Investigating a pollutants effect on cress seeds Essay Example

Investigating a pollutants effect on cress seeds Paper To investigate the effect of phosphates from detergent liquid, at different concentrations, on the germination of cress seeds. Hypothesis: I predict that, at lower concentrations, the detergent liquid containing phosphates will have a small positive effect on growth. However, I believe at stronger concentrations, the detergent liquid will have a negative effect on growth, causing stunted and malformed cress plants. Introduction: Many commercial detergent liquids contain phosphate. Phosphate, (PO43-) is an important inorganic macronutrient which is needed to help plant growth, and as such is a part of the essential small molecule ATP. Although it can be hard to test whether minerals are important in animals, it is far easier to test the effects of phosphate (which in this case will form part of a pollutant). The main reason for my hypothesis is that phosphates can cause eutrophication when found in a water supply, and as such I believe that small percentages (10-20%) detergent liquid will case minor positive changes in growth. However, there are other chemicals present (such as Benzotriazole, colorants and purfumes) in detergent liquid that may cause the cell wall and cell membrane of the cell to break down allowing the cell contents to spill out and the leaves will appear discolored. This may also cause the cress to grow slowly or die prematurely. There may also be an appearance of leaf tip necrosis, iron deficiencies, and some seeds may fail to germinate due to imbalances in the pH of the soil. You dont say why there may be a pH imbalance. We will write a custom essay sample on Investigating a pollutants effect on cress seeds specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Investigating a pollutants effect on cress seeds specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Investigating a pollutants effect on cress seeds specifically for you FOR ONLY $16.38 $13.9/page Hire Writer Cress is a seed which is exceptionally easy to cultivate, and as such will be the plant used for my experiment. Germination in plants occurs when there are suitable conditions. Germination requires water, oxygen and an appropriate temperature. Water is necessary because the final stage in the creation of a seed is a drying out of embryonic tissues. This means that a huge inward water gradient is created, allowing easy osmosis into the seed. Seeds typically absorb so much water that they swell into 1.5 times the size of the seed (statistic taken from broad beans). This is obviously important in measuring the different growth patterns when using different concentrations of a pollutant, as my pollutant (as many pollutants are) will be found solely in the water source of the plant, and will thus have a great effect on a germinating plant. Plan: Some preliminary tests were carried out prior to the experiment to find the best medium for cress growth and the preferable environment for their germination. These are presented and discussed in my appendix, which is found below. This is the reason for using 2 layers of kitchen paper to grow my seeds in, as well as placing them by a large, light window. The aim of this experiment is to add variable concentrations of a phosphate containing detergent to cress seeds water supply and measure the effect upon their germination and growth. The independent variable used will be the detergent concentration and the dependent variables are percentage germinated and the growth rate. I will use a Spearman rank correlation test to determine whether these two variables are linked. Justifications I will be using pipettes and a pipette filler because these are more accurate than traditional pipettes. I require several different pipettes to ensure that each one is not contaminated with a previous concentration of liquid. I will be using tweezers to place my seeds in the grid as these allow me to grip and place my seeds accurately. I plan to repeat each experiment (to obtain two results for each value). This is to restrict the chances of a faulty result skewing results. Ideally, I would repeat these tests many times, but as the experiment is quite slow, and placing too many petri dishes by my window might obscure the light available, Ive decided upon two results. The seeds will be grown for 7 days as my preliminary tests show that 7 days is perfectly adequate time for the cress seeds to germinate and grow to a measurable length. I plan to use cress seeds from the same packet throughout my experiment, as cress seeds found in different places may have different resistance to phosphates. This is because the detergent I am using may have been present in an irrigation system used to when the seeds were produced, and thus using a mixture of seeds would give a mixture of tolerances against phosphates. I plan to use the same amount of liquid throughout my experiment (20ml initially) as using varying amounts may affect my results. This is