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Almost 90% of the extra heat that is generated due to greenhouse gas emissions is absorbed by our oceans- heating them. The Indian Ocean, on of the most productive seas has seen heating much greater than other oceans. In the last century, the Indian Ocean has faced an estimated temperature increase of around 1.2 degrees C. This figure is very large when compared to the heating of the global surface warming which has only increased by 0.8 degrees C in the same period.
A scientific study run by Pune-based Indian Institute of Tropical Meteorology (IITM) has obtained evidence suggesting that the warming of the Indian Ocean is affecting the productivity of its marine ecosystem. Hence, the annual fish catch is decreasing. Heating has reduced the phytoplankton count by up to 20% during the past six decades. Phytoplankton acts as a food source for much of the organisms in the ocean- hence its reduction has lead to a diminish in the organisms which feed from it. Data available from the Indian Ocean Tuna Commission also shows that the tuna catch rates in the Indian Ocean have declined by 50 to 90 percent during the past five decades. Much of this decline has to do with increased industrial fisheries, but reduced availability of phytoplankton also plays a key role. Source: http://m.firstpost.com/world/climate-change-in-our-backyard-warming-of-indian0ocean-threatens-fish-catch-2554582.html
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Population
The biology definition:
Example: The human population. Community The biology definition: An interacting group of various species in a common location Example: a forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria and fungi, constitutes a biological community. Objectives
Apparatus
Safety
Method
Questions
2. The limitations of an investigation are factors that reduce the accuracy and reliability of results. They may arise from variables tat are difficult to control. What are the limitations of this procedure? One limitation was that I only performed the experiment with one plant. Also, I think that there may be some uncertainty in my leaf area as there were a lot of leaves and some were covering others from the fan. 3. What effect will these limitations have on your data? By performing the experiment with a number of plants this would provide more reliable results. If the surface area in contact with the fan is lower than expected this would mean that the effect of wind speed is greater than thought. 4. Suggest ways of reducing the limitations to give more accurate and reliable data. I should perform the experiment with 3 other plants of the same species and age to ensure reliability. I could also perform each experiment with a greater number of distances of the fan as this would provide me with more security that there is a linear trend in wind speed and transpiration. Results Total leaf area = 512cm^2 Apparatus
Method
Variables
Safety precautions
Conclusion The egg from my experiment that provided the most isotonic conditions was that in the most isotonic was the 10% sucrose concentration- as this egg exhibited the smallest mass change. The most hypertonic solution is evidently the 100% sugar- where the egg lost 41.14% of its mass. The most hypotonic egg was the egg in 40% sucrose solution which went from a mass of 97.98 to 112.03 grams. Osmosis Osmosis is the net movement of water from an area of high water potential to an area of low water potential through a selectively permeable membrane. Hence, water flows from high to low salt concentration in order to reach equilibrium. Apparatus
Method
Safety precautions Cut away from yourself when using a scalpel to prevent cutting yourself. Take care with glass apparatus as they break very easily and glass shards can cause cuts. Conclusion My results show that as the concentration of sodium chloride increases, the greater the number of cells plasmolysed. This is because, as the concentration increases, water leaves the cells to dilute the salt- to reach an equilibrium between the concentration inside and outside of the cells. I also conclude that the point of incipient plasmolysis lies between 0.3 and 0.4 moldm^-3. Apparatus:
Safety precautions
Today I read a very interesting article in the new scientist which outlined the risk of heart disease with the consumption of red meat.
Stanley Hazen at the Cleveland Clinic Lerner Research Institute in Ohio performed an experiment where he fed mice diets high in carnitine. The results of the experiment showed that this lead o an increase in atherosclerosis. However, the same experiment was performed with mice who have suppressed gut flora and the results showed no increase in atherosclerosis. Alongside this, the team also studied a number of people undergoing cardiac evaluation and found that those with higher levels of carnitine in their bloodstream had faced more cardiac problems. Carnitine is used as an energy source by some bacteria in the gut. In breaking down carnitine, a waste product known as trimethylamine (TMA) is produced which is converted into TMAO in the liver- which is excreted in the urine. It was found that in mice, consuming high levels of carnatine altered the types of bacteria present in the gut and increased the amount of TMAO produced. TMAO increases the number of bad cholesterol which directly affects plaque build up and atherosclerosis. Other tests revealed that mice with meat diets had higher levels of carnitine that mice with vegetarian and vegan diets. This does not mean however, that carnatine has no use. Carnitine is very important in transporting fuel to the mitochondria. It is suggested however, to avoid carnitine supplementation and consumption of high levels of red meat as the evidence suggests that they increase the risks of cardiovascular disease. https://www.newscientist.com/article/dn23352-red-meat-boosts-gut-bugs-that-raise-heart-disease-risk/ What is atherosclerosis? Atherosclerosis is a disease where plaque builds up in the arteries. The plaque consists of mainly fat, cholesterol and calcium and causes narrowing and hardening of the arteries with accumulation. This restricts blood flow- damaging the organs. Blood clots are also a problem when a plaque ruptures. Blood clots can cause heart attacks (if the coronary artery is blocked), stroke (if the carotid artery is blocked) and therefore death. How does it develop? The exact cause it undetermined however, the following increase risk:
Symptoms Symptoms are not normally presented unless blood circulation is either blocked or restricted. Cardiovascular symptoms include:
Prevention A number of preventative measures can be taken, these include:
http://www.nhs.uk/Conditions/Atherosclerosis/Pages/Introduction.aspx Practical objective
Safety precautions
Apparatus
Method
Prediction I predict that the greater the surface area: volume ratio, the faster the diffusion throughout the whole cube. Factors which are controlled during the experiment The temperature remained constant for all experiments as they were performed at the same place, at the same time. The size of the blocks was also controlled by cutting and measuring blocks to predetermined sizes. I also kept the volume of acid and type of agar the same so not to affect the rates of diffusion. Limitations of the experiment It is very hard to accurately cut and measure the cubes to size. This meant it was very hard to obtain a cube with a constant, exact shape- leading to some degree of error. It is also hard to determine when the pink had completely disappeared from the cubes, relying on the eye. Evaluation My results conclude that the greater the surface are : volume ratio, the greater the rate of diffusion. For example the 2mm cube with a surface area : volume ratio of 3:1 took 30 seconds to lose all colour where as the 10mm cube with ratio of 3:5 took 403 seconds to lose all colour. These findings are important to living organisms as it shows that the larger the animal, the lesser the rate of diffusion therefore the organism must rely specialist systems to receive nutrients and oxygen e.g the circulatory system in humans. |
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