Example 1: The Rock Pocket Mouse1.Type of variation present in population and how it came about: Change in fur colour (dusty brown coloured mice to dark coloured mice). This was caused by a mutation of the MCR1 gene. 2. Environmental change: Different colouration of habitat due to a lava flow causing dark volcanic rock patches in a dusty brown desert 3. Result: The mice found on the dark volcanic rock was more likely of the dark furred variation. The mouse found in the dusty brown dessert were more likely to be of the lighter furred variation. 4. How it may lead to evolution of the species: Any light furred mice on the dark volcanic rock will face a higher selective pressure as they are less camouflaged than their dark furred counterpart and will therefore be predated on more frequently. This will lead to the dark furred mice surviving and a reproducing more often and therefore the allele containing the dark fur characteristic will become more common in the gene pool and more dark furred mice are observed. Example 2: Moth Colour www.peppermoths.weebly.com - has the game on
2. Type of variation present, when it occurred and how it came about
3. State the name given to this type of natural selection Industrial Melanism 4. Explain how the game demonstrates natural selection for dark moths In the game you are playing the role of the predator (a bird) which is the selection pressure for this example of natural selection. In them game you can choose to play on a light tree background or dark tree. Once you start moths of the two colourations begin to appear on the screen and you need to click on them with your mouse to 'eat' them. If you are playing on a black background then you are more likely to click on the highly contrasted white moths and vice versa. This simulates how selective pressure of predators can affect a population as they will tend to predate on the more visible moths. Example 3: Antibiotic Resistancewww.bbc.co.uk/news/health-36396663 www.bbc.co.uk/news/health-34857015 1. List the key reasons for the increasing prevalence of antibiotic resistance in farm animals and hospitals. -Hospitals
2. What would need to happen to cause the actual 'antibiotic apocalypse'. In order for the 'antibiotic apocalypse' to happen there would need to be bacteria that were resistant to all strains of antibiotics. If this happens we would have bacterial infections that were effectively untreatable and would render antibiotics useless. If the resistance to all antibiotics spread across all bacteria that would be the 'antibiotic apocalypse'. 3. Until November, Colistin was the antibiotic of last resort, what has now been found with this antibiotic and why? Discuss how this may eventually pose a problem, for the world. In 2015 in China, bacterial infections with a resistance to the antibiotic Colistin was discovered. This is a problem since Colistin is generally used as an antibiotic of last resort when all other antibiotics have failed. If bacteria become resistant Colistin it means that we no longer have a secure backup to fight infections and that leaves even more people vulnerable to fatal diseases 4. State the name of the genetic mutation found in Colistin It is a mutation in the MCR-1 gene 5. What type of antibiotic is Colistin and what process/structure of the bacteria i killed by it and how. Colistin is a polymyxin A and affects gram negative bacteria. It is a bacteriostatic bacteria that targets the cell membrane of the gram negative bacteria and killls the bacteria by causing it to lyse 6. The mechanisms by which antibiotic resistance can spread between bacteria that are not necessarily the same species Resistance to bacteria can spread through bacteria populations through a process known as conjugation 7. Methods that could be used by farmers to prevent the rise of antibiotic resistance in bacteria in their animals.
8. How does antibiotic resistance spread in bacteria
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Glycolysis: Is the breakdown of glucose and results in Pyruvate and ATP Krebs cycle: is the sequence of reactions by which most living cells generate energy during the process of aerobic respiration. It takes place in the mitochondria, using up oxygen and producing carbon dioxide and water as waste products, and ADP is converted to energy-rich ATP. The step in the above diagram labeled the 'Kreb's Cycle' where the pyruvate made during glycolysis goes to acetyl CoA is known as the link reaction and that is expressed in more detail down below. As you can see during the link reaction Pyruvate is both reduced by NAD and decarbonized to become Acetyl CoA.
Aim: To model how a change in the environment can lead to a change in characteristics due to natural selection in a population over generations Method:
Relationship to how it would work in the natural world
Results: Analysis: As we can see from the graph the percentage of the rice granules that blended into their background (green) increased as more of the blue granules were picked out than the green ones. Opposite to this of course the more obvious blue granules stood out and therefore more were picked out and the percentage of blue granules decreased. A point was reached however where although there was a higher percentages of green granules to blue granules, there was no further change in the percentages This is a good example of natural selection and what would happen to a population of creatures where some have a characteristic that would make them more likely to survive, breed and pass on that positive characteristic. however an equilibrium will be reached and it is very unlikely that the organisms which have the less suited characteristic would die of completely they would just be a lot less common than the ones containing the useful characteristic and this is also shown in my experiment. Intro: Due to the extreme variation of conditions at different heights of a rocky shore, there is a huge difference in the distribution of certain species up the shore. We measured the species distribution using the ACFOR scale. Method:
Results: 1-Lower shore 2-Middle shore 3-Upper shore 4-Splash zone Result Analysis:
Weaknesses:
Aim: Use chromatography techniques to discover and compare the different photosynthetic pigments found within different species of intertidal seaweeds.
