The Sutton Grammar School Biology Magazine Issue 6 Edited by: Christopher Slade, Nichols Weise and Samuel Amis Life A Bat Out Of Hell Everybody has heard the myths that follow Dracula, but just how valid are they? The true story of the misunderstood Vampire Bat point on the unsus- Within minutes of beginning to pecting animal where feed, the bat is already excreting the blood flows close large amounts of blood plasma, to the skin. Unique which has no nutritional value. amongst bats and However, even with this rapid even mammals in processing and digesting of the general, the Common blood, the bat has still gained 20- Vampire Bat is as 30% of its own bodyweight in an manœuvrable on the average 20-minute feed. To take ground as in the air, flight, the bat uses its thumbs to walking on its leap high into the air, propelling thumbs, forwards, itself rapidly upwards before ex- backwards and side- tending its 20 cm wingspan to ways in much the take flight. It then returns to its same way as a spider roost around 2 hours after having does. It approaches set out. its prey on the (continued on page 2) ground, running at speeds of up to 7.9 km/h. If the animal is Article by David Cornish areas from Central and Latin hairy, it uses its canines and cheek Inside This Issue of Life An unfortunate, shared name has America in the North to Brazil, teeth to shear an exposed patch of Chile and Argentina further south. flesh. It then uses its razor sharp made the vampire bat a creature of Amis’ Ailments In many parts of Central and Latin incisors (which lack enamel, mak- 2 myth and misunderstanding. As- America, these bats are regarded ing them easier to keep sharp) to Vampire Bats, sociations with Dracula, justified as dangerous pests, where large make a cut 7 mm long and 8 mm 2 (continued) only by a mutual love of blood, areas of forest are cleared for cattle deep. Vampire bat saliva contains have created endless superstition grazing. Of the three species, only a number of anticoagulants such The Neurology Page - 3 and folk stories: that these re- the Common Vampire bat feeds on as ‘draculin’ to prevent the vic- amygdalae markable flying mammals drink mammal blood (the Hairy-Legged tim’s blood from clotting, keeping Science In Crime human blood, or are capable of Vampire bat and the White- red blood cells from sticking to- 3 shifting in form between man and Winged Vampire bat feed on the gether and veins near the wound Four Limbs Extra bat. However, what the myths blood of birds), but due to supersti- from constricting. This ensures a 4 tion and the potential of the bats to constant blood flow, which the bat conceal is one of the most highly Invasive Species carry rabies which could be passed then ‘laps’, rather than sucks, a 4 evolved and perfectly adapted to the cows, it has become routine popular misconception. animals living on the planet Earth Marfan Syndrome for the ranchers to dynamite and 5 today. burn caves and roosts. A typical vampire bat weighs 40g Molecule of the Month 5 but will consume up to 20g of Vampire Bats (all three species, The Common Vampire Bat only blood in a single feed. This would Sports Science 6 which belong to separate genera) hunts when it is fully dark, using make it impossible for the bat to are native to the Americas, inhab- low energy sound pulses to locate then fly away but for a number of Life Quiz 6 iting tropical and sub-tropical prey, and then infrared to find a other adaptations. Page 2 Life. Issue 6 Amis’ Ailments ‘A look at some of the more gruesome and obscure diseases, that plague mankind’ - Necrotizing Fasciitis By Sam Amis the subcutaneous tissue below, a As far as the producers of medi- large mass of tissue may have cal dramas are concerned, every- already died. Despite the title of one who walks into a hospital ‘flesh eating’ it is the toxic by- nowadays has an aggressive, products of bacterial metabolism debilitating and exceptionally that causes the decay of the tissue rare condition, that they con- and the subsequent surgical re- tracted in some bizarre and en- moval of any dead and diseased tertaining way. Fortunately, this tissue. It is not uncommon for is not the case and the majority someone suffering from this dis- of a doctor’s diagnoses will be ease to lose whole limbs and even far less serious and far more have several surgeries as only a mundane. However, the more tiny segment of diseased tissue uncommon and horrific afflic- has to survive to restart the infec- tions do tend to be far more in- tion. teresting, which is why I’ve de- cided to write this column about Many strains of bacteria can cause the most obscure and gruesome this condition