because plants need water to grow, and thus those with access to more water will probably grow both faster and further than those with less water. It is thus important to keep them as constant as possible. I have chosen to use 50 seeds at each concentration. This will reduce the chance of a percentage error. If using 10 seeds and one fails to germinate, this will be a 10% percentage error, whereas if one fails to germinate with 50 seeds, this gives only a 2% percentage error. This is a simple and effective way of reducing the percentage error. Sufficient replicates to assess reliability of data. Issues highlighted by my preliminary experiments Considering the results of my preliminary tests, I will be growing my cress inside by a window so that it has plenty of access to light and warmth. I will be growing my cress in petri dishes on two circular pieces of kitchen paper. I will be covering each dish with a piece of transparent film slightly larger than the dish itself. This is because the kitchen paper tends to dry out quickly, which would obviously prevent germination and negatively effect plant growth. The reason for using a piece of transparent film is because this will let light through. I will not be sealing these, as this will prevent air getting to the cress, which it requires for growth. This method prevents the seeds from drying out too quickly, although I will still be watering them at intervals specified before. In my preliminary tests, I measured the seed growth by their length above the seed and root length. However, this may not be accurate as some cress seedlings may have longer roots, and longer roots also indicate growth. For this reason I have decided to measure the shoot and root length combined of my seedlings. Ensuring consistancy I need to ensure that the amount of liquid present stays constant, and thus need to ensure that the dilutions of detergent liquid have appropriate amounts of distilled water. I will be using 20ml of water for the control, and various concentrations made up to 20ml for the other experiments. I need to ensure that the environment of the plants stays as consistent as possible throughout the experiment, and thus need to choose a window with enough space beneath it to give equal light to all the plants. I need to ensure that the cress is spread in the same way in each experiment. To give maximum space to each seed, I have chosen the following layout: This gives me enough room for 25 cress seeds in each experiment. I will need to ensure that the temperature around the petri dishes is kept constant between all petri dishes, as an inconsistency will have a small effect on growth. To do this, I shall measure the temperatures near each dish twice daily and record and adjust any anomalies. The petri dishes will need to be clearly labeled with concentration and experiment number (either 1 or 2) so as to avoid confusion when collecting results.

Americas Prison Population Professor Ramos Blog

Americas Prison Population The American criminal justice system holds almost 2.3 million people in 1,719 state prisons, 102 federal prisons, 1,852 juvenile correctional facilities and 3,163 local jails (Wagner and Sawyer). America is by far the leader in people incarcerated into prison systems. There are another 840,000 people on parole and a staggering 3.7 million people on probation (Wagner and Sawyer). People look to America as the land of the free, yet we have so many of our citizens incarcerated and we need to look to the possibilities of why this is. We can start by looking into the growth of juvenile crimes and the punishments behind them. â€Å"The divergence of trends of juvenile and adult violent crime in the last decade represents a potentially alarming development in the fight against crime. The rate at which juveniles were arrested for violent crime rose 79 percent between 1978 and 1993, almost three times the increase over that time period for adults (Levitt 1156).† Each state has different systems when dealing with juvenile and adult criminals but the age majority at which an individual may be tried at an adult court varies between 16 and 19 years of age. So, depending on the crime, a 16 year old teenager may be tried as an adult. â€Å"There are sharp changes in crime rates associated with the transition from the juvenile to the adult court. In the year following the attainment of the age of majority, states that punish adults particularly harshly relative to juveniles see violent crime rates fall by almost 25 p ercent and property crime 10-15 percent relative to states in which adult punishment are relatively lenient (Levitt 1181).† This brings us to another factor we must look at when talking about over population in our prison systems. Are laws being created for more severe prison sentences? â€Å"One of the most significant trends in criminal justice is the growing emphasis on imprisonment. Legislators have continuously responded to constituent fears by establishing longer sentences or mandatory minimum sentences for wide varieties of crimes and criminals. As a result, United States prison populations have increased nearly 400% in the twenty-five years from 1968 to 1993 (Marvell 696).