. Alcoholic beverages have a freezing point between the freezing point of water (0 C, 32 F) and that of pure ethanol (-114 C, -173 F). Most alcoholic beverages contain more water than alcohol, so some will freeze in a home freezer (e.g., beer, wine). High proof alcohol, which contains more alcohol, will not freeze in a home freezer (e.g., vodka, Everclear). Key Takeaways: Freezing Point of Alcohol There is more than one type of alcohol, so there isnt a single value for the freezing point temperature.Generally, alcohol freezes around -100 C or -150 F. This is well below the temperature of most freezers.Mixing alcohol with water or any other chemical changes its freezing point. A water and alcohol mixture freezes but still generally below the temperature of a home freezer. Learn More Explore the science of freezing and boiling: Why Doesnt Vodka Freeze?Boiling Point of AlcoholBoiling Point of Water