as most produce diseases, which you might not similar by-products, but it is im- have even known existed. hour the site of initial infection degree when the diseased tissue portant to note that it is very rare is incredibly painful and has has to be removed. for a bacterial infection to mani- begun to swell. Soon the victim I’m guessing most people read- fest itself as ‘flesh eating bacte- suffers diarrhoea and vomiting ing this will not know what I ria,’ the majority of the time the as the area of inflammation As the disease progresses so mean when I talk about necrotiz- infection will cause a less serious worsens, often with the skin quickly and is at first very simi- ing fasciitis but will instead condition. The worst form of the turning violet and blisters form- lar to any other minor bacterial know it by another, more collo- disease is now caused by MRSA ing. By this stage, only several infection any treatment must be quial name; ‘flesh eating bacte- (Methicillin Resistant Staphylo- hours since contamination, the fast and effective. The appropri- ria.’ This rare condition begins coccus Aureus), which as you’ll swollen tissue is decaying rap- ate antibiotics must be deter- with an often unnoticeable infec- all know from our previous issue, idly and the patient experiences mined quickly as they take time tion that infiltrates the skin at a is resistant to most antibiotics and a high fever as the bacteria over- to act on the infection, time the site of trauma; a small paper cut therefore can cause an even more whelm any ineffectual immune victim does not have. By the for example will be enough. The prolific form of this issues grue- response. There is a 30% mortal- time they have began to control infection then spreads at the fast- some and obscure ailment: ne- ity rate and most of the survivors the spread of infection, through est rate of any disease; within an crotizing fasciitis. suffer disfigurement to some the deeper layers of the skin and (continued from page 1) ciable, with bats grooming each Hopefully this shows that despite other and, when an individual has the controversy surrounding the failed to feed, the regurgitating of vampire bat, stemming from its Vampire bat colonies, in old blood from mouth to mouth to name, it is one of the most highly wells, hollow trees, caves and prevent starvation. buildings, typically number just a evolved and misrepresented of single male and around twenty After a feed, due to the large creatures females and their offspring, amount of protein consumed, though have been known to num- vampire bats excrete extremely ber in the thousands. They will concentrated urine, controlled by The vampire bat is often roost with other species of a number of specialised hor- bat (which has created problems mones. Vampire bats mate all found in areas of when beneficial fruit bats have year round but usually have only Central and South been killed in Latin America by one offspring per year, as their attacks on vampire bat roosts). gestation period is six-eight America These colonies are extremely so- months. Page 3 Life. Issue 6 Corpus Amygdaloideum By Edmund Bradbury works. This conscious, logical area of the The amygdalae are neural structures con- brain is not used to working out facial ex- nected to the hippocampus and the hypo- pressions, explaining the decrease in correct thalamus. These small areas of the brain are answers. mainly responsible for emotional process- ing. More recently, research has shown the Most people’s amygdalae are automatically amygdalae to also play a role in our under- and naturally developed to recognise a huge standing of fear. range of emotions, however, in the case of an autistic person, they must learn to recog- People with autism often have certain skills nise these emotions artificially. Researchers which are more highly developed than the have developed an “encyclopædia of emo- general population, such as advanced tions” which can be learnt and memorised, mathematical skills. However, autistic peo- to help autistic people to improve there so- ple often seem emotionally remote or dis- cial skills. connected socially. If we look at fMRI One of the amygdala’s more intriguing (Functional Magnetic Resonance Imaging) properties, is its ability to store fear memo- scans of people trying to work out how peo- ries. In the 1980s, Professor Joseph LeDoux ple around them are feeling, using facial did an experiment on the fear response in reaction from the amygdala. Then the con- expressions, we see that the amygdala shows rats. A tone was played and simultaneously a scious part of the brain would think of an increased activity.