Apparatus:
Method:
Safety Precautions:
"Fisheries have rarely been 'sustainable'. Rather, fishing has induced serial depletions, long masked by improved technology, geographic expansion and exploitation of previously spurned species lower in the food web." This quote is from an article on Nature written by Daniel Pauly, Villy Christensen, Sylvie Guénette, Tony J. Pitcher, U. Rashid Sumaila, Carl J. Walters, R. Watson & Dirk Zeller. This article writes about how are oceans are being depleted due to overfishing of the aquatic wildlife and how our current level of fishing can not be sustained. The below graph is from the article and shows the averages catches of different aquatic life measured in million tonnes per year. "The trend of this graph clearly shows that the catch per year measured in million tonnes of each aquatic group represented in this graph and the fish caught illegally (IUU) and the fish that is discarded, have been on the rise since 1950.
As for the validity of this data on this graph, the article states that "Figures for invertebrates, groundfish, pelagic fish and Peruvian anchoveta are from FAO catch statistics, with adjustment for over-reporting from China. Fish caught but then discarded were not included in the FAO landings; data relate to the early 1990s were made proportional to the FAO landings for other periods. Other illegal, unreported or unregulated (IUU) catches were estimated by identifying, for each 5-year block, the dominant jurisdiction and gear use (and hence incentive for IUU); reported catches were then raised by the percentage of IUU in major fisheries for each 5-year block. The resulting estimates of IUU are very tentative (note dotted y-axis), and we consider that complementing landings statistics with more reliable estimates of discards and IUU is crucial for a transition to ecosystem-based management." This level of detail in how they collected their data helped to limit the extraneous variables, increasing the reliability of the data portrayed on this graph. However it is of course almost impossible for all the world's fishing to be taken into account, especially the illegal fishing (IUU) which as mentioned was just estimated and inferred from looking at the dominant jurisdiction and gear used. This means that especially for the illegal fishing section of this graph there could be a large percentage error. Article: "Towards sustainability in world fisheries" http://www.nature.com/nature/journal/v418/n6898/full/nature01017.html Discuss, giving named examples, the difficulties of placing organisms in higher trophic levels.17/5/2016 Above we have an example of a food web. This food web shows the transfer of energy through what eats what in a particular environment. Each organism on this food web is defined into a trophic level depending on how high up the food web it is, for example the Plantain is an example of a producer, the rabbit is an example of a primary consumer and the Fox is an example of a secondary consumer. However organisms tend to have very varied diets to aid survival and therefore can end up on more than one trophic level. For example the frog can be classes as a secondary consumer as it eats the butterfly (primary consumer) which eats the berries (producer) the frog however can also be classified as a quaternary consumer as, as well as eating butterflies, the frog also eats dragonflies which are tertiary consumers (They eat ladybirds, which eat greenflies which eat berries). Example like the frog in this food web are very common and make it very hard for ecologists studying these community interactions to place organisms on distinct trophic levels as they often rest on more than one trophic level.
Population:A population is a group of organism of one species that live in the same habitat and interbreed with each other frequently. Community:A community is an assemblage of the populations of two or more different species occupying the same habitat at the same time. When you study a community you look at the different interactions between the separate populations.
A recent article published in the New Scientist by Rebecca Summers has once again set the controversial topic of red meats and their suggested links to heart disease alight. Her recent article looked at the link between the nutrient carnitine and the occurrence of atherosclerosis (the thickening of the artery walls) in organisms with high levels of carnitine which occurs in large quantities in red meat and also in energy drinks. An experiment was carried out by Stanley Hazen at the Cleveland Clinic Lerner Research Institute in Ohio on mice and found that there was indeed a link between the amount of carnitine in the body and the occurrence of atherosclerosis, the higher the levels of carnitine the more likely atherosclerosis was to occur. However it was also discovered that this link did not take place when the mice had suppressed gut flora, suggesting that the carnitine was interacting with bacteria in the gut to produce this increase in the chance of atherosclerosis. Review of an article from the 'New Scientist' https://www.newscientist.com/article/dn23352-red-meat-boosts-gut-bugs-that-raise-heart-disease-risk/ AtherosclerosisWhat is atherosclerosis:
Atherosclerosis is a condition where the arteries become blocked by fatty substances known as plaques or atheroma. It is potentially serious condition which can lead to heart attacks and strokes. What causes atherosclerosis: A variety of things can cause atherosclerosis such as;
What atherosclerosis does specifically: During atherosclerosis arteries harden and narrow which can be dangerous as restricted blood flow can damage organs such as the brain (causing strokes), or the heart (causing a heart attack). If the plaque in the arteries rupture it can cause blood clots which can again block blood to the organs causing serious damage. |
Jack BojanArdingly College Archives
March 2017
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