† According to Michael Tonry the Director of the Institute of Criminology at Cambridge University, â€Å"The large majorities often express the view that sentencing is too lenient, and that people demand that criminal punishment be made tougher. On this account, elected officials have merely respected the public will, and imprisonment rates have risen as a result (420).† In other terms, we look to punish criminals s everely out of fear in the hopes that the criminal doesn’t repeat any crimes anytime soon. But maybe we’re right. Overall, 67.8% of the 404,638 state prisoners released in 2005 in 30 states were arrested within 3 years of release, and 76.6% were arrested within 5 years of release (Durose et al. 1). Over three quarters of the prisoners released in 2005 in 30 states had been re-incarcerated back into our prison systems adding on top of all the new juvenile crimes being tried as adults. The statics show within 5 years of release, 84.1% of inmates who were age 24 or younger at release were arrested, compared to 78.6% of inmates 25 to 39 and 69.2% of those age 40 or older (Durose et al. 1). Most inmates are heading right back into prison within 5 years of their release and so we need to look to factors that might impact this. â€Å"Among the 404,638 prisoners released in 30 states in 2005, 31.8% were in prison for a drug offense, 29.8% for a property offense, 25.7% for a violent offense, and 12.7% for a public order offense (Durose et al. 1).† It isn’t as simple to think all your problems will go away once you’re released from prison. You now have a criminal background which makes it much tougher to find jobs and pass background checks. It is these statistics that encourage repeat offenders such as drug dealers and thieves to go right back into their old habits. Some just looking to it as a means of survival knowing their odds of being arrested again were against them. â€Å"Drug arrests give residents of over-policed communities criminal records, which then reduce employment prospects and increase the likelihood of longer sentences for any future offenses (Wagner and Sawyer)†. It is not only you commit the crime you do the time. It is if you re-commit the crime you are now doi ng longer time. Just adding on to longer prison sentences in already over populated prison system. â€Å"More than 90 percent of prisoners are men, incarceration rates for blacks are about eight times higher than those for whites, and prison inmates average less than 12 years of completed schooling† (Petit and Western 151). Over the years research shows that prisons are filled not only with uneducated inmates but that most prisons are predominantly filled with black males. We can look at poor education in low income areas as a cause and effect and this can point towards why there is an increase in juvenile crimes. Future politicians, Police officers, Correctional officers, Parole officers, Judges, Lawyers are just some of the many these over populated prison systems impact. We keep seeing growth in prisons and less in schools. We have more criminals incarcerated than any other country in the world and we don’t even hold the world’s largest population. We need to look at crimes and their punishments and install proper sentences and infrastructures to help rehabilitate prison inmates while being incarcerated and upon release. We need to target juvenile crimes at the source and figure punishments accordingly instead of preparing juveniles for prison. We must not keep building prisons to fill the beds, America must look deeper into its prison policies and laws and develop new methods to keep its citizens out of jails and committing repeat offenses. Durose, Mathew et al. â€Å"Recidivism of Prisoners Released in 30 States in 2005: Patterns from 2005 to 2010†. Bureau of Justice Statistics. April 2014. NCJ 244205. Pp. 1-30. Levitt, Steven, â€Å"Juvenile Crime and Punishment†. The Journal of Political Economy. Vol. 106, Issue 6, December 1998. Pp 1156-1185. JSTOR. http://pricetheory.uchicago.edu/levitt/Papers/LevittJuvenileCrimePunishment1998.pdf Marvell, Thomas B. â€Å"Sentencing Guidelines and Prison Population Growth.† The Journal of Criminal Law and Criminology. 1973, vol. 85, no. 3, 1995, pp. 696–709. JSTOR, www.jstor.org/stable/1144046. Petit, Becky and Western Bruce. â€Å"Mass Imprisonment and the Life Course: Race and Class Inequality in U.S. Incarceration†. American Sociological Association. Vol. 69, No. 2 April 2004, pp. 151-169. JSTOR, https://www.jstor.org/stable/3593082 Tonry, Michael. â€Å"Why Are U.S. Incarceration Rates So High?† Crime Delinquency, Vol. 45, No. 4, October 1999. Pp. 419-437. https://uakron.edu/dotAsset/1662091.pdf Wagner, Peter and Sawyer, Wendy. â€Å"Mass Incarceration: The Whole Pie 2018†. Prison Policy Initiative. March 2018. https://www.prisonpolicy.org/reports/pie2018.html Eric Kazos English 010 3pm